Is this suspension alright?

[GarlicBreadon]

I've replaced my Subframe bushings about 2 years ago now and put about 50K miles on them. Now I see a bit of a large gap here (see image) is this normal or is the bolt not torqued? Experiencing the same clunking during shifting as before. This and as well as the differential mounts. They seem to touch a bit, what could cause this?

This is only during load on the vehicle. The pictures are with the wheels loaded on the ground. The subframe bushing stay the same when on the two post lift but the touching differential mount is gone.

The car is an E34 525i 1994 with about all suspension stuff replaced but some stuff never resolved itself. Like this.

Imgur link for images(ignore the silicone on the diff : https://imgur.com/a/ZdDa2HJ

[moroza]

No, those subframe bushings look like they weren't pressed in all the way. The diff bushing looks like it has collapsed. Failed subframe mounts result in a rather heavy -THUMP- as the subframe hits the body, and not much in the way of sustained vibrations. I don't know exactly what failed diff bushings sound like, but I would expect a lighter sound and more vibrations.

[GarlicBreadon]

No, those subframe bushings look like they weren't pressed in all the way. The diff bushing looks like it has collapsed. Failed subframe mounts result in a rather heavy -THUMP- as the subframe hits the body, and not much in the way of sustained vibrations. I don't know exactly what failed diff bushings sound like, but I would expect a lighter sound and more vibrations.

Okay thanks. I'll look into it. Might I add that I do remember using a bit of white ptfe grease when installing. I later read that the bushing must be installed dry. Might this be the result of that?

[eddycooper]

Okay thanks. I'll look into it. Might I add that I do remember using a bit of white ptfe grease when installing. I later read that the bushing must be installed dry. Might this be the result of that?

There's a fair chance that's the culprit. There is nothing really to hold them in place other than friction, so for installation it's important not to use anything that will be permanently slippery. Some people use dish soap but I've done fine with just sticking them in the freezer - the thin coating of frost is enough to get them pushed in.

[circuit.heart]

Clunk each shift is probably the diff moving around, I've had this before. Throw the diff bushings out and replace with poly IMO, it can pick up a little NVH if your subframe mounts are stiff, but it's so much easier to replace them when they do wear out vs the OEM rubber bushings.

[GarlicBreadon]

Clunk each shift is probably the diff moving around, I've had this before. Throw the diff bushings out and replace with poly IMO, it can pick up a little NVH if your subframe mounts are stiff, but it's so much easier to replace them when they do wear out vs the OEM rubber bushings.

I was considering this as I am installing my build turbo M50 somewhere coming summer and wanted the diff (and axles) not to 'hop' as much when driving away accelerated and snapping. I am however a bit worried about the NVH increase. Am also a bit annoyed about the diff bushings appearing as failed as I just replaced them in June with Meyle(rear)/BMW OE(front).

The poly fixed it for you? And if I were to replace the subframe bushings as well with poly would this be a terrible experience for a semi-daily-ish car?

[GarlicBreadon]

I'll remember this trick for the next time

[circuit.heart]

I was considering this as I am installing my build turbo M50 somewhere coming summer and wanted the diff (and axles) not to 'hop' as much when driving away accelerated and snapping. I am however a bit worried about the NVH increase. Am also a bit annoyed about the diff bushings appearing as failed as I just replaced them in June with Meyle(rear)/BMW OE(front).

The poly fixed it for you? And if I were to replace the subframe bushings as well with poly would this be a terrible experience for a semi-daily-ish car?

If you have the capability to make your own rubber bushings, do that, since rubber has better internal damping, especially at high frequencies.

In 2023, with pandemic-era parts quality, I refuse to use any more OEM rubber bushings as they fail early. The noise transmission will be OK as long as you don't replace any bushing with a truly solid metal or plastic piece. I run poly subframe and diff bushings with solid RTABs and you can definitely hear more tire noise than a normal E34.

[Missedapex]

One other area to look into…is your rear pitman bushings aka dog bones.
My e34 has 64k on it and those bushings were complete toast to the point the rubber had perished completely out of one. I had clunking and squeaking. Took 30 minutes
to replace and the car feels tight again and weird noises are gone.
These bushing take a lot of twisting during normal driving and acceleration.


Sent from my iPhone using Tapatalk Pro

[moroza]

I've used dish soap and not had any problems, but it dries out. PTFE doesn't, and explains the problem.

Meyle(rear)/BMW OE(front).

It's no surprise that the Meyle ones failed, then. Curious why you chose a very overpriced OE front and bottom-barrel aftermarket rears?

[GarlicBreadon]

I've used dish soap and not had any problems, but it dries out. PTFE doesn't, and explains the problem.



