Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Ken4004 on April 25, 2026, 04:55:10 PM
-
Hi everyone, front brake squeal decided to put a bit more copper slip grease between piston and back of brake pad but the question is when I purchased a new brake pad it came with a nylon washer should it be fitted as shown or not fitted at all
-
I just found a Vedic on utube seems that the washer should be fitted so will add greeds to piston and not back of brake pad and see if it stops squealing
-
If you really want to try and stop brake squeal then maybe fit EBC FA013V semi sintered pads.
Not cheap but cured the problem for me.
https://www.bts24.co.uk/en/brakes/brakefront/brakepads/brakepadssemisintvebcfa013v.html (https://www.bts24.co.uk/en/brakes/brakefront/brakepads/brakepadssemisintvebcfa013v.html)
I've got SBS and Vesrah pads in a junk box under my workshop bench.
Anyhow good luck with the copper brake grease...
-
Busting the glaze will stop the squeal. Just rub each pad over some sandpaper and a flat surface and wipe clean. 120-180 grit will do just a few strokes enough to take off the shine You can do the disc with some 800 grit as well but usually the first option works.
Worth checking if the groove that the rubber seal sits in is not corroded and making the seal tight on the piston and it not retracting properly and polishing the pads.
Taking the glaze off the pads usually works for me. I usually wait until old ladies at the bus stop drop their shopping bags then its time.
Regards
-
Is it not questionable to use copper grease near hydraulics, as it is mineral based? I've amways used the red brake grease, and yes, fit the nylon spacer.
-
The copper grease goes around the perimeter metal part of the moving pad to keep it corrosion free, not on the side of the piston. Copper grease because it tolerant of high temperature and doesn't creep. I use Dot 5 brake fluid so I smear a bit of high temp silicone grease on the side of the piston again just for corrosion protection of the exposed part. With all the grease around and no proper dust seal/boot it will attract cr*p so need to clean things up as part of routine maintenance.
I have always had the nylon ring fitted even though you don't always get a new one with pads.
Regards
Dave
-
A chamfer on the leading edge of the pad can help.
-
Busting the glaze will stop the squeal. Just rub each pad over some sandpaper and a flat surface and wipe clean. 120-180 grit will do just a few strokes enough to take off the shine You can do the disc with some 800 grit as well but usually the first option works.
Worth checking if the groove that the rubber seal sits in is not corroded and making the seal tight on the piston and it not retracting properly and polishing the pads.
Taking the glaze off the pads usually works for me. I usually wait until old ladies at the bus stop drop their shopping bags then its time.
Regards
I agree with this and see pad retraction as primary cause when it's restricted in any way.
I never use coppaslip on pads, not for any particular reason of compatability, just never needed to cure squeal, at all.
Always paid attention to piston freedom and retraction when servicing or assembling brakes, absolutely never had any problems with squeal. That's across single piston, twin, four or six pots, nothing in any systems and numbering into thousands.
It can be "generated" in road use when real competition pad materials are in the system as they rarely reach full operational temperature and loading that they've been designed to cope with. Effectively, light/road use glazes them from not having the severity of conditions they're made to withstand as routine. There's not much way around that, other than significantly raised and aggressive attack to keep them in reasonable surface condition, road use akin to just dragging them a little in reality.
-
Loads of great advice from everyone, the extra grease didn’t change the squeak who needs a noisy exhaust to be noticed with brakes like this.
Going to first deglaze the pads with emery as suggested and start again and see how it goes then will go through all the suggestions one by one until it’s cracked the problem.
Apart from that bikes running great got 200 miles of running in under the belt so far , I really like the tone of the original exhaust .
After the running in period I will take the cam cover off and have a check of the cams and reset the valve clearances but so far so good just a few minor niggles but great fun round the twisty road for n Sussex and I couldn’t get better weather.
Regards to everyone and enjoy the weather
-
I think I might know why my brake pads are glazing over quickly , the screw that adjusts the fixed brake pad uses a counter sunk screw that I believe screws into the right hand fork looking from the front.
I believe this should be a tapped hole but the thread in my fork is stripped down I will need to fit a helicoil to fix it.
