Brake issue - where to start?

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dubdubz

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The setup is a servo assisted , with 71 calipers.

I'm loosing a little fluid in the reservoir but can't find any visible leaks or weeps - I haven't taken the rear hubs off yet to check the cylinders.
Couple this small drop in fluid [say a couple of mm over a long weekend away], with a pedal that sometimes feels very low and soft, the brakes work but the brake activating position on the pedal changes and the pedal almost seems to get stuck down low and won't return, and you have to lift it with your foot??? (the return spring is fitted and not broken)

It's not physically catching anywhere (first thing I checked), and it doesn't do it all the time, it is very much like when you're bleeding the brakes, so I presume I have a leak somewhere but I just can't find it as yet.

What does a MC who's seals are failing feel like?

What's the best order of checks to perform?

It doesn't do it all the time and once it's been pressed down to the 'wrong' position it seems to then hold good pressure at the pedal at the position is normal again for what seems awhile, it does appear to be connected with stopping.
start journey - pedal soft - pumps up is pretty much ok but not perfect at all times...then stop for awhile. The pedal can be ok or it be soft.

Then add the final thing that with reasonable force braking, it pulls to the nearside a fair bit.....

Where should I start, I'm comfortable with spannering, but jobs like brakes I know there is a good order to the fault finding and an order that will hinder the fix!

I'll pop back in here later ....thanx very much in advance....
 
When my MC was leaking I would sit (in traffic) with my foot on the brake and the pedal would go soft, and i would need to let it up and press it down again for the brakes to become firm. I didn't notice much when braking normally to be honest.

hope this makes sence, and helps
 
this sounds similar to what mine is doing, I need to check there is no leaks for definite in the system...the flexi's are 75% new, there's one rear one I haven't yet changed. I might check the hoses and get some fancy stainless ones ! Heritage sells a new servo and mc for 166 which may be the easiest in the long run, by the time I've put a repair kit in the MC, the servo is probably at best 20 years young...although a £20 repair kit does appeal financially!!
 
As you pull a bit to the left, I'd start rear offside and see if you have a leaking cylinder there. Sort that, then adjust the rears and all should be good. A leaking cylinder won't always leave an obvious trail of fluid.
 
ZedBed said:
As you pull a bit to the left, I'd start rear offside and see if you have a leaking cylinder there. Sort that, then adjust the rears and all should be good. A leaking cylinder won't always leave an obvious trail of fluid.

cheers Zed

actually got my sides mixed up, it pulls to the offside!! so I'll start at the nearside...my 46mm went missing lent it out and forgot to where so I'll have to try and knobble one or bite the bullet and buy one!
 
If you want to drive over to the workshop tomorrow I have a Torquemeister for wide 5 and I'll be there all day. You're welcome to come over and use it/jack/stands etc.

But you know you need one if you have a 68.
 

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