Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: TJMart on August 29, 2024, 14:27:02
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I have been working on my brake restoration off and on for awhile. I'm back on it and seem to be near the end.
I had the master cylinder, booster, proportioning valve and calipers all rebuilt.
I replaced all brake lines and hoses.
Put everything back together and bench bled the master cylinder and bled all lines.
Took it out for a short test drive and when I returned all four wheels were very hot. It seemed when driving that the brakes were not fully releasing. The brake pedal did not go down very far when braking.
When installing the Booster, I put the eccentric bolt to the exact position it had been before I started all this. I adjusted the eccentric bolt and backed off the rod from the booster to the master cylinder thinking the rod was too long and not letting the master cylinder pistons return all the way.
Test drove it again and it improved slightly but the wheels still would not turn freely and were not as hot as before. Adjusted the bolt some more and improved it to the point where the rear wheels would release and I could turn them, but the fronts were hard to turn. I cracked open the front lines to the master cylinder while the brakes were hot and this released the front brakes and wheels turned freely.
Took it out again and front brakes would not completely release again.
When I let the brakes cool overnight they fully release and the wheels all turn freely but when I take it out the same thing starts again. So it seems that as the brakes heat up from braking and driving this causes the brakes to not release fully.
Bottom line I'm stuck. :(
Any help is appreciated.
Tony
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Hi Tony, I had a similar problem when I had my power brake booster rebuilt a few years back. The shop that rebuilt the booster did a poor job and it wouldn’t fully release pressure off the master cylinder. When the front brakes heated up they wouldn’t release. Disconnect the vacuum line off the booster; if the brakes release, that rebuilt brake booster could be the culprit.
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Hey Charles,
Thanks! I check it out tomorrow and report back.
Tony
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Hi Tony, I had a similar problem when I had my power brake booster rebuilt a few years back. The shop that rebuilt the booster did a poor job and it wouldn’t fully release pressure off the master cylinder. When the front brakes heated up they wouldn’t release. Disconnect the vacuum line off the booster; if the brakes release, that rebuilt brake booster could be the culprit.
Well I took it out for a drive again and when I returned the fronts were almost locked up but could turn the wheels with some effort. Rears were slightly under pressure but could turn the wheels with less effort.
I disconnected the vacuum line from the Booster and no change to the wheels releasing.
Does this mean that the Master cylinder is the culprit? If so what could the problem be?
Tony
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Since you replaced the brake hoses (so they are not the culprit), and there is some free play between pedal and master cylinder, my next investigation would be into the master cylinder, indeed.
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Adjust the eccentric on the push pin. There should be play at that point or the brakes will lock up.
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..and confirm the intermediate lever isn’t binding https://www.sl113.org/forums/index.php?topic=36889.0.