I wanted to do a fluid change in the rear diff of my e36 and found the plugs to be quite stuck. I'm wondering if I use a longer cheater or maybe even a floor jack to gain more torque am I at risk of cracking the case (or something else?) I'm guessing the tool will fail before, but I don't know. I think I'd rather leave the old fluid than buy a new rear diff. Thanks
Before you over torque try some penetration lubricant first, let sit over night, and if still needed apply a little heat around the plug with a propane torch to see if that loosens things up. Watch out for any nearby rubber or plastic and not too much heat. You could also try tapping gently with a hammer to see if busts lose. Should come out with one or more of these 3. Be gentle!
DO the Fill hole FIRST!!!!! If you get the drain loose and then can't get the fill loose you are in trouble. GR
I think you're on track with penetrating oil and a cheater bar or a deadblow hammer on your wrench. Probably okay but I would avoid using a torch in that area of the car !
I've tried the all the above and definitely working on the fill plug first. Maybe I didn't give the penetrating oil enough chance to do its thing. I think a little more penetrating oil tonight and another try this weekend. So if these guys are permanently seized or damn nearly, do you think it is possible to break the case or torque it enough to break the seals and cause leaks?
Penetrating oil is not going to do anything. This is sealed with a crush washer. Put your ass behind it with a big cheater bar. Really, it'll be OK. Rock it a little as well.
Thats why I was thinking of the floor jack and using the weight of the car. With the jack I could put steady torque on the thing a little at a time. I would think a ton or 2 of force would be sufficient.
Impact torque is often better, like a sharp hit. I know you don't have much clearance with it on stands, and I don't recommend you try to kill yourself by rocking the car on top of you. You can try the jack thing, but make damn sure the allen wrench/socket is all the way in so you don't strip it.
I'm going to have the rear end on ramps when I attempt the loosening. If I can't get it to go, I guess I'll take it into my local indie. They are really good and probably have better access on the lift. I'm kind of curious as to the Allen plugs in the first place.
I agree with paul...put some mucle behind it and i would use a breaker bar with a pipe on end of bar for more torque...Place the car on ramps then when you get them loose you can alway put the jacks back under if you need more clearance. Good luck
After letting the penetrating oil do its thing for a couple of days, those plugs came right out. Thanks for the advice all.
+1. An air socket wrench (ratchet) is your best bet if the only clearance you have are jack stands. An air ratchet works for me everytime: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=91002