Ah Mick, a man after my own heart.. Never use brute force when a bigger hammer will do...

The old boilermakers motto.. When in doubt, give it a clout..

One from the vaults... 3.5 years ago, in a galaxy far, far away...


I've been looking for a way to get some pistons out of my unrestored set of calipers at home - finally found this old thread - eureka! So I can get a grease gun and get angry or use some vinegar and be patient.

Mick: when you pump the grease gun, does the piston slowly drift out or imitate a champagne cork?

Morris: any caveats on the vinegar trick or post-op treatment required?

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I did exactly this job recently on a caliper off my Hilux - one of the pistons was seized solid.

I started thinking about using the grease gun, but didn't really have enough time to spend soaking the caliper in a solvent to get all the grease out afterwards, so I used my home-made hydro pump (identical to Mick's here: http://www.ausmini.com/forums/viewtopic.php?p=701886):



Now, I realise you probably don't have one of these but before I put mine together I just used a regular grease gun and filled it with glycol/water to pump up the suspension.

Same thing will work brilliantly on the calipers, and it's a damn sight easier to clean up afterwards

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Simon

The adventures of an owner builder in the Tallarook Ranges

So grease gun filled with glycol + water? I'm making a shopping list as we go.

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That's what I used, purely because it's what I already had. For this job I don't see why you couldn't just fill the gun with plain ol' water instead.

A caution though, this method is messy -- grease guns aren't designed to hold liquids so I found mine tended to leak all over the place if held the wrong way. Still somehow managed to pump up the hydro with it though, although it did take a while

Just doing a brake caliper with it should be very little trouble. Using the big floor-standing grease gun / hydro pump is no mess at all though (until the piston pops free that is, then it's SPLOOOSH!! )

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Simon

The adventures of an owner builder in the Tallarook Ranges

The piston crept out very slowly. There wasn't any bang either as the grease does not compress.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Damn that's a good idea!

I punched one piston out through the (convenient) hole, then pulled the calliper apart, put the remaining piston in the vice then a little careful tapping with the plastic hammer while twisting and it came out easy. Not quite as rusted as yours were, but still pretty crusty...

cheers

Jacob

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'72 Clubman Van - 1022cc, 295 head, 731 cam - Daily Driver
'69 Morris 1100 S - Dinged by a bus, in shed under repair
'64 Morris 1100 - Early 1100, long term project

I reckon you're caps gonna be covered in scrambled eggs before too long
CPO Mick

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'98 Mpi Sportspack + 7 port alloy head

I can add ingenuity to that list - bought grease gun at Repco + sale price + NRMA discount Took the threaded hose attachment, connected it to my bike pump (the vertical kind), got it up to about 120 PSI and she did go bang after a few secs... drifted the other piston out.

Now what to clean the calipers with? Eventual plan is to paint them.

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I simply blasted mine. I then sit down and clean them out carefully with compressed air and rodding out the few small passages.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

So best to pop the pistons back in (or for the other caliper, not pop them out in the first place) ?

By blast I assume you mean media blasting, and by rodding, do you mean some sort of flexible brush? How best to clean the (I'll call them) "piston recesses" in the calipers?

As usual, the apprentice is full of questions

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When I rod them out, I pole down the drillings with whatever I have, usually a piece of wire because they're small. The holes are drilled so are straight, and there's an inspection plug you can pull off to see straight in. Easy peasy. Wash out with turps and then wash with metho before you rebuild.

Don't use degreaser immediately after the blasting, blow it out first. Degreaser can turn the grit into sludge and is harder to remove at first.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.