fearofweapons Posted August 1, 2023 Share Posted August 1, 2023 Hello, a couple of months ago we had an issue with the front left brake cylinder, which we fixed on the road but decided to replace the wheel cylinder just in case when we got home. One thing led to another and we have ended up replacing the master brake cylinder, all drums, pads and snail cams and bled the system through several times but still can't get a good pedal. Sometimes it goes straight to the floor with minimal resistance and some times will get a half hearted brake and a nice good hard one on the second stroke. I have checked spring placement ( new springs ) going from the peg on the leading shoe to the peg on the back plate and the bottom spring joining both shoes together. Snail cams have been wound wound to stop the hub turning and then back in two clicks/'till the hub turns freely. Any suggestions gratefully received. regards, Richard Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 1, 2023 Share Posted August 1, 2023 Not unheard of to get faulty master cylinders.... Especially if in a blue box. Quote Link to comment Share on other sites More sharing options...
steve b Posted August 1, 2023 Share Posted August 1, 2023 16 minutes ago, Bowie69 said: Not unheard of to get faulty master cylinders.... Especially if in a blue box. If you have rubber flexible hoses clamping these off will tell if the mc is faulty , if good the pedal will be solid aside fro the pre-set free-play Are the springs behind the shoes? And are the springs new? I've had similar down to the new cylinder seals being less tight combined with new springs being too forceful thus pulling the trailing shoe into the cylinder too far. then the next pedal push goes way too far. Does the pedal come up and stay up with pumping then keep pushing on last push? Steve Quote Link to comment Share on other sites More sharing options...
fearofweapons Posted August 2, 2023 Author Share Posted August 2, 2023 Thanks all for feedback. I'll try clamping the rubber hoses and see. At least that will isolate if MC, FOS, FNS, Rear are the issues. The pedal does return to it's resting position when released. And yes if I get a good firm pedal constant pressure will usually force the pedal down to the floor - indicating I suppose fluid is still moving somewhere? Be that past the MC seals or still pushing the pads out to the drums. Further info. springs are new springs are behind the shoes/snail cam it breaks much much better in reverse than forwards. It is absolutely throwing it down here today so 'rain has stopped play' but once / if it dries up I'll report back on findings. Quote Link to comment Share on other sites More sharing options...
GregK Posted August 3, 2023 Share Posted August 3, 2023 If clamping hoses pases the test and master is ok. Other thing you could try is wedge a brake pedal down and keep it down overnight, hopefully this will shift the airlock and give you a good brake pedal. Quote Link to comment Share on other sites More sharing options...
Anderzander Posted August 4, 2023 Share Posted August 4, 2023 If you can … it’s probably worth sharing a picture. Possibly you have more than one thing happening here. With it braking better in reverse .. have you got your shoes the right way around and are your back plates on the right side? Is your snail cam on the front side of the plate? The pedal sinking sounds like the master cylinder to me. If you’ve no fluid leaking anywhere, no build up in the seal behind the rod for example, then I would think your piston seals have failed and pressure is bleeding back to the reservoir side. As has been said - there are carp cylinders out there. Sadly many of them in my experience Quote Link to comment Share on other sites More sharing options...
fearofweapons Posted August 4, 2023 Author Share Posted August 4, 2023 So.... Master cylinder changed everything bled through again. No real change. Clamping off the rear gives me a nice hard pedal. I've checked the pads, springs and gaps. All seems good. But with the back unclamped pedal is soft again. Calling it a night and drinking beer. 1 Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted August 4, 2023 Share Posted August 4, 2023 I’m not sure if it’s just the photo but is the red spring attached to the right side shoe? Or do you have it on the snail cam post? Quote Link to comment Share on other sites More sharing options...
Anderzander Posted August 4, 2023 Share Posted August 4, 2023 Looks like it …. Quote Link to comment Share on other sites More sharing options...
fearofweapons Posted August 4, 2023 Author Share Posted August 4, 2023 The red spring passes behind the snail cam and onto the post attached to the leading shoe. 1 Quote Link to comment Share on other sites More sharing options...
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