BMW Thrust-Arm Bushing Replacement

[The Critic]

I was recently talked into inspecting a co-worker’s 2008 528i. One of his complaints was that the front-end felt a bit loose. Once the car was on the rack, I noticed that the tension strut bushings (some people call them upper control arm bushings or thrust-arm bushings) were moderately torn.

The car has 183k, so the finding was not completely surprising.

One option is to replace just the bushing since the ball joint appears to be OK. The hydraulic bushings are $100 from the dealer and it will be another $10-$15 for the required new hardware. I do have access to a shop press, but I have no experience with pressing bushings. Plus, I am not sure that the shop has the right adapters.

Another option is to replace the two tension struts with a new set from the BMW value line. BMW sells a kit that includes two new arms and all of the required hardware for about $315. While this is certainly the easy route, $200 seems like a steep amount to pay for new arms and ball joints that may not be necessary.

My co-worker only plans to keep the car for another 2 years. With that in mind, I’d like to save him some money – but I also do not want to put myself in a bad situation (i.e. unable to return car in the promised timeframe, or accidentally fubar the arms while pressuing the bushings out). Then again, even if we go with new arms, I’ll still be saving him $300 compared to having it done at an indy BMW shop.

What do you folks suggest – new bushings only, or new arms?

Thanks

 

[Quattro Pete]

Originally Posted By: The Critic
The car has 183k, so the finding was not completely surprising.

Actually it is surprising that they lasted this long. Mine were shot by 35K miles. I had the whole arms replaced.

 

[d00df00d]

Get the whole arms with ball joints, and buy Genuine BMW. If you're already pulling the arms to do the bushings, there's no sense putting 183k mile old ball joints back on the car.

Besides, at that mileage, I'm sure the balljoints could stand to be newer and the arms could stand to be straighter anyway.

Don't forget that swapping in new arms will save you time and effort because you won't have to use a press. That won't completely make up for the price difference on the parts, but it will reduce the delta -- which also makes the new balljoints even more worthwhile.

 

[JHZR2]

What is BMW value line? Is that when Lemfoerder of Febi or someone sells out to make Chinesium or Indium?

I suspect that you could make a tool to get the bushes in, especially if you heat the one part and freeze the other. Ive seen folks make good tools even for LCA bushes where certain parts have to be bent into place and whatnot. But it may not be worth your time...

Another option is if you have a good relationship with a local shop, they may press in the bushings for a nominal fee. Ditto for replacing the ball joints as best practice.

Given your local climate, the intent to save some bucks and the duration of ownership, Id look into how to re-use the arms.

 

[BMWTurboDzl]

I like the $315 route. It may help with resale.

 

[artificialist]

I would prefer to just get new arms, because I wouldn't know how much life is left in the original ball joints. Also, it wouldn't surprise me if the ball joints for this car are permanently attached to the control arm.

 

[andyd]

Heh heh . The 528es have this issue. I can remove the bad bushing in about 15 minutes with hand tools. Hammer , hacksaw, punch. Installation is achieved with the aid of a 6 pound hammer and a piece of pipe. Many specialized tools used for servicing BMWs can be replaced by hammers of various sizes. I would make absolutely sure that the ball joint is good before I re-bushed the arm. They do tend to outlast the bushings about 3:1. The lower arm wears out the ball joint first, BTW.

 

[d00df00d]

Originally Posted By: BMWTurboDzl
I like the $315 route. It may help with resale.

Also true.

 

[The Critic]

Thanks guys.

I did read the following statement in a DIY guide, which does make some sense since the arms are aluminum.

"BMW TIS states that this bushing can only be replaced ONCE. I believe this because doing a few of these I noticed that the aluminum does widen a bit and the sleeve has the ability to POSSIBLY move. It's happened before!"

http://forums.5series.net/diy-do-yoursel...shbones-107786/

So, I guess the potential for error is there, so new arms sound like it would make the most sense.

EDIT - I found a website that hosts the BMW TIS service info, and here's what it says:

5 Series E60 528i (N52K) SAL

2 Repair Instructions > 31 Front Axle > 12 Struts W.rubber Mounts > 3 RA Replacing Rubber Mounts On Both Tension Struts

Replacing rubber mounts on both tension struts
Special tools required: • 31 3 031 • 31 3 032

Important! The rubber mounts on both tension struts must be replaced!

Note that the rubber mounts may only be changed once.

Necessary preliminary tasks:
• Check ball joints of tension struts while installed, replace tension struts if necessary
• Remove tension struts
Important! If the tension struts already feature an identification mark with a centre punch, it is necessary to replace both tension struts.
Mark tension struts with a punch mark in area (A)

Originally Posted By: Quattro Pete
Originally Posted By: The Critic
The car has 183k, so the finding was not completely surprising.

Actually it is surprising that they lasted this long. Mine were shot by 35K miles. I had the whole arms replaced.


What did the repair cost you?

Originally Posted By: JHZR2
What is BMW value line? Is that when Lemfoerder of Febi or someone sells out to make Chinesium or Indium?


Everything I've read online suggests that they're the real Genuine BMW parts, but pre-packaged in kits with new hardware. The price savings is often substantial (20-30%).

This is part of their new "Value Service" campaign that is targeted towards the out-of-warranty vehicles. It supposed to help their dealers better compete with the aftermarket.

 

[kschachn]

They will come out, but with a huge bang. Make sure you hit the socket with a hammer before and during the application of the separator. Just cranking down on the separator is probably not going to work.

Originally Posted By: artificialist
Also, it wouldn't surprise me if the ball joints for this car are permanently attached to the control arm.

 

[Quattro Pete]

Originally Posted By: The Critic
Originally Posted By: Quattro Pete
Originally Posted By: The Critic
The car has 183k, so the finding was not completely surprising.