When you adjust this screw you are moving the fixed pad closer or further away from the disc depending on which way you turn it .
The shop manual says undo locknut and adjust screw so the fixed pad is touching the disc then back off half a turn and do up the locknut.
Because the thread in rhe fork is stripped I have nothing to lock the nut against do to get around this I have added an extra nut and locked the two together.
It lease can someone confirm that there should be a tapped hole in the fork that this screw will is screwed into and not a clearance hole like mine is.
Because I have nothing to lock been able to adjust this properly the pad is continuously rubbing on the disc and glazing the pad , this however is just a theory.
Regards Ken
-
Yes, it needs to have the thread in fork casting intact to work as in the manual description.
Obviously a little fiddly to add another nut, but sufficient to let you adjust correctly in the mean time.
If its left floating around (indeterminate location) then unlikely to avoid continuing pad contact when unwanted.
The seal on these has to retract in dimension according to both sides needing clearance (any single piston hydraulic) with that little spring on adjustment screw "sharing" the clearance with the back pad in line with how much static gap you've set initially.
They are odd in their hybrid arrangement, with the need to chase pad wear with constant check and adjustment, paired with the usual hydraulic characteristics of piston return by that seal method common to general hydraulic disc brake protocol.
-
Yes there should be M6 thread in the fork casting for this.
Normally undo the lock nut and screw the big long countersunk screw to adjust the gap and then tighten the lock nut. I mostly use a feeler guage to set the gap to about 6-10 tho.
The bigger the gap the more the lever travels before the brakes bite.
Regards
Dave
-
Hi Dave many thanks heli coils to the ready
-
Thanks K2-K6
-
I have always found these brakes to squeal and actually find it reassuring that braking is taking place. I have found that the squealing stops when the brakes need adjusting. Once adjustment has been done, the squeal returns, but then so does proper braking force. As we have come to experience with this model, and due to the conservation of energy, braking results in kinetic energy being converted to heat and sound ;D
I never use grease but would recommend replacing the piston with a stainless steel version. Before I found these, rebuilding the calliper due to brake dragging caused by corrosion was a regular event, especially when ridden through the winter as I often do. Since changing to stainless steel I have managed to go six years and calliper working fine.
-
Surely once the initial clearance has been achieved, unless there is a problem, or pads have been renewed, it should not need adjusting. When releasing the brake lever, the seal on the piston reverts back to its normal shape giving the required distance betqeen pad and disc.
-
The gap increases as the static pad wears Mick, so it must be checked every few thousand miles to keep it at max efficiency.
-
Surely once the initial clearance has been achieved, unless there is a problem, or pads have been renewed, it should not need adjusting. When releasing the brake lever, the seal on the piston reverts back to its normal shape giving the required distance betqeen pad and disc.
As Ken notes, they only do half of the adjustment and need regular attention.
The "fixed" pad, once set to clearance by adjustment of the screw, then returns to that same reference by the little spring pressure on that bolt .... that's regardless of how much material is worn away from braking. Effectively you've got to chase that pad's wear with the adjustment.
The hydraulic piston and it's seal has to accommodate BOTH sides in it's return travel to work correctly (same as a single sided one piston caliper does) else the back pad can't get enough clearance when brake is released.
BUT, once the fixed pad gets too much clearance the spring return will then cause the hydraulic piston to drag as it let's the caliper swing too far on release. Also the lever travel gets longer too on brake application.
It's really a hybrid of mechanical and hydraulic and can't just be left alone like single piston floating caliper as many now use.
-
I've often wondered if the use of asbestos free organic brake pads is perhaps the cause of our brakes squealing nowadays.
Back in the 70's when I worked in the MC trade I can't particularly remember having problems with Honda brake pad squeal, but back then they were fitted with asbestos compound pads.
I do remember freeing off lots of seized caliper pivots during the winter months for customers that rode their bikes all year round.
A while back I did first try deglazing the pads as mentioned earlier in this thread and it does work but needs to be done regularly as the squeal just keeps coming back again and again.
For me and others the more expensive and grippy EBC FA013V semi sintered pads seems to mitigate this problem.
