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amazighman

Bmw e39 530i thrust arm replacement questions?

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Hi all.

 

Finally i bought a set of thrust arms to change my failed ones and get rid of steering wheel wobble.

 

I got Meyle HD ones thanks to Dan for his recommendation.

Now the questions I have are whether i can reuse the locking nuts for the thrust arm bolt , balljoint ?

 

Do you guys load the suspension before torquing these arms? Anybody had success without doing that? If necessary whats the best method?

 

Cheers

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I believe the correct process is to weight the car. 

 

I bought bags of sand from wickes (25kg  each I think) weighted the car as per manual and torqued the arms. 

 

I then returned the sand:ph34r:

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45 minutes ago, amazighman said:

Hi all.

 

Finally i bought a set of thrust arms to change my failed ones and get rid of steering wheel wobble.

 

I got Meyle HD ones thanks to Dan for his recommendation.

Now the questions I have are whether i can reuse the locking nuts for the thrust arm bolt , balljoint ?

 

Do you guys load the suspension before torquing these arms? Anybody had success without doing that? If necessary whats the best method?

 

Cheers

 

The kit should come with lock nuts. Jack up the hub to simulate car in normal position and then tighten the lock nut to spec.

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1 hour ago, jake13 said:

 

The kit should come with lock nuts. Jack up the hub to simulate car in normal position and then tighten the lock nut to spec.

I  think these kits come with balljoint nuts only ,no Bush to subframe nut and bolt.

Was wondering if i can reuse the locking nuts or have to replace them.

Edited by amazighman

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IIRC they should come with everything that's needed

 

If not; then yes, you should be fine to re-use the nuts, but there's no harm in replacing them either

 

From my recollection; when I've had these fitted; the car was always lowered onto corner weighting boxes, so the suspension was under load before they were fully torqued down. The suspension does need to be under load for these to be torqued properly, so either as I've had done (or on a 4 post lift etc) or use a transmission jack to get the suspension under load and then torque them up

 

Failure to do this will result in them failing fairly quickly

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8 hours ago, amazighman said:

I  think these kits come with balljoint nuts only ,no Bush to subframe nut and bolt.

Was wondering if i can reuse the locking nuts or have to replace them.

 

With lemforder, they came with the lock nuts. However, use blue thread lock when reusuing the same fastner.

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BMW's TIS (dealer service manual) says to replace self-locking nuts on both the bushing end and ball joint end. Most DIYs re-use the nuts, some with Loctite, some without. I've never seen a report of re-used nuts coming loose in service. FWIW, I've seen other references that state re-using compressed/squeezed self locking nuts (as these are) up to 5 times is perfectly acceptable practice.

 

Folks who tightened the bushing end with the suspension in full droop have reported premature bushing failure in as few as 10k miles. The theory goes that the bushings are permanently in a twisted state while subjected to driving loads & this causes failure. This sounds sensible since the spec for orienting the bushing in the thrust arm is +/- 3 degrees.

 

TIS says the car should be in "normal position" which involves putting the car on the ground and adding weights to the car's seats and trunk. However that sinks the front suspension by ~5mm compared to let's call it "usual position" which works out to a change of ~1/2 degree. Compared to the orientation spec that's not a significant difference. I've done mine with the front strut at unweighted height (see next paragraph) with no failure in several years and over 100k miles.

 

Torquing the bushing end with the car on the ground is very difficult even using ramps. Many folks leave the car on jack stands and use a floor jack with a wood or rubber pad carefully positioned under the upright to jack the strut up to typical/usual ride height. Then torque the bushing end.

 

I should note that the rear suspension is a different matter. Weighting to normal position drops the rear by 25 to 30 mm over shorter arms than the trust link, so the angular change is larger. There I would use the TIS recommendation.

 

Regards

RDL

Edited by rdl
clarification

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52 minutes ago, rdl said:

BMW's TIS (dealer service manual) says to replace self-locking nuts on both the bushing end and ball joint end. Most DIYs re-use the nuts, some with Loctite, some without. I've never seen a report of re-used nuts coming loose in service. FWIW, I've seen other references that state re-using compressed/squeezed self locking nuts (as these are) up to 5 times is perfectly acceptable practice.

 

Folks who tightened the bushing end with the suspension in full droop have reported premature bushing failure in as few as 10k miles. The theory goes that the bushings are permanently in a twisted state while subjected to driving loads & this causes failure. This sounds sensible since the spec for orienting the bushing in the thrust arm is +/- 3 degrees.

