Brake is locking up tire - ABS + TC

[metroplex]

I have a 2000 Crown Vic with ABS and Trac Ctrl, and 4 wheel disc brakes. I have found that my right front brake will grab and lock up the tire when I apply the brakes on a slippery surface. The left front brake won't do it.

I have less than 23k miles on the original factory calipers and rotors. The pads are about 20k miles. However, the factory pads sort of grooved the rotors and that was part of the reason why I got new brake pads.

I have lubed the caliper slide pins in the past and I checked the rotor surface and brake pads to see if anything was wrong. I can't figure out why it grabs more than the left side and why ABS doesn't kick in.

It also pulls to the right when I get on the brakes. Otherwise the car tracks straight on a flat road.

 

[Willy_G]

You might have a problem with the ABS controller, solenoids, wheel speed sensor, proportioning valve or something else.

I would not take chances with brakes. Get it checked out ASAP.

 

[metroplex]

The "brake shops" will charge up the wazoo for something I can do in my own garage. I can throw money at it and get all new rotors and all new pads, but I'd like to know why its mechanically locking up on the right front. Technically, if it were a really hard and fast stop, both front brakes should lock up.

I've gotten my old 1981 Ford to do that sometimes. That should be a situation where ABS kicks in, but it's not really normal for my right front to lock up first and start pulling my car to the right.

But if it is the ABS HCU, it'll be a rather costly replacement.

 

[brianl703]

I don't think the ABS has anything to do with it, if it's not kicking in.

Remove the ABS fuse and see if that changes anything. If not, the problem is not ABS.

 

[metroplex]

the fuse for ABS is also used for the instrument panel. I looked at the HCU fluid circuit and it bypasses the solenoids.

I'm guessing here but i'm pretty sure its not related to the fluid circuit.

 

[labman]

''I don't think the ABS has anything to do with it, if it's not kicking in.''

If it is not kicking in, when it should, it isn't working right.

5 years is a little early for a brake hose to go bad, but if the inner lining cracks, it can work like a one way valve locking the wheel up. Might try replacing it.

Remembered after I posted. This thing has set a lot, and then you replaced the pads? Crud could have built up on the outer part of the caliper piston, and it could be sticking and failing to push back in. Maybe even the other 3 are failing to extend leaving that one doing all the work. If so, flushing the fluid won't help a bit. You may need to rebuild/replace all the calipers.

 

[Gary Allan]

I was going to suggest a kinked hose ..but with the age of the car I thought it would be a little early. When my hose kinked/blocked/whatever it caused two pulls. A delay in initial application and a delay in release. Basically you would get jerked when you applied and then jerked when you released. It was just out of phase with the rest of the brakes.

If you're not getting a malfunction light on the dash ..then something is truly unright here. I would think that the system would be advanced enough to indicate when there was a lack of compliance with a release of the brake. I can't see how the system could interpret between a locked up wheel when it's locked up by a faulty hardware (calipers/etc.) or a faulty ABS solenoid

 

[brianl703]

Before anything can be said about whether the ABS is working properly, it seems to me that the brake problem that is causing the right wheel to grab first on a slippery surface needs to be corrected.

This is standard troubleshooting practice: Make sure the simple system is operating correctly before blaming the complex one for the problem.

(The ABS controller in this vehicle may be smart enough to know that something isn't right, and it may not light up a dash indicator because it's not a problem with the ABS system but with the brake hardware itself).

 

[metroplex]

It always starts doing it when it is wet outside.

 

[Harvey]

Labman, I've seen the little flap of rubber inside the hose do exactly what you said. (thought I was the only one that happened to)

 

[Willy_G]

How about a jammed-up master cylinder? Maybe the the R/F circuit is not releasing hyd. pressure.

I would have to say that there is something wrong with the ABS. If the ABS controller was reading a locked wheel (regardless of mechanical fault or other), it should at least try (fire the solenoids) to modulate that wheel. Something is not right. I hope you have the proper ABS diagnostic tools in your garage to rule out any electro-mechanical problem with the ABS.

If you come down to Indianapolis, let me know. I want to get out of your way so you don't slide into me and my family stopped at a red light during a rain storm.

 

[metroplex]

Actually the ABS increases stopping distance. If it was a jammed up M/C, it wouldn't act up only when it starts to rain/or is wet.

 

[brianl703]

Maybe the wheelspeed sensor or it's connector/wire is damaged and water is getting inside.

I had a similar problem with my 1996 Contour. Washing the car (or even getting water in the front right wheel area) would cause the ABS fault light to come on, and the ABS was disabled due to that fault until the wiring dried out.

It was fixed when I had the wiring harnesses replaced under the 100K extended warranty that Ford issued for that purpose. (The insulation on the wires became brittle and started cracking; not a problem you'll have with a Crown Vic, but it shows what sort of strange problems faulty or damaged wiring can cause).

 

[Shaman]

Have you checked with crownvic.net to see if they have had anything similar? Great people. Might want to check there if you haven't.

 

[Harvey]

Shaman, how in the world would you find a site like crownvic.net? just curious.

 

[Shaman]

I had an 87 5.0 Lo Po for about a year. Got it from my grandma. Actually had everything but the ECU and heads to convert it over to a hi po 5.0 motor, but moved on after it chipped a piston. Didn’t have everything I needed to get it converted, so it went back to lo-po, and I picked up a Grand Prix after it sold.

I am a member of A LOT of websites. I like to learn about all cars, so it was just a natural thing when I got the car.

 

[theguru]

Metroplex,

Have the rotors been turned to remove the grooves in them?

 

[metroplex]

No. I would rather get new rotors instead, but the cost for new brake parts is about $360.

 

[theguru]

So, are you saying that the existing rotors have grooves in them? If so, that would be my starting point.

 

[cousincletus]

Yep. If that doesn't fix, then I would replace flexible hoses, then if that doesn't work replace calipers.