Installed new thrust and control arm bushings (only) last weekend

[Jeff N.]

Interesting job. Bit of pain but really gives you a good understanding of how the frontend works.

Inspection showed that the ball joints themselves all looked really good. No play and the boots were in good shape. Bushings seemed to be another story. If you grabbed onto the thrust arm, you could deflect the arm if you pushed/pulled on the arm itself. Bushing itself *looked* ok - plastic plug was all there and no tears. Still, figured all the track work, stiff sways, etc had softened up the bushing and it was time for new ones. Additionally, the car had really started tramlining badly in the last couple months which was really annoying.

Decided to just do the bushings themselves and not the whole arms. Co$t was a big factor. 2 thrust arms, 2 control arms from BMA were getting close to $400. 2 thrust bushings and 2 control bushings were just $56 or so. Much better.

After consulting with the one of our resident experts, decided to go for just a bushing replacement. Bill suggested pulling the entire "steering knuckle" vs attemping to pull all three ball joints. Huge suggestion! All I needed to do was to pop one tie rod end and then pull the three bolts holding the knuckle to the strut and the 2 bolts for the bushings. Of course, to get access to all this, I had to drop the strut and hang the brake caliper.

Once the knuckle was out, I took them both to a local Midas and they pressed in the new bushings for $50 for all 4.

Re-installed the setup and whoohoo! What a nice improvement! The car was much much stiffer overall, better turn-in response and the tramlining was basically gone. VERY happy with the results. Worst part of the job (I think) was figuring out how to torque up the bolts with a load on the front end. The thrust arm bushings need 96 (!) foot/lbs - not easy when you have the wheels loaded. I used some 4x4 blocks to set the wheels up but that 18" pull on the torque wrench didn't help... Some ramps would have been really nice for sure!

Moral to the story I suppose is that those bushings seem to last about 60K miles and then they get soft. Even when they are not torn, they loose their stiffness. As these bushings work in tandem to locate the bottom of the strut, the strut then can move dramatically contributing to tramlining and other front end issues. I wonder if this isn't a cause of some of the tramlining complaints for our cars?

Cheers!

Jeff

[Robin-535im]

I've wondered about cooling brakes on E34's - Do I read you correct, is there some factory setup?

- Robin

[Bill R.]

Interesting job. Bit of pain but really gives you a good understanding of how the frontend works.

Inspection showed that the ball joints themselves all looked really good. No play and the boots were in good shape. Bushings seemed to be another story. If you grabbed onto the thrust arm, you could deflect the arm if you pushed/pulled on the arm itself. Bushing itself *looked* ok - plastic plug was all there and no tears. Still, figured all the track work, stiff sways, etc had softened up the bushing and it was time for new ones. Additionally, the car had really started tramlining badly in the last couple months which was really annoying.

Decided to just do the bushings themselves and not the whole arms. Co$t was a big factor. 2 thrust arms, 2 control arms from BMA were getting close to $400. 2 thrust bushings and 2 control bushings were just $56 or so. Much better.

After consulting with the one of our resident experts, decided to go for just a bushing replacement. Bill suggested pulling the entire "steering knuckle" vs attemping to pull all three ball joints. Huge suggestion! All I needed to do was to pop one tie rod end and then pull the three bolts holding the knuckle to the strut and the 2 bolts for the bushings. Of course, to get access to all this, I had to drop the strut and hang the brake caliper.

Once the knuckle was out, I took them both to a local Midas and they pressed in the new bushings for $50 for all 4.

Re-installed the setup and whoohoo! What a nice improvement! The car was much much stiffer overall, better turn-in response and the tramlining was basically gone. VERY happy with the results. Worst part of the job (I think) was figuring out how to torque up the bolts with a load on the front end. The thrust arm bushings need 96 (!) foot/lbs - not easy when you have the wheels loaded. I used some 4x4 blocks to set the wheels up but that 18" pull on the torque wrench didn't help... Some ramps would have been really nice for sure!

Moral to the story I suppose is that those bushings seem to last about 60K miles and then they get soft. Even when they are not torn, they loose their stiffness. As these bushings work in tandem to locate the bottom of the strut, the strut then can move dramatically contributing to tramlining and other front end issues. I wonder if this isn't a cause of some of the tramlining complaints for our cars?

Cheers!

Jeff

[Hector]

to replace the thrust arm but then gave up because I didn't have a way to torque the bolt with the front end loaded. Took it to the shop instead. A few days latter I realized I had some ramps in storage I had forgotten about. That figures!

Interesting job. Bit of pain but really gives you a good understanding of how the frontend works.

Inspection showed that the ball joints themselves all looked really good. No play and the boots were in good shape. Bushings seemed to be another story. If you grabbed onto the thrust arm, you could deflect the arm if you pushed/pulled on the arm itself. Bushing itself *looked* ok - plastic plug was all there and no tears. Still, figured all the track work, stiff sways, etc had softened up the bushing and it was time for new ones. Additionally, the car had really started tramlining badly in the last couple months which was really annoying.

