[sx4sx4]

After driving about 5 minutes the brakes start to almost lock up. It's like someone is holding there foot on the brakes. First I noticed the vacuum line going into the Mechanical vacuum pump was loose so I shooved it into the pump farther and the car began to smoke like crazy. Bad Vacuum pump. So I got a new one from saab and installed it. Well, the smoke is gone but the brakes still feel like they are stuck on and the petal barely moves. You do not need to push hard at all either to get it to stop. No ABS light or anything else goofy is going on. Any ideas?????

 

[valbowski1980]

Welcome to SC

Sticky caliper(s) maybe? How long have you had the car for and when was the last time you had a look at your brakes?

 

[sx4sx4]

Well, I actually bought it as a repairable. Previous owner stated it just started doing it one day. He said he had it looked at and that mechanic thought it was the turbo. I don't really think so. When I got it, I had to replace the timing chain and guides as it was noisier then heck. Also check for sludge inthe oil pan and found nothing.

All 4 wheels are sticking as all 4 wheels get hot and it does not pull to one side or another. Because of this I have not even looked at the calipers but I guess I shouldn't rule that out but all 4 locking up seems weird.

 

[valbowski1980]

Well, I actually bought it as a repairable. Previous owner stated it just started doing it one day. He said he had it looked at and that mechanic thought it was the turbo. I don't really think so. When I got it, I had to replace the timing chain and guides as it was noisier then heck. Also check for sludge inthe oil pan and found nothing.

All 4 wheels are sticking as all 4 wheels get hot and it does not pull to one side or another. Because of this I have not even looked at the calipers but I guess I shouldn't rule that out but all 4 locking up seems weird.

That is pretty weird indeed. Did the car stand for a long time right before you bought it? It is possible that the rotors have rusted and warped and the same goes for the pads if they have any metal to them.

 

[sx4sx4]

no more then a month of sitting.

 

[sx4sx4]

so I went out and worked on the 9-5 a little tonight. Took the car on another test drive. Brakes were all locked up again after the drive. I pulled the vacuum line out of the booster and a ton of vacuum pressure was released and you could also hear the brake calipers release from the rotors. Also noticed oil oozing out of the booster. Then I pulled the master cylinder out of the booster and about a 1/2 quart of oil came out of the booster. So I used a oil pump and pumped the rest of the oil out of the booster. All and all the booster was filled with about a quart of oil. The only way I see possible for this oil to have built up in the booster is through the vaccum pump which has now been replaced.

Put everything back together and took it for another test drive. After 15 min of driving the brakes became all locked up. pulled air line from booster and calipers released. I didn't see oil oosing but also did not pull the master cylinder out yet.

Seems to me I am building up to much to much vaccum inside the booster. Is this regulated somehow? Should excess pressure escape through a valve or something?

 

[Al's Red Wagon]

This Link Will take you to a vacuum diagram...I hope it serves you well...

http://www.saabcentral.com/forums/showpost.php?p=1163747&postcount=6

 

[Al's Red Wagon]

Do you have a mechanichal brake booster, or an electric one?

There are several check valves in the mechanical brake booster setup that may be misbehaving...

Aside from check valves, the electrical brake booster is controled by a sensor...It resides along the same vacuum path as the servo...it may be malfunctioning...

If none of these are the problem, then it could be possible that the spring in your servo is weak and continuously letting in pressure to the system and engaging the brakes...Don't think the servo is servicable...so a new servo might be the solution...

 

[sx4sx4]

servo = brake booster?

That is what I am thinking too.

I found this:
http://www.saabcentral.com/forums/showthread.php?t=124570&highlight=brake+booster

I don't really think it's loosing brake fluid though. I find it hard to believe the master cylinder is bad.

maybe i'll try the booster first.

 

[Al's Red Wagon]

The "brake booster" is a system with many parts that includes a booster pump and a servo...

Servo is the large circular item up against the firewall..

http://www.eeuroparts.com/Main/PartDetail.aspx?id=4836656

 

[planosaab]

Ya it sounds like your vacuum pump is running way to much pressure.

if its the electric pump does it run constantly? its a black compressor just infront of the battery. or do you have the mechanical mounted where the distributor would be if it wasn't direct ignition?

 

[sx4sx4]

it's a mechanical pump and its brand new. Checked check valve in plastic vacuum line and that was good too. Only thing left is the actual booster or servo.

 

[Al's Red Wagon]

Ya it sounds like your vacuum pump is running way to much pressure.

?

or...the spring in the servo can't handle the correct pressure that is being created and finally let's go to the point that the brakes engage...

You actually might be able to drive if you diconnected the vacuum hose from the servo, you'd have to push the pedal 5 times as hard, but it would be possible...

 

[planosaab]

Ya I was sitting here scratching my head looking at diagrams of brake boosters lol. Very well makes since Al.

 

[sx4sx4]

Yep, I agree. Seems like the pressure is pulling so hard on the booster that it's engaging the brakes. I will throw in a booster on Monday and let you guys know what happens.

 

[sx4sx4]

For the record.

Heres what happened.

Mechanical Vacuum pump failed alowing oil to pass into the brake booster. Brake booster completely filled with engine oil forcing the brakes to be applied all the time. Even after pumping the oil out the valve in the booster was not allowing atmospheric pressure to the cabin side of the booster.

A new vacuum pump and brake booster fixed the problem.

No master cylinder was required.

 

[MacNoob]

Heh I drove a car once (not 9-5) where the booster was bad. As soon as you moved the brake pedal it would suck itself right to the floor and lock all four wheels. Exciting.

 

[jgchester]

Help with my SAAB 9-5

I was looking everywhere for someone with the same problem. I have a 99 9-5 wagon 2.3 turbo. Just put a newer engine in and brakes are locking up just as in your experience. Can you point me to where you purchased your vacuum pump and brake booster for you Saab?

email martyandjeremyat g male dot com

For the record.
thanks
Heres what happened.

Mechanical Vacuum pump failed alowing oil to pass into the brake booster. Brake booster completely filled with engine oil forcing the brakes to be applied all the time. Even after pumping the oil out the valve in the booster was not allowing atmospheric pressure to the cabin side of the booster.

A new vacuum pump and brake booster fixed the problem.

No master cylinder was required.

 

[toxicavenger]

I was looking everywhere for someone with the same problem. I have a 99 9-5 wagon 2.3 turbo. Just put a newer engine in and brakes are locking up just as in your experience. Can you point me to where you purchased your vacuum pump and brake booster for you Saab?

email martyandjeremyat g male dot com

this thread is 4 years old.

so do a search on the forum for brake booster or make a new thread if you want some replies.

 

[Saabjason111]

Can anyone tell me where I can find a vacuum pump or check valve for my 1999 Saab 9-5 2.3t I am having the same issue just replaced the booster......saw this and need other parts I cannot find. Any help would be appreciated!