Best bushes for rear wishbone-to-hub (outer bushes)

[Liam22]

I wanted to wait until I had the rear hubs off the car before deciding whether to replace the bushes.

Items 2 & 3 here
http://www.realoem.com/bmw/enUS/showparts?id=DU53-USA-10-2007-E86-BMW-Z4_30si&diagId=33_1139

The upper bushes/joints have a small amount of play, which will become a large amount of play very quickly with track use.

Read this great post from Curtis about bushes and noticed that top and bottom bushes are the same size, and might that the ball joint type can be fitted in both locations.
https://z4-forum.com/forum/viewtopic.php?f=2&t=4162&p=59370#p59370

Strongflex do a hard bush but given that BMW fitted a ball joint (not just a rubber bush) for the upper wishbone, I'm worried that PU type bushes may not be suitable.
https://www.strongflex.eu/en/bmw-e36/39-031175a-rear-lower-arm-outer-bush-sport-5902553501674.html

Any thoughts or experience here? Is going OEM top and bottom a better approach for track work? Or will reduced suspension travel on stiff springs negate that, and PU will be fine?

 

[Darkangelv2]

I wanted to wait until I had the rear hubs off the car before deciding whether to replace the bushes.

Any thoughts or experience here? Is going OEM top and bottom a better approach for track work? Or will reduced suspension travel on stiff springs negate that, and PU will be fine?

Did you make a decision on this in the end?

I’m at the same point and want to understand the reasoning why you might go for solid over ball joints.

 

[GuidoK]

Both PU and the ball joint are fine.
I've used the shore90A PU bushing for 6 or 7 years now, but the ball joint will be just as good (the z4m uses the same ball joint for the upper and lower outer bushing/pivot point)

The ball joint might even be cheaper in the aftermarket (but be sure to get a quality one like lemforder or febi), but is more difficult to fit obviously (press fit versus hand fit)

 

[Liam22]

I went with ball joints top and bottom.

Photos here https://z4-forum.com/forum/viewtopic.php?f=2&t=112593&start=45

 

[Jakg]

I would go balljoint over polyurethane as per M3 on it.

They can be very stuck and difficult to be remove without a proper tool (something hydraulic).

 

[Darkangelv2]

Thanks all for your input - It does seem that most seem to suggest keeping it stock. I'll check the condition of mine before i attack my car's rear end.

The limiting factor for me is the lack of a press. I guess part of the reason for the creation of the poly 'component' version is so that home mechanics like me can fit them more easily (bit like the RTAB).

 

[Jakg]

The limiting factor for me is the lack of a press. I guess part of the reason for the creation of the poly 'component' version is so that home mechanics like me can fit them more easily (bit like the RTAB).

I didn't say stock, just the same design. The M3 part is different (stiffer?).

Even with a press, you'd need to remove the part from the car, which is a lot more work.

It's not cheap, but if you do much work with bushes one of these - https://www.ebay.co.uk/itm/10-Ton-Tonne-Hydraulic-Internal-External-Bearing-Gear-Hub-Separator-Puller-Kit/272938519116?epid=1240421102&hash=item3f8c674a4c:g:~U8AAOSwUM5aDg66&frcectupt=true - can come in super handy.

You can see it in use here replacing the balljoint on my RenaultSport Megane - without removing the arm from the car.

 

[Darkangelv2]

The limiting factor for me is the lack of a press. I guess part of the reason for the creation of the poly 'component' version is so that home mechanics like me can fit them more easily (bit like the RTAB).

I didn't say stock, just the same design. The M3 part is different (stiffer?).

Ah OK, didn't realise the M3 component was different. I'll check it out.

 

[GuidoK]

Ah OK, didn't realise the M3 component was different. I'll check it out.

The M3 has balljoints for upper and lower outer pivot points, just like the z4m.
You can check the configuration in realoem and the likes.

