Never Ending Brake Problems

[Chesh]

Went to my future in-laws on Friday night and on the way, someone cut me off and I had to jump on the brakes hard. I completely lost the pedal at that point. This morning, I went and got a new master cyl and installed it. Bench bled it and then gravity fed the brakes for about two hours.

I still have no pedal. When I pressure bleed them, I get no air out of the back brakes at all. The right front is nothing but air.

Any help on this would be great!

 

[brusso]

I had a similar problem with the rear brakes. I bled them using a one person bleeder system. You know, one of those little bottles with a magnet to mount to the frame and a hose that goes to the bleeder screw. Anyway, I must have gone through two quarts of brake fluid, never letting the m/c go dry, and had massive amounts of air bubles comming out. This was also after a hard stop and losing the pedal. To make a long story short, I had a brake line that had rotted out. It wouldn't hold pressure when the power brake booster was functioning(engine running) and wasn't totally busted open spilling on the floor either. The best way to describe it is pourous. While trying to bleed the brakes, the system was constantly sucking in air. Replace line trouble gone.

 

[Copdogcorvettes]

Sounds kinda like a bad brake line, the flex type. I had something like you have; Couldn't get a brake pedal no matter how much I bleed them. Replacing all the flex lines finally made a difference. This may not be your problem, but it's something to look at. Good Luck


Gary

 

[drags1998]

I gotta to be missing something, Double check for leaks, check ALL brake lines,check the hoses,not only for leaks,but also for weak spots that could expand under pressure. Two person bleed them,If you still get air in the rt.front Then IM LOST!!!!!!!!:L

 

[Copdogcorvettes]

The inner layers on the hose break down from age and other things. Expandsion is one thing. They can also suck air without leaking. The caliber could also be bad. If you have tried everything, like I did, with no fix; Then I'd replace the flex lines and the caliber. Just to be safe I'd do both in the front since that seem to be the problem area.

On mine I tried everything I could think of and finally loaded it up on the trailer and took it to the shop. They told me it was the brake lines. since I already had new caliber purchased to do a replacement, becuase of age, I had them replace the lines and install the new calibers. PROBLEM FIXED. I wish I'd done that sooner. I spend about 3 weeks playing with the D## thing before taking it to the shop. That would of save me all that hair I pulled out as well.

Hope this help you understand what it is I was trying to say.

Gary

 

[Copdogcorvettes]

OH YES, I tried the master cly replacement too. I thought that had to be the problem. It wasn't.


Good Luck

Gary

 

[texancanuc]

boggy brakes

been there done that i read about a recall on calipers for GM's aftewr markets not ac delcos i went thru 16 calipers 5 masters and 2 proportioning valves i changed all the lines too always had a small air leak in a short time rear calipers were to blame i still have a soft pedal but all 4 wheels lock up when needed i used orrielly auto parts and while the returns were free the follow up sucked ill never use orrielly again for anything
i cant remember where i read about the recall but it was recently

 

[Chesh]

Ok, new master cyl, new brake lines, new calipers.........no pedal....~!

 

[Ludigdrums]

Chesh, I feel your pain. I have been dealing with a "brake problem" that turned out not being the brakes, but messed up rear spindles/bearings, etc.

Anyhow, in the diagnostics of this problem, I bled the brakes a lot...vacuum type, 2 person type, and finally pressure type. I came across the same problem as you with my right rear caliper. I couldn't get anything out of it. Basically, I kept at it, and hit it a couple of times (hand/rubber mallet), and eventually got it to flow. The pressure bleed is definately the best way to bleed, but make sure that you master cylinder is only half filled when using a pressure bleeder as having it to the top can cause air to get in soemehow (not sure exactly why, but that's what my manual says for the bleeder [Branick G300].

Another thought...proportioning valve. If working properly, it should give full power to either the front or the rear brakes in the event that one fails, enabling you to stop. Did your brake warning light come on in the dash?

Good luck!

- Jeremy

 

[wishuwerehere82]

Chesh:

Just a thought. Did you prime your master cylinder by recirculating the fluid until all the air was pumped out before you connected the brake lines?
That's a pretty important step that a lot of us forget until it's too late. You will get a HUGE air space in the proportioning valve and wherever it wants to go after that.
Try pulling your wheels too! You may have blown a caliper seal when you braked hard. if it's a blown line or caliper seal you will see it on the driveway or the inside of your wheels somewhere.
Once you have verified that there is no leak anywhere, bleed the whole system a couple of times.
Bleeding the system completely is always a real pain, do the fronts, then the backs, then go back and do them again a couple of times. If you have a buddy who can pump the pedal for you, you can go back and forth pretty quickly. It is necessary to have the wheels off and the car on jackstands.

 

[Ludigdrums]

Hey Pete...about that bleeding procedure...my '81 Shop Manual says to bleed in the following order: LR Inner, LR Outer, RR Inner, RR Outer, FL, FR (Left being drivers side).

- Jeremy

 

[wishuwerehere82]

That is true. The point I was trying to make is that just bleeding them once is not enough. And it may require some road work shaking to get all the air to the tops of the calipers.
Thanks for the clarification on the proper order, that will bleed the longest lines first. I had to bleed my system 3 times to get the pull out of the braking after my friendly mechanic bled my left rear when replacing the wheel bearing.

 

[Ludigdrums]

Yeah, I hear ya...like I said in an earlier post, I must have bled mine a million times, using many different methods.

I tell ya...I definately got out some chocolate milk looking fluid...that's gotta be a good thing!

- Jeremy

 

[BeaterShark]

When do you lose the pedal? When you pump your pedal a few times after you bleed it, or after you drive around for a while?

Somehow you are getting air in the system. I don't believe it to be due to the MC as you are only getting air in the right front. If it was the MC, you would get air at both front brakes.