I've also got a stainless steel piston fitted, which I think is a worth while modification as it eliminates possible corrosion problems.
-
I've had no squealing on my 400F in the 2+ years since I overhauled the front brake system. It didn't squeal before the overhaul either but it also didn't stop! :)
I did a thorough bedding in procedure - not sure if that helped to prevent squealing but it made a huge difference in braking power/feel. Also, the pads were factory beveled at the edges which may also help re squealing.
FWIW I tried five different pads/types when sorting out the brakes and, as I recall, all of them had factory beveled edges.
-
I have just repaired the damaged thread on the fork that the adjusting screw fits into and taken the glaze off the pads as suggested so hopefully will have time to go for a ride tomorrow and the bed the pads in again and keep my fingers crossed.
-
The gap increases as the static pad wears Mick, so it must be checked every few thousand miles to keep it at max efficiency.
Both parts of the caliper are bolted rigidly together, so when pressure is applied the piston pushing on the pad forces the caliper to swing outwards until the static pad makes contact. When releasing the brake lever the piston seal returns from its distorted shape back to normal moving the piston back a fraction. If the static pad were to go further back it would pull the whole caliper with it, thereby making the moving pad come into contact with the disc again. I've never had a vehicle yet where the disc brakes needed adjusting once set up. The biggest problem with the brake on out Hondas is tightness of movement on the swinging spindle. The spigot needs gentle use with fine emery cloth and then given a dollop of coppaslip.
-
The gap increases as the static pad wears Mick, so it must be checked every few thousand miles to keep it at max efficiency.
Both parts of the caliper are bolted rigidly together, so when pressure is applied the piston pushing on the pad forces the caliper to swing outwards until the static pad makes contact. When releasing the brake lever the piston seal returns from its distorted shape back to normal moving the piston back a fraction. If the static pad were to go further back it would pull the whole caliper with it, thereby making the moving pad come into contact with the disc again. I've never had a vehicle yet where the disc brakes needed adjusting once set up. The biggest problem with the brake on out Hondas is tightness of movement on the swinging spindle. The spigot needs gentle use with fine emery cloth and then given a dollop of coppaslip.
Thats because this caliper design is unique (dont think anyone else used it at all) and definitely needs to have the adjustment manually applied to track the static pad wear. Then the screw has to be backed out again when new pads are used in replacement. It's just normal for this operation.
There's something similar in virtually all VW group car rear calipers, those having a mechanical operation of handbrake, concentric and inside the single hydraulic piston. That one ratchets itself in tracking the wear (unseen by driver) to keep pads correctly adjusted. This is facilitated by the operation of handbrake while footbrake is held down and clamping the disc, to allow ratchet mech most advantage in creeping with wear. They too need winding back out when pads are replaced.
-
Can’t add much to Niges explanation tbh, you do seem to be missing the role the spring is doing here Mick. It pushes the arm back when the hydraulic pressure is released. So the pad wearing means the gap continuously increases.
-
My final attempt, theoretical example, if the hydraulic piston had to move 1/2 inch before the pads make contact, due to the nature of the seal, when pressure is released the seal returns to its normal shape by retracting just a few thou. It does not travel all the way back inside the chamber, therefore, if the static pad tries to spring outwards it will pull the other pad into contact with the disc leading to binding.
-
A chamfer on the leading edge of the pad can help.
That's what I do besides the copper grease treatment. I always called it a bevel myself. 8)
-
Fair play to you Mick for sticking with it. Sometimes things can just elude you until you finally have an epiphany and it all slots into place.
Let me see if I can cause that. The adjusting screw is threaded into the slider and locked into position by the locknut. So the spring can only force it back as far as the screw allows. IF it wasn’t threaded then you’d be correct and it would indeed cause some brake pad drag.
