how can i compress HP2 caliper pistons?
11-16-2008, 08:34 AM
#1
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how can i compress HP2 caliper pistons?
well i accidentally stood on the brake wit the caliper off the rotor when i was trying to break the axle bolt loose... the pistons are fully extended and will not just slide back in... i feel like there is some sort of alignment slot or something that is preventing my from just pushing the piston back in. i had a c-clamp in it but once i realized it was not budging i stopped before anything got damaged/crushed...
so guys, what am i missing here? TIA
so guys, what am i missing here? TIA
11-16-2008, 09:37 AM
#2
If they're all the way out of the caliper, you have to be VERY CAREFUL....
most often, once they are beyond the seal, they're done for..
I'd remove the caliper from the car, and try to very very carefully coax the pistons back into their homes.
I'd remove the caliper from the car, and try to very very carefully coax the pistons back into their homes.
11-16-2008, 02:47 PM
#5
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I agree. Once out of the caliper, old seals will be unlikely to be good once re-inserted.....
there is always a layer of muck built up around the un-used part of the inner bore which will most likely have damaged the seal - a bit like the lip at the top of a cylinder bore.
Try by removing it completely and then clean up the whole inner bore - with brake fluid on lint free cloth - nothing abrasive. Then the piston will have to be pushed in exactly square to the bore with plenty of brake fluid to lubricate it.
The only consolation is that it is unlikley both will have come out too far as once the first pops out all the pressure will be lost.
Good luck and assume you will need to find a good replacement caliper - not too hard as there are many who replace them anyway.
Try by removing it completely and then clean up the whole inner bore - with brake fluid on lint free cloth - nothing abrasive. Then the piston will have to be pushed in exactly square to the bore with plenty of brake fluid to lubricate it.
The only consolation is that it is unlikley both will have come out too far as once the first pops out all the pressure will be lost.
Good luck and assume you will need to find a good replacement caliper - not too hard as there are many who replace them anyway.
11-16-2008, 03:55 PM
#6
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Re-build kits w/ new seals and boots are available from the dealer, no need to...
...replace entire caliper - I have the part number for the re-build kit around here somewhere if anyone needs it, about $15 IIRC.
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11-16-2008, 06:11 PM
#8
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bummer - be very careful with the seals, as others have said. Best to use a
tool that looks like this one:
<img src="http://www.harborfreight.com/cpi/photos/34300-34399/34304.gif"><ul><li><a href="http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=34304">Clamp available here:</a></li></ul>
<img src="http://www.harborfreight.com/cpi/photos/34300-34399/34304.gif"><ul><li><a href="http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=34304">Clamp available here:</a></li></ul>
11-16-2008, 06:27 PM
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do you/anyone have a diagram of what exactly the inside of the caliper looks like?
like an exploded view of the piston bore/piston... or possibly just picture of the caliper taken apart?
11-16-2008, 11:59 PM
#10
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There is not much to see. The piston is, well, a plain hollow piston with a groove....
machined round the perimeter on the inner end for the seal and the inside of the caliper is simply a cylindrical chamber with a small hole for the fluid on the upper most side at the inner most edge.
Very simple parts with nothing complex to be concerned with - unlike the rear calipers.
Very simple parts with nothing complex to be concerned with - unlike the rear calipers.