4corners

I'm having the rear diff replaced today and my mechanic friend just called and said the allen bolts are frozen and they neet to be broken off.
I am away from my regular computer and away from my Bentley so I ask if anyone can tell me the thread pitch and length of the bolts connecting the shaft and diff together. All help appreciated.
BTW- it's a '91 80q---Thanks

dtompsett

The input shaft is an M8x48 (you'll have to get M8x50's... 48mm is an uncommon length, but the holes aren't blind holes, so you can use the 50mm bolts without concern... I've done so.)

The Output shafts are M8x48 (again, need 50mm length), but they use a 12pt triple square bit... not a regular socket headed cap screw head (six point hex).

the thread pitch is the standard metric pitch for that diameter... 1.25mm iirc.

The input shaft bolts are probably tight... my experience is that they have red loctite on them.

4corners

Thanks. Know a good way of getting the stuck input bolts out without cutting the heads off?

JPCady

Use it to make a notch in the bolt head, then turn it (the chisel) to the side, and use it to walk the bolt out. With these cars, it seems that you only need to loosen it a little, then it will thread out by hand. It's how I took the half shafts out of my old 90q, and out of a Jetta that I had, works well, but renders the bolts useless.

Jake

dtompsett

grind two flats on the sides of the bolts... dremel/die grinder help a lot... heat the bolt up good and hot, then use vice grips on the flats, and a proper metric hex on the bolt... they'll come out.

Last ones I took out were a major PITA... had to do that to three bolts. The previous input shaft bolts (2 other 90q's) I've had to undo were never that bad... but were hard to start.

Merkin

i use regular 10.9 hex bolts from hardware store

CvTech

grab it with something and pray

Merkin

fire, I ended up cutting the head off and use more fire

CvTech

HAHA, you would suggest that.