Left rear brake locked up.

[cn90]

850, S/V70 guru, quick question...

I recently replaced Parking Brake Shoes, new rear rotors, and check: no rear wheel binding.

But I notice that after moderate and hard braking, the left rear wheel seems to lock (then ABS activated) sooner than the other 3 wheels.
I understand the REAR tires are general lighter than the FRONT tires (where the engine is located), so it probably makes sense to see the REAR tires locking up sooner than the rest.

Is this normal from factory (REAR tires locking up before FRONT tires)?

PS: Does anyone know if this car has a "proportionating valve"?

[abscate]

It's also possible the parking brake pads have fallen off their backing and jammed in the rotor...it does happen every now and then to these cars.

DItto this my experience on my 1999 - parking brake shoes replaced in 2010 - the linings had fallen off and were making awful grinding noises in the back.

On the 1999, there were two different sizes of rear rotors with internal drum parking brakes used. I have a spare set of linings that dont fit my car btw...

[jblackburn]

850, S/V70 guru, quick question...

I recently replaced Parking Brake Shoes, new rear rotors, and check: no rear wheel binding.

But I notice that after moderate and hard braking, the left rear wheel seems to lock (then ABS activated) sooner than the other 3 wheels.
I understand the REAR tires are general lighter than the FRONT tires (where the engine is located), so it probably makes sense to see the REAR tires locking up sooner than the rest.

Is this normal from factory (REAR tires locking up before FRONT tires)?

PS: Does anyone know if this car has a "proportionating valve"?

In slick conditions, yeah, that's normal with most sedans for the rear wheels to lock. My S70, Accord, and 900 all did that.

However, I'd bleed the brakes - the rear wheels should lock at the same time. I'd also suggest cleaning the rear ABS sensors. My S70 had the most INCREDIBLY sensitive ABS system I've ever driven. Just moderate braking would set it off.

[mercuric]

Cold can bring out any sort of close-clearance mechanical item into an annoyed state, but it's only bringing out an existing problem if it's cold related.

Yank the caliper, spin wheel, make sure the noise is still there (should be gone unless it's the parking brake).

My guess is you're going to find some busted hardware, but if everything looks good, try re-seating the piston with a c-clamp, put everything back together, pump the brakes a few times and go for a test drive.

You might find the piston is seized and at an angle.. You might also just need pads... But with grinding, my bet is on busted hardware or your pads are gone.

Any way you slice it, the problem is likely pretty obvious once you get in there

[Beck]

Busted e-brake shoes. Take them out and don't use the e-brake again. Terrible design. Happened twice to me.