Jadz928

87 S4
Quick story. Cruising on the highway, I feel a serious drag. I take the next exit (about a mile up the road). The rear of the car is rumbling. Park the car and the brake rotors are red hot and smoking. Fluid burbling out the bleeder valve. Rear brakes, both sides.

I just flushed my system last weekend. Brake pressure felt great.

Could this be tied to the E-brake system? Is it possible the E-brake did not disengage?

Let the car cool off. Moved the E-brake up and down a few times. Rolled freely. Brake pressure is up then fade (most likely fluid too hot still).

Left the car because I have a meeting at 9am.

Any suggestions?

Dean_Fuller

I don't see how it could be the emergency brake if the disks were red hot. Both sides is strange as well. I had this happen years ago when I replaced a rotor on ONE side...that caliper locked up...after it cooled down it never did it again. Both sides locking up has to be the system and not a caliper problem. This may be one of those "never happened again" things. If it rolls free this evening I would just drive it and see. Might be a good idea to flush again....sounds like some crud may of gotten into or moved around when flushing. Just my 2 cents.

Jadz928

Thanks Dean,
I didn't think it was e-brake as it is it's own system.

the flyin' scotsman

Did you bleed the master cylinder when you flushed the fluid?

Did you use a power bleeder?

What type of brake fluid?

stolarzj

I have had this happen on another vehicle. After replacing the pads and compressing the pistons in the process, one caliper took to locking up after a week so I replaced it, then a week later another one did it and I replaced that one. The only thing I could think of was compressing of the pistons dislodged some garbage or something in the system and caused it to make it's way to the piston and cause it to lockup. I suppose the same could happen on a flush, did you flush from both bleeders on the caliper?

Jadz928

I'm a real idiot. I figured out what I did wrong. I used PENTOSIN
POWER STEERING FLUID CHF7.1
I really thought it was brake fluid. I'm going to have the car flatbedded home. Will thouroughly flush system tonite.
I can't believe I did this. And to add insult to injury, I lost my wheel lug lock key.

Courtshark

You are lucky to be alive.

Mrmerlin

your braking system may need a complete overhaul, to include new flexible brake lines (get the stainless type) a new master and the rear regulator valve and a rebuild of all of the calipers, the PS fluid will swell the seals and thus cause the brakes to possibly fail or lock.
You would also want to flush the brake lines out afer removing the calipers with some brake cleaner and compressed air.

ew928

Ow!

Anyone know if Pentosin (hydraulic fluid, I believe. I used it in the steering rack of my ex-Audi) will harm the seals in the calipers and master cylinders?
Just asking to see if the whole system needs to be rebuilt as well as flushed.

Jim M.

How are the brake hoses? If original they are now 21 years old. On my 89GT I had one front hose failing internally and would lock fluid in the caliper when under pressure. That would keep the caliper engaged.

I agree with a second flush, using both bleeders. If it repeats replace the hoses. The factory hoses are good but they are getting old.

Jadz928

Yea, thanks. Seriously.

the flyin' scotsman

wow!!!

I'm not sure I trust any component of the system without a full rebuild of the master cylinder and all calipers and the lines.

Jadz928

You've got to be kidding me. It's only been in the system for two days.

heinrich

I'd say Jim, you should buy a whole system off a parts car and replace. You could call the manufacturer of the fluid to get their opinion. Mistakes happen.... but indeed the rears absolutely need replacing. I wonder why the fronts showed no issue?

Jadz928

Believe me, from a safety standpoint, I understand where you are coming from. From a pocketbook point of view, I'm a little shy. Just spent my money on TB/WP ect...

Looks like I'll be drving Chewy for a little while until I get this sorted out.