Bought a 1990 Trofeo 2 months ago,with anti lock problem of wheels locking up after driving a short distance or jamming them on hard and locking up - they release after the car sits for a couple hours, being winter here, I bit the bullet and instead of fixing it myself in the driveway I took it to my local repair shop - 1st time he replaced all 4 calipers and put on a used master cylinder and accum/pump assy I got from a u-pull - got my power assist back(pump motor was bad) but brakes still lock up- the shop charged me $900 - I took the car back 2nd time he put all new hoses on - still same problem and now he wants to charge me another $300 and give the car back to me as is - I told him no way am I paying $1200 for brakes that don't work - he said he doesn't know the Teves system very well - I am trying to help because I want the car back - should have just let the car sit in my driveway til spring and fixed it myself, so any ideas? car is in pretty good cond overall - so far - new master,calipers,pads,hoses,supposedly no kinked lines,also guy I bought it from replaced ABS module - would a wheel sensor cause all 4 wheels to lock like this - I have a Snap-on Solus Pro scanner w/OBD1 adapter, but haven't scanned it because the shop told me he would scan it and fix it - I'm reluctant to borrow him my scanner. What'* the next step?

Has this car sat outside for a long time?
Which DOT fluid has been used in the bleeding?

I do most of my own repairs, but winter in MN this year kinda forced me to take this one in to a small one man neighborhood shop - Huge, EXPENSIVE
mistake.Mechanic told me pump and accumulator were bad, rear calipers froze - fair enough, I said. Est $800. Brought him a used master cyl and pump assy from a 1990 Bonneville, told him take the pump and accum. off and replace the Toro'* pump and accum. He replaced the whole master assy instead, brakes were locking up as soon as I picked it up from the shop, so back it went. He had this car 2-3 times over a 2-3 month period, could not fix it, then told me the car died in his shop, without my consent installed new ign module and coil pack and crank sensor, brakes still locking up. after stopping by to inspect my car, I noticed the brake pedal had NO free play, I pointed this out to him, stating that this was the problem, he jacked me around for another 2-3 weeks, then demanded that I pick up the car and that I now owed him $1250, brakes still locked up to the point of barely being able to move the car. After a few phone calls to the Attn Generals office, still insisted if I want my car back unrepaired, it would cost me $1250. Was so pissed and frustrated, I finally caved in(should not have), paid him and got my car back.

Here is a photo of what went wrong, when he swapped master cyl assy from
Bonneville to Toro.( I specifically told him do not change out the master cyl) The pedal pushrod that threads on to the master is longer on H/C body cars than on the Toro/Reatta/Riv/Seville. I had this fixed in under an hour. Now I have warped rotors, shot brake pads, and will have to rebleed the system. Sorry I took so long to post a reply, I realize a lot of this post is redundant, have been busy with life.

Lesson learned - be careful who you take your Teves equipped car to for repairs.

I don't get it......you never give a car back to a customer, without a test drive, which includes application of the ABS system......says a lot about this "tech"...he wants you to pay for all the parts that he put in, that didn't fix the car....

This guy obviously was in over his head, and became a parts changer......

You are at the point now where you don't even know what the hell this guy actually did to your vehicle....Teves system requires special tools and diagnosis......you should have brought this to a GM dealer in the first place....