How to remove a REALLY stuck brake piston when it is rusted and siezed in the caliper.

[@m60kaf]

You're so patient - like the drill and tap idea ... do you think it would have come out if you had done that first?

[@MikesMercsandothercars]

I think not....but I'll soon find out as I have many more to do. I think the tapped threads would give out first....that's what happened when I used a smaller pat. Mike

[@BrianPaterson-f3i]

If it was stuck I would have used compressed air ,throw a towel over for safety first then stick a nozzle in the bleed hole and give it a blast of air,good chance of it working do you think?

[@MikesMercsandothercars]

Compressed air sounds good in theory (if you happen to have a compressor) but...if the piston isn't moving with the master cylinder and your foot on the brake, I don't think compressed air will cut it. Mike

[@konnybenzfan9708]

Don't disassemble the both sides of the caliper. These are special expansion bolts for single use only and you cant buy new one. ☝️

[@MikesMercsandothercars]

Thanks for your comment. That is really interesting because it is indeed difficult to get m12 70mm bolts with an undersized head (let alone stretch bolts) and I was surprised there were no spring washers, but…..to change the small O rings that come in the kit, you would need to take the caliper apart? It is often my experience that people leaving comments are far more knowledgeable than me so thx again. Mike

[@konnybenzfan9708]

@@MikesMercsandothercars I spoke with ATE when I tried to overhaul the calipers of my W111. They told me there is a reason that you dont get the bolt and o ring from them.

[@MikesMercsandothercars]

@@konnybenzfan9708 I have done some more research and it transpires that it is OK to split the calipers and reuse those bolts. They need to be torqued in 2 stages 12 ft/lbs first and then 24 ft/lbs. That torque wouldn't be enough to stretch an M10 bolt. Apparently, manufacturers of calipers never condone splitting calipers because if you put them back together incorrectly and they leak/fail you could potentially sue the manufacturer. Easier just to say you cant do it and not supply the parts. Mike

[@konnybenzfan9708]

@@MikesMercsandothercars Interesting. But that contradicts the purpose of stretch bolts. 🤷‍♂️ Btw: A new ATE caliper costs about 120€. Aftermarket much cheaper. 😉

[@MikesMercsandothercars]

@@konnybenzfan9708 The next video is all about rebuilding the calipers...and one of the things I mention is that it is often more cost effective simply to buy new calipers. I'm not sure the bolts in the calipers are stretch bolts...but what do I know? Mike