biffy1984 Posted May 25, 2018 Share Posted May 25, 2018 I'm having a problem with what seems to be just my front brakes binding, its not binding much at all but just enough to notice it, especially after a run when the brakes are hot. I'm using Astra calipers and Audi 80 discs on the front and Astra discs and calipers on the back with goodridge braided hoses all round. Everything is brand new and free so it's nothing to do with the calipers/slides or flexys. Has anyone ever had bother with master cylinders sticking?? It's an ATE master cylinder. Any ideas would be much appreciated Quote Link to comment Share on other sites More sharing options...
cam.in.head Posted May 25, 2018 Share Posted May 25, 2018 Make sure that with servo exhausted that there is 6mm of free movement at the pedal before it operates the servo piston. Not enough or no free play can cause the brakes to not release fully. Quote Link to comment Share on other sites More sharing options...
biffy1984 Posted May 30, 2018 Author Share Posted May 30, 2018 Been looking at this again and yeah there would be around 6mm of free play with the pedal released and the servo piston fully returns every time. It would seem the more you work the brakes the more they bind, but pumping the pedal will release them. Think I'll try another master cylinder and see from there. I'm assuming what I'm describing isn't a common problem then? Quote Link to comment Share on other sites More sharing options...
®evo03 Posted May 31, 2018 Share Posted May 31, 2018 Would it be worth, try bleeding again, i use a manual bleeder pressurised from a car wheel, furthest wheel, rear passangers, rear drivers, front passangers, then drivers front, apologies if sucking eggs, just seams weird if pumping is releasing, maybe trapped air. Could save you replacing servo, your saving grace is that its extended away from bulkhead Are you running carbs on a redtop? Is vaccum all ok, with the servo. And free from leaks? Are all fluid fittings and hose free from leaks. what about that brake divider thingy, it reduces and divides the rear brake pressure, all ok? Quote Link to comment Share on other sites More sharing options...
cam.in.head Posted June 1, 2018 Share Posted June 1, 2018 Also you could try clamping off the three hoses and trying each section at a time to confirm which wheel is sticking if it is a wheel or if its the return spring inside the master cylinder. Ive never heard of it happening personally but it could in theory especially if the rear bit of the cylinder is rusty or gunged up or the spring is weak/ broken. Also ..Just make 100% certain that the servo piston is moving in and out of the servo body ok and not sticking on the sides or due to a very dry oil seal. Very awkward to see as its up behind the pedals and behind a big rubber boot.you could also unbolt the master cylinder from the servo if need be to observe .but add a small smear of silicone to the o ring on refitting unless absolutely perfect or you may get a small air leak. Quote Link to comment Share on other sites More sharing options...
biffy1984 Posted June 10, 2018 Author Share Posted June 10, 2018 Update on this lads, new master cylinder fitted and problem solved thankfully so must of been a sticky return spring or seal, I'll maybe take the old one apart for a look sometime. Cheers for the suggestions 1 Quote Link to comment Share on other sites More sharing options...
cam.in.head Posted June 10, 2018 Share Posted June 10, 2018 No problem .glad to be of help .and glad you got it sorted. 1 Quote Link to comment Share on other sites More sharing options...
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