Bluewasp

EDIT: Subject should read: "Brake" NOT "break" :D
HI,

I have a 1980 with a problem. When I push on the brake to stop the car it pulls to the right. This started about 3 weeks after I purchased the car. Since that time I replace the master cylinder, 4 rebuilt “LoneSar” calipers, new pads, 4 new rubber brake lines and new metal brake lines for the rear. I rebuilt the front end suspension, and rebuilt the rear end suspension..

Even after I replace almost everything under the car she still pulls to the right. I have bled the brakes and bled them some more. I took the car to Tony’s corvette shop for some work on the right side and he bled the brakes again, and it was fine for about 50 to 75 miles then it started doing it again. It pulls harder as you drive the car more. I had the rotors turned and it still pulls to the right. I swapped rotors and pads from the left to the right and vise versa, and she still pulls to the right.

At this point I have no idea what else it could be, and sometimes it won't pull then other times it pulls so hard the wheel leaves your hand.

The only thing I can think of is a bad caliper on the right side, but that is the second one on there. I am going to buy one from another manufacture and see if that fixes it, but I don't think it will..

I don’t have any puddles of brake fluid under the car either.

Anyone have any ideas???!?!?!?!??!?!!?!?



[Modified by Bluewasp, 9:01 PM 2/23/2002]

curly

Maybe the problem is on the left. Perhaps air bubbles have worked their way in the left front and does grab as strong as the right :confused:

Pete79L82

Sound like the brake distribution block may have a restiction in it. I have seen this happen when someone replaces the master cylinder and gets some debrie in the line.

ROD NOCK

Blue-
These old cars of ours can sure come up with problems to perplex! My guess is that the left side is sucking air into the system somehow, not applying the same pressure as the right. It was OK after a bleed, but soon returned. The more you drove it (used brakes) the more air was sucked in. Don't neglect to check the rear brake system and bleed it too! I'm saying this assuming everything was done correctly on the parts replacement, and all 'new' parts are good. (don't always assume new parts are good either)
I would inspect all lines for a sign of seepage, (correct it if found) then I would flush/bleed the entire system. Good Luck -Rod :chevy

Bluewasp

Thanks everyone. I put about 100 miles on the car last night because I bled the system again, front and back. It wasn't too bad this time but by the end of the night the pedal started to feel like I was in FULL ABS MODE but C3's don't have ABS.. :D There has to be air getting in someplace.


How can I clean the brake distribution block, or should I buy a new one????

Also, I noticed in the morning she drives fine until I put like maybe 5 to 10 miles on the car. Then she will start to pull to the right.


Keep in mind it was pulling to the right with the stock 22 year old, or however old master cylinder... I replace it because I was installing new calipers and lines, and figured might as well replace it...

thanks :cheers: :cheers: :cheers: :cheers: :cheers:

Tyler Townsley

Recheck the flex line that goes from the steel lines to the brake calipers. These lines can cause all kinds of wierd brake problems. I had one close up completely on a midyear which would keep it from activation of that brake until I really hit the brakes it then it worked and would hold the brake on that wheel which made it pull with the brake off. It sounds like the wheel cyl has something keeping the fluid from returning to the master cyl rather than air in the system.

Tyler
66 coupe
68 vert
87 ZR1
90 ZR1



[Modified by Tyler Townsley, 10:08 AM 2/24/2002]

427V8

runout. You NEED to MEASURE the runout of the rotors.
Runout is the bane of Corvette brakes!

Also you said that the car felt like it had ABS brakes after driving it?
Does this mean that the pedal is vibrating?
I'm wondering if the rotors are warping when they get hot, so when you measure them cold they are fine but once they warm up they warp and pump air into the calipers!

You should NOT feel ANY vibration in the pedal of a Vette!!!
If yo do the rotors are BAD

VegasJen

, i agree, check run out. also, check wheel bearings! if you drive the car when it is cold and the brakes don't pull too bad but get progressively worse, it's possible it is a wheel bearing. try removing your center caps and drive the car (after cooling) for 20-25 miles then checking the temp between the two hubs. this works great if you have an infrared temp gun but you can tell just by touch too, just be careful as bad wheel bearings get really hot.
when you do your brakes, always make sure that you wire brush both your spindle and the inside hub of the rotor before you put them together. years and years of built up rust can account for more runout than you can imagine.

dman535

My 77 had had the same affliction for a while now to. I went through all the same steps that Bluewasp did, including having the problem on old calipers and suspension pieces. One thing I do notice is that if I do a brake-torgue when the brakes are acting up. She will drag her right front wheel and the car will not hold properly, hence I cannot light up the tires. This tells me that the left front is not getting enough pressure. I had the car up on a hoist and ran compressed air into the distribution block, with the bleeders open I could feel no restriction.

The only thing I have left to look at is the front steel lines. I would guess that there is something perhaps trapped in the left front steel line ? Something that is moving around in there ? Is it possible that there is something broken on the frame that is causing this ? I don't hear a clunk and the car drives normally when you are not on the brakes. When the rotors were off the bearings looked ok and there is no noise or vibration underway.

