Forgive me for this, but I can find no thread which answers this.
Having rebuilt my calipers and master cylinder, my front brakes are still binding! It appears that the front circuit is failing to release the pressure.
I have checked the push rod length and made adjustments to ensure some free play before contact is made with the piston, but this hasn't helped.
I have dismantled the master cylinder and it appears all clean and clear, as does the small breather hole. I have checked the servo and that is not the cause either!
I have a spare piston set and thought of using that, but find that , although it is the same overall length as the one I am using, the actual chamber length on the smaller piston is longer - about 19mm compared to 17mm on the one I am using. Both pistons are for a 21mm bore.
Having tested the piston in the cyclinder, I get good pressure from the rear chamber, but none at the front chamber! I think this is because the piston is not being forced backwards far enough to clear the access hole to the fluid chamber.
Bizarrely, having driven alot of miles recently, stopping to release the pressure, I find that after about 3 stops to release the pressure, I no longer have a problem! (Until the next day, when it starts all over again!)
I think I have assembled it all correctly (as per the manual), but obviously have soemthing wrong. I think the key problem may be the springs. The two are differing lengths and I am using the shorter one in the middle. Has anyone got the dimensions etc of these springs - I am thinking of trying a shorter one to ensure access to the fluid chamber.
Any help is much appreciated
Mat
Binding brakes
Re: Binding brakes
Well, after 3 rebuilds and bleeding sessions, fault found.
I discovered the front piston has sezied. The front cylinder consists of a shaft and then a sliding cylinder with the drilled pressure release holes it in. This has stuck to the main shaft and explains why the spare I have is show a slightly longer chamber length on the piston - this one too had stuck, but 'open'. The result was that one applied pressure to the brake piston but wouldn't relase it and the other wouldn't apply pressure.
Apologies to the knowledgeable who knew this.
a bit of heat and its now free and pressure release restored. I now think a piston in the caliper is sticking, so no peace!
For anyone else, the spring in the master cylinder, nearest the foot pedal should measure 64.5mm and the other 60.00mm (this one is also stiffer, but I don't have the values.)
mat
I discovered the front piston has sezied. The front cylinder consists of a shaft and then a sliding cylinder with the drilled pressure release holes it in. This has stuck to the main shaft and explains why the spare I have is show a slightly longer chamber length on the piston - this one too had stuck, but 'open'. The result was that one applied pressure to the brake piston but wouldn't relase it and the other wouldn't apply pressure.
Apologies to the knowledgeable who knew this.
a bit of heat and its now free and pressure release restored. I now think a piston in the caliper is sticking, so no peace!
For anyone else, the spring in the master cylinder, nearest the foot pedal should measure 64.5mm and the other 60.00mm (this one is also stiffer, but I don't have the values.)
mat