Hard Pedal & Brakes Binding After Running Jul 11, 2017 12:49:08 GMT
Post by paddymk2 on Jul 11, 2017 12:49:08 GMT
Jun 13, 2016 at 8:17am Penguin45 said:
Brake problem now resolved. Snoopy came over this morning and between us we worked out that the servo was indeed the problem. Cracking a caliper nipple simply releases the pressure on the brakes. Having got the brakes locked, releasing a joint between the master cylinder and the servo would show that:
1/ If they release, it's the brake maaster cylinder
2/ If they don't, it's the servo.
We did, they didn't, so servo time. I'm afraid that being in a bit of a rush we didn't get photos, but stripped, cleaned and polished everything and fitted new seals. I am 99% certain that the air valve was the culprit. Anyway, it's all back together and a comprehensive bleeding has yielded an excellent pedal.
And, as fair exchange is no robbery, I spent the afternoon doing a bit of welding on GLE.
I seem to have a very similar situation.
The brakes had been grabbing - so I changed the flexible hoses - bled the lines and it seemed to be ok for a short drive. But then it started again.
I jacked up the car - disconnected the booster and the front wheels still seemed to be really hard to turn.
I took off the calipers - the wheels turned fine so the bearings seem ok.
I got the calipers serviced (the pistons were pitted), put them back on and refilled the master cylinder (it took an effort to get all the air through) eventually the brakes pedal feel came good. Took it for a drive round the block and all seemed good.
But took it out for a longer run yesterday and (a) the brake pedal was very hard (b) the brakes seemed to be dragging a lot. At this point I put it back in the garage and closed the roller door :-(
The booster seems to be operational - when I press on the brake pedal with the engine off and then turn the engine on, the pedal goes down a little. There is plenty of vacuum from the manifold and the one way valve to the booster is operating.
Looking at your note I suspect the master cylinder.
In your check above are you running the car till the problem is obvious (brakes and fluid are hot) and then (carefully- I assume liquid will squirt out) cracking open the front brake line at the master cylinder. After that the brakes should release (if its the master cylinder)?
Its easier for me to tell if the brakes are binding by seeing how it rolls on the incline of my driveway and feeling in the pedal pressure.
Hi Again (probably makes more sense to put this into the technical discussion)
- I took the car round the block to warm things up again.
Pulled back into the driveway - the brakes kind of groaned but the car still rolled.
I jacked up the front end onto stands and checked the wheels in neutral.
They turned but only just.
Then I cracked open the brake line between the master cylinder and the booster (the brake system is the remote PBR unit, not Girling.)
And the wheels came free.
Now it's to decide - rebuild the master cylinder myself or take it out and get the friendly brake specialist to do a rebuild or take the car into the shop? I guess it depends on how hard it is to rebuild and what else might need fixing (rather than just a rubber seal)?