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Discussion Starter · #1 · (Edited)
I had a set of X5 thrust arm bushings installed in my 00 m5 yesterday. My first set of oe bushings failed at 45k, second set started getting soft at 65k (i'm now at 73k, the latest bushings have not failed completely, but there is a significant amount of movement in the suspension from their fatigue).

Track time, with big tires on the front, especially R compound tires is hard on the bushings. I was hesitant to go with polyurethane, due to past use (admittenly in other cars, probably older technology too), squeeks and sometimes failure with hard use. I had heard some internet rumors that X5 bushings would work, and were significantly "heavier duty." Makes sense, the X5 is a heavy truck, with huge wheels. I went to my parts dept to check them out, side by side with the M5 bushings (which incidentally are the same as e38 7 series bushings). I had my parts guy pull a set of x5 4.8is bushings (turns out they all have the same p/n).

I have attatched a couple of pics below. First thing is the housing. It's steel rather than aluminum. The metal part in the center, where it mounts, is much larger on the X5 part than the x5 part, easily 50% more metal at it's central mounting point. Also, in the upper part of the photo, the area where the metal mounts to the rubber, the x5 part has a lot more contact area. I wish i had my camera to photograph the m5 part, but there is easily 2-3x the contact area, where the metal and rubber are joined. The rubber itself felt harder with the x5 bush too. Physically, the bushings are the same size.

The install. My local independent shop (M service, in walnut creek, ca.) did the install. No issues, simple remove and reinstall. The shop is staffed by fellow bmw cca instructors, they were interested in the project, since the bushing did look "beefier" than the oe m5 part. Proof will be told over time, but they thought this might be a good upgrade for anyone who tracks thier e39, or has had multiple failures. I was replacing worn out parts, so it's hard to say how much better the car feels. Certainly there is some found precision back in the steering. Car is more stable under braking, and doesn't dart around on bumpier roads. No loss of smoothness, no increased noise or vibration. So far i'm pleased. The car had felt rather 'sloppy' over the past, say 6 months. I figured the recently replaced thrust arm bushings were too new, but there was quite a bit of play in my old ones, mostly on the drivers side. The front end feels much better, subjective i know, but that's all i can offer! I can see no downside to using these as a routine replacement when the OE bushings fail, especially those of you running larger tires on the front, or with heavier wheels.

Mike
 

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Thanks for posting, Mike. Any concerns about the steel portions vs. the aluminum arms? Are the arms on the X5 also aluminum?
 

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Discussion Starter · #3 · (Edited)
Need4Spd said:
Thanks for posting, Mike. Any concerns about the steel portions vs. the aluminum arms? Are the arms on the X5 also aluminum?
I don't know. Not sure if the x5 has steel or Al arms, nor do i know if there would be some type of metal incompatibility. I would think there would be more of an issue with steel bushing shells in a steel arm, from a corrosion standpoint.

my shop had said getting the new ones in was no problem, getting the old ones out (al/al) was a pita, and they've been in there under a year!
Mike
 

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Works for me.
 

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My understanding is that you can't successfully (or perhaps shouldn't) remove the bushings from Aluminum thrust arms. The problem is that the Al to Al contact & friction causes " galling ".

For pictures of this (much discussed & debated topic on the e31 board) I point you to MWrench's website, and a large collection of photos .

I now step back and watch the debate re-kindle.
 

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Great post. Exactly the info we need to duplicate. I notice a little wander on real bumpy roads, so even though I only have 20k miles on mine, I suspect an X5 upgrade is in my not too distant future.
Regards,
Jerry
 

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Just curious, from a cost standpoint, how much are oem M5 bushings, how much are X5 bushings, and how much are poly upgrades? (And who makes a poly upgrade for the M5?)
 

