For several months I have noticed a very gradual loss of brake fluid at the reservoir. Something finally presented itself in the form of a squishy brake pedal. With the winter season approaching, I figured this was about time to check out the brakes.

 

The parking brake shoes have long since been worn out - 178,000 miles on them with the obligatory leaving them engaged with driving around to worsen the effect. So those were definitely up for replacement - I had planned on pads and rotors.

 

But I knew SOMEWHERE there was a leaking caliper. Since I had been in the fronts already for a pad replacement, I checked, but expected no problems there. That would have to leave the rears.

 

Sure enough, a leaking piston seal on the left rear caliper. The dust boot had been damaged from some bungling around of pad replacement in the past. I bled the system just to eliminate the squishiness for a few more days while I waited for the rebuild kit I ordered.

 

I was glad that I have both an air compressor and some advance warning about using said air compressor for extracting the piston from the caliper bore. Once it popped out of the bore, it can easily bang on your hand and give a nasty injury. Fortunately I had packed a rag around the piston to catch it and avoid getting pinched by it.

 

 

 

The cylinder bore revealed that the piston had been getting cock-eyed in the bore under load. Similar to the engine piston-slap concept, the "skirt" of the piston was touching the side of the bore. This slack also means that the brake pads twist in the caliper and wear unevenly.

 

Unfortunately, the sealing ring in the kit (from the Subaru dealer no less) was not the right size. It was MUCH larger than the ring I pulled out of the caliper. I was hoping that this was the way it's supposed to be. But there was no way this was going to work.

 

So knowing that the caliper and piston on one side is kind of toast, it doesn't really matter what is going on with the rebuild kit.

 

Next step, unloaded rebuilt calipers.:-\

Once it popped out of the bore, it can easily bang on your hand and give a nasty injury. Fortunately I had packed a rag around the piston to catch it and avoid getting pinched by it.

You're supposed to keep your hands and fingers out of the way.

 

Did you try to fit the new seal in the caliper at all? They usually have to be... persuaded. But then they fit nice and tight against the piston.

With the cockeyed bore, I don't see how trying to work to repair it, is worth the time & trouble. If it were me, I would buy a rebuilt caliper from a parts store, and install it.

With the cockeyed bore, I don't see how trying to work to repair it, is worth the time & trouble. If it were me, I would buy a rebuilt caliper from a parts store, and install it.

 

Usually I am too cheap to simply buy rebuilt parts. So a seal repair is how I would normally go. To satisfy my curiosity, I am going to try again to see if the seal from the kit will go in the caliper bore. I just don't see how it is going to work since the ring would crinkle up in the groove - it just seemed way to big.

 

You can see the indentation in the bore in this photo. The piston itself was fine.

So in this case I have no choice but to get rebuilt calipers.

 

Usually I am too cheap to simply buy rebuilt parts. So a seal repair is how I would normally go. To satisfy my curiosity, I am going to try again to see if the seal from the kit will go in the caliper bore. I just don't see how it is going to work since the ring would crinkle up in the groove - it just seemed way to big.

 

You can see the indentation in the bore in this photo. The piston itself was fine.

So in this case I have no choice but to get rebuilt calipers.

 

 

 

Rebuilt Calipers?? Are you thinking about replacing both?? If it were me, I would replace only the one that is bad.