problem bleeding brakes

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Tnplumber

Tnplumber

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I had a replace a leaking mater cylinder. I bench bled the master cylinder, reinstalled it and began trying to bleed the brakes. I opened the rr bleeder screw. I had someone try and pump up the brakes. After about 30 tries I never got the first sign of any brake fluid. I then tried the LR and couldn't get any fluid to come out. I then tried the fronts. They bled easily. What am I doing wrong? I little more info, 1972 Dart, 10" drums all around and manual brakes. Thansk for any help I need it.

Scott
 
You didnt mention if you bled the whole system or just replaced the master cylinder? Did you use a rebuild kit? I dont know about others here but I have had 50 / 50 luck with the rebuild kits..... you may have air in the lines? I put the extended brake lines on the jeep a while back it took some pumping to get the fluid through the rear line.
Joe
 
The bleeders may be clogged. Take one all the way out to inspect it.
 
Did you bench bleed the master cylinder before you installed it? Sounds like there's air in there somewhere. I'd try that first. Unfortunately that involves removing the MC but it should always be done when replacing.

You might also want to try gravity bleeding - jack up the car on all fours (lift is best if you have one, jack stands will do) top off master, leave the cap off, open all bleeder screws. (remember to place something to catch the fluid underneath) Walk away for a little while - have a sandwich or something. When you get back, you should see fluid dripping out. If not, then you need to bench bleed.
 
Tnplumber said:
I had a replace a leaking mater cylinder. I bench bled the master cylinder, reinstalled it and began trying to bleed the brakes. I opened the rr bleeder screw. I had someone try and pump up the brakes. After about 30 tries I never got the first sign of any brake fluid. I then tried the LR and couldn't get any fluid to come out. I then tried the fronts. They bled easily. What am I doing wrong? I little more info, 1972 Dart, 10" drums all around and manual brakes. Thansk for any help I need it.

Scott
Click to expand...
You said that you opened rr bleeder screw and had someone try and pumpup the brakes..that,s wrong,you,ll have air in the system now!You should pump up and hold down then open the bleeder,til your pedal hits bottom.Tighten the bleeder and repeat this til all air is out and you just get fluid.This should help with a harder pedal.If you get no pedal(hard)your gonna have to remove the master and bench bleed properly.Hope you get it fixed!Do all 4 corners!
 
did you Bleed at the master cylinder.....open the lines...Cover all you can on engine bay....
 
Guys....his second sentence says that he bench bled the master.

I would open a bleeder and leave it open until you see fluid, even taking the bleeder all the way out as suggested. AKA- gravity bleeding. If not, go to where the hard line meets the rubber line and crack that open to see if fluid wants to come out. You may have a collapsed rear hose or alot of air in the system.
 
It could be a number of things. As these guy's are saying. Check the bleeders. Check the hard lines, they may be crimped, keep doing it there could be a lot of air in there. I'm going to be doing my whole brake system as soon as the weather permits as well. The system is all original. It will be fun.
 
First I'd make sure ALL the drum brakes are adjusted correctly. If you have to pump the pedal to make contact it'll take forever to bleed....

Secondly, make sure your getting line pressure to the rear wheel cylinders. Check the proportioning valve under the drivers frame rail in the engine compartment.

If you bled the master, have the drums adjusted, and there is pressure to the rear, CLOSE the bleeders, have an assitant pump the pedal SLOWLY approx. 8-10 times and while they are holding pressure on the pedal, open the bleeder. It may take a few attempts. Watch the reservoir to make sure you don't run dry.... Make sure you start at the R/R, then L/R, R/F, and finally the L/F.

If all else fails, see if you can borrow a power bleeder. These use shop air pressure to create a vacumn to pull ALL the air & fluid out of the lines. THE best way to do this. Gravity bleeding could take overnight. There is a product that reverse bleeds the system where you pump fluid INTO the bleeder nipple and force the air up into the master cylinder. Either way, check the basics first.

Good luck! 8)
 
pettybludart said:
You said that you opened rr bleeder screw and had someone try and pumpup the brakes..that,s wrong,you,ll have air in the system now!You should pump up and hold down then open the bleeder,til your pedal hits bottom.Tighten the bleeder and repeat this til all air is out and you just get fluid.This should help with a harder pedal.If you get no pedal(hard)your gonna have to remove the master and bench bleed properly.Hope you get it fixed!Do all 4 corners!
Click to expand...

No matter how many times I pump the brakes, the pressure on the pedal never changes, it is a very hard pedal. The pedal never hits bottom no matter how long you hold it down. I have never bled a master cylinder before. The new cylinder came with plugs, not hoses that extended back into the resevoir, I pushed until I didn't see any bubbles in the resevoir. Maybe that is what is wrong. After I couldn't get any fluid to come out of the rr bleeder, I removed the line to the rear brakes at the MC and fluid squirted out when the brakes where pushed.

After reading the posts, I tried bleeding as stated by having someone press the brakes 10-12 times and holding, I opened up the bleeder and nothing happened, no fluid or air. The pedal never at anytime lost it's hard petal.
 
Someone allready mention this didn't know if you caught it or not. Under the driver seat on some cars is a second prop valve that is really a delay valve that helps to keep the rear brakes from locking up under hard braking. I had the same problem with mine, check and see if you have that valve. Its small only maybe only an inch or so long. if you do it is a pain in the a##.
 
fishman said:
Someone allready mention this didn't know if you caught it or not. Under the driver seat on some cars is a second prop valve that is really a delay valve that helps to keep the rear brakes from locking up under hard braking. I had the same problem with mine, check and see if you have that valve. Its small only maybe only an inch or so long. if you do it is a pain in the a##.
Click to expand...

I do what was your solution???
 
Tnplumber said:
I do what was your solution???
Click to expand...

There is a small plug in the top you can take it out and see if you have fluid there. If you do you can stick a small screw driver down in it and reset the check valve. Then gravity bleed the system. If you try to pump it again it will just lock it up again. I had a hard time with mine.
 
fishman said:
There is a small plug in the top you can take it out and see if you have fluid there. If you do you can stick a small screw driver down in it and reset the check valve. Then gravity bleed the system. If you try to pump it again it will just lock it up again. I had a hard time with mine.
Click to expand...

ok I'll check it out, thanks a lot.
 
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