It's no surprise that the Meyle ones failed, then. Curious why you chose a very overpriced OE front and bottom-barrel aftermarket rears?

The front was not available third party and cost me about 55USD for the single (The realoem part number was different so assumed it was a different size or design compared to the rears). Couldn't find lemforder or equivalent locally apart from febi or meyle and those were 20 each. The rears were as expensive from BMW, but in hindsight should have just bit the bullet.

- - - Updated - - -

One other area to look into…is your rear pitman bushings aka dog bones.
My e34 has 64k on it and those bushings were complete toast to the point the rubber had perished completely out of one. I had clunking and squeaking. Took 30 minutes
to replace and the car feels tight again and weird noises are gone.
These bushing take a lot of twisting during normal driving and acceleration.


Sent from my iPhone using Tapatalk Pro

I changed all bushings in the rear and shocks/springs (Koni/eibach res.) last summer with lemforder where possible. Also did trailing arm bushings and the dog bones. They are fine still.

[GarlicBreadon]

If you have the capability to make your own rubber bushings, do that, since rubber has better internal damping, especially at high frequencies.

In 2023, with pandemic-era parts quality, I refuse to use any more OEM rubber bushings as they fail early. The noise transmission will be OK as long as you don't replace any bushing with a truly solid metal or plastic piece. I run poly subframe and diff bushings with solid RTABs and you can definitely hear more tire noise than a normal E34.

My own rubber bushings? Thought you only could make your own poly bushings. I don't really have any experience with that specifically.

I would guess though that the solid RTAB's transmit most of that vibration. Could always begin with poly subframe bushings as it seems they need some
adjustment anyway..

Why did you go solid RTAB's? Didn't think they would add that much or do you mainly track the E34?

[Missedapex]

Here’s a pic of my subframe bushing to compare. Yours definitely looks to not be fully seated. And I think other poster also commented…this could definitely cause your subframe to slap on body when shifting or heavy on/off gas.


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[GarlicBreadon]

Here’s a pic of my subframe bushing to compare. Yours definitely looks to not be fully seated. And I think other poster also commented…this could definitely cause your subframe to slap on body when shifting or heavy on/off gas.


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Very much appreciated! It is really difficult to find a picture of this online without it already being halve burned out .

Looks like mine are really out there compared to yours. Gonna try to at least rectify it before considering swapping to poly. Unless they are already too far gone by being out soo much.

[moroza]

Can you post or PM me a link to the 55USD front bushing?

The mounts are relatively new, so if they were either genuine BMW or older German-made Lemförder (as opposed to more recent Chinese-made), I would reuse them after cleaning off the PTFE, but be prepared to find they're damaged in ways that aren't yet apparent, and find replacements on short notice. My first choice would be genuine OE, but they appear to be out of production. Second would be German Lemf., but they appear to have changed production no later than 2018, making the newest you might find on a shelf somewhere at least four years old. Third choice... SWAG, perhaps?

[GarlicBreadon]

Can you post or PM me a link to the 55USD front bushing?

The mounts are relatively new, so if they were either genuine BMW or older German-made Lemförder (as opposed to more recent Chinese-made), I would reuse them after cleaning off the PTFE, but be prepared to find they're damaged in ways that aren't yet apparent, and find replacements on short notice. My first choice would be genuine OE, but they appear to be out of production. Second would be German Lemf., but they appear to have changed production no later than 2018, making the newest you might find on a shelf somewhere at least four years old. Third choice... SWAG, perhaps?

I sourced the bushings from my local dealer (got the BCE price reduction as well). I live in the Netherlands so ordering is basically overnight delivery as the national German warehouse is on the border. Just saw that the front diff bushings (33171140308) cost increased to 100USD . The subframe bushings cost 50 each (33311128670) and lemforder costs 29 USD so I'll be going with one of those if they end up being broken.

The main thing is I never could find any information comparing the front bushings to the rear diff bushings (33171131903 vs 33171140308) They appear the same but have different bmw part numbers and different pricing as well. The rears from bmw cost 63 USD compared to the 100 USD for the front.

(If you want you can check it out here: https://bmwshop.ekris.nl/nl/zoeken-op-onderdeelnummer but it's in dutch natively)

[circuit.heart]

I would guess though that the solid RTAB's transmit most of that vibration. Could always begin with poly subframe bushings as it seems they need some
adjustment anyway..

Why did you go solid RTAB's? Didn't think they would add that much or do you mainly track the E34?

Correct, poly subframe bushings with rubber or poly RTABs is totally fine from a tire NVH standpoint. Rubber RTABs would be preferred for any non-track application as it just makes things more gentle.

I have M5 slide bearing RTABs because I can tear or slip any soft RTAB material on track. You pick your battles, basically. I don't have to fight parts breakages anymore in this area, just noise.

