HarleyTechTalk

1990 FXR rear caliper bolts froze. Been soaking with PB Blaster but no go. Used a hammer impact with no luck. It has rubber bushings and it is loose. Is the bolt a special ? Looks like a Torx bit. Don't really want to use any heat. Open for help. Thought about using a air impact but afraid it would just ruin the bolt.

do what you have to to get them  off  then replace bolts  your year uses a t40 torks  and new were t45
I usually weld a nut to them and 1/2 inch impact spin them off replace and never sieze the threads 

You may have to use heat if someone in the past used red loc tite on that bolt...

Tried heat No Go Will try some more heat. Head is stripped now. If not I will have nuts welded on. Am I right in thinking these bolts only thread is on the head and they only thread into the outside of the caliper? That is what my parts book shows. I know the rubber inserts are gone now as from the caliper being loose and after the heat got to them. I ve never had a bolt this stuck.

I have found a mixture of 50% acetone and 50% ATF to be the best penetrating solution.
It even finds a way to seep out an oil can with a seam.
Worth a try.

I got this:
https://www.ebay.com/itm/CHROME-REAR-CALIPER-MOUNT-BOLT-SET-Replaces-OEM-No-44039-86-FXST-1987-1999/142354086925?hash=item2124f6fc0d:g:y3AAAOSwtZJY9to2
I also had one bolt that had I partially rounded out the torx area, and if you don't want chrome you can get a black set.  All of them seem to come with the rubber bushings which don't last that long, but I am thinking that someone put these in with Loctite, which is a no-no imo.  I just replaced all my rotors and used my electric impact gun (mine is 110 volt) to get the torx bolts out.  you would not believe how tight they were in.  Impact tools actually seem less likely to ruin fasteners than hand tools.  Might want to see if you can hammer your torx bit in then use the air gun on it after applying plenty of heat.  I doubt any sort of penetration solution will work at this point.

You Could just step drill them beginning with a 1/8" and going incrementally until they're removed with an easy out. Use a Thread Chase to clean the thread good prior to re-inserting new bolts.

I tried my electric impact and it just rounded it off. That was after two days of PB and heat. So will try to weld it this weekend and use a air impact on the nut. If that doesn't go I will have to take it all off and look for a machine shop. Wish me luck.

Got them off. Thanks for the idea's. I had a bud weld the 1/2 nuts and we took them right off. Couldn't tell if there was any sealer on them but I am going to put a good dose of anti seaze on them and not over tighten.

No need for a good dose of anti-sieze, just a small dab'll do ya. Don't over do it. If you have a thread chaser, you may want to clean the caliper threads up first.

In the future, use the 50/50 voodoo juice or buy a can of Kroil.

They used that same caliper till 1999.  Every time I take the back wheel off I remove it.  It is not necessary but for me it makes reinstalling the wheel a bit easier.  I use a tiny bit of grease on the pin part of these bolts.  I think the bracket slides on them.  In the future I might add a little to the threaded part as well.  They are usually in pretty tight every time I go to remove them.