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I have some poly's backordered from Bav Auto. They were around 50 -75 bucks...I dont really remember them being excessive. They said 4wks, about a week ago. The X5 idea is interesting....I may ask the parts guy to pull both when I go pick my car up in the next day or two. My guess is the X5 as mentioned is beefier and probably cheaper than the M5 bushing.

ernest


trackstar said:
Just curious, from a cost standpoint, how much are oem M5 bushings, how much are X5 bushings, and how much are poly upgrades? (And who makes a poly upgrade for the M5?)
 

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Discussion Starter · #10 ·
trackstar said:
Just curious, from a cost standpoint, how much are oem M5 bushings, how much are X5 bushings, and how much are poly upgrades? (And who makes a poly upgrade for the M5?)

I'd have to look at the invoice to be certain, but i think the x5 bushings were about $45-50 per pair, not much difference than the OE bushings. Poly, from bimmerworld (powerflex, i think) is about $80 iirc.
Mike
 
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Discussion Starter · #11 ·
eMpwrd5 said:
what are the p/n's for the x5 bushings..
Look at the first pic in my post above, i have the label with pn showing.
Mike
 

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Great write-up, Mike!

The OEM E39 thrust arm bushings are indeed weak and short-lived. At the other end of the spectrum, I similarly feel that poly bushings on such a sedan is "too radical". Cons tend to outweigh pros as I've been there and done that on various cars.

There is another GOOD option to improve performance and/or longevity. A more aggressive E39 bushing with aluminum shell is being offered as OEM replacement thru ebay. These bushings feature an integral plastic orange compression puck/slider, more rubber stiffness and fewer rubber voids. These units look very durable & well-suited to a 4dr performance sedan. The reinforcement puck is clearly intended to manage severe loads under braking and potholes. This bushing simply can not deflect under braking loads, as designed. I bet my front suspension will quit "flapping around" when I bed HT-10's for a day at the track (thanks again, Mike)! You can not see light through cavities in these bushings!

A pair of these German-manufactured aluminum arms with these nice bushings already pressed-in goes for a measily $130. It's almost scary cheap. I have a set and they are very impressive looking from a QA/QC and design standpoint. Vines is oblivious to the upgraded bushings, as you can not even get a decent pic on their site. One benefit to swapping the whole assembly is you don't need to worry about damaging the thrust arm ball joint covers upon removal.

The quality/strength of these aftermarket aluminum arms does concern me some, not being OEM. Lots of load on them and it's hard to guess the strength looking at them. They appear similar quality to OEM. They even come with stylish, temporary ball joint boot protectors (shown in pic#3).

ebay item#8023159457, Vines Automotive
 

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Discussion Starter · #14 ·
Thanks for posting Rick. Do you happen to have a pic of an OE M5 bushing? THe ones in your aftermarket control arms are considerably beefier looking, much more rubber than the oe ones i looked at, and a similar looking "central metal mount" to my x5 parts. I wonder if those are fluid filled as well?
Mike
 

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Great post, Mike! Gotta love evergreen education as it relates to our Beasts.

Lscman said:
The OEM E39 thrust arm bushings are indeed weak and short-lived. At the other end of the spectrum, I similarly feel that poly bushings on such a sedan is "too radical". Cons tend to outweigh pros as I've been there and done that on various cars.ive
Add another vote to the 'been there, done that' club. I went with the PowerFlex polyurethane thrust arm bushings from BimmerWorld when my originals cratered. While they did provide a much 'crisper' steering feel and handling response, the trade-off was molar-jarring thuds from potholes and road imperfections.

As this was my daily driver, I would likely have been happier with a middle-of-the-road solution, whether the X5 variety or the German-mit-arm assembly.

I'd suggest starting with one of these options, and working up to the p/u bushing route only if you're a die-hard track whore--and of course then a two-ton E39 is not the ideal instrument for that. Fun, absolutely; ideal, nope.

-Dave
 

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Discussion Starter · #16 ·
Teutonaddict said:
I'd suggest starting with one of these options, and working up to the p/u bushing route only if you're a die-hard track whore--and of course then a two-ton E39 is not the ideal instrument for that. Fun, absolutely; ideal, nope.

