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Stuck Caliper Piston


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a couple of evenings this week for me has involved sorting out some brake calipers for the mother-in-laws discovery, not that exciting until 1 piston refused to come out. I thought a few of you would be interested in the fun that followed....

The easy way of doing this is to strap the caliper down on a Mill Table, naturally the mill at work was busy so off to the colchester we went.

First thing i did was turn a "peg" that fits the offending piston and the drill chuck of the Lathe, hods the caliper so you have 2 hands to see where the Jaws will end up... I then wind the jaws in. Remove peg and keep nipping each jaw until its tight.. Dont go near it with a clock.

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Then make a hole right through the end.

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followed by a bigger hole.

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And then start boring.

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Eventually you'll end up with a very lopsided hole that you can start pealing the metal away with pliers giving you more of an idea where your going.

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A bit more boring after the above picture brings you to a point where the metal will start to curl as can be seen at the bottom of the next picture.

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Where you shove (with care) a flat bladed screwdriver under the thin bit of metal and the crusty bits should release and a good tug with the pliers should give you:

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The same theory should work on anything that has a liner that needs removing. I hope a few find this interesting/useful.... if not, thats 15 minutes of my life I wont get back.

Cheers, David.

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I had the same problem with the callipers on my Disco, my method was to drill and tap the rear of each piston with a 1/8" NPT and use a drift to knock the offending pistons out and afterwards screw in socket head stainless steel plugs, effective and simple. I honed the bores and fitted stainless steel pistons in the hope that I don't have the same problem again, but if I do it's now an easy fix, unscrew the 1/8" plug and use the drift !

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Quite interesting and I commend your efforts.

I've never rebuilt a caliper for my landy and don't ever intend too. The time, uncertainty and shear effort that can go int doing it I find is vastly overrated, especially when refurbished calipers you can pick up for a reasonable price these days.

But good effort :)

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It would probably let go if you sat it on its back and filled the dirt seal gap with phosphoric acid. It penetrates and converts the rust.

I suspect that I actually would have picked up a welder and given it a few runs to shrink the piston? It's my weapon of choice for most jobs ;)

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Inspired by this thread,I literally did this yesterday, welded a scrap bolt to the inside of the piston, once it had cooled off I freed things of with a spanner, and once cooled a bit they popped out with two screwdrivers very easily.

This is on calipers that have been sat outside in rematch open for 10 years.

About 5 mins per piston come the end :)

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I push them out with air.

Don't strip the caliber apart. Get some flat bar and bend up 3 ''C' shapes the fit over the caliber body and piston such that it stops them coming out.

Get a tyre valve and shape the end that would go in the rim into a cone. Put valve in a foot pump. Put on a full face visor, ram the tyre valve in the fluid inlet on the caliber and pump.

3 Pistons will come out against the bend steel C's. The 4th will pop out.

Replace seals and piston, swop over the C's and continue.

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How thick is the bottom of the piston? Why not drill and tap the bottom of the piston then use a screw to jack it. You shouldn't drill the caliper by accident as there usually extended when you want to get them out and any scratches from the screw wouldn't matter as they're on the back. Just thinking people at home are more likely to have a drill and tap than lathe :)

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Mine were fully home, don't know how thick the piston was, but it was on morris ital calipers, not LR.

Personally I wouldn't drill and tap either way, if grease didn't move it, it needed freeing some other way than just pushing, you could crack the calipers, it is only cast after all.

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Was it on here someone posted a link to a mini sparker for getting studs out? If anyone had one of those you could use that I guess, don't know how good they are? If a bit of hardened tooling gets broken at work I often have take it to be sparked out :glare:

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  • 2 weeks later...

Quite interesting and I commend your efforts.

I've never rebuilt a caliper for my landy and don't ever intend too. The time, uncertainty and shear effort that can go int doing it I find is vastly overrated, especially when refurbished calipers you can pick up for a reasonable price these days.

But good effort :)

I did the front calipers on my 110 the other day and it is pretty simple and quick provided you aren't into painting them. Even getting the retaining rings in was easy using a tip I read on here somewhere, I just used a piece of flat steel plate and a G clamp. After all I'd read I thought they would be a nightmare but they were quite a relaxing job :)

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Given the costed time/effort of doing this, and the cost of new OEM [Lockheed/Delphi] calipers. I really wouldn't bother.

I can swap a caliper in 15 minutes, including brake-bleeding. And then know I won't ever be seeing the vehicle again for the same issue (unless $CLIENT insists on keeping it for a decade).

OK, if you're in some faroff place with no decent spares-support you *might* want to machine-out the cups and rebuild a caliper - but it'll probably take just as long to source a new set of cups/seals as it will to source a new caliper.

And the labour-costs will be as much as the cost of a new caliper.

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