Decided to just do the bushings themselves and not the whole arms. Co$t was a big factor. 2 thrust arms, 2 control arms from BMA were getting close to $400. 2 thrust bushings and 2 control bushings were just $56 or so. Much better.

After consulting with the one of our resident experts, decided to go for just a bushing replacement. Bill suggested pulling the entire "steering knuckle" vs attemping to pull all three ball joints. Huge suggestion! All I needed to do was to pop one tie rod end and then pull the three bolts holding the knuckle to the strut and the 2 bolts for the bushings. Of course, to get access to all this, I had to drop the strut and hang the brake caliper.

Once the knuckle was out, I took them both to a local Midas and they pressed in the new bushings for $50 for all 4.

Re-installed the setup and whoohoo! What a nice improvement! The car was much much stiffer overall, better turn-in response and the tramlining was basically gone. VERY happy with the results. Worst part of the job (I think) was figuring out how to torque up the bolts with a load on the front end. The thrust arm bushings need 96 (!) foot/lbs - not easy when you have the wheels loaded. I used some 4x4 blocks to set the wheels up but that 18" pull on the torque wrench didn't help... Some ramps would have been really nice for sure!

Moral to the story I suppose is that those bushings seem to last about 60K miles and then they get soft. Even when they are not torn, they loose their stiffness. As these bushings work in tandem to locate the bottom of the strut, the strut then can move dramatically contributing to tramlining and other front end issues. I wonder if this isn't a cause of some of the tramlining complaints for our cars?

Cheers!

Jeff

[winfred]

bill

[NoSpeedLimits]

pleazzzze tell me you have step-by-step pics to share. Had to ask, because my front end just started to shaking. Movie is an acceptable alternative
Otherwise, if you have a few minutes to spare and feel like providing more details -- it would be much appreciated. Thanks.

[ilya]

pleazzzze tell me you have step-by-step pics to share. Had to ask, because my front end just started to shaking. Movie is an acceptable alternative
Otherwise, if you have a few minutes to spare and feel like providing more details -- it would be much appreciated. Thanks.

www.bmwe34.net actually has a write up for this as well.

[George M]

tritto...and with further elucidation...believe what Bill and Winfred are referring to Jeff is all you need to do to swap out your upper and lower control arm bushings is:
- Jack up the front end
- Remove the wheel
- knock or press out one end of the outer tie rod...either at the knuckle or center/
drag link.
- Remove (3) knuckle/steering arm plate retaining bolts
- Disconnect upper and lower control arms from X-mbrs
You now have the upper and lower control arm attached to steering knuck plate in your hands without removing the strut, or brake caliper/carrier.

A question for you Bill please...you mentioned a pickle fork and BFHammer is effective for breaking the upper and lower arm ball joints free of the steering knuckle
plate by mounting the plate in a vice. My question is what is your practice for this?
Do you squeeze the vice onto the plate itself, thereby risk marring the mating surface to the knuckle and beat away....or do you put the steering arm into the vice and beat on it since the arms are generally replaced and what are a few jaw marks on old arms among friends?
Appreciate your lessons learned for best way to break the ball joints loose from the steering plate(s)
Thanks,
George

[NoSpeedLimits]

Thanks. Yep.. gotta love the info. at BMWE34! Although the thrust arm explanation includes good info., I am more of a visual guy. Otherwise, I need tons of detailed explanation, because I am always second guessing myself...know what I mean? The more details the better. Unfortunately for me, I have only just started to read the written instructions provided with new toys. I have always relied way to heavily on the pictures when putting stuff together. I am paying for it now.

[Dave M]

Been gone for a while, but the thrust arm conversation caught my eye as I removed both recently. I'd love to do a complete 'How To', but I'm still putting together one for the shift linkage and trying to finish the suspension work in the evenings.
Anyhow, the first photo below depicts one way to accomplish the task (pretend that the thrust arm is still attached). Since I am swapping springs and possibly stuts, I pulled the strut assembly, which is very simple if you know your way around the brakes. The small puller took the ball joint in two attempts. If you try to use a puller, make sure it has has a narrow, sharp 'claw' rather han the common wide, flat I've often seen. If it holds it should work. Before you remove it, grab it and try to determine where the play is. The ball joint boots were cracked on mine and had significant play. I replaced the entire arms with Lemforderes and 750 bushings ($85 each from BMA).
The second photo is a better shot of the steering knucke that I believe Bill spoke of removing without removing the strut and brake assembly, thereby allowing you to hammer away at the control arms in a vice. Take your pick. I suppose it would partially depend on your plans for other front end components and you available tools.