Guest fortyninebuick Posted May 21, 2011 Share Posted May 21, 2011 Hi,My 49 Buick is back together after a complete body off restoration. My problem is while driving on normal roads and braking normally, my pedal gets hard and I get a drag from the brakes. Ive found this to be the rears. After it sits awhile it is back to normal. The shoes are adjusted correctly when cold, all lines are new and routed exactly as they were originally. Any input on what is happening ?Thanks in advanceAl Link to comment Share on other sites More sharing options...
Guest Albert Posted May 22, 2011 Share Posted May 22, 2011 Is the rear flex hose new as well? have seen flex hoses act as a check valve.. Link to comment Share on other sites More sharing options...
Guest fortyninebuick Posted May 22, 2011 Share Posted May 22, 2011 yes, everything is brand new, hydraulic and mechanical. To me it seems heat related ???? Link to comment Share on other sites More sharing options...
Owen_Dyneto Posted May 22, 2011 Share Posted May 22, 2011 Sounds like the classic. Readjust the pedal free play, the pedal isn't allowing the MC piston to return far enough to uncover the port back to the reservoir. Link to comment Share on other sites More sharing options...
Guest fortyninebuick Posted May 22, 2011 Share Posted May 22, 2011 That sounds like a good idea, I will inspect and adjust tomarrow. Wouldnt that be a problem though all the time ? It doesnt happen untill a few miles of stop and start driving ? Link to comment Share on other sites More sharing options...
Rusty_OToole Posted May 22, 2011 Share Posted May 22, 2011 That sounds like a good idea, I will inspect and adjust tomarrow. Wouldnt that be a problem though all the time ? It doesnt happen untill a few miles of stop and start driving ?If the pedal does not have enough free play the brakes will not release. There is a little hole in the master cylinder that lets the brake fluid flow back into the reservoir when you release the brake pedal. If this hole is covered the brakes will not release.You won't notice until you use the brakes a few times. But once they start to drag, heat expansion makes the brakes drag worse. If you leave the car set for a while the pressure oozes out and the brakes return to normal, until you use them again.The brake rod that pushes the master cylinder must release completely and have a little clearance. This usually translates to an inch of pedal travel before the brake cylinder is actuated. Link to comment Share on other sites More sharing options...
61polara Posted May 22, 2011 Share Posted May 22, 2011 Check the rear flex hose again. I had the same problem on a '47 Roadmaster. Replaced all hoses and in a few months had the same problem. Took off the rear flex hose and cut it open. The inside of the hose had swollen to the point the opening was less than 1/16". Put on another new hose and that corrected the problem. If it was a problem with the master cylinder push rod adjustment, you would have problems on all wheels not just the rear. Link to comment Share on other sites More sharing options...
Guest fortyninebuick Posted May 23, 2011 Share Posted May 23, 2011 Thanks guys, that was it. I had NO free pedal play. I gave it about an inch of play and took it out 3-4 times and no dragging. What threw me off was that it only started doing it after driving a bit, I kept thinking it was shoe adjustment or something. On to another problem !!THANKS !!! Link to comment Share on other sites More sharing options...
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