-Dave

I agree with you Dave. I've been 'undoing' a few mods that i felt pushed the car beyond what I want for daily driver. Resonators went back in, oe trans mounts etc... So far, i'm extremely pleased with the bushings. There's definately a little more stiffness (even compared to what i remember with new oe bushings) but still very comfortable.
Mike
 

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Resonators went back in, oe trans mounts etc... So far, i'm extremely pleased with the bushings.
No need to go back to OE tranny mounts, Mike. I have the Rogue mounts (same as UUC black mounts, I think), and there was no noticeable increase in noise or vibration.

As for the replacement arms, I would be concerned about the quality of the arm, too, but it does look ok from the pics. Are the stock arms forged pieces? I guess they didn't also come with the ball joints, or did they? Just plug a play, then, w/o having to press out the old bushings.
 

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Lscman said:
Great write-up, Mike!

The OEM E39 thrust arm bushings are indeed weak and short-lived. At the other end of the spectrum, I similarly feel that poly bushings on such a sedan is "too radical". Cons tend to outweigh pros as I've been there and done that on various cars.

There is another GOOD option to improve performance and/or longevity. A more aggressive E39 bushing with aluminum shell is being offered as OEM replacement thru ebay. These bushings feature an integral plastic orange compression puck/slider, more rubber stiffness and fewer rubber voids. These units look very durable & well-suited to a 4dr performance sedan. The reinforcement puck is clearly intended to manage severe loads under braking and potholes. This bushing simply can not deflect under braking loads, as designed. I bet my front suspension will quit "flapping around" when I bed HT-10's for a day at the track (thanks again, Mike)! You can not see light through cavities in these bushings!

A pair of these German-manufactured aluminum arms with these nice bushings already pressed-in goes for a measily $130. It's almost scary cheap. I have a set and they are very impressive looking from a QA/QC and design standpoint. Vines is oblivious to the upgraded bushings, as you can not even get a decent pic on their site. One benefit to swapping the whole assembly is you don't need to worry about damaging the thrust arm ball joint covers upon removal.

The quality/strength of these aftermarket aluminum arms does concern me some, not being OEM. Lots of load on them and it's hard to guess the strength looking at them. They appear similar quality to OEM. They even come with stylish, temporary ball joint boot protectors (shown in pic#3).

ebay item#8023159457, Vines Automotive
If these are TUV certified parts MADE IN GERMANY I'd be much less concerned than non OE parts from other markets... the germans take their certs seriously....
 

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Mike, thanks for posting your experience. Please give us an update in a quarter or so, come spring I will be upgrading my suspension (not fully finalized which setup just yet GC/PSS9/Dinan, etc.) but will likely be putting rear rims up front, so will be curious whether the X5 bushings absorb the extra beating better then stock ones.

Cheers
 

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mottati said:
Thanks for posting Rick. Do you happen to have a pic of an OE M5 bushing? THe ones in your aftermarket control arms are considerably beefier looking, much more rubber than the oe ones i looked at, and a similar looking "central metal mount" to my x5 parts. I wonder if those are fluid filled as well?
Mike
Mike,

Per your inquiry......

Vines E39 bushings are not fluid filled. They are high density, high durometer solid rubber with some molded indentations to maintain reasonable compliance and flex. The plastic hardware does not pass all the way through the bushing assembly; separate pieces fit each end. These bushings easily have double the rubber compared to OEM.

The E39 M5 bushing is not fluid filled. They are softer rubber with huge voids that pass all the way through the bushing shell to maximize compliance.

A E39 540i non-sport bushing carries the same part# as M5, so the M5 part is not so racey. Failure rates on 540i are alarming and M5 will likely follow with age.

Here's some pics of a brand new M5 & 540i V8 BMW OEM bushing, about 6 mo old (P/N 31-12-0-006-482). Pencils and silverware are for illustration only:
 

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