I rebuilt my Master cylinder, rebuilt wheel cylinder, new brake lines at wheel and Master. Went for a ride yesterday 125 miles, motorhome pulls in front of me when I'm runnin 65 mph I have to jamb on the brakes and hurry up and switch lanes, I'm telling you if I didn't I was in Serious Serious Trouble, I was very lucky that there was no cars coming at me, in real they pulled out 20 feet in front of me in this Huge Diesel Pusher Pulling a Jeep,this is the first time in damn near 6 years I took the Ol Girl out and let her stretch.
Now my quandary is my back brakes I did all the work to did not respond as they use to, I mashed the pedal to no real stopping, I get the rest of the way home about 6 miles and the rear brake is hot and hanging up and that is all the rebuilding I had done, any idea as to what I need to do, is it the Master Cylinder ? I rebuilt it ran a little hone in there cleaned it all but it sure as heck didn't stop me when I needed it most, riding around the neighborhood briefly before my excursion the Brakes worked great.
(Drum Brake Rear)
Of course you used DOT5 fluid. Sounds like either it is holding pressure do to no freeplay at the master or the oring in the caliper isn't doing the job of retracting the puck.
"oring in the caliper isn't doing the job of retracting the puck."
Think he has a drum in the rear.
If the hone isn't straight, you'll have problems.
Quote from: Deye76 on August 18, 2022, 07:11:23 AM"oring in the caliper isn't doing the job of retracting the puck."
Think he has a drum in the rear.
If the hone isn't straight, you'll have problems.
My bad..."wheel cylinder" should have been a clue. Did the old juice brakes use DOT3 or 5?
Dot 3 was used in all the drum brakes. The first rear disc appeared in 1973 and about that time Dot 5 became the spec.
If it is getting hot with no pedal, could be one of two things. The drain back hole in the master cylinder is blocked, or the pedal adjustment is not correct, not letting the m-c piston retract as far as it should. Make sure the pedal is adjusted per TFM.
-JW
Did you readjust the brake pads? did you get all the air bled out. did you replace the rubber hose on the rear drum. Had one of those swell shut on me,and you need some freeplay at the pedal.
I also used dot 5 fluid never had a problem with it.
I used dot 5, replaced rubber line with russell braided, readjusted New pads and chamfered the leading edge slightly, the hone was very light by hand as it was very clean.
May just buy a new Master cylinder, have not opened the cap yet to see if I lost fluid but I did not have anything on the tire etc. It felt like Pedal was locked would not respond at all when this happened but the first 75 miles there NO Problems the Old Shovel was Performing Great Like I remembered. :SM: :SM: :SM:
Quote from: 72fl on August 20, 2022, 03:36:42 AMPedal was locked would not respond at all when this happened
Say what? It sounds like you've just identified the problem.
-JW
Very likely that the plnhole in the bottom of the master that returns fluid from the rear has DOT 3 crud blockage.
Dot 5 will make bubbles when you pump the brake, as in when you pump to bleed the system. These little bubbles aren't quite like foam but they can be persistent and can cause problems like you describe. The fix is to wait for the fluid to settle down and use a long 5 count with each pump. Both in and out. This will stop the bubbles from forming. There is still the possibility of a bubble trapped somewhere in the system. Naturally, it will be in the worst possible place to remove.
It also helps with dot5 to tie the handle and brake pedal down overnight. It seems to work to remove any lasting bubbles.
Ended up putting a New Wagner Lockheed Master on and finally got to take it out couple days ago seems to have solved my problem. What I did notice is when I took the Old one off Brake Fluid was coming out of the Rod End, I rebuilt per the OEM Shop Manual I wonder if something was dried out in the kit or something was stuck, I kept it one day I will examine closer.