It's not cheap, but if you do much work with bushes one of these - https://www.ebay.co.uk/itm/10-Ton-Tonne-Hydraulic-Internal-External-Bearing-Gear-Hub-Separator-Puller-Kit/272938519116?epid=1240421102&hash=item3f8c674a4c:g:~U8AAOSwUM5aDg66&frcectupt=true - can come in super handy.

I might be very stupid, but how is thàt tool going to help replace the outer upper and lower balljoints/bushings on the z4 trailing arm?
The way I look at it, that'll be impossible to fit, so if he buys that tool for this job, he's throwing away money imho.

Imho there are way better kits for replacing bushings for similar money that are especially designed for that (although there's no such thing as too many tools of course...)

 

[Jakg]

I might be very stupid, but how is thàt tool going to help replace the outer upper and lower balljoints/bushings on the z4 trailing arm?
The way I look at it, that'll be impossible to fit, so if he buys that tool for this job, he's throwing away money imho.

Imho there are way better kits for replacing bushings for similar money that are especially designed for that (although there's no such thing as too many tools of course...)

It's a tight fit, but it works. You don't need to use the big bit at the bottom, here's it doing the RTABs.



I used it on my MG ZT to do the upper rear ball joints, which uses the same bushes and a very very similar rear trailing arm setup.

The "special tools" are all a weak bit of metal on a threaded rod. I made one and it was useless. Even with my 10 ton hydraulic ram it was hard work, but I got it shifted.

 

[GuidoK]

It's a tight fit, but it works. You don't need to use the big bit at the bottom, here's it doing the RTABs.

Thats not the bushing we're talking about here....

And in that picture you're not using the tool you're referring to, and you're also using a cup from a bearing extractor set, which is not included.

Have you actually used that hydraulic knive puller (thats what it is) to replace the lower and upper outer rear suspension bushings?
So not something very very similar but the acutal part and setup we're talking about, with the tool you're linking to?

Darkangelv2 is way way better off buying a generic bushing extractor set like this:
https://www.ebay.co.uk/itm/Universal-Press-And-Pull-Sleeve-Kit-Bush-and-Bearing-Removal-Set/282777137419

And even then he probably also needs large socket and/or some rings to use as a cup to get the bushings started as space is very tight, depending on how much you want to remove.

The set above works. I did my COMPLETE rear axle (yes I removed ALL 17 press fit bushings) in about 3,5 hours after I dropped the rear axle.
So extraction took about 15min per bushing. And I was taking it easy.

A hydraulic knive puller like that I use to remove bearings from inside the diff. If you think suspension bushings are stuck/tight, don't ever try to work on output bearings of the diff :rofl:

 

[Jakg]

ave you actually used that hydraulic knive puller (thats what it is) to replace the lower and upper outer rear suspension bushings?
So not something very very similar but the acutal part and setup we're talking about, with the tool you're linking to?

Yes - I just don't have a picture to hand. I used an old socket as a mandrel.

 

[Liam22]

Some photos of rear trailing arm outboard bush/joint removal with a sleeve kit: https://z4-forum.com/forum/viewtopic.php?f=2&t=112593&start=30

 

[GuidoK]

^lol yes that is exactly the same setup I used too, with on one side the cup from the kit and on the other side a socket that fit. (on those outer joints)

And I also heated up the subframe a bit to get those bushings going (TIS recommended to burn out the bushings I believe but thats quite extreme, a light heat does the trick ). Indeed fitting the cups on that spot is tricky.

Here was my old bushing collection :lol: I didnt have to saw/cut the rubber of the trailing arm bushing, I just pressed it out.


I looked it up, I did this job in 2013, 6 years ago. Time flies...

I completely painted the rear suspension and bead blasted the aluminium parts to get rid of the corrosion:

As you can see I used the red strongflex ones for the subframe and the yellow ones for the suspension, so a shore80a and 90a mix (I use shore80A for all the monocoque contact points)

 

[Liam22]

Beautiful work

I found some of your old posts which guided me on the right path