If you lose your pedal without driving, you may be able to put a plug in place of the line at various places and see which section (ie after the prop valve, just before the hose, just before the caliper) you are getting air from. Again, because it is only the right side, logic says the leak is after the prop valve.

 

[mvftw]

You have already spent alot of $$$ & time. Go buy this, it may save the day http://www.motiveproducts.com/ordernow_bleeders.htm I don't have one, but it sure looks like it would be the ticket...

 

[Chesh]

Thanks for all your input. I did bench bleed the master cyl. Pumped it a while with no air.

I get no air out of any of the calipers. Just fluid. We went through a half a gallon of brake fluid through this whole ordeal.

I never really get a pedal. It's mush all the time. The brake light comes on when the car is running. As soon as I turn the car off and pump the pedal, the proportioning valve opens.

I bled them mutiple times, front back, back front.

I thought I was getting air from the right front caliper, so I changed both fronts and now, I get no pedal at all.

We tried pressure bleeding and gravity. Neither seemed to work.

I am going to invest in a pressure bleeder, no doubt.

Car is still at my future in laws. We had to get a ride home. Just not sure what to do next.

 

[BOB SWEETING]

Brakes Sucking Air

Hi It's Bob From Power Brake Service. I Have A 70 454, But These Brake Are My Business. The Number 1 Problem With Duntov's H.d. Brakes Was That They Used A "v" Type Seal In The Caliper. When They Are New, They Work Great. But, Remember, Any Variation In The Rotor Forces The Caliper Pistons To Follow The Rotor. As You Drive, The Seals Work In And Out Following The Rotor. If There Is Any Rust Or Corrosion In The Calipers, The Seals Scrub And Wear Out Quickly. This Type Of Seal Can Hold Almost Any Pressure On The Back Side, But Lay Down On The Other Side, And Allow Air In Any Weak Spot. The Rotors Must Be True! And Like Someone Else Found Out The Wheel Brgs Must Hold The Rotor From Wallowing, As The Pistons Will Move In. When You Bleed Any Of These 65-82 Cars, You Must Leave The Cap Loose To Allow The Fluid To Drop Rapidly When Bleeding. With The Cap Tight, And You Bleed The Bleeder Screws, A Vacuum Will Occur In The Reservoir, Causing The System To Draw Air In Any Weak Caliper Seal. I Do Add A 3/8 Flat Washer Between The Clevis Yoke And The Booster's Threaded Rod To Raise The Pedal. Another Neat Trick To Really Keep The Pedal Up, Is To Add 2-6lb Residual Check Valves Between The Master And The Calipers. This Keeps The "v" Seals Tight Inside The Caliper, And Air From Re-entering. We Do Have The Residual Check Valves Here At Power Brake, And Also Any Rebulding Or Up-grading Of Any Type Of Brake System See Me At Powerbrakeservice.net Or Phone 800 504 1060

 

[reegeemon]

brakes sucking air

Has anyone tried vettebrakes o ring pistons ?
fully understand problem as described by bob re pressure and vacuum and is completely right.
I have gone thru gallons of brake fluid and still NEVER have gotten a decient pedal.
new items are, master, booster, flex lines repl w/braided stainless, all hard lines flushed, stainless sleeved calipers (not vette brakes and not o'ringed), new rotors, even new parking brakes, & "speed bleeders"...still stops marginally (considering type and size of brakes). Should flat spot the tires if you want to, but doesn't.

have ordered pressure bleeder, (know of anyone interested in old Wagner "power ball" ? have one w/no adapters), and am ordering oring conversion kit from vettebrakes.

I have never had so much trouble w/brakes on any vehicle.

hopefully these changes will correct, or else !

 

[BOB SWEETING]

Final Cure For Brake Problem

Nobody likes the low spongy pedal on these cars. There are 16 caliper pistons to feed, requiring a large volume of fluid. to stay with the stock system, we have added a flat washer under the yoke between the booster threaded rod and the yoke. there is only room for one, unless we custom build a longer booster rod. We can build 4lb. residual check valves that screw directly into the master ports, and bring up the pedal, and keep the calipers sealed. The "final cure" for these cars is to convert to the HYDROBOOST system. The big advantage of the hydroboost is that it runs off of the power steering pump pressure, and requires no vacuum. The second advantage is that the hydroboost is capable of pushing up to a 1.625" master cyl. The Corvette would be really happy with the hydroboost and a 1.250" master. The pedal would be up top, with all the pressure you could ask for. This system would out-stop absolutely any other car, old or new. POWER BRAKE SERVICE is the only authorized distributor of new hydroboosts. The dealers sell them for double the price, and the brackets and pedal rods will not fit. We make the mounting plate and rods to fit the car and set up the master. pbs can be reached at 800 504 1060, you can view the hydroboost in color at powerbrakeservice.com We are helping out the TurboBuick.com guys with their Grand Nationals by converting the original system to the hydroboost

 

[Chesh]

It turns out, all mine needed, after the new master cyl, front hoses, and front calipers, was a good pressure bleed. A local buy my future father in law knows, came an flat bed her in, pressure bled the brakes and all seems fine now. He said there was tons of air in the system, yet when we gavity and pump bled the brakes, we were not getting any air.

I am going to invest in a power bleeder, the one listed above, and will probably get 4 of the VBP SS sleeved O-ring calipers in the future. Going to see how these play out for now. I know eventually, the rears are going to screw up and now sure how long the fronts are going to last, cause they are re-built.

Lastly, I went to powerbrakeservice.com and it said coming soon! I would be interested in looking at the alternatives, cause eventually this problem will be back. It seems to be the biggest b*tch C3 owners have.

Thanks for everyones help and input!

Brent