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View Full Version : Proper Torque for Thrust & Control Arms



Evan
09-21-2006, 02:02 PM
Is it wise for me to put my car up on ramps to torque the thrust and control arms?

Does anyone have any tips or tricks to make it easier?


How about the rear shock to trailing arm bolt... what's the best way to torque it properly?

Cheers,
Evan

Blitzkrieg Bob
09-21-2006, 02:14 PM
http://www.bmwe34.net/e34main/maintenance/suspension/lower_arm.htm

Evan
09-21-2006, 03:00 PM
I've read every page on Bruno's site. It's the best reference in the world for E34 DIY mechanics.

I'm looking for more specific info concerning tightening the control arm to the chassis and teering arm.. and for tightening the thrust arm to the subframe crossmember and steering arm.

Thanks for your reply!

632 Regal
09-21-2006, 03:23 PM
control arm to the chassis about 90 lbs
steering arm to strurt housing unsure
thrust arm to the subframe crossmember about 90lbs
control to steering arm about 68 lbs

these are from memory use at your own risk

mamilapon
09-21-2006, 04:27 PM
I did mine two weeks ago. Drive it on on to ramps, get a couple of your friends to sit in the front and be patient.Because it is almost impossible to get a proper torque wrench under there, I just went by how terribly hard it was to undo the nuts in the first place. So ring wrench on the nut and ratchet on the head and do them up very tight.

RobPatt
09-21-2006, 04:54 PM
... and after you put the arms on, snug down gently, no strongarming... then gently drive up on a lift, then the long torque wrench can reach, and you can torque properly... even after doing this, I still have to replace mine about evey 15K miles... even when using the 750 bushings. oh well.

Evan
09-21-2006, 05:37 PM
the only problem im having is getting a wrench on the nut to hold it from turning.. i have no problem getting at any other nut..

i let the crossmember down a little by undoing the (2) 15mm bolts and (1) 18mm bolt out.. that gave me room to get an open ended 22mm wrench on the nut... I torqued to 94 ft/lbs and the open ended wrench is now stuck in there :)

I'm thinking I may let the shop finish it up and torque the rear shock to trailing arm bolts

632 Regal
09-21-2006, 05:43 PM
you have to grind a wrench so that its real narrow so you can pull it out. Believe me I know all the tricks now. I dont even get under the car anymore, do it all through the wheel well.

Alexlind123
09-21-2006, 05:54 PM
... and after you put the arms on, snug down gently, no strongarming... then gently drive up on a lift, then the long torque wrench can reach, and you can torque properly... even after doing this, I still have to replace mine about evey 15K miles... even when using the 750 bushings. oh well.

Thats horrible! Don't the bushings from the factory usually last around 100k? Perhaps some other suspension part is worn or something is out of alignment causing your bushings to wear prematurely.

BTW, what sort of roads do you drive on and what is your driving style (sedate, moderate, spirited or insane)?

ryan roopnarine
09-21-2006, 09:12 PM
take the closed end of a 7/8 wrench and stick it in the opening, it will fit. if you don't have a spare 7/8 wrench or 22 mm wrench lying around, then i'm surprised that you got as far as you did.

figure out which direction you need to turn the torque wrench so that the 7/8 will turn towards the roof of the car and jam against the underside (ie hold still for you).

turn the wrench until you reach desired torque. at this point you can do one of four things:

1. back the nut off slightly using the torque wrench, then experiment (holding the 7/8 manually but still bracing it--enough to get it unstuck easily) until you get to the spec torque again.

2. back the nut off '' '' ''. use the closed end of another wrench to give you some leverage so you can hold the 7/8 manually and get to torque spec.

3. stick a prybar inbetween where the 7/8 rests against the car, and, after getting to spec, pry it out as little as possible to extricate it (will ballpark torque, not exact)

4. (if you can judge torques by feel), overtorque the nut as much as you think will be reversed when you back the nut off to get the wrench out.

per unkle bentlee's "vehicles of the third reich"

steering arm to strut housing: 81 lb ft
thrust arm balljoint to steering arm: 68 lb ft
thrust arm to crossmember: 94lb ft
control arm balljoint to steering arm: 68 lb ft
control arm to crossmember: 57 lb ft

usual disclaimer: no guarantees to the fitness of the instructions that i'm giving you. the numbers are from uncle bentley.

632 Regal
09-21-2006, 11:14 PM
seems strange as both bolts seem to be the same size, i just reefed them real tight.

thrust arm to crossmember: 94lb ft

control arm to crossmember: 57 lb ft