I am hesitant to let other people drive the car becuase if they get on the brakes hard and she decieds to act up there is potential for an accident. Ideas ???

Thanks !

Bluewasp

New spindle on the right side and new bearings all around. Installed by Tony's corvette shop..

Let the car sit overnight and she pulls now all the time. Its not bad like before I replace everthing but it keeps getting worse. More and more pull...

How can I do a pressure test? Could my Brake Proportioing Valve be bad??? Zip sells them for $79.99. I could have some damage to the front steel lines as well??. The front calipers are dry.. I don't see any fuild leaking from them. If Air could get in from the calipers, won't there be fuild coming out????

Robert

Juliet

It sounds like runout to me. I don't think if you're adding air that you necessarily need to see brake fluid. Also, doesn't that distribution block control pressure front to rear and isn't that what triggers the brake light? I didn't think it affected right / left... ???? Also, the fIuid could be disappearing while you drive and not just dripping out when parked. Talk with Tony about it too though. He stands behind his work 110%. ~Juliet


[Modified by Juliet, 10:24 PM 2/24/2002]

Pete79L82

The Proportioning Valve could be bad. But before you replace it I would back flush the system. Remove the front line from the master cylinder and hook a vacumn bleeder to it. Then open the outer bleeder screw on the right caliper. Close that bleeder screw and then do the left front outer screw. Any debrie should come out that way. Once you have vacumned all the fluid out, reattach the line and rebleed both front brakes.


This might be a little off the wall but have you looked at the upper and lower control arm bushings to make sure they are not cocking when you apply the brakes?


Also, you seem to be focused on the right front caliper because it is pulling that way but your problem could be the left front caliper not applying enough pressure. That would be the case if it is a run-out or proportioning valve problem.


[Modified by Pete79L82, 9:32 PM 2/24/2002]

Bluewasp

The car feels like I am in full ABS mode.. There is a considerable about of vibration, after driving the car for 10 to 20 minutes, when I apply the brakes…

Also, when the brakes get hot they start to make these odd noises… It sounds like.. I have know idea what it sounds like but it sounds bad. When I come to a stop from 10 mph I can hear the brakes moan and it starts to vibrate to a stop.. IT ONLY DOES all this when they get hot.. It pulls now all the time, even cold, but she didn’t before….

I had the rotors turned and Tony at Tony’s corvette shop said that the rotors shouldn’t have any run out since I had them turned.. Is he correct??? They are also still riveted to the hub..

Pete79L82

Are you feeling the vibration from the brake pedal pulsation or from the steering wheel or a from the whole car (you can feel it through the seat)?

Juliet

What compound of brake pads are you using? I'm wondering if you're not feeling the results of some sort of glazing on the pads when it gets real hot? :confused:

Bluewasp

I had new poly control arm bushings installed..... I will try to suck some fuild from the valve and see if anything could be in there, but I don't think so because I purchased the car and it was fine for 3 weeks.. Then it started with this problem. I didn't do anything to the brake system. I replace everthing and it keeps doing it.

Can dirt get into the valve from normal day to day driving? I guess anything is possible

I replaced the following on the car after the problem started:
new ball joints
new springs
new a-arm bushings
new bearings
new spindle on right side
turned rotors
new rubber brake lines
calipers
master cylinder
shocks
idler arm
tie rod ends
new power stearing pump, ram, valve and lines


rear has new spring
shocks
t-arms
bearings
struts
calipers
short steel lines and new rubber brake lines
shock mounts
u joints
etc....


[Modified by Bluewasp, 10:49 PM 2/24/2002]

Bluewasp

pedal only... Its not a warped rotor type vibration.....

Pete79L82

I agree with Joliet on the brake pad glazing. a definate possibility.

Debrie can get into the master cylinder any time you check the fluid. It can lay in there for a long time before it finds it's way into a line.

That you are feeling the vibration in the pedal only limits the problem to the brake system not suspension. Even though you had the rotors machined I would check the run-out to eliminate that.

Only three possible things can cause a vibration in the pedal.

1. Run-out or warped rotor.

2. Contamination on the pads. (Glazing or fluid contamination)

3. Defective proportioning valve. (broken spring or sticking valve)


[Modified by Pete79L82, 9:57 PM 2/24/2002]

Bluewasp

I have no idea... Might be stupid on my part.. The pads came with the "LoneStar" brake package. They are brown in color...

I sanded down the pads today to get what looked like glaze off them and she still pulled to the right. She pulled to the right as I was leaving my driveway.

dman535

The distribution block on the C3 only does front to back. The Front half of the valve is a big open block, one line in and two lines out.



Its my understanding that problems with run-out stem from the pistons being pumped back and forth, causing air to be drawn in to the system. I have o-ring calipers on my car which should elminate any run-out related issues.