Actually it is surprising that they lasted this long. Mine were shot by 35K miles. I had the whole arms replaced.


What did the repair cost you?

Around $450, parts + labor. That was 7 years ago.

 

[Merkava_4]

Get the arms. About $200 from RockAuto.

MOOG CK620125
MOOG CK620126

 

[KDonkey]

My experiences on two BMW cars:

1. Replaced only the bushings. Regretted not changing the arms because 50,000 miles later the ball joints feel loose.

2. Replaced whole arms with Meyle parts made in Turkey. 20,000 miles later the steering feels loose. I actually replaced most of the front end except for one tie rod which I did not install because it seemed fine at the time. Have not inspected yet. But the Meyle arms were the only aftermarket parts I used, the tie rod, center link and idler arm were Lem or TRW, same brand as installed by factory.

In each case I tried to upgrade the control arms/bushings. Car #1 is a 3 series and I used the M3 bushings. Car #2 is a 5 series and I used parts for the largest 7 series car.

If I found myself in the OP's situation I would inspect the original parts for the supplier's logo, for instance Lemfoerder's owl or whatever. I'd research whether there is a higher spec part that will fit, such as one from the same series but bigger engine, M car, or heavier car. Then I'd look for those parts from the "original supplier" in the aftermarket to avoid paying a dealer.

Good luck.

 

[The Critic]

Thanks for your insight, KDonkey.

Merk, aftermarket is no longer my first point of contact for most parts. The quality is simply inconsistent and/or the fitment is usually not up to my standard.

I always try to go for OE from the dealer or get something from the original supplier of the part.

I ended up getting a set of arms from the dealer for about $150/arm under the Value Line program. I'll be installing them next weekend and will update the thread with some pictures.

 

[Merkava_4]

Originally Posted By: The Critic
Merk, aftermarket is no longer my first point of contact for most parts. The quality is simply inconsistent and/or the fitment is usually not up to my standard.


I can understand that. I recommended Moog because the lower control arms and stabilizer bar end link kits I recently installed on my Buick have been spectacular quality. They made some improvements to the parts making them better than OEM. The lower control arm bushings are heavier duty and the ball joints have grease fittings. Plus, they're bolted to the control arms instead of riveted. The stabilizer bar end link kits have been phenomenal. They use extra firm polyurethane bushings and special support washers for each bushing. I'll be going with the Moog Problem Solver line for all my future suspension parts. By the way, the part numbers I gave you are for the CK series which is Moog's premium line.

 

[The Critic]

Yesterday, the car came by for the bushing replacement and for a vehicle check (as per the CBS).

While I already inspected the bushings during the last visit, I decided to take a test drive before replacement, so that I can make a before/after comparison.

Before replacement, the car felt extremely loose. It wandered all over the road, felt soft, and the steering felt unusually inaccurate for a BMW. I could easily see why an untrained driver could assume that his car needed new struts.

Here are some pictures of the new tension struts installed, and some pictures of the old ones. The Value Line tension struts from the dealer came with new hardware; I installed a new locking nut for the ball joint and a new thru-bolt and washer for the bushing. I used a manual jack stand to place the suspension under load before final tightening of the bushing bolt.

New arm installed, right-side:

DSC_1320 by thecritic89, on Flickr

New arm installed, left-side:
DSC_1319 by thecritic89, on Flickr

Old bushing, left-side (notice the crack that is deep inside the bushing):
DSC_1324 by thecritic89, on Flickr

Old bushing, right-side (major crack, right in the center):
DSC_1327 by thecritic89, on Flickr

While the damage does not look severe, when the arms were installed on the vehicle, the cracks are much more severe when the bushing is under load (and stress).

After replacement, it drove like an entirely different car. Sure, the struts are at marginal at 185k. But the steering was now accurate, the car felt solid, and no longer wandered. There was also a slight shimmy between 40-60 that is now gone, and during braking, the car now stops straight.

If someone had sold this owner a set of struts before fully inspecting the suspension, it would have been a complete disservice. These arms were about $315 from the dealer and given the circumstances, they were a much better investment than a $900 set of struts and hardware.

 

[kschachn]

Those bushings aren't hydraulic? They are on my 530i, and that vibration at 40-60 is characteristic of bushing failure via fluid loss. I could see a fluid streak running back from the failed bushing.

It's amazing how much those arms look like the ones on my BMW. The whole suspension setup really.

 

[The Critic]

Originally Posted By: kschachn
Those bushings aren't hydraulic? They are on my 530i, and that vibration at 40-60 is characteristic of bushing failure via fluid loss. I could see a fluid streak running back from the failed bushing.

It's amazing how much those arms look like the ones on my BMW. The whole suspension setup really.


They are. He said he had been noticing vibration for the last 15k or so, so my guess is that the fluid has been long gone.

 

[kschachn]

"Noticing"? Wow, my car was vibrating so annoyingly I fixed it almost immediately. There's no way, no how I would have driven that thing 15,000 miles.

That couldn't have been good for the rest of the suspension either.

Originally Posted By: The Critic
They are. He said he had been noticing vibration for the last 15k or so, so my guess is that the fluid has been long gone.

 

[The Critic]

Originally Posted By: kschachn
"Noticing"? Wow, my car was vibrating so annoyingly I fixed it almost immediately. There's no way, no how I would have driven that thing 15,000 miles.

That couldn't have been good for the rest of the suspension either.

Originally Posted By: The Critic
They are. He said he had been noticing vibration for the last 15k or so, so my guess is that the fluid has been long gone.


Well, I had made it about a mile down the street before I concluded that the car was very unpleasant to drive...pre-repair.