Lollipop bushes

[fredej]

I recently inspected the brakes on my Z4 as it recently passed 90k km (~56k miles). They're supposedly original to the car and still had about half of its life left.

I then thought I would look at whatever bushings I could see as well.
So I checked the lower control arm bushings. The right side bushing looked great. The left side, not so much... It's missing some rubber material.

Both bushings were replaced just before I bought the car. (they look to be BMW original parts) Since then it has been driven less than 20k km (~12500 miles).
How is it possible one of them not lasting longer than that?

 

[Andrew Sheldon]

Just a thought, maybe they were damaged whilst being installed, has the bush cracked and parted company such that the bush makes a clonking noise ?

 

[Rockhopper]

looks like its got oil on it - some types of rubber don't like oil.

 

[fredej]

Just a thought, maybe they were damaged whilst being installed, has the bush cracked and parted company such that the bush makes a clonking noise ?

Thanks Andrew. It has crossed my mind as well.
I haven't actually noticed any clonking sound. I assume it would be quite obvious when going over a speed bump for example.
What is concerning to me is that I can slightly move around the rubber part with my fingers when I feel the bushing.

looks like its got oil on it - some types of rubber don't like oil.

Yes, could be. Hard to tell in that dirty area.
My understanding is that these are a hydro type bearing. So it can be leaking?

 

[bigwinn]

They don’t look degraded or in poor condition from the photos-

Is it possible that the rubber got damaged on installation?

I’d check movement of the control arm first to see if it’s lost it’s integrity as a bush?

 

[fredej]

They don’t look degraded or in poor condition from the photos-

Is it possible that the rubber got damaged on installation?

I’d check movement of the control arm first to see if it’s lost it’s integrity as a bush?

I guess it could have been damaged on installation.

Is it possible for the bushing to be functional despite having that rubber part damaged / partly missing?

What concerns me is that when I touch the bushing I can feel a hole (rubber missing/damaged?) in the marked area shown in the photo. I can aslo slightly move some of the damaged rubber around with my fingers.

I will try to check for movement/play when I get a chance.

 

[bigwinn]

They don’t look degraded or in poor condition from the photos-

Is it possible that the rubber got damaged on installation?

I’d check movement of the control arm first to see if it’s lost it’s integrity as a bush?

I guess it could have been damaged on installation.

Is it possible for the bushing to be functional despite having that rubber part damaged / partly missing?

What concerns me is that when I touch the bushing I can feel a hole (rubber missing/damaged?) in the marked area shown in the photo. I can aslo slightly move some of the damaged rubber around with my fingers.

I will try to check for movement/play when I get a chance.

Do the usual test with a pry bar on the joints and arms- if it moves too much or starts to knock I'd think about changing it out?

 

[fredej]

A late update to this thread.
I still haven't experienced any knocking or weird behavior when driving.
When I had the car in for an oil change, I had the garage do a general inspection of the underside of the car (including bushes). They reported no problems.
So everything is likely fine.
I assume the rubber part somehow got damaged during installation but that it is not affecting the function of the bushing.

 

[Ewazix]

Just to put your mind at rest, providing the pry-bar test Bigwinn mentions is passed, you have no wobbles or knocking then they are probably OK. Below is a pic of mine a few years ago, you will see that the outer rubber band had come away (in fact it appears to have no structural function) I changed them just in case and found the hydraulic centre filling was intact and they were actually functioning OK, but obviously looked knackered.

 

[fredej]

Just to put your mind at rest, providing the pry-bar test Bigwinn mentions is passed, you have no wobbles or knocking then they are probably OK. Below is a pic of mine a few years ago, you will see that the outer rubber band had come away (in fact it appears to have no structural function) I changed them just in case and found the hydraulic centre filling was intact and they were actually functioning OK, but obviously looked knackered.

P1020399.JPG

I wasn't exactly sure how the rubber parts were designed. But from your photo it all make sense now. Thank you.
Since the car drives fine I will leave them as they are for now.

 

[fredej]

The outer rubber band had come away (in fact it appears to have no structural function) I changed them just in case and found the hydraulic centre filling was intact and they were actually functioning OK, but obviously looked knackered.

Eventually the rubber band / ring (on the left bush) came away for me as well. 4 years and an additional 18k km after I initially posted about it.

I reversed in to a parking space (with full steering lock) and heard something snap off. Initially I did not understand what the sound was. But when I stepped out of the car I found the (BMW branded) rubber band on the ground in front of the car. After a while I realized where it came from.

The car drove fine afterwards. So the bush is probably still okay without the rubber band, as stated by Ewazix. I will monitor the issue and change the bushes eventually.
I plan to replace the shocks sometime soon-ish. So probably good to take a look at the rest of the suspension at the same time.