The piston pad is self adjusting, in that it will allow the pad to slide out further as the pad wears, evidenced by the fact the piston needs to be pushed back into the housing when you fit new pads which will of course be so much thicker they’ll cause severe drag or even bind the wheel solid. The most gap between the piston pad and the disc is only ever a few thou if it’s working correctly. Hence minimal travel on the brake lever. You apply the lever, that causes the pad to travel out, and yes you are 100% correct, the piston seal distorts as it does so. When the piston pad touches the disc then as you apply more pressure the arm is forced to move and the back pad starts to touch. If it’s out of adjustment then you find the lever has to travel further to compensate. When you release the pressure, the spring on the adjusting screw forces the arm away from the disc, causing the rear pad to disengage. It will go back as far as the screw allows it to and no further. By this time the piston pad is also being retracted by the force of the seal distortion, it’s a really small movement and is just enough to allow the pad to clear the disc surface. You may still hear some pad drag on the surface however as even a modern caliper does that sometimes, I can hear my 4 pot calipers allowing it as a sort of hiss as the pad slides across the drillings on the disc.
I hope that helps you.
-
FWIW, I mentioned bedding-in as being important for braking power/feel and MAYBE for squealing. I thought I should explain that the procedure I found so successful is NOT the typical recommendation that you hear for a new bike/new pads which is typically to perform gentle stops for the first 100-200 miles. I tried to find the post where another member posted a break in procedure which I used but couldn't find it. So below is a link to a site that has the same procedure. https://www.denniskirk.com/blog/2019/03/06/how-to-break-in-motorcycle-brakes/
-
FWIW, I mentioned bedding-in as being important for braking power/feel and MAYBE for squealing. I thought I should explain that the procedure I found so successful is NOT the typical recommendation that you hear for a new bike/new pads which is typically to perform gentle stops for the first 100-200 miles. I tried to find the post where another member posted a break in procedure which I used but couldn't find it. So below is a link to a site that has the same procedure. https://www.denniskirk.com/blog/2019/03/06/how-to-break-in-motorcycle-brakes/
Agree with bedding the pads.
Some time ago and working with pads in more extreme use, speaking to AP, Ferodo, Mintex etc about this as it was routine in competition systems where glazing is more prevalent. Broadly, the initial phase is to get the two surfaces to match through gentle wear, then to condition the pads and rotor surface by higher heat input that both burns out any unwanted production "contamination" and eventually transfers some of the pad material to the disc surface.
Often claimed that Sintered type didn't need this, but experience over different materials showed benefit nonetheless.
For road application, in the order of 50 miles light use will complete the first step of physically matching surfaces without problem. Then to drive them up into higher temperature range to complete the process. Successive hard stops and or dragging the brake to build heat prior to some very high energy braking will work well. You'll feel the change coming into the system as you do this.
-
The seal and it's operation.
A single piston caliper must have seal arrangement to cope with clearance for two pads. How that's distributed here is what seems misunderstood.
With a sliding pin caliper, the body floats in doing this, and freely depending on how the pins are lubricated.
These Honda type are restricted float (by setting that adjustment screw) and need to be moved in tracking/accommodating wear in that static pad.
If, for example, you set the static pad clearance at 5 thou, and the seal rollback had 10 thou capability, then you'd see 5 thou each side when releasing the brake. Then as the static clearance rises during use, the piston has to first pull the static pad into contact before braking occurs. When its released, that increaese in static clearance will be "consumed" by the static pad and forced by the spring.
Once 10 thou static clearance is reached thats all of the seal capability now taken by that location. Wear from then onwards will always leave the hydraulic pad dragging excessively on the rotor surface, ultimately to glaze that pad.
The seal cross section and seal groove taper are designed for each application, a four piston "rigid" caliper will use different dimensions to facilitate that type, bringing down rollback specification is used to get more immediate clamping when applied and fine with dead straight rotor and rigid caliper mounting.
-
GOT IT!!! Thanks everyone.
-
Oddly enough Mike it was me that posted the bedding in method some time ago. I got it off the SBS website and found it worked very well. The link you posted isn’t as good as the SBS one IMO, no mention of removing the old bedding in material for instance.
-
Thanks!! Yes, it was your procedure that I followed with extremely successful results. I had forgotten that it included removing the old material. The link I posted sounded the same to me re the bedding but it is not as thorough as the one you posted/I followed!!
