So this am I was hoping to change the final drive oil for my '90 Tip. Theoretically easy, right? Remove fill plug, remove drain plug, etc. except I can not get the fill plug to budge. Soaked in PB blaster, etc. but am working with a somewhat stripped Allen bolt. I am wondering if I could use heat but the fill plug is very close to the axle. So what now? I don't want to get metal shavings into the final drive but this bugging me. The bolt is pretty rusted and looks like it hasn't moved in ages. Any good ideas?

 

Get a new plug for when you reassemble.

If you get stuck and start looking at last resorts, get a sacrificial allen socket- 1/2 drive. Clean the nut on the trans very well, and then epoxy the allen into the plug. Let that set over night, crack loose in the morning. Throw it away.

Someone else may have a much better suggestion - but that would be my last resort.

 

I don’t remember how much room under there but maybe possible to use an impact driver you know the kind you hit with a hammer to loosen it

This kind

 

I tried an impact wrench and that helped round the plug. I have drenched it with PB blaster overnight and hope that helps.

Sacrificing an allen key may not help because the bolt is already rounded. How much torque can epoxy glue hold? I think my impact wrench delivers about 500 lb ft. I am losing the plug for sure, I already ordered a new one.

 

What about screw extractors? Worked a charm to pull a stripped bolt from my expansion valve. Shouldn't get any shavings into the trans either.

 

Yep, screw extractor is what i used to break loose a stripped hex bolt from the rear caliper. One thing though I had to cut the tip off the extractor to get it to bite good in the rounded out hex hole
I did not have to drill the hole out. After that it broke loose pretty easily.

 

How bad is the stripped Allen bolt. Dipping the Allen wrench in oil, then into fine sand takes up the slack. Has worked for me, worth a try.

 

I hadn't heard that trick before. At this point I have nothing to lose and will try this. Have been soaking it in PB Blaster for a day and will try again tomorrow.

 

I can't find any metric extractors so I will try to find a standard that fits a 10 mm rounded hex if all else fails.