Subframe bushing torque?

[ryan_george]

Hey. Just spent a few days doing the subframe and trailing arm bushings and got a question.
I couldn't find it in the Bentley (or maybe I'm just dumb), but what is the torque of the large nut for the subframe?

-Ryan

[Brew]

Braaap! Brap! Brap! (1/2" impact)

But seriously, just tighten it.

[ryan_george]

Well I put my weight into a 2' breaker bar. So it's probably tight enough then.

[FredK]

If it's M14x1.5mm then 140 Nm or 103 lbs-ft. Or braaap! brap! brap! But, what if you only do braap! brap! brap. Then 300 miles down the road, ka-chunk, ka-chunk, hmm, wtf is that noise?

[delatlanta1281]

Pft

[T.Dot E30]

If it's M14x1.5mm then 140 Nm or 103 lbs-ft. Or braaap! brap! brap! But, what if you only do braap! brap! brap. Then 300 miles down the road, ka-chunk, ka-chunk, hmm, wtf is that noise?

I can't believe i actually understand what ur talkin about.
:D

[Stu]

Like Brew said, seriously tighten the bajesus out of them. I think they call for 210 ft/lb, but my torque-spec book is not handy at the moment. Perhaps I'm wrong and someone can correct me

Just remember that this is a piece running from the body to the rear suspension. Movement of the subframe would be like a variable camber and toe setup

[nando]

the purpose behind using a torque value (rather than just wrenching on it until it's tight) is not just to keep it from falling off; by using a proper torque value (instead of say, an impact wrench) it makes it much easier to remove the nut/bolt next time you have to work on your car. I wouldn't want to try and remove subframe nuts that had been torqued to 200+ft-lbs and then rusted on, and I don't think you would either.

look, a halfway decent torque wrench is cheap (mine was under $50), and you're going to (well you should) use it all the time. for some things you can't use it because it won't fit, so you have to fudge a bit there, but on something like the subframe nuts I don't see why you would even think about doing it without a torque wrench! Things like lug nuts are much easier to remove when they are put on properly instead of an impact wrench, I've broken tons of extensions and sockets trying to remove nuts that were just way too fucking tight.

[SpecM]

-Nah man... tighten to one-quarter turn BEFORE breaking.

-I like the braaaaap brap brap! method tho!

[1991 318is]

If they weren't loose and were holding tight then tighten the same way when you put them back in. Torque wrenches are for head bolts and pinion crush sleeves and stuff like that. Most of the time even professional mechanics don't use them but they'll lie and say they do if you ask them. I've watched them never touch one for days.

[Brew]

If they weren't loose and were holding tight then tighten the same way when you put them back in. Torque wrenches are for head bolts and pinion crush sleeves and stuff like that. Most of the time even professional mechanics don't use them but they'll lie and say they do if you ask them. I've watched them never touch one for days.

Word. I really only use torque wrenches for internal engine work or clutch/flywheel bolts. There are a few guys who tighten lugs with a torque wrench, but a newer torque stick on a 1/2" impact is just fine. One thing I learned when I first started was that its a good idea to break bolts by hand, so you can get a feel for how tight certain things are. I'm sure some of the more experienced guys can torque hardware to within 10% of a spec without a torque wrench.

[ryan_george]

Well I do own a wrench, that's why I was asking. Do these things really need 210 ft.lb? Cause I probably didn't tighten them that much. I know the center nuts on the half-shafts are 150 ft.lb and that was really giving 'er.
If anyone can confirm a number that'd be swell.

[Simon S]

i can't confirm torque spec (yeah, Bentley doesn't seem to acknowledge subframe bushings) . .

but would suggest use of a stainless lock washer and loc-tite. Those, along with your "weight into a 2' breaker bar" should be more than enough to insure that those nuts are not going anywhere.


.

[FredK]

I believe that nut is already a lock nut.

M14x1.5, TIS says 140 N-m. Or 103 lbs-ft. Check out section 3AZ on the attached image.

Anyway, this is not a super critcal measurement, and putting your weight into a 2 ft cheater bar should be enough. This is an E30, not the Space Shuttle. :D

I agree that there's no reason to go overboard trying to measure this particular fastener accurately; you just want to make sure that you don't under or over tighten by too much. This is a M14 nut, it's not gonna go anywhere once you put the proper torque on it. Also, you'll know if it's loose.

This is just one of those philosophical things. Do you necessarily need to torque the front ball joints with a 22mm crowsfoot attached to a torque wrench, and make a calculation to reduce the torque wrench setting because of the additional length of the crowsfoot? Probably not. But if you're the kind of guy that uses a torque wrench to tighten the oil drain plug, you will. I'm not that kind of guy though.

A torque wrench is not the end-all either. It can fall out of calibration very easily. Especially junky quality ones, or ones that have been used full scale a lot.

Stu, I think you're thinking of the front hub collar nut. That requires 210 lbs-ft. But it's way bigger than the subframe nut.

[Axxe]

Really tight + 1.