Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Bradders on December 27, 2019, 01:26:52 PM
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Afternoon all. I have some grungy stuff in the bottom of my brake Caliper reservoir and wanted to clean it out. I’m thinking it would be a good time to renew the brake fluid as well at the same time. I’ve looked on the internet and I think it’s within my mechanical capabilities ( famous last words). Any tips or advice would be greatly appreciated. Also it says to use DOT 3 but have not seen that around. Is DOT 4 ok to use? Regards, Chris.
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You will be OK with DOT 4 or DOT 5 but do not use DOT 5.1 unless you are doing a complete overhaul and changing all rubbers etc as 5.1 is not compatible with DOT 3, 4 or 5.
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Thanks Julie. No just going to renew the oil.
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Top tip, learned the hard way.
When pumping the new fluid through the system, don't be pulling the lever all the way to the bar, things will not go well, as you are taking the seals past their normal range of travel.
You can tape a matchbox or similar to the grip to stop this happening.
Ash will be along soon to point you at the appropriate service bulletin.
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Here's one (sorry Ash!)...
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Thanks MrDavo for that tip. This forum is so useful for tips like that.
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Be careful with the bleed nipple.it could be corroded shut.
After you made sure you can loosen the nipple.I take apart the caliper. Remove sliding pad.and carefully press the piston into the caliper as far as it will go.
Suck old dirty oil from the master cylinder. Then partially fill with fresh oil and start to flush the system.
Careful operating the brake lever. As oil will spurt out. And ruin your paint work.
Once fresh oil comes out.
Replace the pad.assemble the caliper and pump the brake lever. Checking the fluid level at all times.
Replace top.check all bolts are tight. Should work for another umpteen years
Sent from my SM-A750FN using Tapatalk
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Good point about the bleed nipple John, they can be a bit of a nightmare. Chris, if you want a new bleed nipple, I have them in stock and will pop one in the post to you.
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Thanks guys. Do you all change the oil every 2 years or is that a bit of overkill ?
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Thanks guys. Do you all change the oil every 2 years or is that a bit of overkill ?
Over kill.
It's worth while swapping the caliper seal every 10/15 years.
That retracts the piston. And makes the system work sweetly
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Thanks guys. Do you all change the oil every 2 years or is that a bit of overkill ?
Over kill.
It's worth while swapping the caliper seal every 10/15 years.
That retracts the piston. And makes the system work sweetly
Sent from my SM-A750FN using Tapatalk
Agree, we don't change ours until there are crispy bits in the bottom of the resovoir 😊. Saying that, most of our bikes have had the systems completely re furbed and rebuilt so we use DOT 5 silicone fluid.
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I think Peter the previous owner overhauled the whole lot about 3 years ago. The Caliper etc looks in very good condition. I’m wondering whether I need to do it now, it was more the stuff in the bottom and the internet saying needs doing every 2 years that made me think I needed to do it?
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I was most amused by the use of “matchbox”. Are they still a thing?
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I was most amused by the use of “matchbox”. Are they still a thing?
I dare say modern smokers can substitute their electronic vapourising device for the matchbox.
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I was most amused by the use of “matchbox”. Are they still a thing?
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Steve- Might not have any matchboxes left but i was glad Im still a smoken when a fuse I broke down a while back due to a cracked fuse. Out fwith the fag-paper and home I rode! (as for lighting them, the wife upgraded me to a Zippo about 25 years ago!)
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I’m wondering whether I need to do it now, it was more the stuff in the bottom and the internet saying needs doing every 2 years that made me think I needed to do it?
Or, perhaps, the maintenance schedule in the owners manual? (;)). I do often hear that Mr. Honda did things for a reason...
On the other hand: interestingly, the factory service manual doesn't specify any brake fluid change interval at all - only "checking" and topping up... so directly from Honda, it's either "every two years," or "never"... ;D
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Re the use of smoking requisites to maintain motorcycles:
I used to be able to time a BSA pre-unit twin using a pencil and a Rizla. If I remember it correctly:
Shove the pencil in the plughole, and mark where TDC is. Find out the distance BTDC where it was meant to spark, (it was given in inches, not just degrees) mark the pencil that distance above the TDC mark, turn engine back to there. When you have done it once just keep the pencil in your toolbox, you won't need to measure and mark next time.
Set the magneto so it is just letting go of the fag paper placed between the points (ie points just opening). Tighten up the magneto sprocket, which was on a taper.
Done, two minute job. Five if you include taking the timing cover off and putting it back on again.
Regarding brake fluid (best post something on topic) I've sometimes spotted blobs of water running around in the bottom of master cylinders (it doesn't mix), that's a good sign it needs changing!
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Regarding longevity of fluid, the Japanese original fit flexible brake hoses have always been very good quality and far less risk ( moisture migrates inwards through the hose to contaminate the fluid) than other automotive supply materials. In addition, the bike's mastercylinders generally have the flexible bladder under the cap which makes the biggest difference to moisture ingress, which cars don't normally use.
These don't normally need to schedule a change with anything like the frequency of cars, but if you do then all the fluid should be pushed through the system as it will all have the same moisture density dispersed right throughout it.
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While we're here, I guess...
I've dumped way more brake fluid than I've put into brakes - "they" say not to save open bottles of fluid for later use as it will absorb atmospheric moisture and be ruined. If you could open a bottle, use whatever you needed, then could positively seal the bottle against further exposure - at least until the next time you open it - can you save an open bottle on the shelf for later use?
For example, what if I open a bottle, use about 1/4 of the fluid over about 15-minute interval, then close the bottle and vacuum-seal it in a plastic bag which can't let air in...
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If it's in a flexible bottle, just squeeze the bottle until liquid is at the top and put the cap back on to exclude air and it'll last longer. Probably a year or two.
Nitrogen fill is used in lab situations to help things like this. Probably cost more than the fluid to do it though, although they do nitrogen fill tires in racing to prevent pressure changes due to heat build up in critical application. Some tire fit places offer that to general consumers here.
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Thanks all for your advice. Sounds to me I might leave it another couple of years yet. The oil in the reservoir is quite a clear colour and it seems that maybe it doesn’t need doing just yet.
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Thanks all for your advice. Sounds to me I might leave it another couple of years yet. The oil in the reservoir is quite a clear colour and it seems that maybe it doesn’t need doing just yet.
Good. If the brakes are working well and stopping the bike in time ( As well as 400/4 brakes have ever worked that is 😊😊😊) leave it for now and do it when you change the pads next.
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Great advice Julie thanks. My pads have always looked Like there’s less thickness on the inside pad than the outside one. Is that normal?
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Yes, original pads had a line/groove around them painted red and were ok till the line was worn into. Outer pad wears morn as it touches disc first before pulling caliper over for inner pad to touch, at least that is what i was i was told years ago
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Thanks Bryanj. That makes sense.