Ok i just bought a 90 deville for $500.00 with 160,000 miles. the interior isnt the best but it doesnt have a dent on it. When i got the car the brakes only worked if you pushed them to the floor and then locked up. I was told it was the power booster. After testing i did not think it was the booster. The guy i bought the car from said the brakes just locked up one day so he replaced both front calipers/pads rotors and master cylinder. I just didnt think he bleed the brakes so i took the wheels off to find driver side line tore in half so i replaced it. The passenger side did not have any fluid coming out of it so i replaced it to, I then got fluid out of it. The back lines looked to have been replaced not long ago so i left them. I have bleed the brakes twice now and still only have a little bit of pedal. It seems like air will never quit coming out when i bleed the brakes and i only get small amounts SOMETIMEs out of the rear drums. Is there a porportioning valve on here somewhere I cant seem to find it on the internet i saw other lacs have them so does mine ? I dont have any fluid leaking anywhere. Master cylinder, calipers, pads, rotors, brake hoses, and now power booster have been replaced. Do i just need to keep bleeding? porportioning valve? if so how do i do that? Someone please drop me some knowledge im new to brake jobs this technicle I used to have an 84 eldo never had to do nothing but change pads. Please help, Its greatly appreciated thanks.

 

Can anyone help?

 

Car has ABS - ABS vlave block can get air trapped in it causing issues with bleeding without scanner to cycle valves to purge air. From what previous owner had done, brake system may have been contaninated with incorrect fluid(GM - DOT3 only), which would require all part containing rubber to be rebuilt or replaced. You could opt to take to dealer and have "Brake Flush" done call around to get best price. Ask them if they will "Auto-Bleed" ABS as part of that service - it should be included in service. If flushing does not correct problem - you will need to figure out what else needs replaced or get diagnostic test by qualified tech to tell you.

 

Yeah its kind of wierd everyone keeps saying it has abs but my 90 deville doesnt and i have a friend with an 89 that does not have abs either. Was it an option? Yesterday i took 6 hours out of my day to bleed my brakes. I could not find a proportionating valve anywhere on the car. I bleed and bleed and bleed till i finally got fluid out of the rear drums and all of the air out of the lines. Now my brakes are perfect! Im guessing the guy that i bought it from that replaced the master cylinder did not bench bleed it because he didnt even know how to bleed brakes let alonE check the lines for leaks. I guess sometimes people are stupid if you dont know ASK someone thats what places like the cadillac forum are for. And about the dealer, I NEVER take my car to the dealer unless i absolutely have to. Its hard enough taking it to a shop, i cant afford it and thats how i learn.

 

dont know the answer to the abs question.

on the bleed, can you tell us how much fluid you used up .. estimate if you must, but that will be helpful to others.



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I'll add this to the brake bleeding conundrum...
A pressure bleeder is your friend.
Some early ABS systems will not have a "bleed" option on a scanner, tho some do.
Also, some Cads of that era had a screwy "diagonal" system, meaning the RR and the LF were tied together, and the LR and RF were tied together, which makes bleeding them a pita if you're not aware of the design.