Rear Suspension Update - Few Questions

[Bladecatcher]

'98 2.8; 86K miles

It's time to go through my suspension and update what needs updating. Starting with the rear, as I've never done suspension work before and it seems very straight-forward. Bilstein Touring shocks and Rogue RSMs are on their way.

1. Do the Rogues come with everything that I will need (other than the shocks obviously), or is there any additional hardware that I need to get ordered?
2. Is there anything else I should refresh "while I'm in there"? Sway bar links/bushings? Is this pretty straight-forward? Any product advice?
3. Would it be wise to replace the springs as well (I'm not lowering the car)?

[Pelican Parts]

Take a look at the link below for a guide on replacing multiple suspension components on your Z3. Let us know if you have any questions!

http://www.pelicanparts.com/BMW/tech...htm#suspension

[KBH22102]

Definitely replace the subframe carrier bushings with urethane units. Consider doing the weld in toe/camber adjustment plates.

[zellamay]

Definitely replace the sub-frame bushings. Mine had about 97k on it, and the change was very noticeable. So much that I'd say every one of our cars should have it. I used IE bushings and most will say they are best. Springs should be fine. I don't know, but have read that Koni's are preferred shocks for street use. I'm getting ready to buy a set. ..... Shameless plug: I'm selling the sub-frame busing removal/install tool, ad on this site or Phoenix CraigsList.

[bluptgm3]

New body gaskets for RSMs.


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[Randy Forbes]

The RSMs don't include gaskets__one (1) per side as original, but I've been known to put one (1) between the reinforcement plate and top of the tower too.

Polyurethane subframe bushes (I use Ireland's but they all do the same thing) and leave the OE rubber bush in the differential cover (upgrading to the 3.0/M version optional__and expensive).

Personally, I find the Bilsteins to be too harsh, but at least you chose their Touring shock; the Sports/HD are brutal.

Rear suspension isn't so bad, but if you let the trailing arms go to full droop with the shock removed, make sure to check that the stub-axles are fully seated in the diff when you're all done (they just pop back in, and should lock into place thanks to a circlip).

[LannVouivre]

I dropped the rear trailing arm off the jack and into my lap while getting it back on the subframe carrier because the axle popped out.

This is the only vehicle I've ever worked on that the axles don't need a pry bar. I had fun lifting the arm, rotor, axle, and caliper all up to put the axle back in.

I pulled it out again in to check the seal and all it took was flexing my fingers a little. Sure beat prying and turning the axle for 3 hours.

[potxoli]

I'm about to do the rear shocks on my 2.8 and have a quick question. I got Sachs RSMs, gaskets and reinforcement plate for the RSM. I'm guessing the gasket goes between the RSM and the body *under* the car and the reinforcement plate goes *over* the body on the inside of the car before bolts are put back on right?

[BladeRunner919]

I'm about to do the rear shocks on my 2.8 and have a quick question. I got Sachs RSMs, gaskets and reinforcement plate for the RSM. I'm guessing the gasket goes between the RSM and the body *under* the car and the reinforcement plate goes *over* the body on the inside of the car before bolts are put back on right?

That's it!

[Bladecatcher]

Great info. Thanks, everyone!

I actually cancelled the order for the Rogue RSM because I totally forgot that TC Kline is right around the corner from me. Picking up their RSM this afternoon. Last week I learned that an Amsoil dealer is also right down the street from me, so that made my diff and transmission fluid choice for me. Can't say the transmission feels a whole lot different, but the fresh fluid in the differential is definitely noticeable. I have to assume both had never been replaced.

Since I've only owned this Z for about 6 weeks, I can't wait to see what every piece of this refresh is going to improve.

[potxoli]

Great info. Thanks, everyone!

I actually cancelled the order for the Rogue RSM because I totally forgot that TC Kline is right around the corner from me. Picking up their RSM this afternoon. Last week I learned that an Amsoil dealer is also right down the street from me, so that made my diff and transmission fluid choice for me. Can't say the transmission feels a whole lot different, but the fresh fluid in the differential is definitely noticeable. I have to assume both had never been replaced.

Since I've only owned this Z for about 6 weeks, I can't wait to see what every piece of this refresh is going to improve.

What did you notice with the diff that is different? I'm curious since I have both of those on my todo list (diff and transmission fluid change)

[Bladecatcher]

What did you notice with the diff that is different? I'm curious since I have both of those on my todo list (diff and transmission fluid change)

I didn't think that I had any issues with the differential, but when I filled it with the new fluid it quieted down quite a bit. It is definitely quieter and just feels smoother (this may be just because it's quieter).

I'm glad I did it (and the transmission) if for nothing more than the fluids were almost 20 years old.

[Bladecatcher]

I guess my only remaining question is about the springs. Since I'm sticking with stock height, is there any need to replace my springs? Assuming that there is no damage to them, is there any disadvantage with sticking with the originals?

[buckscrape]

I guess my only remaining question is about the springs. Since I'm sticking with stock height, is there any need to replace my springs? Assuming that there is no damage to them, is there any disadvantage with sticking with the originals?

IMHO there is nothing wrong with the originals as long as the ride height is still in tolerance. Check your Bentley if you have one for the ride height. I am at work and cant check for you, but maybe some one can chime in.

[BladeRunner919]

I guess my only remaining question is about the springs. Since I'm sticking with stock height, is there any need to replace my springs? Assuming that there is no damage to them, is there any disadvantage with sticking with the originals?

Do check them though - the rears can snap the last coil off and it's not always obvious until you're looking closely. Mine even passed its MOT (annual inspection) with a broken rear spring, and it was only because I was back there swapping the subframe mounts that I noticed it.