-
Worthwhile in emphasis, that of any disc brake system that's giving poor results, one way or another, its all but 100% related to that seal function bring compromised, that's across all system whatever the scale of components.
The hydraulic piston caliper is brutally simple, only the moving piston and its accompanying seal ultimately affect operation. That's aside from leaking etc.
Most, after reasonable time, will get the seal's movement compromised through that operation. These original Honda type have effectively nil weatherproof mitigation with piston boot or other external seal arrangement, and so are vulnerable to the effects of localised atmosphere in way of moisture etc.
Stainless piston will resolve the corrosion of the original plated piston, but it can't do anything for galvanic corrosion of the piston seal groove in aluminium material of caliper. That risk remains there given any electrolytic activity potential. Honda's original 750 manual specifies silicone grease around that area behind the pad, that being extremely repellent to any water ingress etc.
The seal land needs very close detail in cleaning it and removing any of the accumulated aluminium corrosion from the taper space where the seal moves to in normal operation. They have a different lever feel, release characteristics and very low pad to disc friction when thoroughly cleaned and assembled. A compromised example usually exhibiting reduced travel from home position of lever (less pad rollback) and harder/more difficult effort to use the brake, the rotor surface usually taking on a more polished surface appearance is another sign or pad continuous dragging.
I haven't tried one in these caliper, but a Phenolic resin piston may hold advantage in conductivity to ultimately reduce galvanic potential in these system.
-
Worthwhile in emphasis, that of any disc brake system that's giving poor results, one way or another, its all but 100% related to that seal function bring compromised, that's across all system whatever the scale of components.
The hydraulic piston caliper is brutally simple, only the moving piston and its accompanying seal ultimately affect operation. That's aside from leaking etc.
Most, after reasonable time, will get the seal's movement compromised through that operation. These original Honda type have effectively nil weatherproof mitigation with piston boot or other external seal arrangement, and so are vulnerable to the effects of localised atmosphere in way of moisture etc.
Stainless piston will resolve the corrosion of the original plated piston, but it can't do anything for galvanic corrosion of the piston seal groove in aluminium material of caliper. That risk remains there given any electrolytic activity potential. Honda's original 750 manual specifies silicone grease around that area behind the pad, that being extremely repellent to any water ingress etc.
The seal land needs very close detail in cleaning it and removing any of the accumulated aluminium corrosion from the taper space where the seal moves to in normal operation. They have a different lever feel, release characteristics and very low pad to disc friction when thoroughly cleaned and assembled. A compromised example usually exhibiting reduced travel from home position of lever (less pad rollback) and harder/more difficult effort to use the brake, the rotor surface usually taking on a more polished surface appearance is another sign or pad continuous dragging.
I haven't tried one in these caliper, but a Phenolic resin piston may hold advantage in conductivity to ultimately reduce galvanic potential in these system.
Good post and very informative.
But are we not veering off topic a little?
The original post being " Front brake squealing".
-
Surely K2-K6s post is still very much 'on topic'. The effects of a dragging pad causes the glazing which in most - but not all cases, ultimately causes the squeal. Although fitting a stainless steel piston prevents the corrosion starting, as we often see with the OEM plated version, it plays no part in preventing the build up of oxides under the outer diameter of the seal. Coming from the aircraft industry, stainless steel was NEVER put into contact with aluminium alloys without a barrier paste. The presence of brake fluid around the piston possibly helps in that respect. Regular maintenance is the only answer on this simple system.
Ian
-
Really informative input from everyone, it good to see all the opinions on this forum and just shows that there is a broad knowledge base on this subject.
Knowledge is gained by trial and error and it’s always better to learn from other peoples mistakes thats where you get experience from.
Still have not had time road test my brakes do hopefully over the weekend but will post my findings.
I have stripped my brakes down completely and I can confirm that there was as log of evidence of corrosion between the piston and aluminium calliper body caused by water ingress which took quick a bit of cleaning up.
Initially when I was bleeding the brakes I did notice a leak around the piston seal but after a few more minutes it stopped do put this down to the seal bedding in, has not leaked since .
