I just want to know if this is happening to others. I went to do a three hole oil change. All went well till it was time to take the Derby cover off. I had two bolts strip out on me. And I was using a T 27. The bad part was that after I drilled them out the first one came out no problem with and easy out. The second one was not so good the easy out broke off. It took about 9 hours to get the bolt out and a big pain. I got new bolts and installed them. But I went 10 pounds under torque specs. But this is the problem 2 months later I go to adjust my clutch and I had two more bolts strip out. Is there anything I can do differently to stop this. Thanks Jim

 

Are you using thread locker?

That hasn't been an issue for my EVO, twinkie or m8.

 

Do you loosen each one fully before loosening the others? If so:

I always loosen each one a half turn first in the same manner as torquing them, then loosen them all the way. This takes the tension off the screws put on by the derby cover if the holes are out by a fraction or two.

I don't use loctite and just torque them to the normal torque after starting and hand tightening them down in the pattern shown in the service manual.

 

DONT use Torx, go to allen head.....thats what I did.....

 

 

OP This guy says it right

WP

 

No thread locker just torque and went 10 under this time and I just lose them a little in the same pattern I torqued them. And I think that I will probably go to a allen head this time. Looks like I will have to have it off this week I lost my stator or regular on Saturday.

 

Before switching to allen head, consider this.

I suspect the majority of failures are due to poor fitting tools.

 

I agree with this statement Barney, but from the pictures above, it looks like a metric Allen Wrench in an SAE Socket head, lol. That diagram looks like a VERY sloppy fit to me. 60* in one direction (tighten), then 60* in the other direction (loosen), would give your Allen Wrench 120* of slop as soon as you put the wrench to the bolt?

 

Torx is stronger/better than allen. The issue isn't the type of drive, it's the dissimilar metals that corrode and get the bolt stuck in there. Your allen head bolts are going to do the same thing if you don't use antiseize.

I switched mine to allens because that was what was available locally, but since then, I bought a whole box of T-27 head new bolts from McMaster Carr. Yes they were expensive--over a dollar a piece with shipping. But having new bolts and chasing the threads with a tap and using anti-seize should fix them for a long time.

I also bought a T-27 torx screwdriver and rather than torque them, I snug them up with that at the suggestion of some guys here.

I managed to get all of mine out by using an impact driver but I thought I was going to be welding a nut on them or drilling too; mine were pretty corroded. But changing to another drive is not going to change/fix the problem, the problem is stainless screws going into aluminum threads.