i have a 93 caddy that has a brake problem. I have changed the master cylinder twice and still have no pedal.?

Question

I have bleed the brakes at the master cylinder and all four wheels and still have no good pedal. I have been told the brake booster is bad by one mechanic. Another mechanic says there is still air in the system. It has 4 wheel ABS. Has anyone had this problem?

Answer 1

1st off, without proper diagnostics you cannot get a proper repair.

2nd, you have a 93 Cadillac with ABS, that in itself is the major part of your problem, being that once air gets trapped in the abs pump its hard to get out (sometimes) especially considering the age of the vehicle and that there are proper procedures for bleeding most ABS equipped vehicles recommended by the manufacturers.

3rd, the actual problem is most likely not in the ABS pump or in the master cylinder but in the power booster. If you have no pedal, it could be that your booster isn't working properly. Another sign of a bad booster would be a hard pedal.

4th, being as you have already changed the master cylinder twice, and have bled the system at both the cylinder and all 4 wheels, my advise to you would be to check(replace) the booster. Also, Cadillacs are known for having a "soft" pedal and what you might think as a problem might also be normal for it. Consult your local GM dealer before you start tearing everything apart and possibly causing an accident because of your brakes.

Good luck and hope this helps.

Answer 2

No. i could wager that they pushed contaminated brake fluid returned for the duration of the ABS valving whilst they reset the calipers. this could reason the valves to adhere, or probably harm the grasp cylinder. additionally, some fashions won't be able to be appropriate bled without some state-of-the-artwork digital kit to open the ABS gadget whilst bleeding. commonly, an undemanding pad replace does not require brake bleeding. whilst the caliper pistons are reset returned into the calipers, you need to OPEN THE BLEEDER VALVES to evade PUSHING the tainted FLUID INTO THE gadget. yet another hazard, and that i see it from DIYers each and all the time, is pinching off the brake lines to evade the an infection situation. THIS DAMAGES BRAKE lines, and could reason a vulnerable spot in the line. i think that they probable led to the subject. i wish they're going to restoration it without too lots hardship. considering Midas is a chain, you may touch the community supervisor, if the community keep isn't cooperating. stable luck.

Answer 3

YOU REQUIRE A FULL POWER BLEED OF BRAKE SYSTEM using NEW FRESH genuine GM AC DELCO brake fluid int here! Your system is FULL OF WATER from aging BRAKE FLUID< which is a WATER LOVING ester compound! FIRST it absorbs MOISTURE from the AIR, then turns into TOXIC WASTE and eventually into LIQUID SANDPAPER ! THIS IS NOT A NEW THING at all This is true for ANY CAR, ANY YEAR< made by ANY CAR COMPANY, that has BRAKES IN THEM! GM uses an inferior ABS system on most cars that is only a THREE CHANNEL SYSTEM to save MONEY! BE CAREFUL where you buy your MASTER FROM! MANY of them are BAD from the shelf! GOOD LUCK!!

Answer 4

You have some good answers here, but one possibility that hasn't been mentioned is that you may not have "pre-bled" the new master cyl. If you read the directions that come with the unit, they usually say you are supposed to "bench bleed" the unit before it is put on the car, and most directions tell you how to do this.

Answer 5

hound is exactly right if you don't "bench bleed" the master cylinder before bleeding the rest of the system you will never get the pedal to come all the way up

Answer 6

Try bleeding the brakes at the proportioning valve, sometimes a air bubble gets in it.

Answer 7

contact a repair shop