10 replies to this topic

[Big_Adam]

Evening,

I got a set of S-calipers in the garage (7.5) and as I bought them they are rusted and the callipers are stuck. I got one out via the use of a drift through the hole where the flex pipe goes and this gave me an (possibly stupid) idea.

Why not just drill the OTHER side of the calliper with a small hole (big enough for the drift) then tap it afterwards, fit a bolt with copper washer and be done.

Seems like a good idea to me but it dose mean adding a possible fail point to the calliper and I'm sure someone will point more than likely point out something else massively important.

So good idea, bad idea or "just take calliper to the machine shop" idea.

Ta for any information.

[Ethel]

I think you'd be better off connecting it up to your clutch or brake master cylinder and pumping it out. Of course, you'd have to pop the other piston back in and secure it somehow - possibly a monster socket that will fit over the stuck piston?

Changed my mind on the big socket. Bad idea, it might get stuck if you can't lever the piston back in. Use a brake pad and something really chunky across the slot where the brake disc runs - like a brake disc!

Edited by Ethel, 26 August 2008 - 02:56 PM.

[dklawson]

Adam, that's a very interesting idea for a solution.

Please don't take this wrong because I'm in no way implying that you are not very creative. However, you have to ask yourself, if drilling and tapping the caliper to provide an access hole for a drift is so obvious... why isn't this common practice? Perhaps the caliper isn't as thick as you think on the back wall. Who knows.

A method I saw used once that was heavy handed was to split the caliper and weld a bolt to the stuck piston. A huge slide hammer was then used to pull the piston out.

[freaker]

the thing ive done with the cooper ones i got whas to but them between the thing thats on your work top, to hold something when your hammering it or similar , and clamp the piston between there and then turn the caliper half and pull it gently backwards.
got a picky for it



freaker

[Guess-Works.com]

to be honest, if they are that badly rusted in the the piston bores are going to be fubar anyway....

[Big_Adam]

Please don't take this wrong because I'm in no way implying that you are not very creative.

Translation: "Adam, it's a silly idea. No".

So, I won't drill it.

Cheers folks.

[dklawson]

Once you get the piston out you may indeed find the bores have pits and rust. However, you can live with a bit of that if the surface at the bottom of the square cut gland for the seals is OK. You don't want pitting where the square cut seals sit.

[WiredbyWilson]

i used an airline on mine - did scare the be-jesus out of me when it finally went back and pushed the piston out!

I G-clamped the free piston to stop it moving then i put a blow-jet in the hole and through a rubber gromit i found, pulled the trigger and it fianlly went bang

[scrippo]

If an airline is too expensive. I used a humble bicycle pump. I cut an old mountain bike inner tube valve from the tube. Inserted this into the hole where the brake line goes (I made sure to leave enough tube around the valve to make an air tight seal around the hole), then put the piston back in and held it there with cable ties. I then pumped away..... and eventually the other piston went pop. Watch your fingers! A floor pump would probably do the same job.

This is the way I did it, but is by no means the best, just a way I saw a solution to a problem.

[dklawson]

Now Adam... I didn't say that and I don't think it's a silly idea. I really am curious why it hasn't been suggested before with people dealing with this for almost 40 years.

[partsguy1]

If you can't get it to release with air pressure, I would fit a grease nipple in the hose fitting, clamp the other piston and pump it full of grease. It is amazing how much pressure a grease gun can produce. A little messy but it should push it out.