14 replies to this topic

[Patchmini]

HI
I've just found a pair of metro 4 pot calipers at the back of my shed and throught that would be a good upgrade, but I can't get the pistons out as they not seen the light of day for about 4 years and are well rusted in.
Any ideas on how to get them out and can you still get new pistons and sills for them?
Thanks

[TOMMO0302]

Yes you can get new pistons/seals/nipples no problems....you should take a look on ebay at a company called BiggRed (or very similar) as they will recon and paint them for you (or more accurately send you some already reconned) for approx £75/80 and they look superb...

...by the time you have 8 pistons at £8 each, seals at about £10 and 6 nipples you are looking at the same cost!

Getting them out can be a pain!

The company is called Bigg Red and their website is here but i can;t find out their ebay name im afriad where im pretty sure they offered them cheaper!

Edited by TOMMO0302, 12 January 2007 - 05:11 PM.

[Purtsi]

I used a compressor and an air pressure pistol (or what ever that is called). by sealing all other holes in the caliper and blowing the air into the caliber, the piston literally fly off from the caliper (to the wall actually)

[Guess-Works.com]

of if pistons are scrap anyway, get the ever so useful pump wrench out and twist.....

[Retro_10s]

is there nothing apump wrench can't do? part from cure biggav!

[TOMMO0302]

is there nothing apump wrench can't do? part from cure biggav!

To be fair, has anyone tried yet? He might be game to prove Guessworks' 'most useful tool' claim?

[supermotolee]

split the calipers hold them in the vice pistons facing up get 2 lever bars (small crow/pry bar type tools) puth them both in the pison facing away from each other than lever them together this grips the piston mega tight then spin and wiggle untill they are free

[dklawson]

What's a pump wrench? Is that what we over here call "water pump pliers"?
http://www.hyperclaw...er_pump_4_L.jpg

If you're rebuilding them anyway, I agree, wrench them out. If there's any chance the pistons are still good, use C-clamps to limit the piston motion and "blow" them out a little bit at a time as mentioned above. Another method I've knows people to use is to adapt a grease (Zirk) fitting to fit the bleed nipple hole. Then you use a grease gun to pump the calipers full of grease until you blow the pistons out. Very powerful, very messy.

[TOMMO0302]

That's the one DK!

With your grease method, i assume you have to use compressed air to get all the grease out afterwards? How can you be sure its all out, or does it stand no chance against compressed air im guessing!?

I didn't think splitting calipers was at all adviseable? Although, on my first mini i accidentally undid the bolts holding them together as opposed to the ones holding them to the hubs and they went back together with no problems..

[Guess-Works.com]

when down the the bare caliper, soak them in petrol, that'll loosen off the grease...

ps, I think they are actually called pump pliers over here too... but I've always called them a wrench... more befitting the abuse they get... you don't plier something you wrench it

anyway, you lot call spanners, wrenches

Edited by GuessWorks, 12 January 2007 - 06:39 PM.

[mini1976]

Lat time I had some stuck piston's I just fitted them to the car and pumped them out with the brake pedal. Once one starts to move place a spanner or somthing where the disk would sit and carry on. The spanner stops one coming all the way out. Then repeat for the second one. I know you do then have to re bleed your system but you also get new fluid in ther too which must be a good thing. Also air sounds a bit dangerous especially if they dont come out easily you will end up with alot of pressure forcing them out at some speed when they go.

[dklawson]

Mini1976, as I read the start of this thread I understood these to be old calipers that are not currently on the car so the brake pedal method isn't necessarily a good option in this case. It certainly would work for calipers on the car.

I've always avoided splitting any car's calipers. Getting new middle seals hasn't always been possible so it was risky to do. You guys have access to more parts than I do so maybe it is OK.

Removing grease is as GuessWorks said. Since you're tearing the calipers all the way down, you scoop out the lumps of grease and follow that with pipe-cleaners and solvent to remove the rest. Soaking in solvent overnight, followed by washing using a strong water based degreaser is a good idea.

Yes, we do have a few words different from yours. After working on LBCs for a couple of decades I understand most but every now and then you guys hit me with one I haven't heard. There is one term I saw used in my Triumph's factory repair manual that even my British friends had never heard of. The Triumph people called a hub cap (wheel cover) a "nave plate". I've never seen or heard the term before or anywhere else since. I think the factory made it up.

[mark clark]

i think by "pump pliers" you might mean water pump pliers???

they're what i used to remove a seized piston in my minisport 4 pots


http://www.justoffba...ter-Pump-Pliers

[fikus01]

never ever heard of a nave plate, and neither have any of the older motoring folk i know! triumph got a loner there with that name!!

[Guess-Works.com]

The nave is an old term for the hub of a wheel, comes from cart wheels and spoked wheels etc.. so in terms of a triumph, of which quite a few had spoked wheels, the term nave may have been used hand in hand with hub