 

TIS says the car should be in "normal position" which involves putting the car on the ground and adding weights to the car's seats and trunk. However that sinks the front suspension by ~5mm compared to let's call it "usual position" which works out to a change of ~1/2 degree. Compared to the orientation spec that's not a significant difference. I've done mine with the front strut at unweighted height (see next paragraph) with no failure in several years and over 100k miles.

 

Torquing the bushing end with the car on the ground is very difficult even using ramps. Many folks leave the car on jack stands and use a floor jack with a wood or rubber pad carefully positioned under the upright to jack the strut up to typical/usual ride height. Then torque the bushing end.

 

I should note that the rear suspension is a different matter. Weighting to normal position drops the rear by 25 to 30 mm over shorter arms than the trust link, so the angular change is larger. There I would use the TIS recommendation.

 

Regards

RDL

Thanks for clarifying everything RDL... brilliant post

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I just got two people to sit in the front seats (car had front wheels on blocks so I could reach underneath, wheels chocked, handbrake+park engaged). had the same effect :)

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I would still say that majority of its life the car will just stand without load. So I've always done the job without additional load, just the vehicles own weight on the hub.

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Injabe replaced the thrust arms., shaking is gone and car handles like it should.

 

Only thing left is a slight knock noise when I press the brakes... I might be a track rod end or a tie rod not sure, any ideas?

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8 hours ago, amazighman said:

Injabe replaced the thrust arms., shaking is gone and car handles like it should.

 

Only thing left is a slight knock noise when I press the brakes... I might be a track rod end or a tie rod not sure, any ideas?

Either/or both really

 

Not expensive to replace. Meyle again via bmwmotormec etc

 

Are your top mounts ok? 

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11 minutes ago, d_a_n1979 said:

 

 

Are your top mounts ok? 

My track rod ends look a bit shabby but rubber on balljoint looks fine, i ll replace them for good measure not expensive to buy.

Not sure about top mounts though but i think the knock is coming from bottom of the car.

 

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I jacked the car up and rocked the wheels trying to see if there is  any excessive movement.

Nothing found except a little side way play in the tie rods which i think it is the free play in steering lock.

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My experience is that you wont find free play by just jacking up the car

 

What happens is that as the suspension drops, the balljoint is in a position that isnt worn and therefore wont show up any play

 

I diagnosed mine by getting somone to wiggle the steering wheel whilst I was underneath feeling each joint. It soon became apparent there was wear in the thrust arm balljoint - this hadnt shown up when doing the uaul check with the front jacked up.

 

Alternatively some MOT garages have a wheel shaker, this moves the wheel up and down but with the weight of the car on the suspension.

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11 minutes ago, pt530i said:

My experience is that you wont find free play by just jacking up the car

 

What happens is that as the suspension drops, the balljoint is in a position that isnt worn and therefore wont show up any play

 

I diagnosed mine by getting somone to wiggle the steering wheel whilst I was underneath feeling each joint. It soon became apparent there was wear in the thrust arm balljoint - this hadnt shown up when doing the uaul check with the front jacked up.

 

Alternatively some MOT garages have a wheel shaker, this moves the wheel up and down but with the weight of the car on the suspension.

 

I agree, plus as they're not expensive, I'd change them out any way! 

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I figured out my thrust arm bushings are worn by using a pry bar, there was a lots of play, after removal the bushes were split in various places.

 

I will replace lower control arms, anti roll bar bushes, drop links this month, next month I would do the tie rods, if it is still knocking i will do the top strut mounts which i think it is better to fit a new shocks and springs and will be job well done , just sachs shocks are pricey , found online from Germany with top mounts for little over 200 quid.Not sure if Meyle shocks are good as they dont look they are aluminum as they are black

 

In all honesty what could i expect, the car is 18 years old

Edited by amazighman

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2 hours ago, amazighman said:

I figured out my thrust arm bushings are worn by using a pry bar, there was a lots of play, after removal the bushes were split in various places.

 

Another method is to simply "tighten" the wheel bolt and see how much longitudinal play the wheel/hub has. Of course you have to have some clue what is normal.

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Fitting some poly anti roll bar bushes Tomorrow for my E39 530i se, does anybody know the torque specs for the bushings brackets bolts?

I find the right side bush a pain to get to due to a heat shield and the way the anti roll bar is mounted above subframe, what a thing!

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