clunking while applying the brakes AFTER installing new thrust arms

[twastheglow]

I'm a brand spanking new member on this forum (not new to BMW and not new to BMW forums, lol). I'm hoping you guys can help a brother out!

I purchased Lemforder thrust arms for my '95 540i to eliminate the horrible shimmy it had at highway speeds. I installed them correctly...left and right, bushing torqued down while the suspension was loaded on ramps...and as soon as I got the car all buttoned up to test drive it I now have a VERY pronounced clunk as soon as I hit the brakes. It doesn't matter if I'm going 5mph or 50mph. It will clunk every time I press the brake. The shimmy is gone, but apparently at the expense of my new clunk.

I tried unhooking the sway bar end links and the car still made the same clunk. So I ruled that out. After I put it back together I decided to take a couple mile drive to try to further discern the symptoms better. This is what I found:

The front end clunks once when hitting the brakes then again when releasing them. It'll also clunk once when applying the brakes all the way to a dead stop then clunk again when the vehicle stops; even without letting off the pedal. The car will clunk if it goes over a severe enough bump, but truly tends to remain clunk free while driving as long as the brakes are not applied. I found that applying the brakes VERY lightly will NOT make it clunk. I also found that if I travel at the same rate of speed (no acceleration or deceleration) while applying the brakes AND pressing the gas the front will clunk like over every little fault in the road. My father stood outside each front wheel while rolling the car at less than 5 mph and seems to think the clunk is coming from both sides.

I've spent 3 full days since the install going back over everything. My procedure was this...

-jack the front of the car and put both sides up on stands
-remove wheels
-loosen the sway bar bracket enough to get a box wrench in to the bushing nut to hold it while breaking loose the bushing bolt
-break loose the ball joint nut and remove
-use a pickle fork to pop ball joint out
-have one person hold the box wrench while I used a socket to remove bushing side bolt
-same on the other side
-install new arm
-install the ball joint and snug up the nut a bit
-install the bushing side and snug up the nut/bolt a bit
-tighten the ball joint nut all the way
-same on the other side
-put the wheels back on and lower the car down onto ramps so the front suspension is fully loaded
-torque down the bushing side nut/bolt
-tighten up the 3 bolts on the sway bar bracket
-torque wheel bolts

So as you can see, I really didn't touch much. And I'm having a really hard time believing it's another part all the sudden.

I think it's even more than the weight shift as it'll clunk like a mother over every fault in the road while maintaining speed while pressing the brake pedal (using both the gas and brake). I think it has more to do with the stress and pressure put on the front suspension during braking. I did have someone walk next to the car while going less than 5mph and pumping the brakes. That's how we determined it's happening on both sides...again more of an indication as to my procedure being the culprit. We did not try it with the hood open because it's coming from right inside the wheels.

With all things considered I think it's the new ball joints. Which would imply it was my installation job. But those nuts are damn tight. Could I not have "seated" them correctly since the car was in the air? Whatever it is, it's happening on both sides.

Any help would be greatly appreciated. Thanks.

-Mike

[genphreak]

I'd expect one of the arms has a faulty bush, joint or bearing if your checks were thorough. You may well be right though, it is probably a joint.

Jack it up and use a pry bar to put pressure on each and 'feel' for nice, smooth movement. Maybe you'll get a clunk :-)

However when you remove the steering arm/lower strut knuckle/tie-rod arm (part 1 in http://www.realoem.com/bmw/showparts...34&hg=32&fg=25) you may have broken a ball joint in one of the tie-rod arms. Never seen it, but perhaps they can be damaged if you bashed the old ones to remove them and didn't replace them too. They are a high wear item, so its best in to replace both tie rod assemblies as well as the arms.

BTW, the easiest (and right way), as you may well know is to use a joint puller to pressure the joint and then tap the joint to release the pin from the knuckle. Doing it this way you can't really damage a ball joint.

Hopefully this might help- but let us know.

[twastheglow]

Thank you for the reply.

