Many years ago, there were a couple products listed as "top engine cleaners" that would free gummed and carboned rings. A couple really did work. But they contained some rather nasty chemicals and there was some question if they would damage catalytic converters.  The newer formulations are safer, but don't work nearly as well.  In the US, the ACDelco GM Original Equipment 10-3007 Top Engine Cleaner seems closest to the older formulations and does work somewhat, although it isn't a miracle product.  Other car manufacturers also sell similar products. Some people try Seafoam, but most report it doesn't do much.

Trying a cleaner like the ACDelco probably won't hurt anything, but none of the current cleaners will fix badly stuck rings, and ultimately a tear down will be needed.

Quote from: J88TEO on Yesterday at 13:30I have a few sets of bolts for the rear arms.

Hey cheers for the offer- will come back to you for future ones!

@MrChris
Am I now correct in thinking that the bracket is partially fixed in your car and cannot be removed?
That being the case my suggestion of using a bench vice is impractical!
I also suggest that applying heat may cause unwanted further problems.
I now believe that the bracket cannot be removed because of the rounded off head fixing, a nut remover may help, or a Stilson type plumbers wrench.
Once removed you will have one or two broken " studs" which would likely best be removed with an extractor tool or drilling out and retapping/ fitting a Helicoil as above mentioned.

Thought for the day : Understanding  the problem helps in finding a solution.

Which location exactly?

@MrChris
It is generally a corroded fixing that causes your problem, however this is not so in your case!

If possible in your situation and you have a sturdy bench and engineers vice the rounded off head could be put into the vice and turn the bracket, hopefully to release. Tighten/ untighten motion does sometimes help together with release fluid of some type.

The broken fixing, if flush with the surface may succumb to a removal tool as mentioned above if you are very fortunate. Most likely to be successful is to drill it out very carefully and accurately to the Minor diameter of the thread and then re tap it.

Fallback option if you're not precious is drill them out then re-tap, or use a helicoil kit.

You 'could' try an ester cleaner something like AutoRx or similar to free off the rings. I have read it is effective if you rigorously follow the instructions, but I admit I have never had to try it

Patience and heat are your friends here. I'd start with a good easing oil,   I use Plus Gas or I have heard Bulldog BDX is really good, also 50:50 acetone and ATF.  WD40 not so good. Give it time to work (days), and keep applying it . If you can apply heat, even moderate heat, that helps. Also if you can give a couple of sharp taps to the screw head it can help loosen corrosion.  But then you are into easy outs, left hand drill bits, Anglo Saxon vocabulary etc. If you can move it at all either way, work it to and fro, don't attempt to get it out in one go.

Quote from: jvanzyl on Yesterday at 13:18Cheers, yeah I don't think it's the arms.. just a bolt.

I have a few sets of bolts for the rear arms.

Quote from: Carolyn on Yesterday at 11:11Spray outer joints with plus gas.  Wire brush exposed threads.  Spray again.  Heat up till very hot with plumber's torch.  Crack loose.

Thanks - this would be my approach if I had more time.. having looked at the costs of replacements and how much time I have over the next week it looks like it's best to just let this place sort it.. I've had a good run doing everything else myself, I've just reached the end of energy right now.

Quote from: Call the midlife! on Yesterday at 12:14Joe has another set of rear arms for sale £175 or so, might be worth a look.

Cheers, yeah I don't think it's the arms.. just a bolt.

Current timeline is to get it back Monday or Tuesday next week and then putter about with it going in a straight line and finally rid myself of the air lock prior to dyno.