Help! brake problem

[Brian 92]

just bought my first corvette when I bought it the rubber brake lines in the front where busted .I replaced them and bled the lines .After I drove the car 15 Min the brakes locked up for an hour or so .Thinking it was the brake calipers in the front I replaced them with new ones and I'm still having the same problem, ;help

 

[93Rubie]

All four wheels or just the front? How is the pedal hard, soft, etc...any other details for the good of the order?

 

[Brian 92]

All four wheels or just the front? How is the pedal hard, soft, etc...any other details for the good of the order?

all 4 wheels are locking up and when that happens the pedal gets hard.now know that the pedal is fine when the bakes are not locked up, have a clue????

 

[93Rubie]

all 4 wheels are locking up and when that happens the pedal gets hard.now know that the pedal is fine when the bakes are not locked up, have a clue????

Ok, lets think about this for a second, if all 4 wheels are doing it then, you can probably rule out individual calipers, lines to calipers,etc, b/c it is doing it to ALL 4 wheels. ABS unit could be causing this, so could the master cylinder. Your problem most likely is in one of those two units.

Any ABS codes? I am assuming the pads/rotors are in good shape, fluid is decently clean???

So it stops normally sometimes?

 

[Brian 92]

Ok, lets think about this for a second, if all 4 wheels are doing it then, you can probably rule out individual calipers, lines to calipers,etc, b/c it is doing it to ALL 4 wheels. ABS unit could be causing this, so could the master cylinder. Your problem most likely is in one of those two units.

Any ABS codes? I am assuming the pads/rotors are in good shape, fluid is decently clean???

So it stops normally sometimes?

sometimes it stops normally and when i hooked it up to the tech 1 scanner it did give a few abs codes codes 62 64 72 still working it out with the scanner i need to clear it out and run the scanner w/o the abs connected.(maybe) not really sure what to do still thinking on it

 

[93Rubie]

I would pursue sorting out your codes first, as that likely is the source of your problem.

 

[Schrade]

Trying to pin the rap on ABS for brake problems is the most common wild guess I see. :eyerole

When ABS is working properly, it is NOT doing anything.

If activated, it STOPS something from happening (hydraulic pressure being maintained in the line).

If it fails when activated, it is doing nothing. And it won't make something happen that wouldn't have been happening that way already.

And if it's not working when you started up, it's doing nothing, and still won't make something happen (when you hit the brakes) that wasn't going to happen that way anyway.

 

[tcxd40]

The FSM (Factory shop manual) has a procedure for bleeding brakes with the ABS unit, they are not like bleeding brakes the old way..

 

[Schrade]

The FSM (Factory shop manual) has a procedure for bleeding brakes with the ABS unit, they are not like bleeding brakes the old way..

True. Abs must be de-activated when bleeding since planting the brake pedal trips ABS to RELEASE the pressure in the line, and the fluid AND AIR, is allowed back UP the line.

Codes don't have a single thing to do with dragging brakes. ABS CANNOT CREATE FLUID PRESSURE IN THE LINES. BROKEN ABS CANNOT CREATE FLUID PRESSURE IN THE LINES.

 

[Hot Rod Roy]

When you say the front brake lines were "busted", are you saying they leaked so much you couldn't test drive the car when you bought it? If that's true, you probably don't know whether the brakes worked properly before you bought the car. Is there a chance the previous owner replaced the brake booster? If the push rod between the booster and the master cylinder is too long, the brakes will lock up when the brakes get warm.

Check this by removing the caps from your master cylinder. Gently push the brake pedal. You should see a short gush of brake fluid in the master cylinder just as the pedal starts to move. This gush of fluid indicates the ports are opening properly, which vents pressure from the system when the pedal is all the way up. If you don't see the gush of fluid, the pistons in the master cylinder are blocking these ports, and the pressure is not being released from the system when you take your foot off the brake pedal. As the brakes warm up, the fluid expands, causing the brakes to drag.

Remove the master cylinder from the booster, which you should be able to do without removing the hydraulic brake lines. The push rod length in the booster is adjustable.