I got a freshly turbo'ed Pinto that I can't drive more than around the building because the brakes won't stay fixed. I can bleed and bleed and bleed them and they turn back to spongey crap a moment later. I replaced the master cylinder and more of the same crap. Help! This is driving me up the wall!
Does your car have power brakes? What is the condition of the rest of your brake system? Did you bench bleed the MC before you installed it? You can bleed the system all you want but if there is air in the MC you will have a mushy pedal. You also could have a bad MC? In the early 90's I went thru 6 mastercylinders in a two month period as all the rebuilds I was getting were junk and leaking.
Will get a bench bleed kit tomorrow morning and try it. Will also check the length of the push rod from the booster.
BTW, since the last time that the brakes have worked, I have swapped in a power booster and proportioner, and replaced the front pads and disks.
I concur with Tigger. He is right about bad master cylinders. I had a 93 Mercury Topaz that I could not get a solid peda on so I replaced the master cylinder. I went through three from the parts store before I gave up & got one off an 87 Tempo. The car stopped fine afterwards.
Oh, I shoulda mentioned that your symptoms described my Topaz brake issues to the letter. I say exchange it & see what happens if re-bench bleeding does not work.
I borrowed a bleeding kit and took master cylinder out, clamped it in the vice, and spent 45 minutes massaging every last air bubble out. And that thing was so full of bubbles that it took 45 minutes. Also adjusted the power booster rod. I put everything back together and bled the wheels yet again and now I'm down to only three or four pumps to get the thing stopped instead of seven or eight. Still not something I'd want to drive around town. I am going try a real manual bleeding kit next time, instead of dangling a hose into a fruit jar, unless I get some better advice.
This is getting so frustrating. >:(
Oh, man, I wish you the best, this is killing me, too. I have been fighting getting my brake system working also, new hoses, proportioning valve, master cylinder, rear cylinders, hardware, and can't get a solid pedal. I >really< don't want to take it to a garage and spend the bux, because it's not even driveable and I would have to pay for a tow, etc.
I bought a NEW master cylinder Monday, the Cardone rebuilt is lousy, so I am going new. I even bought a clamp and bench bleed kit so I could follow the step by step instructions in the box. I just hope I can get the system working as well. I never thought it would be so ornery.
Chris
Get a pump bleeder from Autozone or something and start at the farthest point from the Master Cyl, and work your way around if you have to i would Overturn a bottle of dot3 into the reservoir and Just start sucking it out till its comes clean and you dont have Bubbles, I had to do that to a VW beetle a few years back and it took a long time to get all the air out of the lines. I wish you luck though. btw i think the part at Autozone is like 15 Dollars and it pays for it self
I think there has got to be something wrong with your master cylinder. It has to be letting air in somewhere as it should not take 45 min to bleed ??? You may want to exchange it for a different or new unit. Good luck man, I was in your shoes about 15 years ago...
Tigger couldn't be more right. You have to figure the master cylinder has the most air trapped inside of it when it is put together. All are like that and like Tigger I have never heard of a master cylinder taking 45 minutes to bench bleed. If it is taking you that long there has to be a problem. Besides, what's it gonna hurt to take it back in exchange for a different one? The time you take is worth more than the trouble you are having bleeding the brakes.
As for the way you are bleeding the brakes I bleed mine the same exact way and I have zero problems bleeding the brakes. As long as the tube connected to the bleeder screw is submerged in brake fluid you should not have any problems. I've done many brake jobs this way and the only one I had an issue with was the Pinto. What solved it? Replacing the master cylinder.
It seems to me that, in general, power brakes use a much longer actuating rod than non-power brakes in the same model.
Perhaps someone could check the parts catalogs to see if this is true with the Pinto?
Mike
When I put the V8 in my car I had to change all of the front brake lines and maybe reroute part of the rear or something, anyway, I filled the M/C, opened all of the bleeders and put a hose on them and into an empty plastic bottle and let it gravity bleed for a few hours. Thats all the bleeding I had to do.
After you bleed the system, if you still have to pump the pedal you are picking up air, and the only place that can happen is at the M/C.