At first I thought that the seal groove was damaged by the corrosion and I would need to buy a as new calliper but all good now and good braking force .
-
Interesting about the suspected fluid leak, most of my experience is on disc brakes on cars.
I have put new seal rings in calipers after using 1000 grit wet & dry to remove corrosion from the steel caliper walls with no leak when built up. I've assumed the pressure seals any minor imperfections.
I have always thought that when you release the pressure from the master cylinder that it's high spots on the disc that push the brake pad and hence the piston back. It appears that on these old bikes it's the piston seal that does the final pull back if I am understanding it correctly.
-
If you have the brakes bleed and the moving pad housing in your hand, just rest your finger on the piston and squeeze the lever a small fraction, you should feel the piston move out and then retract a fraction when you release.
Regards
Dave
-
Interesting about the suspected fluid leak, most of my experience is on disc brakes on cars.
I have put new seal rings in calipers after using 1000 grit wet & dry to remove corrosion from the steel caliper walls with no leak when built up. I've assumed the pressure seals any minor imperfections.
I have always thought that when you release the pressure from the master cylinder that it's high spots on the disc that push the brake pad and hence the piston back. It appears that on these old bikes it's the piston seal that does the final pull back if I am understanding it correctly.
Yes Ted, the seal is square in section, and when pressure is applied to move the piston outwards it distorts slightly. When the pressure is released the seal reverts to its normal shape, pulling the piston back slightly. If you trawl through You tube there are a few clips showing this in action. Rather like a hydraulic ratchet.
-
Ted, the old Girling twin piston calipers like on most Fords used the seal to retract the pistons, just they were cast iron calipers and had dust seals as well as fluid seals
-
Worthwhile in emphasis, that of any disc brake system that's giving poor results, one way or another, its all but 100% related to that seal function bring compromised, that's across all system whatever the scale of components.
The hydraulic piston caliper is brutally simple, only the moving piston and its accompanying seal ultimately affect operation. That's aside from leaking etc.
Most, after reasonable time, will get the seal's movement compromised through that operation. These original Honda type have effectively nil weatherproof mitigation with piston boot or other external seal arrangement, and so are vulnerable to the effects of localised atmosphere in way of moisture etc.
Stainless piston will resolve the corrosion of the original plated piston, but it can't do anything for galvanic corrosion of the piston seal groove in aluminium material of caliper. That risk remains there given any electrolytic activity potential. Honda's original 750 manual specifies silicone grease around that area behind the pad, that being extremely repellent to any water ingress etc.
The seal land needs very close detail in cleaning it and removing any of the accumulated aluminium corrosion from the taper space where the seal moves to in normal operation. They have a different lever feel, release characteristics and very low pad to disc friction when thoroughly cleaned and assembled. A compromised example usually exhibiting reduced travel from home position of lever (less pad rollback) and harder/more difficult effort to use the brake, the rotor surface usually taking on a more polished surface appearance is another sign or pad continuous dragging.
I haven't tried one in these caliper, but a Phenolic resin piston may hold advantage in conductivity to ultimately reduce galvanic potential in these system.
Good post and very informative.
But are we not veering off topic a little?
The original post being " Front brake squealing".
As noted above , I think this is absolutely core to the topic and adds to discussion in understanding cause etc for these caliper system.
It is a Forum, after all. My intention is to put my experience/view that can add or draw contrary view from others on site with relevant experiences too. This to further the appreciation of technical aspects and help in looking after these design.
I'd credit the site contributors with the intelligence to skip posts that they have no interest in, but of course its anyone's prerogative to prove that incorrect :)
Important for me is that the effects of non performance are completely rooted in how the piston and seal perform in the first place. Degradation of that interaction causes many subtle issue which often draw a lot of phaffing (out in general internet-land) as to coping or mitigation of that, like trying different pad materials etc, when putting foundation of how a caliper operates right primarily, will most likely not deliver those problems in the first place.
-
If you have the brakes bleed and the moving pad housing in your hand, just rest your finger on the piston and squeeze the lever a small fraction, you should feel the piston move out and then retract a fraction when you release.
Regards
Dave
I agree, and like a small heartbeat as it moves out and retracts with pressure released.
