Front brakes seem to be o.k. but rear brakes lock up every time brake is used. I don't know how to isolate if this is a mechanical problem or an abs problem.

Likely mechanical, due to not changing the brake fluid every two years. You will probably have to replace the rear wheel cylinders or calipers, which are not retracting properly. Afterwards, replace the rear brake shoes/pads and completely change the brake fluid. Items 1, 2, and 3, in the link below, may help:

https://www.askmehelpdesk.com/cars-t...ml#post2369101

Only use an ABS-approved brake fluid; e.g. Valvoline. This will likely solve your problem.

Once the problem is solved, engage the ABS to replace the brake fluid in the internal reservoir. Corrosion in the ABS will result in a $2,000 repair bill.

Hi TXgreasemonkey, I spent a few years in Austin myself. Great country. I was hoping for a less expensive solution. Can I just clean everything good and replace the brake fluid?

Hi again greasemonkey. I forgot a couple of questions. How do I "engage" the abs? And how do I completely drain the brake fluid? Thanks,

Buy a wheel cylinder/caliper rebuild kit and do it inexpensively.

Thanks greasemonkey. I will try your suggestions.

Bleed ABS brakes, just as you would conventional brakes. Bleed them in this order: RR, LF, LR, and RF.

You engage the ABS by stopping suddenly on a safe street, with no one around. You'll hear the classic noise, if you do it right.

Buy a battery squeeze bulb at Advance Auto. Suck the brake master cylinder reservoir down to a safe level, refill with fresh brake fluid, replace cap, and begin bleeding the RR brake cylinder. Look for the bleeder valve. Refill the reservoir after bleeding each wheel. Works best with two people.

Clamp off the brake line with the recommended homemade tool, if you replace the wheel cylinder/caliper.

I would also recommend a thorough brake inspection.
That particular vehicle is prone to rear axle seal failure. That would allow gear lube to contaminate the brake linings and result in binding of the rear brakes.

When the brakes are operating properly, you can (and should) test ABS engagement not only to find out if it works, but also to learn what it feels like to be in an anti-lock event.

• Find an area where there is NO traffic.
• A vacant parking lot or side road will do.
• Seatbelts buckled and both hands on the steering wheel.
• Drive you vehicle with one side traveling on dry clean pavement and the other on sand or grass... anything that would cause a lock-up situation.
• Apply and hold the brakes firmly while holding the steering wheel in a straight line and the anti-lock system should activate.

You'll hear and feel the ABS cycling the brakes rapidly. That noise and feel is normal. Just maintaine brake pressure and the vehicle should stop in a straight line.
Do this for both side of your vehicle, maybe even a couple times. This not only gives you a feel for what to expect but also verifies that the system will more likely be able to work when it's needed.