[moroza]

I sourced the bushings from my local dealer (got the BCE price reduction as well). I live in the Netherlands so ordering is basically overnight delivery as the national German warehouse is on the border. Just saw that the front diff bushings (33171140308) cost increased to 100USD . The subframe bushings cost 50 each (33311128670) and lemforder costs 29 USD so I'll be going with one of those if they end up being broken.

The main thing is I never could find any information comparing the front bushings to the rear diff bushings (33171131903 vs 33171140308) They appear the same but have different bmw part numbers and different pricing as well. The rears from bmw cost 63 USD compared to the 100 USD for the front.

(If you want you can check it out here: https://bmwshop.ekris.nl/nl/zoeken-op-onderdeelnummer but it's in dutch natively)

Dank U. Ik kan een bitje Nederlands...

FWIW, the Lemförder-branded Chinese-made subframe mounts I received in 2018 looked very badly made, and somehow I doubt it was a mere coincidence that about at the same time, there began appearing numerous detailed and consistent reports of mass Chinese prison labor, much of it tied to the auto parts industry in particular. I sent them back. The genuine BMW replacements cost over double but looked properly made, have been working fine ever since, and cast into their rubber were Lemförder's owl logo and an internal part number. Similar story with Stabilus and Touring hatch struts, though Mexico in that case.

The difference between the diff front and side bushings appears to be that the former has a steel stiffening plate embedded in it. The rubber may also be a different durometer.

[BleedsBlue]

@GarlicBreadon do you have more photos of your car on track? How often do you track it? There is a small but passionate group of us that enjoy tracking these old things

[GarlicBreadon]

Dank U. Ik kan een bitje Nederlands...

FWIW, the Lemförder-branded Chinese-made subframe mounts I received in 2018 looked very badly made, and somehow I doubt it was a mere coincidence that about at the same time, there began appearing numerous detailed and consistent reports of mass Chinese prison labor, much of it tied to the auto parts industry in particular. I sent them back. The genuine BMW replacements cost over double but looked properly made, have been working fine ever since, and cast into their rubber were Lemförder's owl logo and an internal part number. Similar story with Stabilus and Touring hatch struts, though Mexico in that case.

The difference between the diff front and side bushings appears to be that the former has a steel stiffening plate embedded in it. The rubber may also be a different durometer.

Haha that's cool man!
Okay so quick update. The OEM subframe bushings aren't being made anymore by BMW they discontinued them recently, I checked with 3 seperate dealers and the german warehouse doesn't have any old stock, so from now on I suppose I have to source them elsewhere. Even though you said lemforder changed I might go with lemforder.. As I don't have any other choice other than poly.

Is there any major difference with poly brands by the way (besides the hardness 80Sha vs 90Sha and such)? Cause there are a lot of brands.

[GarlicBreadon]

@GarlicBreadon do you have more photos of your car on track? How often do you track it? There is a small but passionate group of us that enjoy tracking these old things

I do mainly just street the car (I know with the turbo build being ready) but I want to go more often as I have quite a few tracks around me. Nürburgring being one of them. Got the car in a good enough state for the grip so that I finally could go with this car last year, so I only have been there a couple of times. Not a lot of pictures sadly. When the turbo build is in I definitely want to see how it feels on track. The time on the straights will be waayy better.

https://imgur.com/a/oPfB6dY

This is about it. Added some beauty shots I did in the same period. Went with the blue E46 driving behind me. He actually spun out after the next corner . Got the fender pretty bad but nothing major, we drove home in the same cars.

[circuit.heart]

Haha that's cool man!
Okay so quick update. The OEM subframe bushings aren't being made anymore by BMW they discontinued them recently, I checked with 3 seperate dealers and the german warehouse doesn't have any old stock, so from now on I suppose I have to source them elsewhere. Even though you said lemforder changed I might go with lemforder.. As I don't have any other choice other than poly.

Is there any major difference with poly brands by the way (besides the hardness 80Sha vs 90Sha and such)? Cause there are a lot of brands.

Polyurethane mostly comes from the same few suppliers as far as I can tell, but for subframe mounts, you want them stiff. You have rubber trailing arm bushings and diff bushings already, there is little reason that the subframe itself needs to move. Replacing the two big circular mounts with poly also reduces some load on the rectangular one (above the diff), which does not have a good replacement (poly or otherwise) in the USA. Maybe Eastern Europe has something for this, I've seen some designs before.

But yeah, I am very against using rubber subframe bushings. Taking them out once is bad enough, taking them out a second time because modern parts quality is shittier, is just really annoying.

[BleedsBlue]

Very cool. You have great access to some epic tracks!