I check cycle (MTB disc systems) like this with fingers on pads to assess freedom of movement, many use jet wash to clean bikes which plays havoc with caliper health.
-
Worthwhile in emphasis, that of any disc brake system that's giving poor results, one way or another, its all but 100% related to that seal function bring compromised, that's across all system whatever the scale of components.
The hydraulic piston caliper is brutally simple, only the moving piston and its accompanying seal ultimately affect operation. That's aside from leaking etc.
Most, after reasonable time, will get the seal's movement compromised through that operation. These original Honda type have effectively nil weatherproof mitigation with piston boot or other external seal arrangement, and so are vulnerable to the effects of localised atmosphere in way of moisture etc.
Stainless piston will resolve the corrosion of the original plated piston, but it can't do anything for galvanic corrosion of the piston seal groove in aluminium material of caliper. That risk remains there given any electrolytic activity potential. Honda's original 750 manual specifies silicone grease around that area behind the pad, that being extremely repellent to any water ingress etc.
The seal land needs very close detail in cleaning it and removing any of the accumulated aluminium corrosion from the taper space where the seal moves to in normal operation. They have a different lever feel, release characteristics and very low pad to disc friction when thoroughly cleaned and assembled. A compromised example usually exhibiting reduced travel from home position of lever (less pad rollback) and harder/more difficult effort to use the brake, the rotor surface usually taking on a more polished surface appearance is another sign or pad continuous dragging.
I haven't tried one in these caliper, but a Phenolic resin piston may hold advantage in conductivity to ultimately reduce galvanic potential in these system.
Good post and very informative.
But are we not veering off topic a little?
The original post being " Front brake squealing".
As noted above , I think this is absolutely core to the topic and adds to discussion in understanding cause etc for these caliper system.
It is a Forum, after all. My intention is to put my experience/view that can add or draw contrary view from others on site with relevant experiences too. This to further the appreciation of technical aspects and help in looking after these design.
I'd credit the site contributors with the intelligence to skip posts that they have no interest in, but of course its anyone's prerogative to prove that incorrect :)
Important for me is that the effects of non performance are completely rooted in how the piston and seal perform in the first place. Degradation of that interaction causes many subtle issue which often draw a lot of phaffing (out in general internet-land) as to coping or mitigation of that, like trying different pad materials etc, when putting foundation of how a caliper operates right primarily, will most likely not deliver those problems in the first place.
Thanks for another great post, really explaining the technicalities well.
Much to agree with.
But may I respectfully enquire on behalf of us who understand exactly how the caliper functions and have phaffed about servicing it and setting it up accordingly but still suffer brake squeal what you think the cure may be?
Also bearing in mind that the proper asbestos compound pads that the brake was originally designed to operate with are no longer available.
-
The short answer is you cant cure it, some people get lucky with the combination of pad and rebuilt others dont, i have yet to find one specific reason for the noise
-
Agree. After refurbishing my front brake system NONE of the five different pads I tried/bedded-in squealed. So it seems very arbitrary... ;)
-
Any squealing noise must come from a vibration, either from the pads or part of the caliper/pivot arm assembly. Bevelling the edge of the pads cures the squeal in some cases, but not all so that could point to the noise coming from somewhere other than the pads.
The nylon disc on the back of one pad was put there to reduce squeal, I assume, so it looks like Honda deduced that it came from that source.
My brake squeals so I'm going to change to EBC Organic pads and see if that makes any difference.
-
Same here, never had any issues with old asbestos pads, I was tempted to put them back in but there's not much meat left on them. I currently have EBC pads fitted around 2005 ish , I think it must be something to do with the combination of resin binders in the pads and the stainless steel disc that makes the issue more likely.
The only alternative is pads that are more abrasive but the you have increased disc wear.
Back in the day, I remember having to give the caliper the heel of my boot at traffic lights on a few occasions because it was dragging but there was never any squeal.
