Hi,

I've searched the archives, and haven't found anything here or on the web about success on rebuilding the front calipers. I have a 1997 Subaru Impreza Outback Sport, and have already rebuilt the calipers, but encountered some stumbling blocks.

What is the method for getting the dust boot fully seated in the caliper and on the piston?

Other than that, it went well. Not that there is much to do anyway on stock calipers. Those speed bleeders are far better than tubing/fluid, hand vacuum bleeding, or two-person brake bleeding...

Thanks!
--Joe.
Austin, TX

 

Well you can put the dust boot on and the wire snap ring in before you put the piston in the caliper then use two small scribes to run the edge of the boot up onto the base of the piston. That or do it by putting the piston in first and then using a small screwdriver work the dust boot lip down into the groove that it rests it. The only hard part about rebuilding brakes is that damn snap ring. Getting it back in and not ripping anything in the process cause the damn thing wants to spin instead of compress. I've got a walk through in a manual around here somewhere. When I find it I'll post it up for you.

 

Okay, finally got it done. I knew there had to be a trick to this.

I bought two complete rebuild kits (all rubber replacement parts).
I asked a brother, a friend, and two auto shop clerks.

My brother indicated there was a tool that would stretch the seal through which the piston would slide. I tried that, and had no joy.

My friend, who would probably have had my answer, was unavailable to take calls.

One shop clerk knew absolutely nothing, about brakes, about parts, or about cars. He did show interest in solving my problem, but couldn't get past the drawing of a caliper. I was polite, and left.

The other shop clerk indicated the use of dental type pick instruments to slide around the rear of the piston to get the seal onto the piston from behind. I wondered aloud to him whether there was anyway to prevent puncturing the seal with the tool. No, just slide it around, and it will be fine, he said.

Got home, tried my brother's method by fashioning different spreaders from materials I had, and managed to tear one dust seal. Tried the pick method and promptly holed two dust seals out of a total of four. Finally, I figured to increase the length of the seal by
sliding the seal from the front to the back and that gave me enough slack to insert the seal in the caliper and get the piston back into the caliper without damage.

price for two caliper rebuild kits $55 at Van's Auto Parts.
price for friendly conversation and no help $7.95 (I did buy something)
price for lousy auto parts advice $28
price for doing it right, priceless

It was easy actually:
turn wheel to opposite direction from side being worked on
remove wheel
remove two caliper bolts
place caliper in small bucket
pump brakes about fifteen times (shallow, or power brake damage may result)
pull piston and seal out of caliper
remove brake line from caliper
general cleanup of caliper
remove and install new internal caliper seal
slide new seal over top of piston and slide to the bottom
insert new seal's lip into caliper
push piston all the way into caliper
push piston halfway out to ensure the seal is in the piston's groove
use the bolt hole in the back and a phillips screwdriver, etc
push piston all the way in, seal should be flush all the way around
re-install caliper on car (two bolts, remember?)
re-attach brake line (one bolt, two washers)
bleed brakes (need two people or one speed bleeder)

It took less than an hour, beyond the 8.5 hours it took to do it wrong the first time...

Hope this helps someone else,
--Joe.
Austin, TX

 

Did you remember to apply the supplied high temp grease around the piston first? That usually helps things out. Also if you can try using the small L shaped scribes to get ahold of the boot. You don't have to dig into the seal just use the flat part of the lower section to pull the seal back. Rebuilds only really suck when the brakes are frozen up and you have to wrap them in a rag and pound them on the ground to get the piston to pop out. I've had to do it before on Mitsubishi brakes. After that you have to scrape at the rust to get it all off the groove for the snap ring and the inside of the caliper. Not to mention the fact that usually you have to replace the damn piston cause they get so pitted by the rust.

The Suzuki Escudos in Japan don't even use a snap ring to make sure there is a seal. They just sit in the groove. Maybe thats why they are always being rebuilt.

 

I didn't have to reinstall high temp grease. that would contaminate the brake fluid. It only required a seal around the piston. The high temp grease goes in the caliper pin guides.

There was no need for the L-shaped dental picks because there is ample room if the caliper seal is pulled down to the base of the piston and stretched out. The bottom of the seal can then be worked around the groove in the caliper without any great deal of effort. I didn't require any force to remove OR insert the piston into the caliper body, only hand pressure, but that was after the brake line had been removed from the rear of the caliper.

The only problem I have remaining on the build (and probably the only initial problem) is the caliper guide with the rubber piston/seal at the end of the guide pin. I guess I'll have to get a brass bore brush from my gun cleaning kit to get the tarnish out of the hole. It just doesn't seem to have great travel when installed.

--Joe.

 

They sell the attachments for cleaning the guides at the store which is pretty useful since you can use the kit to also clean the inside of a master or slave cylinder if your doing a rebuild on them.

 

I forgot to mention the kit is used with a cordless drill to clean the cylinders. Don't use a gun cleaning brush cause it might be too abbrasive.