Subaru 4-pot Piston Removal/Rebuild

[JayGold]

Recently tracked the sedan and in the process melted the outer piston seals on my front Subaru 4-pot's. I purchased the caliper pair overseas without prior knowledge of use or mileage on them, they were from a '98 WRX Spec RA.

Seven years later I believe they are due for a rebuild (purchased the Subaru seal kit 26297FA050), other then removing the calipers and with use of compressed air forcing the pistons out, is it safe to remove the pads, unbolt the calipers from the vehicle, leave the lines attached and appily pressure to the brake forcing the pistons out safely? Then disconnect the lines and drain the calipers for clean-up and rebuild.

Would this technique be detremental to the caliper in any way?

Has any one ever disassembled a 4-pot caliper to view the internal components? Do these wear?

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[Loaf]

Wow, excellent question..

I think you may be able to get them rebuilt in the UK by a company called godspeed uk or something.. have the link at the office.

I was also wondering this, for service in the states.
ALex

[JayGold]

Originally Posted by Loaf

Wow, excellent question..

I think you may be able to get them rebuilt in the UK by a company called godspeed uk or something.. have the link at the office.

I was also wondering this, for service in the states.
ALex

Alex, I'm rebuilding them myself.

[Uncle Scotty]

Originally Posted by JayGold

Recently tracked the sedan and in the process melted the outer piston seals on my front Subaru 4-pot's. I purchased the caliper pair overseas without prior knowledge of use or mileage on them, they were from a '98 WRX Spec RA.

Seven years later I believe they are due for a rebuild (purchased the Subaru seal kit 26297FA050), other then removing the calipers and with use of compressed air forcing the pistons out, is it safe to remove the pads, unbolt the calipers from the vehicle, leave the lines attached and appily pressure to the brake forcing the pistons out safely? Then disconnect the lines and drain the calipers for clean-up and rebuild.
Would this technique be detremental to the caliper in any way?

Has any one ever disassembled a 4-pot caliper to view the internal components? Do these wear?

....do it.....put a piece of 2x4 or some such in the caliper between the pistons so that they all push out far enough to pull the rest of the way out....without having one/2/3 push out and leave one/2/3 stuck....if ya get my drift....

....and all the hardware(EXCEPT the pad pins) for the last years Nissan 300ZX TT(Z32), including the rebuild kit, and pads....will fit/work for the 'Subaru' 4-pots...red or black, they are the same, but for the color

[JayGold]

Originally Posted by Uncle Scotty

....do it.....put a piece of 2x4 or some such in the caliper between the pistons so that they all push out far enough to pull the rest of the way out....without having one/2/3 push out and leave one/2/3 stuck....if ya get my drift....

....and all the hardware(EXCEPT the pad pins) for the last years Nissan 300ZX TT(Z32), including the rebuild kit, and pads....will fit/work for the 'Subaru' 4-pots...red or black, they are the same, but for the color

I completely understand. Wedging a block of wood with in the caliper (once removed) to take the space of the rotor and pads would effectively allow the pistons to extend far enough out for safe removal by hand. This way I can confirm if one piston extends or both equally...further providing some feedback for possible failures within the caliper (ie. seized pistons) because I really don't know the current condition of them other then the fact that they do stop the vehicle

Thanks

[Loaf]

still confused.. Slow morning..

Not following the whole wood thing inside the caliper space where the pistons are..

Can we get new pistons for these from nissan.. are there any other seals besides piston seals that would need to be replaced..

Alex

[infantsam]

Originally Posted by JayGold

Recently tracked the sedan and in the process melted the outer piston seals on my front Subaru 4-pot's. I purchased the caliper pair overseas without prior knowledge of use or mileage on them, they were from a '98 WRX Spec RA.

Seven years later I believe they are due for a rebuild (purchased the Subaru seal kit 26297FA050), other then removing the calipers and with use of compressed air forcing the pistons out, is it safe to remove the pads, unbolt the calipers from the vehicle, leave the lines attached and appily pressure to the brake forcing the pistons out safely? Then disconnect the lines and drain the calipers for clean-up and rebuild.

Would this technique be detremental to the caliper in any way?

Has any one ever disassembled a 4-pot caliper to view the internal components? Do these wear?

Other than being messy that should work

The trick is getting them all out at the same time - it's like a barrel of monkeys

Clean it well and look it over for and cracks or signs of fatigue but as it's cast iron it should be fine

Check the bore and piston (specs anyone?) - hone the bore and put it back together

I'd guess the pistons will eventually wear - just maek sur eyou replace with steel and not phenolic

[JayGold]

Has anyone disassembled the each caliper half, such as shown in the diagram below? Its a generic illustration but if the Subaru 4-pots have seal #4(as shown below) I may damage these or need replacements once the halfs are seperated from each other.
Am I making this more difficult then it really is?

[JayGold]

Here's another pic of a generic exploded calpier assembly view for those interested:




Some good info can be found here:

http://www.head2head.free-online.co....er/caliper.htm

[BIGSKYWRX]

I've mentioned this a couple of times earlier- someone needs to do a good tutorial w/ pics on a rebuild.

Mine are still like new, otherwise I'd volunteer

[Uncle Scotty]

....the damn things are just about bulletproof, by most accounts....

[BIGSKYWRX]

^ Did you end up getting an 06 ?

Mike

[infantsam]

Originally Posted by BIGSKYWRX

^ Did you end up getting an 06 ?

Mike

maybe he'll be nicer to the noobs now - me included