|
Car = 1993 945, 131,000 miles.
Sound = There is a clunk coming from the Rt. front brake area. It is most obvious when I back up, apply the brakes, then move forward and apply the brakes again. On applying the brakes in the forward direction, the clunk is loudest. Sometimes I hear a rattly clunk when I drive over a rough surface like a railroad crossing.
I've checked the ball joints and strut mounts and, as far as I can tell, these are ok. The bushings on the stabilizer bars were replaced when the strut cartridges were replaced. No change in the clunk. The anti-rattle springs in the calipers are intact and look good.
Two days ago, I replaced the front brake pads. Now the clunk is not as loud. I think the may confirm my idea that the clunk comes from shifting calipers. The new, thicker, pads have shifted the postion of the sliding caliper to a point where there is less clunking.
While doing the brake pad replacement, I removed, cleaned, and greased the caliper pins as I have done every summer since buying the car. I could see wear on the two ends of the caliper pins. The upper pins had more wear than the lower ones. I've no way to measure the wear but it is obvious and the pins can be wiggled a small amount in the bushings of the caliper carrier.
Up to 1992, or so, Volvo used a two piston caliper in the front of the 740/940 series. They issued a TSB (TSB 51097) about replacing the pins and pin bushings to stop a rattle in the front calipers as these wore. Volvo produced a caliper repair kit to do this. The single piston caliper in later 940s doesn't appear to have any way to replace the bushings in the carrier. I have not found any supplier of both pins and bushings nor have I found any Volvo TSB covering this. However, you can buy new caliper pins for about $50 USD.
Before I buy new caliper pins, I wanted to ask if anyone has put in new pins and thus stopped the clunk from the calipers? I assume they will help but, if the bushings the pins slide in are also worn, the new pins may not help much.
A second question comes to mind. Do any of the caliper rebuilders replace both pins and bushings when they rebuild the calipers?
|
