Hose fittings for brake caliper piston removal

[mangocrazy]

I wasn't really sure what section this should go in, but as it involves a compressor, I thought I'd put it here. If the mods think it belongs elsewhere, please move it.

Anyway, I've got a 1980 Lancia Beta and certain spares are getting hard to come by and/or expensive. I have a spares stash which includes about 6 old brake calipers that I want to renovate and get back to a useable state. I've managed to acquire enough seal kits to renovate all of them, but a lot of these calipers have been sitting around in a box for over 20 years.

I'm intending to dump all these calipers into a bucket full of diesel and forget about them for a month or so. When they're as freed up as they're going to get, I want to blow the pistons out with compressed air. (Yes I will be very careful not to point the caliper at myself, passers by, windows or small furry animals when doing this...)

To do this I'll need a banjo clamped on to a hose at one end, and a Schrader type valve clamped on at the other. Does anybody sell something like this, or will I need to get one made up? If I need to get one made up, where would I get the fittings from? Pardon my ignorance; I'm a total compressor newbie...

 

[exciton]

Hi there,

Not sure if it will work for you but previous when I had two seized calipers on a Peugeot I was able to free them with a foot pump. I used a conical plastic nozzle adapter that came with the pump to allow it to blow up air beds etc. I was able to hold this in pace on the caliper by hand and then cautiously pumped. Both popped out easily.

Cheers
Mark

 

[gordon stephenson]

I have removed seized pistons from calipers a few times using a lever type grease gun adapted to fit, safer than using compressed air and the lever grease guns can develop up to around 7'000 lbs psi.

 

[Wallace]

If they are really stuck Gordons hydraulic method with grease will be safer and easier or use a hydraulic hand pump.

 

[rtbcomp]

+1 for grease or other liquid.

 

[Lawnmowerboy]

+2 for grease gun, weld a grease nipple to a union and pump away, It shouldnt go with a bang as the grease can't be streched when it comes out.

 

[500e]

Grease Gun or body ram pump, but if seized that tight pistons will be shot chrome long gone, especially on a Beta that's a heroes job to start with, had one when new you could hear the rust, had a Monte Carlo as well, I never learnt, lovely road holding if set up properly.
Factory bought a lot back, they went to a Somerset yard where they were removed from the gene pool, the yard was told on pain of death not to let any escape.

 

[normspanners]

You can get a goodridge hose made up to suit the caliper and the grease gun for about |£15 with metric banjo at one end and 1/8 bsp the other to fit the grease gun it all will fit perfectly, then you can have the pistons ground and resized to standard with chrome at a hydraulic rod rechromers.

 

[mangocrazy]

Thanks for the replies - so basically I need to buy something like this:

http://www.ebay.co.uk/itm/GREASE-GU...t=UK_Hand_Tools_Equipment&hash=item4ab4a7e2ce

And then get a Goodridge hose made up with metric banjo (M10, in my case) at one end and 1/8 BSP at the other and I'm good to go...?

 

[dannymac]

A blow gun pressed into the hole will do it,,they dont come out that fast after 20years ,feather the trigger just wen it starts moving,it will pop out eventually into ur hand,jeezz,i wish the did come out that easy!

 

[Lawnmowerboy]

I wouldn't use a pistol type one, The best ones are the big cartridge lever ones, Work at enormous pressures. If you can weld, Weld a m10 brake union to a plain old grease nipple and pump!

 

[steveo3002]

i used a air gun like this
http://www.ebay.co.uk/itm/Snap-On-B...202?pt=LH_DefaultDomain_3&hash=item35c42cf482

the rubber end seals enough to push them out ...put a block of wood where the pads would be as they come out like a bomb

 

[normspanners]

I did some old RollsRoyce 4 pot ones a few months back they where seized solid and did them with the grease gun if 2 or 4 pots you will find one side will go easier, the ones that move easiest will push out first, so just disconnect the hose and push them back in, then clamp the easy pistons in , because they will pop out with an airline when the caliper is stripped, then push out the seized one, on 4 pots have few strips of thick steel to use as shims to keep the seized ones moving one at a time till you get to the good chrome and they move easilly. Because once you have popped one piston its game over for the seized ones.

 

[mangocrazy]

Hi Norm, yes - I've done bike calipers that are 2 or 4 piston, and there's always one piston that's free and one (or more) that's seized. With opposed piston types I stick a block of wood of a suitable size into the groove where the disc would run then wrap a big old rubber band (cut from an inner tube) around the lot, so that none of the pistons can come out too far. With bike calipers most of the time you can split the two halves, which makes things a bit easier.

Unfortunately the Beta calipers are of the sliding caliper, single piston type. Worse still, the aluminium piston is mounted in a cast iron carrier. Add in 20-30 years of differential corrosion and the two become welded together. And you have to get the carrier off before you can do anything to the caliper. The only approach I've found that works is loads of penetrating fluid (or a long soak in diesel), copious amounts of heat, a big solid vice, judiciously applied hammer blows and lots of swearing. And that's just getting the carrier off...

 

[Fergus]

The last really stuck calipers I had ended up attached to my old hydrolastic pump via a Metro Schrader valve.

 

[Wallace]

Alloy pistons might be a bonus, do you know what the calipers are made from?

 

[mangocrazy]

Sorry - I lied. The caliper bodies are aluminium, the pistons are chromed steel. I meant to say 'Worse still, the aluminium caliper is mounted in a cast iron carrier.'

The calipers will be getting immersed in diesel any day now...

 

[PSweeney]

I use a blow gun and a latex glove finger as a seal. Put the caliper in the vice, put the latex finger over the end of the blow gun, prick the latex and press it into the thread hard forming a seal, give it one big blast at about 150psi and it'll pop out, done a few like this. No greasy mess to clean either

 

[normspanners]

If a brake pedal with several thousands psi wont move a seized piston an air line with max 150 (even if you can get a perfect seal) has no chance.
An air line will only move unseized pistons.

 

[lloydh]

A blow gun pressed into the hole will do it,,they dont come out that fast after 20years ,feather the trigger just wen it starts moving,it will pop out eventually into ur hand

I removed some non-seized pistons with a blow gun and I wouldn't have wanted my hand to have been in the calliper! It could be there's a knack to it but I'd pad the caliper with a towel to catch the piston, just to be safe.