Did a front disc conversion and am trying to bleed my brakes. After a couple quarts of brake fluid still no rear brakes. Have good flow from calipers while bleeding, and flow from the back brakes not a strong stream. Put car in the air and started engine let out the clutch and rear wheels still spin with no resistance with pedal smashed to the floor. Front calipers lock up solid but nothing on the rear. Rear brakes are adjusted as tight a possible, was told it could be a bad master cylinder, cup torn. Tested the proportioning valve and no light was on, therefore it must be centered. Took out the master cylinder and am going to get another. Hpe you guys can help with this pia problem running out of ideas.
No brakes on rear
- Thread starter Smokey1963
- Start date
If you had rear brakes prior to installing the front disc brake conversion, there is only the master cylinder or proportioning valve. Crack the rear brake line at the master, is there any pressure there? If none, master air locked or bad. If there is pressure, crack the line on each side of the prop. valve. Pressure in and none out is a bad or uncentered valve.
Keep bleeding, I say you have air in lines. It takes a lot of bleeding to remove all air especially to the rear line as it's quite long and pumping pedal is not good as rear circuit of master is reduced compared to front. Use a power bleeder, you'll be there forever if you're pumping the pedal.
Got a new master cylinder. Friend that is a mechanic said may an interlnal leak maybe torn cup. Once it is bled and installed will go back to bleeding lines again. Any suggestions on a good power bleeder.
Could the hose to the rear wheels be bad or collapsed?
Could the hose to the rear wheels be bad or collapsed?
The hose could be collapsed. Crack the line before it while pressing the pedal to check for any pressure(air or fluid).
Yes,while not common,that rubber section of hose can internally fail.Power bleeders are fast,but not necessary here.Fill the master.open the bleeders on the rear wheel cylinders,one at a time,and when you see fluid coming out close it ad do the other side.Keep a close eye on the fluid level in the master.This is best done with the car level,or since you're working with the rear,slightly nose high.
Harbor freight has a vacuum bleeder with an automatic refill bottle for the master cylinder for 35.
Snap on’s version is around 150.
Both use air you supply to create a vacuum.You pull fluid until the air bubbles stop.These work well for changing fluid as well.Start with the longest brake line.
Snap on’s version is around 150.
Both use air you supply to create a vacuum.You pull fluid until the air bubbles stop.These work well for changing fluid as well.Start with the longest brake line.
will check the hose to look for defects, have replaced the master cylinder as a mechanic told me it may have an internal leak.
I have bench bled the master cylinder each and every time that I have changed it.
I had a hose on rear of my 66 pickup that would prevent bleeding of rear brakes. I removed it and could not blow through it. I had a hose cutter and i started cutting it in several place's and it was collapsed complete length of hose. I did a total brake job on rear and went to bleed is when i noticed it would not gravity bleed. What a difference when rear brakes are applying.