1998 V70 | Rear drivers woosh woosh sound | log

[yanga001]

Hi Everyone,

I recently had a seized rear drivers caliper that caused one of my brake pads to rub out and scratch up the caliper about 0.25 mm from my estimation when compared to the other side. The caliper was replaced, and newish pads were put in to wear the rotor back into a smooth surface. Fast forward a bit and the rear drivers now catches once a revolution when spinning the wheel on the hub. It catches in both directions, however the rotor visibly did not look warped and my pads do not appear to be wearing out unevenly or catching. Im thinking it is the parking brake but not sure at the moment.

Recently (yesterday) the car started to pull right when braking hard, and it feels a little more sluggish. Ill take it to my indy next week after diagnosing it, but ive got a 500km trip this weekend so i gotta check tonight if its anything that will ground the trip.

When driving at 110-130 i can feel a vibration in the seat and wheel coming from the rear drivers.

This is more of a log then a question, but any input is readily accepted. I didnt think it would be the rotor warped as it is a recent development, it happens once a revoloution, and the caliper is new. I am going to do all 4 pads soon as they were getting used up, however that will need to wait until things get a little less busy.

[RickHaleParker]

Use a straight edge to check the Rotor for warpage.

[FireFox31]

A dial indicator on a magnetic holder is the best way to check rotor run-out. I use a Mitutoyo 2416S indicator ($60) on a NOGA DG10533 holder ($90). You can also check for run-out at the hub in the unlikely case that it has a problem. Ensure that the hub face and rotor inner faces are clean and smooth because debris there can cause an imperfect mount, introducing run-out. One of my rotors rocks a little bit when installed, causing 10/1000" run-out.

Your parking brake shoes might be incorrectly adjusted and dragging. Adjusting them to the proper tension should help. According to everything I've read, they should drag just a little when properly adjusted.

I've been fighting with rear brakes all year, having a much worse version of your problem (serious rear wheel brake drag). I just drove 1000 miles one way with my parking brakes dragging "the right amount" (I hope). I stopped at one point to check the brakes for excessive heat and there was none.

Here are my notes and good forum threads:

Brake overhaul by cn90
A must-read for anyone learning to work on their brakes.

Parking brake tips by cn90

Shoe replacement on 1994 850 sedan by Ozark Lee
"The toughest part of [reassembly] is getting the lower spring hooked back up to the new brake shoes."
Contains procedure for shoe adjustment after rotor install.

Parking brake failure by QuirkySwede

850 cable replace by Pauloil

"During removal, the force of pulling off the rotors will pull the Retaining Clips outward a bit. Just push them back in with a screwdriver so they hug the new shoes properly." per cn90

"The clips that hold the Ebrake shoes in place tend to bend easily which permits the brake shoes to drift away from the drums and cause a scraping sound -- especially at low speeds." per E Showell

[yanga001]

It seemed to be the parking brake, damn thing never really worked right to start. I star adjusted to the maximum slack and it turns out both sides were rubbing pretty bad. Highway vibrations are gone and sluggishness is gone. Looks like another project for down the line. Thanks for your help!

[scot850]

It is most likely:

1) Parking brake cable seizing in sheath usually just forward of the rear wheels where it mounts to the underside of the car. The cable splits with age and water and grot get into the sheath rusting the cable.
2) Parking brake shoe failure. Again with age and heat the shoes delaminate from the metal position.

A simple way to check the run-out is to tape a pencil to the brake caliper and turn the rotor and see if it touches the rotor at any point.

Good Luck!

Neil.