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Brake booster and ABS brakes

3684 Views 4 Replies 4 Participants Last post by  DeLorean
so im about to buy a mint 1990 saab 9000 turbo for 1500 bucks, brand new exhaust, rebuilt turbo, new cpu and no rust damage whatsoever!

only problem is... before she can pass inspection she needs a brake booster, now the guy im buying it off of said it may just be a sensor knocked loose or something happened while she was sitting in his garage. but if that is not the case how much are these to replace ( or do i even need to replace it to pass inspection at all, cause they might be stupid or something .. ) or can they be fixed and if not how hard is it to find one of these bad boys, can i just haul one off an old caviler or another 2L car and swap it out ??? or is it model specific ?

plz write back asap if possible, thanks cause im buying it in 3 daysssssss
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What is the "problem" which indicates a bad Booster? Either its ABS or Brake Booster.... If it's an ABS fault you may just need to clean or replace a faulty sensor. Could also be a bad ABS unit (not the brake booster). There are a few things it COULD be - but if the light is on in the dash - and cleaning the wheel speed sensors does not fix it - get a Saab shop with a ISAT scanner to pull the codes... (not sure if a TECH 2 w/adapter would talk to a 1990 ABS system)
What are you Smoking? 1990 900's Don't even have a Brake Booster. Usually the Failure of the Mk1 ABS in old 900's is the Nitrogen Sphere on top. Its the Black Ball thingy on top. Its the same one used on Ford TBirds & Dodge Caravans of the same age. Go get one and screw it on and see if your "Booster" works now. And No sorry No diagnaostic interface with tech 2 and 1990 ABS Brains. I have Pluged in Later model ABS Brains to figure out which Wheel speed sensors have failed. Just Use a 91+ abs brain for diagnostics
Really - no brake booster? lol I've never had to change one - or anything on the 9000 brake system aside calipers and lines. Strange - b/c I have removed booster assemblies with the ABS units from later 9000's - I figured they were all the same. I'll have to look on EPC later - this is strange to me. The chambers sound right - I did recall those to mention - you are right on that! As for communication - that's good to know about the 91' ABS ECU for DIAG. Either way I don't think his problem is a booster :)
What typically goes wrong with this system, if it's NOT the nitrogen ball, is the hydraulic pump, the hydraulic pump pressure switch, or they just leak all their fluid out all over the place. The unit you should pretty much always replace is this-

See if the pump is running. If it is not, there is a way to jumper it to test if it CAN run. If it does, the pressure switch is bad. -

If the pump itself it bad, the car is not worth fixing. Well, if you had to buy a NEW part anyway. It really just means you have to go to the junk yard and find an 88-92 9000 in the yard and grab the entire ABS assembly out of it for $50 and install it into your car.
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