If the noise was coming from one side, I would agree that it could possibly be a faulty part. But the likelihood of receiving two is ridiculously low. Low enough to assume that isn't the issue.

I did try jacking it up and using a pry bar to locate any loose parts. Nothing was loose. Everything was tight as it should be.

I did not remove part 1 in that diagram to install these arms. I literally did everything I outlined in the initial post. Nothing was removed with the exception of the thrust arms themselves; and the only other part that was "moved" was the sway bar bracket. As a side note, both tie rods and drag link (center link) were replaced a few weeks ago.

[BigKriss]

sounds like the balljoints for the control arms? or swaybar link?

[twastheglow]

sounds like the balljoints for the control arms? or swaybar link?

Right, but how and why? They're brand new.

I mentioned that I already tried disconnecting the sway bar end links and it still clunks.

[BigKriss]

i dont know mate.

your symptoms sound like bad balljoints

[twastheglow]

i dont know mate.

your symptoms sound like bad balljoints

Yeah, I definitely agree with you. I'm just not sure what to do about it.

I'm thinking I may uninstall the ball joint end of both arms and try reinstalling them I guess. I don't know what else to do. Although at the same time I don't know what that will achieve either. Is there a trick to installing them that I'm not aware of? I got the threaded post through enough to get a nut on it and tightened it up. Does it matter if the car is jacked up or down on it's wheels?

[BigKriss]

I dont think it matters if its jacked up or not. are you using hand tools or air tools?

[genphreak]

Don't trust the perfectness of your 'noise analysis' (sorry, no easy way to say it). I have been amazed how noises around cars (certainly these ones) can travel from one side or end to another and seem to be clearly something- but end up totally different. If the noise is emanating from underneath, this is to be expected.

Since you only changed the arm/bj/bush, it's the bj or the bush 1,2,3 or 4). Of course it should only be 1 part, the chances of more than 1 faulty part are incredibly low.

You can check the ball-joints with a pry bar or by wiggling the front wheels back and forth/in and out (hard) if you jack it up unsupported by the wheels.

With the bushes (in the middle of the car, not on one side so much), many people complain that OEM (non-OE) ones break on installation. it is very easy to do even if you are being careful. Many suspect these kind of complaints are due to incorrect application of the installation procedure.

I install the arms with the upper arm bush bolts loose, drop the car and tighten after bouncing the car a little. It is even more important to get this right if the car is lowered.

[twastheglow]

I dont think it matters if its jacked up or not. are you using hand tools or air tools?

Hand tools.

Don't trust the perfectness of your 'noise analysis' (sorry, no easy way to say it). I have been amazed how noises around cars (certainly these ones) can travel from one side or end to another and seem to be clearly something- but end up totally different. If the noise is emanating from underneath, this is to be expected.

Since you only changed the arm/bj/bush, it's the bj or the bush 1,2,3 or 4). Of course it should only be 1 part, the chances of more than 1 faulty part are incredibly low.

You can check the ball-joints with a pry bar or by wiggling the front wheels back and forth/in and out (hard) if you jack it up unsupported by the wheels.

With the bushes (in the middle of the car, not on one side so much), many people complain that OEM (non-OE) ones break on installation. it is very easy to do even if you are being careful. Many suspect these kind of complaints are due to incorrect application of the installation procedure.

I install the arms with the upper arm bush bolts loose, drop the car and tighten after bouncing the car a little. It is even more important to get this right if the car is lowered.

I understand what you're saying about noise emanating to other parts of the car. That could very well be the case. Unfortunately it's incredibly difficult to figure out what side the noise is coming from.

I did check the ball joints using a pry bar to no avail.

I'm not sure how to tell if I damaged the bushings on install. When I took the last set out, I could not discern ANY failure in them at all through appearance. But with the new ones installed (never mind the clunk) the shimmy was gone...meaning the bushings in this last set were bad. I would have had NO idea just by looking at them.

I did install the bushings loosely then lowered the car down to it's wheels to tighten them. And yes, the car IS lowered.

With that being said, based on everything I've read, I'm still inclined to think the noise is the result of one (or both) of the ball joints.