'98 olds break problems

[Donolie]

1998 olds intrigue, 3800, auto, 4 wheel disc.
Spongy breaks (ABS/Trac/Check engine/service engine soon)

Friend brought her 'new' car over the weekend complaining about breaks feeling spongy.

First looked at the car and noticed the driver front passenger rear rotors had a lot of rust. They were also cool to the touch, odd after a 20 mile trip.

The driver rear speed sensor has been repaired, and was unplugged.

The breaks are not working on the passenger rear, driver left. There is not any pressure at all at the calipers, and the rusty rotors show this.
Put the car on jack stands and with breaks depressed, the driver front/passenger rear wheels spun freely.
checked break lines/fluid, no obvious leaks.

I tried bleeding from the valve assembly attached to the master cylinder, and got only fluid out of the one bleeder, but not the other one.




Could this be the master cylinder causing this, or the other assembly?


http://imageshack.us/photo/my-images/85/wp0 00007.j...

The bleeder on the right had nothing, the bleeder on the left that had fluid/pressure.


Thanks for any advice-

Don

[douglas linderman]

[quote=Donolie;6942713]1998 olds intrigue, 3800, auto, 4 wheel disc.
Spongy breaks (ABS/Trac/Check engine/service engine soon)

Friend brought her 'new' car over the weekend complaining about breaks feeling spongy.

First looked at the car and noticed the driver front passenger rear rotors had a lot of rust. They were also cool to the touch, odd after a 20 mile trip.

The driver rear speed sensor has been repaired, and was unplugged.

The breaks are not working on the passenger rear, driver left. There is not any pressure at all at the calipers, and the rusty rotors show this.
Put the car on jack stands and with breaks depressed, the driver front/passenger rear wheels spun freely.
checked break lines/fluid, no obvious leaks.

I tried bleeding from the valve assembly attached to the master cylinder, and got only fluid out of the one bleeder, but not the other one.




Could this be the master cylinder causing this, or the other assembly?


http://imageshack.us/photo/my-images/85/wp0 00007.j...

The bleeder on the right had nothing, the bleeder on the left that had fluid/pressure.


Thanks for any advice-
I would check for any unhooked lines. Along with any Internal fluid leaks in ABS hydraulic modulator. The Speed sensor was not hooked up for a reason. One being a malfunction with the ABS? Possibly Master Cylinder but I highly doubt it. It sounds like a leak or air problem.

[maxwedge]

I'd be looking at the abs unit here.

[gmtech1]

Could be master cylinder. The brake system on this is a diagonally split system, meaning the primary piston in the master applies pressure to the left front and right rear caliper, and the secondary piston services the other two. Don't usually bleed the brakes from the bleeders you showed, those are for the initial installation at the factory, always bleed at the calipers.

[Donolie]

Originally Posted by gmtech1

Could be master cylinder. The brake system on this is a diagonally split system, meaning the primary piston in the master applies pressure to the left front and right rear caliper, and the secondary piston services the other two. Don't usually bleed the brakes from the bleeders you showed, those are for the initial installation at the factory, always bleed at the calipers.

GMTech1,

I assumed this to be the case with the breaks not working in the order, but could it be the assembly attached to the master cylinder? If so, what is it called?

I tried bleeding at the two break calipers that had no pressure, and got nothing, so as a last resort tried at the two bleeders attached to the unknown assembly/manifold.

I've seen something similar on k series trucks but it would be the rear breaks not working, and it is always the master cylinder if there is no pressure to the wheel cylinders... The only differance is a standard Front/Rear system with out the ABS manifold?

[gmtech1]

The part with the brake lines going to it is the ABS brake modulator, the black unit attatched to it is the ABS motor pack. There is a procedure that requires a scanner to seperate the two, gear tension relief and motor rehome. If you decide to replaced them, check salvage yards. They usually sell them as a set for around 200.00 and you won't have to worry about the tension relief and rehome. Besides, they are VERY expensive new.

You can break the brake lines loose one at a time and the modulator and check for brake pressure from the master to the modulator.

[benjarvischuck]

I have a question related to this topic. If anyone knowledgeable could help, I'd appreciate it. It started when I realized that both rear brakes of my Oldsmobile Intrigue 1998 had quit working simultaneously. I traced the problem back to the ABS. I got a replacement ABS but while trying to replace the ABS, I had to remove the ABS motor pack in order to attach the modulator to the master cylinder because of the design. As I pulled the ABS motor pack away from the modulator, the spring loaded gears released. Is there any way to reset those spring loaded gears correctly and if not, do they need to be loaded for the brakes to work? The ABS has not worked for years, so I don't care about that. I do care about the having my rear brakes functional. If anyone could help, I'd appreciate it. Thanks!