I give up

[Michael 427]

I posted a reply to my thread I guess dumb under 1967 brakes, I guess fighting this problem for over 18 months stupid things will be done. The problem the car darts to the right when applying brakes, installed all new brake lines and hoses had calipers redone didin't solve the problem, then I purchased all new calipers new castings from Delco never been a car and pads and bleed the system with pressue one of the new items and fit to master cylinder and the problem still is still there, front right caliper works fine left front skips when applying a lot of pressure the right one locks up. No the car does not have a portioning value no J56 brakes any ideas would be appreciated, I don't want the big block to sit all year but no choice, I guess I will drive the chevelle. People at work say the calipers must float on the rotor no sure what this means, how can you determine if the calipers float, only other item I have not tried are wheel bearings both both wheels spin freely and no grinding noise, I also mic the rotors and both are the same. Help.


Thanks
Michael 427

 

[Eric]

Michael,

Sorry but I can't give you any additional insight since it appears that you've done everything there is to do. The only thing you don't mention is checking for run-out on the rotors. The rotors need to be turned while on the car in order for the rotors to be true with the hubs. If the rotors are machined off of the car, it is impossible to account for variations in the hub as it spins.

As for "floating", yes your car does have floating calipers. In most disc brake systems the pad is attached to the piston(s) so that when the brake pedal is released the vac of the fluid drawing back through the lines pulls the pistons and the attached pad back away from the rotor. On older Vettes, the pads hang on the cotter pin and are not attached to the pistons. When the pedal is released, the pad just hangs there and shou;s essentially drift back under normal driving. A problem occurs when the rotor is not true (runout) causing the pad to be pushed back and forth bumping against and sometimes even pushing the piston in. At highway speeds this cavetation can cause air to leak into the lines and also cause a host of other problems.

Find a Vette shop in your area to check the rotors if you don't have a micrometer yourself. This may not solve the problem but it will at least eliminate one possible issue.

Good luck!

 

[Jack]

Good info so far.

Front LEFT sounds like too much rotor runout/warpage.

Yep... sounds like you've done a lot ... seems most if not all is new... but what about the lines?

If car darts to RIGHT then you might also look for a pinched/kinked/collapsed/clogged line on LEFT circuit. Worth a close inspection ... & cheap!
JACK:gap

 

[Michael 427]

71 Shark

I check the runout on the rotors and did not see any difference, I returned to garage and I noticed when the car is raised and I spin the passenger side there is a clicking noice and its from the brake pad moving against the rotor this does not happen on the drivers side which does not seem to work, I had the wife apply the brakes and tried to turm each wheel they would not turn, I guess the thing would be take the rotors off and have them turned probably will buy new ones, I do not want to drill out the rivets they are the orginial ones.


Michael 427

 

[Michael 427]

Jack,

All new lines and hoses

 

[JohnZ]

Don't remove the rotors and have them turned, and don't buy new rotors unless your old ones don't have enough meat left to be resurfaced - either case will most likely introduce more lateral runout than you have now (as indicated by the "ticking" noise on one side). The rotors need to be resurfaced ON THE CAR to achieve runout within specs (no more than .004" total indicated runout) - most well-equipped dealers, and QUALITY brake shops [not the discount brake shop in the converted gas station on the corner] have equipment to surface rotors "on the car", which is absolutely essential on '65-'82 Corvettes.

The '65-'82 Corvette fixed-caliper constant pad contact design is unique (except for Brembo and Alcon calipers used on Viper, Porsche, and Ferrari), and most discount brake shops simply don't understand them, as they deal all day long with single-piston floating caliper designs. If you get your front rotors resurfaced ON THE CAR, I think your problem will disappear.

 

[cntrhub]

I'd almost check the suspension parts on the car? You might have a ball joint that is lose/worn and when the brakes are applied, the wheel buckels under, and that's what might be pulling your car to one side? Have you check all the suspension parts looking for this "darting" effect?
I'd also check the springs and shocks. Push down on one of the front fenders (or bumper) and see if either side feels weaker then the other side? Look for cracks/sag on the springs?

 

[Michael 427]

John Z

Thanks for the information after posting this subject I decided to switch the rotors, my the problem has moved to the drivers side and datrs left, so with that change it must be the rotors but which one, I will take your suggestion and find a capable brake shop and have the rotors resurfaced,

Thanks
Michael 427

 

[corvetjerryd]

Hey Michael427
Just wanted to say HI and I hope you get aggravating brake problem fixed once and for all. Then we can do some more shows and Cruze-in's before summer's over............I think your getting close now..........Don't ever give up..........