Over-tightening cost $$$$

[L84THSKY]

Just pulled my diff out today, to have the halfshaft seals and drive shaft seal replaced. Seems my buddy over tightened the top 4 bolts that hold the diff onto the carrier. Two snapped off, while trying to remove them. We brought the diff to a local shop, and they replaced all my seals and gaskets, with the BMW parts I supplied. The job cost $310.00.:frown:

Reality is, the job would have cost only about $110.00, the rest is the time to drill out the busted bolts. This time I put anti-seize on the bolts, and they went in hand tight till I needed to torque the last few turns.

I had my rear wheel bearings replaced at a cost of $500.00, because my buddy over tightened the hub nuts too tight. Both over tightening issues happened at the same time while doing the whole halfshaft/diff swap last year.

A very valuable lesson.:smile:

[aceyx]

If just the head snaps off the bolt, try these: (http://www.irwin.com/irwin/consumer/jhtml/detail.jhtml?prodId=IrwinProd100519)
or these: (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=120126397647)
and a WHOLE lot of penetrating oil. A hammer helps, sometimes you'll need a propane torch.

During reassembly, I have a syringes filled with Mobil1, Krytox, grease, red/blue loctite, anti-seize that I use on the bolts. It's incredibly handy and less messy, making me more likely to remember to use it.

Also, any job that you do, re-torque the bolts after 50 miles.

[larryn]

Damn, L84THSKY, I remember you having some other over loose, or over tight problems in another thread, right after you installed the diff. Sorry to hear.

Is there a moral to both stories though (other than foregoing the 8th beer on automotive projects, and having ham-fisted friends help)? ;)

[DustenT]

Did you use an air ratchet or impact driver to tighten?

[teetime4one]

do it yourself from now on!
you only have yourself to blame the next time.
besides, i get the feeling your friend is "learning" on your car and not at the local community college like he should.

[L84THSKY]

Both issues I had with the hub bearings, and the diff bolts were caused during the same diff/halfshafts swap last year. My friend figured the tighter the better.

Damn, L84THSKY, I remember you having some other over loose, or over tight problems in another thread, right after you installed the diff. Sorry to hear.

Is there a moral to both stories though (other than foregoing the 8th beer on automotive projects, and having ham-fisted friends help)? ;)

[L84THSKY]

Neither.

We just use brute force to tighten. My torque wrench wouldn't fit to tighten the diff bolts. The hub bearin nuts could of/should of been torqued correctly, since I could have fit the torque wrench for that part.



Did you use an air ratchet or impact driver to tighten?

[L84THSKY]

I didn't leave the car with him, we were both side by side. He is my my tightener and loosener, I'm not getting any younger. In other words, I'm the brains and he the brawn.

do it yourself from now on!
you only have yourself to blame the next time.
besides, i get the feeling your friend is "learning" on your car and not at the local community college like he should.

[Mallard]

do it yourself from now on!
you only have yourself to blame the next time.
besides, i get the feeling your friend is "learning" on your car and not at the local community college like he should.



i was gonna say the same,

who is your friend?? King Kong ??

[teetime4one]

lol

[angel318ti]

so you bolts were torqued to german specs.................. Guten Tight................... sorry thats my idea of humor.

[teetime4one]

ROTFL

[JedzE36/5]

lol

[b.u.ti-ful]

Too bad about your snapped bolts.

I've been using the same torque wrench I bought when I was 16. That was 26 years ago.

When I can't fit the torque wrench in the space, or I'm just too lazy to bother, I think of it this way:

10 ft lbs = small wrench, just snug it down, nothing more.

15 ft lbs = small wrench, snug it down and then give it a little 1/8 to 1/4 turn grunt.

25 ft lbs = large wrench - tighten it down and add solid 1/4 turn grunt.

When I had to do 85 ft lbs on my bike's fork spring retaining nuts it was a serious vein in the neck bulging crank-up.

For aluminum threads always use a light touch.

So, even if I can't fit the torque wrench in I still look up the spec so I know what the engineer is after.