Girling calipers - dust boot not seated?

[fuzzpuddle]

I've searched and searched, and I can't find a definite answer on this.

I'm in the process of rebuilding the Girling calipers (for my first time) from the front of an '89 325i.
I seated the piston dust boot inside the caliper, then inserted the piston using the wood block with c-clamp/hammer method. Not quite all the way in flush with the boot, but almost. The dust boot does not appear to be seating well into the grove on the piston.

Is there a certain trick to get this boot to seat? Is it possible that I pushed the piston too far or not far enough?

Any info would be greatly appreciated! Meanwhile, I'll work on the rear ATE's.

[cabriodster87]

Make sure all the rust chunks are out of the caliper dust seal groove, use brake fluid as assy lube and assemble components, easy peasy. gl

[36brua]

Maybe this? not my write up

http://r3vlimited.com/board/showthread.php?t=48505

Pull off the dust boot and carefully pry the seal out of the caliper bore.
Clean all the crud out of the piston bore with brake cleaner and let dry. Use ONLY a plastic scraper or fingernail to clean the piston.....a scratch on the piston will destroy the seal. Remove the bleeder screw and clean the passage. Blow it out with compressed air.
Install the new square O-ring seal in the caliper first.
The dust boot is internal on the front calipers. Lube the piston and caliper bore with clean brake fluid and slide the new dust boot over the center of the piston. Don't put the dust boot in the piston groove yet. Slide the boot to the bottom end (flat end) of the piston and insert the boot in the groove in the caliper. Making sure the boot is in the caliper groove all the way around, insert the piston and squeeze it in about halfway. Then pull the outer part of the dust boot out to the piston groove. Now you can press the piston the rest of the way into the caliper. Take care that the boot isn't pinched by the piston. If the boot is properly installed, it will be even all the way around.
On the rear calipers, the boot installs on the outside of the caliper. In that case, go ahead and put the boot on the piston groove before installing it. Press the piston all the way into the caliper, then stretch the boot around the lip on the caliper bore. Install the steel ring to hold the boot on the caliper.

[fuzzpuddle]

Thanks for that, 36brua. Not sure how I missed that one. All the other how to's showed the boot on the calipers first. I'll give this method a try and post results.

[fuzzpuddle]

Definitely put the boot on the cylinder first. By doing the opposite, seating it in the caliper first then inserting the cylinder, I actually sheared the lip from the boot, which explains why it wouldn't seat. Luckily I ordered two repair kits, not knowing that one kit will rebuild both front calipers.
Lesson learned. Thanks again!