Zootal Posted October 7, 2016 Share Posted October 7, 2016 The front brake caliper piston has a boot. One end of the boot goes into a groove inside the caliper, and the other end into the groove in the piston. How do you assemble these? If you put the boot on the piston and then shove it into the caliper, the piston goes in and the boot looks like it is in, but the lip of the boot will NOT seat into the groove in the caliper. it will just sit there with the lip out of the groove, and you can't shove it in. I even tried to push it in with a screwdriver, but it would not go, and I was afraid I would damage the boot. It will not seat, and eventually water will get in and shorten the life of the piston. If you put the boot into the caliper first, you can't get the piston in - you can't just shove it, it jams against the boot. The part of the boot that goes around the piston is quite tight and needs to be stretched over the piston, and pushing it won't make this happen. This is extremely difficult if not impossible to do by hand, there isn't enough room to get your fingers in to manually stretch it around the piston. You end up pulling the boot out of the groove in the caliper I finally got it in by first seating the boot into the caliper, and then I cut a strip of plastic from a soda bottle and used that as a guide to force the boot around the piston. It took two of us, and it was a bloody kludge but it seemed to work, as near as I can tell the boot remained seated in the caliper. Is anyone familiar with these calipers and knows what I'm talking about? Is there an easier way to do this? Link to comment Share on other sites More sharing options...
Zootal Posted October 7, 2016 Author Share Posted October 7, 2016 I've looked in two manuals, and both say to put the boot on the piston and shove it into the caliper. I think they assume the lip of the boot will seat into the caliper groove, but it doesn't. I wonder how many people assemble these things, not knowing the boot is not full seated into the groove in the caliper? Link to comment Share on other sites More sharing options...
Osei Posted October 7, 2016 Share Posted October 7, 2016 There should've been a metal ring that goes on top of the boot that seats in the groove. This keeps the boot from being pulled out too far. They are a pain to assemble at times, but way cheaper than replacing the whole caliper. O. Link to comment Share on other sites More sharing options...
Zootal Posted October 7, 2016 Author Share Posted October 7, 2016 I think that only the dual piston setup with 43mm bore has the metal ring. The 57mm bore single piston models don't seem to, at least this one doesn't have it. When I pulled them apart, there was no metal ring, nor does the caliper seem to have any place for one. And these were factory calipers, the calipers have never been touched. I think the manual is wrong. You can't put the boot on the piston and just shove it in place, there is no way the boot will magically seat into the caliper. You have to seat the boot first, and then figure out how to get the piston in without pulling the boot out of the groove. I rather strongly suspect the factory has(had) a tool for this - just a simple sleeve that expands the boot so you can slip the piston in is all it would take, nothing fancy. I was able to jury rig a plastic sleeve from a soda bottle that worked fine once I figured out how to do it. Link to comment Share on other sites More sharing options...
Osei Posted October 7, 2016 Share Posted October 7, 2016 Odd. The repair kits all show a metal clip for this unit. Either way, glad it's resolved. O. Link to comment Share on other sites More sharing options...
Zootal Posted October 8, 2016 Author Share Posted October 8, 2016 Yah, it just bugs me. I feel like I'm missing something, it should not be so difficult to put together. Back in my day (1960-1970-ish cars) the boots went around the outside of the caliper and were very easy to slip on. This one has the boot seating *inside* the bore, and is very difficult to put together. Make me think I'm missing something.... Link to comment Share on other sites More sharing options...
Zootal Posted October 9, 2016 Author Share Posted October 9, 2016 Annnddd the second went together in about 5 minutes. So, the book is WRONG. The correct assembly procedure is to: 1) Insert o-ring in groove in caliper. 2) Seat boot in groove in caliper, the groove is right in front of the o-ring groove, and the lip of the boot must be gently pressed into the groove with your fingers. It will not seat by itself, it will not magically fall into the groove - you have to push it in, which is very easy. 3) Insert piston into boot - this is next to impossible without a tool of some sort because you have brake fluid all over everything and the boot is slippery and it has to be stretched over the piston and there is no room to get your fingers in there. I used a piece of plastic as a guide - I took a soda bottle and cut a strip of plastic about 2" by 2" or so, enough to reach the bottom of the bore, and to go about 2/3 of the way around the piston. Gently pull the boot out, but not so hard it pulls out of the groove, because it comes out fairly easily. Drop the piston in place, the plastic insert keeps the one side from collapsing, and you work the other side around the piston with your fingers. Once you get the hang of it, you can do it in 30 seconds flat. I know this doesn't make much sense if you are not familiar with the caliper, but once you get in there and look at it, the above will make perfect sense. And AFAICT, some models have a metal clip to hold the boot in, and others do not. The four door legacy fwd does not have a metal clip, nor is there any place for it. Maybe later 2nd gen Subaru's have this and the early ones don't because it's so difficult to get the boot in? Link to comment Share on other sites More sharing options...
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