When you are bleeding your brakes, are you starting from the wheel farthest from the master cylinder? You should start at the wheels farthest from the cylinder and move closer.
On a Pinto, this would be...
Rear Passenger
Rear Driver
Front Passenger
Front Driver
This is what I did for my brakes after I rebuilt them and before I started driving the car, and I haven't had a problem since.
I've been bleeding them in that order all along.
This almost makes me miss the '70s and '80s when a 30 year old vehicle was from the '40s or '50s and it had a really simple single master cylinder under the floor that you just bled and it worked. Or even slowly finessed the pedal to work the bubbles out without bleeding!
So are these dual master cylinders so delicate and fragile that they rupture a seal and they start leaking air if they aren't properly bench bled before installation?
Anyway, I'm going to check the rear brakes. I could never get the emergency brake to adjust and the one cable has no spring to it and I'm going to see if something is off a peg or a notch to cause this problem. Then I'm going to bleed the original cylinder (which wasn't bench bled in the first place) and try it again to satisfy my curiosity. If that doesn't work, I'm breaking down and buying a new master cylinder. And if that doesn't work, I'm having a professional mechanic come out and look at it.
It's not that the dual master cylinders are delicate that they easily rupture.. It's pretty much that in order to rebuild the master cylinder it's generally honed out which then causes the seals not to seal from time to time. When that happens the seals naturally leak causing basically the same issue you had before. That's why most people just buy new verses remanufactured parts like that.
dholvrsn,
Whenever I buy an old car, I find it is better to go through all the brakes. It eliminates any guess work.
Not only is it safe, but you don't need to do any more brake work except change the linings at a future date.
Also it is a good feeling to have a firm pedal with balanced braking.
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* Change all the wheel cylinders (& calipers if disc brakes). Buy new wheel cylinders and rebuilt calipers. They are cheap.
* Change every flex line. One on each front wheel (left & right) and the one in the rear that goes from the frame to the axle. These old flex lines can get weak and expand when pressurized. Hence, a spongy pedal.
* Adjust the new brakes so that the shoes create some drag on the brake drums.
* Install a new master cylinder as follows.
Buy some short brake lines (and adapters if necessary to fit the master cylinder) Cut the brakes lines about 2 inches long and pound the end closed. Screw them into the master cylinder. Now mount the master cylinder in a vise. Do not over-squeeze in the vise. Fill the master cylinder with brake fluid. Take a large philips screw driver and push on the master cylinder plunger. Push VERY SLOW and do not "bottom" it out. Then slowly release. You should see some air bubbles. Wait 5 seconds and repeat. Do this many times until you do not see any more air bubbles. Next, crack the front brake line slightly loose. Repeat the pushing method with the brake line slightly loose. It should start to leak and squirt around the threads. Repeat until you do not get any air. (you can hear it) Tighten the brake line. Now do the same to the other brake line.
Tighten both brake lines. Next push on the philips screw driver while slowly loosening one of the brake lines. As it leaks out retighten the brake line before it bottoms out. Pump once to refill. Repeat with the other brake line. Now pump the philips screw driver one more time and wait 10 seconds. Now push the philips screwdriver, you should have a FIRM master cylinder in the vise.
Now install the master cylinder into the car with the short brake lines still in place. Check the brake pedal, it should be FIRM. That tells you the master cylinder is good. Next, remove the short blocked-off brakes lines and install the vehicle brake lines.
* Bleed the brakes - sounds like you are doing this correctly. Make sure you do not run out of fluid.
* If the brakes feel good, drive a short distance making many easy stops. This is to seat the brake shoes a little. Return to your start point and let the brakes cool. Remember I said to have the brakes slightly dragging when you adjusted them, well they should now be free.
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Excellent idea!!!! I should have pointed that out since I myself always do that. Give the guy a cookie.
BTW, I just thought of something.. Is the fluid light amber to clear coming out of the bleeder screws at each wheel or is it medium to dark brown? That can be an indication of old fluid.
Brake fluid is hydroscopic (retains a certain amount of moisture).. Where you have moisture present you can have air present as well.
That is why they say to flush the brake system once every year, two at the most. That is especially good to do on a car that sits since the varying temperature can cause condensation in the brake system.