Regards
Dave
-
I can only relate to my own bike, and unfortunately I cannot remember the brand of pads I fitted. They squeal like stuffed pigs when cold, and just 'feathering' the brake, especially when pushing it out of the garage first thing. The whole brake system (except the disc) was renewed 6 years ago and the squealing started about a year after that. I'v dismantled it a couple of times to change pads, clean and coppaslip the pivot pin, wet & dry the disc and pads, which is effective for a couple of months or so. The noise is loudest, as said, when cold and only braking very lightly. Fairly firm braking on a warm disc is virtually silent. Do not recollect hearing about this problem on many other vehicles, but, I am wondering, are these CB 4 cylinder models the only vehicles to be equipped with a stainless disc, and didn't give a problem until the end of asbestos? Just as an aside, back in the early 90's, I used to drive a Volvo coach which had drum brakes, remember them?, and when it was first fitted with asbestos free linings they were quiet until they reached running temperature, then the noise became horrendous, I could alter the note by changing the pedal pressure! Can't remember the outcome as I changed companies.
-
Excluding pads, are the "squealers" using "HONDA" brake parts, aftermarket brake parts, or a combination? Just wondering - an OEM piston, for example, may have a different "vibration period" compared to an aftermarket piston.
What about brake lines? Could a more "expandable" brake line allow pulsing/ vibration compared to a stiffer brake line as the pads move across any unevenness in the rotor surface.?
OR...could uneven torque of the rotor attachment fittings contribute?
-
Everything in my front brake is OEM except for dot 5 brake fluid.
There is a little play on the pivot pin, it's well greased so I wouldn't expect the squeal to be coming from there. Pretty sure its the glaze on the pads which is then depositing on the disc. A quick wipe of the pad surface with medium sandpaper always clears it.
Mine is probably made worse by too much gentle braking in urban traffic.
Regards
Dave
-
I don't know if this will help in every (any?) other case but when I go out on my motos, I always do a couple of "emergency stops" at the beginning of each ride as traffic permits - braking as hard as possible from 50-60MPH . On my modern bikes that activates the ABS; on the 400F the front tire will "howl" just short of lockup. I don't REALLY know if this procedure helps keep the brake system in good order but I've convinced myself that it does! ;)
-
Front brake update,
I have run through the pad bedding in procedure after removing pads and rubbing off the glaze with emery cloth and as soon as I applied the brake I had the squeak but it has improved after a 50 mile ride but is still there.
I think this is because the brakes and disc were getting hot and this seem improve the squealing which now is only slight.
You could hear the brakes squealing a bit before I went out for a ride will pushing it around to get the bike out of the garage.
I think I will let the pads wear down again and continue to clean and de glaze over a couple of rides and see if they improve.
Again thanks for all the advice , a very interesting subject that has provoked a good chat on the forum.
-
If its squealing pushing it around the caliper/pivot is not moving free enough or slight hydraulic pressure is staying on, lines/master
-
For something to compare with mine start to squeal after about 600 miles after deglazing. But I do quite a bit of around town riding so you tend to be on the brakes gently quite a bit.
When it was mot tested the numbers were always good even when squeaking.
Regards
Dave
-
For something to compare with mine start to squeal after about 600 miles after deglazing. But I do quite a bit of around town riding so you tend to be on the brakes gently quite a bit.
When it was mot tested the numbers were always good even when squeaking.
Regards
Dave
.
I have not had an issue with the braking force it stops quite well for an old bike,
-
If its squealing pushing it around the caliper/pivot is not moving free enough or slight hydraulic pressure is staying on, lines/master
Like this
https://youtube.com/shorts/IIXshEcfX28?si=oC4CLmS_usQEw9R_
Regards
Dave
-
Ok thanks Dave
-
If its squealing pushing it around the caliper/pivot is not moving free enough or slight hydraulic pressure is staying on, lines/master
Like this
https://youtube.com/shorts/IIXshEcfX28?si=oC4CLmS_usQEw9R_
Regards
Hi Dave thanks for the video, just checked the brake arm as you suggested and it’s very free so behaving like yours , just going to scuff up the pads again while it’s off.
Dave
-
Slight glazing after bedding in again but not as bad as it was probably going to have to live with cleaning the pads every now and then simple job so not the end of the world