Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: billy192 on July 07, 2012, 06:37:55 PM
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Hi,
when I push the bike back and turn the bars to one side the wheel binds, doesn't matter which way I turn same thing. Straight line OK. Jack the front wheel off the ground and wheel is free going backwards lock to lock. only when the weight is on it does this happen.
any ideas?
Billy
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Something trapping the brake flexi and sqeezing fluid to the caliper OR front wheel bearing play
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Thanks Bryanj
Brake pipe not being trapped so i will look at the wheel bearings.
Billy
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Hi Billy,
May sound strange but check how the front mudguard is mounted. I originally incorrectly fitted mine so the brake side bracket was between the top brake mounting bracket and the fork leg, this put the caliper very slightly out of line and caused me a lot of brake dragging problems ( although admittedly the handlebar position didnt alter this )
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Hi,
Thanks for all the advice but in the end Bryanj was spot on, front bearings were totally shot.
nice new ones in and smooth as a smooth thing.
One thing though there was no bearing retainer is this dangerous? if so where do I get one from?
Billy
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Should be a screw in retainer and seal on one side only, Try Dave silver
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Thought it had gone but looking again.
I have trouble getting the wheel off as the pads are tight against the disk.
stripped the calliper to find that the piston is v pitted and will not go back in with out a lot of effot.
plus one of the last owners must wear spurs as the bleed nipple has had the thread stripped so he/she rammed a 12mm bolt in.
now need a new piston + seal and a new outer half of the calliper.
Billy
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Billy, send Bryanj a message he did have some bleed nipple repair kits for sale 8), easy to do and work a treat ;), let us no how you get on getting a piston & seal and were from & how much please my F1 needs front & back replacing :'(, cheers Mick.
(http://i234.photobucket.com/albums/ee75/mcpuffett/26.jpg)
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Can't remember the price Mick but I used stainless steel pistons and sealing rings for my F1 brakes (front and rear) from wemoto on the basis they shouldn't pit etc, they were fine but I had to get the pukka grit seals as the general purpose ones supplied with the pistons didn't really fit properly ( got them from DSS )
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Hi Billy 192
Here's the link to the same problem which I had.
http://www.sohc.co.uk/index.php/topic,3954.msg16866.html#msg16866
I bought a phenolic piston from the States which together with my caliper bracket mod cured the problem.
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Dave Silver now does pattern stainless pistons of excellent quality and yes i still have some repair kits
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I don't make 'em they are imported from the USA and retailed by NAPA. I just sourced them and paid for them then got stung by HMRC for the temerity of bringing in something usefull!!
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Cheers Waggles for the info, Bill how much did the phenolic one cost you if you don't mind me asking?, cheers Mick.
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Bill how much did the phenolic one cost you if you don't mind me asking?, cheers Mick.
Hi Mick,
No I don't mind at all - I'm happy to help.
The total payment was $38 at 31/10/2011 which worked out at £24.29 via PayPal.
I was very impressed with Kevin's attention to detail in even making a small cardboard box to post it in.
I wouldn't hesitate to recommend him to anyone.
Regards, Bill
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Still having problems with the front brake binding. the brake leaver is tight no play as soon as you touch the brake is on. when stationary it will not roll forward or backward.
here is a list of thing I have done so far
1 new front wheel bearings
2 new front axle
3 new SS piston and genuine seal
4 new bleed nipple (thanks to Bryanj)
5 new pads
fed up Billy :(
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Have you cleaned out the fluid return in the master cylinder? If this is blocked it will not let the pads return.
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Still having problems with the front brake binding. the brake leaver is tight no play as soon as you touch the brake is on. when stationary it will not roll forward or backward.
:-\ have you changed the front brake lever,because you must have play on the brake lever i cant recall the exact measurement,i have several spare levers and some have more freeplay than others,if there is not enough freeplay on the lever it will cause the brakes to bind and boil the oil.it must not be touching the master cylinder plunger and should return freely,failing that are you sure the circlip is fully home,in anycase remove lever and then try and rotate the wheel, just in case that's your problem. BTW i also changed my wheel bearings when bike was pull backwards on left hand full lock the wheel was binding, and yes new bearings cured that.
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See my earlier post, is caliper mounted correctly and true to the disc? also, is the caliper arm pivot seized? finally, are new pads correct size? if they are too thick it will never release.
I assume you cleaned out the caliper seal groove ( they are often bunged up with crud which causes seal to seal too well and not let piston move )
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yes there was play before i fitted new seals
and yes i did clean out the caliper seal grove
and also yes the mudguard bracket is in the correct place.
not touched the master cylinder,
where is this fluid return? do i have to renew all the seals in the master?
thanks for all the ideas, i am sure i will get there with your help.
billy
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The fluid return is inside the master cylinder. There are two holes in there, it is the smaller one.
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Yeah Lesterpiglet is right when it works good watch out for the fluid squirting out like a geyser take your tank off.
Cheers
Bitsa
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Hi Lesterpiglet
(http://i1209.photobucket.com/albums/cc393/njwill1/IMG_6576small.jpg)
the hole to the left is clean but the hole to the right seems blocked.
how small is this hole? Is it sewing needle size or can i buy a fine drill bit?
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the hole is tiny, i used a drillbit used for modeling, was 0.3 mm!
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Two strads of copper wire from a speaker cable twisted together is about the size, or in other words TINY
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If the brake is still binding under weight but not when the front wheel is raised - and bearing in mind all the other stuff you've checked, I'd be looking at two things - the brake caliper pivot pin and the fork oil levels.
The pivot pin is well know for seizing, and if it does it won't allow the calliper to float. That won't help.
Failing that,you may well find one (or both) fork oil levels are low, which would cause the front wheel to be unbalanced when under weight.
HTH
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Thanks to all,
the 0.3 drill did the trick it worked a treat breaks are now perfect. No binding and i can wheel it back and forth with ease well it is a 500lb bike.
thanks
Billy
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Bike goes great, it must have been binding a lot as now it takes far less revs to move off. great
Billy
;D ;D ;D ;D ;D ;D ;D ;D