You may have hit on something when you said "check the rear brakes."
I recently worked on a bus with a mushy pedal, another shop installed two new M/C's and you still had to pump the brakes. What I found was the rear adjusters were frozen and the brakes were way out of adjustment. What happens is the first stroke of the pedal is not enough to push the wheel cylinders out enough to engage the rear brakes and the pedal goes to the floor. Bleeding helps a little (for a while) but does not fix it. I guess this problem came on slowly and they didn't pay much attention to it untill the pedal went down far enough to turn on the red brake light.
Quote from: Starliner on November 02, 2008, 09:20:37 PM
dholvrsn,
Whenever I buy an old car, I find it is better to go through all the brakes. It eliminates any guess work.
Not only is it safe, but you don't need to do any more brake work except change the linings at a future date.
Also it is a good feeling to have a firm pedal with balanced braking.
==============
* Change all the wheel cylinders (& calipers if disc brakes). Buy new wheel cylinders and rebuilt calipers. They are cheap.
* Change every flex line. One on each front wheel (left & right) and the one in the rear that goes from the frame to the axle. These old flex lines can get weak and expand when pressurized. Hence, a spongy pedal.
* Adjust the new brakes so that the shoes create some drag on the brake drums.
* Install a new master cylinder as follows.
Buy some short brake lines (and adapters if necessary to fit the master cylinder) Cut the brakes lines about 2 inches long and pound the end closed. Screw them into the master cylinder. Now mount the master cylinder in a vise. Do not over-squeeze in the vise. Fill the master cylinder with brake fluid. Take a large philips screw driver and push on the master cylinder plunger. Push VERY SLOW and do not "bottom" it out. Then slowly release. You should see some air bubbles. Wait 5 seconds and repeat. Do this many times until you do not see any more air bubbles. Next, crack the front brake line slightly loose. Repeat the pushing method with the brake line slightly loose. It should start to leak and squirt around the threads. Repeat until you do not get any air. (you can hear it) Tighten the brake line. Now do the same to the other brake line.
Tighten both brake lines. Next push on the philips screw driver while slowly loosening one of the brake lines. As it leaks out retighten the brake line before it bottoms out. Pump once to refill. Repeat with the other brake line. Now pump the philips screw driver one more time and wait 10 seconds. Now push the philips screwdriver, you should have a FIRM master cylinder in the vise.
Now install the master cylinder into the car with the short brake lines still in place. Check the brake pedal, it should be FIRM. That tells you the master cylinder is good. Next, remove the short blocked-off brakes lines and install the vehicle brake lines.
* Bleed the brakes - sounds like you are doing this correctly. Make sure you do not run out of fluid.
* If the brakes feel good, drive a short distance making many easy stops. This is to seat the brake shoes a little. Return to your start point and let the brakes cool. Remember I said to have the brakes slightly dragging when you adjusted them, well they should now be free.
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+1 for you dang nice Info. *copied/pasted*
FWIW, I had the rear brakes apart yesterday. The emergency brake cable is gummy and sticky and was stuck halfway pulled out. I am teetering on buying a new cable unless there is a good way to lube these. I miss being able to get that spray can of chain and cable lube down at my Grandpa's Allis Chalmers dealership.
If the cable is that gummy it's prolly time to replace it. They are available at the parts stores, atleast to be ordered.. They are also a reasonable price so I say if you are going to remove it just replace it, especially since it is almost or atleast thirty years old.
Got one ordered. Also waiting for new rear springs from Jaycee Gypmee.
Quote from: 71pintoracer on October 30, 2008, 12:52:18 PM
When I put the V8 in my car I had to change all of the front brake lines and maybe reroute part of the rear or something, anyway, I filled the M/C, opened all of the bleeders and put a hose on them and into an empty plastic bottle and let it gravity bleed for a few hours. Thats all the bleeding I had to do.
After you bleed the system, if you still have to pump the pedal you are picking up air, and the only place that can happen is at the M/C.
my sentiments exactly....been there, done that
I use this same method, plus I rap on the calipers with a plastic hammer to dislodge the air bubbles. Works great. And its a one man job.