[eljay]

So, I am refreshing my rear suspension completely and installing a new-to-me clean subframe from a 2011 car with only 20k miles. The bushings in the subframe (not the main ones), to which the control arms connect look pretty good and clean.
I have already bought new bushings.

But now, I'm debating whether to mess with those bushings if they look OK.
It is obviously easier to replace them now with the subframe out, but there's a chance the new ones won't be seated in like the factory originals etc.

Question: is 20k mile rubber bushing old because it is 10 years old and I shoukd replace them?
Or is the low mileage OK and I should leave them alone?

[eljay]

Well, I'll just talk to myself then...
All the bushings are out! They are in very good condition, but it will be nice to get fresh new ones in.

I'll be selling this used set along with control arms in case anyone is thinking of a refresh of their high mileage rear suspension bits.

[Phil325i]

20K should be nothing for a bush. Why not keep using them until they fail? Failure will be obvious due to knocking noises or vibration...

[srey]

It depends on which bushings. Control arms at 20k miles should be just fine, even at 10 years old. Over the last 10k miles I've replaced just about all suspension and driveline bushings in my car (2007 MY at 129k miles right now). It drives like new and feels better than new in many respects. With all that context, I think my control arms were original, and had no play in them. Maybe a little vibration, but it's hard to differentiate NVH in control arms from any caused by other components.

Here's everything I've done. Car was stock prior to this.

- M3 front control arms (monoball ftw)
- Meyle HD end links front and rear
- New stock sway bushing front and rear
- New shocks and struts, stock sport package Bilsteins with stock mounts, but upgraded Monroe upper mounts for the rears.
- New 335is engine mounts
- New stock trans mounts
- New stock center driveshaft bearing
- Whiteline poly bushings for rear subframe (not inserts)
- Diff lockdown bracket from BMW
- 15mm spacers on rear wheels
- Regular summer tires instead of runflats (Firehawk Indy 500's)
- four wheel alignments with -1.5' camber on the front

The car drives so nice right now.

[eljay]

Originally Posted by srey

It depends on which bushings. Control arms at 20k miles should be just fine, even at 10 years old. Over the last 10k miles I've replaced just about all suspension and driveline bushings in my car (2007 MY at 129k miles right now). It drives like new and feels better than new in many respects. With all that context, I think my control arms were original, and had no play in them. Maybe a little vibration, but it's hard to differentiate NVH in control arms from any caused by other components.

Here's everything I've done. Car was stock prior to this.

- M3 front control arms (monoball ftw)
- Meyle HD end links front and rear
- New stock sway bushing front and rear
- New shocks and struts, stock sport package Bilsteins with stock mounts, but upgraded Monroe upper mounts for the rears.
- New 335is engine mounts
- New stock trans mounts
- New stock center driveshaft bearing
- Whiteline poly bushings for rear subframe (not inserts)
- Diff lockdown bracket from BMW
- 15mm spacers on rear wheels
- Regular summer tires instead of runflats (Firehawk Indy 500's)
- four wheel alignments with -1.5' camber on the front

The car drives so nice right now.

That's a very nice list!

I am almost at that level. Everything except the driveshaft bearing is getting replaced.

Yes, the rubber on the 20k bushings still looks good. If I didn't already buy new ones, I would leave them, but I have the subframe out and wouldn't want to replace anything on the car down the road.
This should be good for another 10 years.

[C12H24]

I literally did engineering/application for one of the largest bushing/damper suppliers in the world for a few years.

Modern bushings will not break down due to age, like the old stuff. 20k miles is not even breaking them in. It's not worth the hassle of swapping them out, for the sake of swapping them out.

[eljay]

Originally Posted by C12H24

I literally did engineering/application for one of the largest bushing/damper suppliers in the world for a few years.

Modern bushings will not break down due to age, like the old stuff. 20k miles is not even breaking them in. It's not worth the hassle of swapping them out, for the sake of swapping them out.

Thanks for the post.
I wish I had thought of getting a low mileage subframe before I ordered all the bushings and control arms.
And yes, the 20k bushings look to be in excellent condition.

[e90yyc]

eljay What did you use for tool for removing RTAB and the other pressed in bushings?

I’m contemplating refreshing some of my rear suspension and the bushings are cheap, but I know they’re basically impossible to replace without the right tool, DIY or otherwise.

My car has 220k miles on it and I’ve only got play in one of the upper control arms… the others still seem extremely tight.

[eljay]

Originally Posted by e90yyc

eljay What did you use for tool for removing RTAB and the other pressed in bushings?

I'm contemplating refreshing some of my rear suspension and the bushings are cheap, but I know they're basically impossible to replace without the right tool, DIY or otherwise.

My car has 220k miles on it and I've only got play in one of the upper control arms… the others still seem extremely tight.

I rented a bushing press kit from Canadian Tire and managed to get all of them out and in with that. Now that was with the subframe out.
This wouldn't work with subframe in as some don't give you enough clearance like the trailing arm by the fuel tank and on the wheel carrier.

I'll get the kit number and I even made some videos along the way that I hope to post when I get time.

I'll be selling the low mileage bushings and control arms soon to get some pennies back towards the obscene amount I just spent on this car.

[e90yyc]

Originally Posted by eljay

I rented a bushing press kit from Canadian Tire and managed to get all of them out and in with that. Now that was with the subframe out.
This wouldn't work with subframe in as some don't give you enough clearance like the trailing arm by the fuel tank and on the wheel carrier.

I'll get the kit number and I even made some videos along the way that I hope to post when I get time.

I'll be selling the low mileage bushings and control arms soon to get some pennies back towards the obscene amount I just spent on this car.

Thanks for the info!

Let me know about price for the control arms and bushings. Might be interested.

[rararat4]

Sorry for being so late to the party.

I have a scratchy ball joint in the rear of a 2009 328i. So, that one has got to go but the question is should the other three (per side) be replaced as well. This includes the inner one on the control arm supporting the coil spring and the inner and outer on the other lower arm that is squarish and full of holes.

With all due respect, nowhere in this thread or any other that I bumped into is the question of when a bushing needs to be replaced addressed. I do appreciate the comment by C12H24 above about the modern bushings being long lived. However my car has roughly 250,000 kms. Also, if there was audible clunking or obvious play in the suspension then the offending element would have to be identified and replaced. But, I do not have any obvious play when grabbing the rear wheel and trying to pull on it.

So I have a question to anyone who replaced the bushings I am asking about: when you pull the bushing out, does it seem loose compared to a new one?

[Andy198712]

Originally Posted by C12H24

I literally did engineering/application for one of the largest bushing/damper suppliers in the world for a few years.

Modern bushings will not break down due to age, like the old stuff. 20k miles is not even breaking them in. It's not worth the hassle of swapping them out, for the sake of swapping them out.

What about quality VS brands though?

[Tambohamilton]

Originally Posted by C12H24

I literally did engineering/application for one of the largest bushing/damper suppliers in the world for a few years.

Modern bushings will not break down due to age, like the old stuff. 20k miles is not even breaking them in. It's not worth the hassle of swapping them out, for the sake of swapping them out.

Interesting. I have a friend who used to work for Aston Martin. He said the chassis team called bushings done at less than 40k miles and only a few years old. Granted they were probably measuring nvh with sensors rather than their butts, though...

I would definitely have replaced the bushings too. Did mine fairly recently at about 14y/140k mi, and the aluminium was corroding and the rubber delaminating from it. Was impressed how far I could force the rubber still without it tearing off. I ended up drilling into some of the bushings so I could tear the core out and collapse the outer shell to remove it.