Advice on Bushes / Polybushes

[heavymetalthunder]

Hello, having spent the past few days reading about bushes/poly bushes, I am a bit confused and looking for some advice from the knowledgable folk here! The last MOT on my car (2004 3.0i Roadster on 142k) highlighted advisories on the front bushes:

Nearside Front Suspension arm rubber bush deteriorated but not resulting in excessive movement rear bush (2.4.G.2)
Offside Front Suspension arm rubber bush deteriorated but not resulting in excessive movement rear bush (2.4.G.2)
Nearside Front Anti-roll bar rubber bush deteriorated but not resulting in excessive movement d bush (2.4.G.2)
Offside Front Anti-roll bar rubber bush deteriorated but not resulting in excessive movement d bush (2.4.G.2)

I have a few queries:

1. I am considering going for poly bushes, but do these make the ride much harsher? I am on 18" wheels if that makes much of a difference.

2. Is it worth changing the rear bushes too or leave them for now? I have read some topics where people advise poly on the front and regular on the rear?

3. I'm not too sure on exactly the parts/sizes I need - is there an easy guide which explains this anywhere? From what I can gather, for the front I will need for each side an anti roll bar bush (24 or 25mm?), front wishbone rear bush (60 or 66mm?) and possibly an aluminium outer housing? Is this correct?

4. I have seen Powerflex come up on most recommendation threads, are these the best or any others to consider? Meyle HD?

5. Is there anything else I should consider getting swapped out at the same time? Drop links?

Any advice much appreciated! Many thanks

 

[MACK]

As a general rule poly bushes are a bit harder. But some folks are fine with them on there zeds and others don't like them. So it a person choice thing, if your worried I stick with OEM or Meyle HD (have these on mine). Iirc all standard zeds have 66mm front bushes. The anti roll bar ones will be dependant on m sport suspension or not. Basically all pre 3.0i left the factory on m sport unless the owner asked for a switch to se. So should be 25mm IIRC. Using one of the online vintage checkers and the last 7 digits of your chassis will tell you this, as will REALOEM.
Rear bushes, it depends really if anything has been already done to be honest. If not at your milage I would definitely do rear trailing arm bushes with the addition of a limiter kit. After all this your going to need an alignment aswell and if it's not be refreshed the sus pension must be goosed as most on here reported their original shocks to be dead below 100k. However that's when things get pricey!

 

[philbo909]

the change in ride is a personal thing, I didn't bother changing to polybush just in case I ruined the ride (same as not changing to bilstein b12)
at 140,000 miles I would be surprised if your suspension is still functioning properly, i changed bushes/suspension this year on 120,000 miles and everything was pretty shot, front n/s shock couldn't stay out under it's own strength!

 

[Ewazix]

You will get lots of very definite opinions both ways, I can only say that I replaced various bushes on the Zed with OEM spec items and it dramatically improved steering, handling and 'looseness'. But I've recently re-bushed my Subaru with poly-bushes and regret it as it's added some road noise and jittery'ness that wasn't there before without adding anything other than some additional stiffness that isn't really positive for usability on the road.
One other issue with poly bushes, they can squeak and groan depending on the weather and temperature. I've cured this in the past with some silicone spray a couple of times a year so is not a deal breaker if you are inclined towards poly's.
Personally I'd stick to OEM specification.

 

[GuidoK]

I've driven around for about 20k miles with just front suspension arms powerflex bushings and front/rear ARB powerflex bushings in shore80a (the purple ones), and I didnt really found them giving a harsher ride. Something like eibach springs is more feelable in that department.
I think its more comparable with the feedback you get when you start driving a brand new car. You feel that its nice and tight with just the right amount of feedback without being harsh. And the nice thing is that polyurethane will keep that consistency; normal rubber bushings will slowly get spongy again after 10-20k miles or so.
Even the rear trailing arm bushings replacing for poly ones dont really add to a harsher ride (but will partly get rid of tramlining due to the build in limiters).
When I replaced the bushings in the rear lateral control arms (so the ones going from diff to wheels) for shore90a bushings (which are way harder than the purple powerflex ones to begin with) I started to feel that everthing became harsher and more rigid.
But even that you have to look at it in perspective: fully polybushing your car (with shore90A bushings in the rear control arms; the rest is 80a on my car)), so including diff polybushings, subframe polybushings the lot (23 in total I believe) AND installing stiffer H&R antirollbars, is probably still a smaller jump in harshness than installing a coilover kit from companies like KW.
To give an idea for people who drive on coilovers.

As for size brands: for the front control arms you need 66mm, and get the powerflex ones (the street ones, with the purple inserts). Other brands are known to fail, powerflex has a unique construction.
Meyle HD are conventional rubber bushings, not polyurethane.
As for the anti rollbar bushings, you can go to other brands like strongflex (cheaper).

 

[heavymetalthunder]

Thanks for the responses, I think they have helped a bit! I have checked a VIN decoder and it does say S704A M Sports suspension.

I think the first thing is to check through my paperwork to see if there is anything relating to suspension, if not I guess I could try a visual check (removing the wheel) to see the condition of the shocks. From that I can get an idea of how empty my wallet is going to become!

 

[MACK]

Thanks for the responses, I think they have helped a bit! I have checked a VIN decoder and it does say S704A M Sports suspension.

I think the first thing is to check through my paperwork to see if there is anything relating to suspension, if not I guess I could try a visual check (removing the wheel) to see the condition of the shocks. From that I can get an idea of how empty my wallet is going to become!

Unfortunately that may not tell you anything. The shocks don't need to be leaking to be shot. I would probably look for original BMW Parts on the car, stickers with part numbers that sort of thing. If they're genuine the likelihood is their original

 

[heavymetalthunder]

I didn't see anything in the paperwork regarding new shocks (only new springs a few years back) so I thought I'd take the wheels off and examine the condition of the shocks to see if they had any clues. It looks like the car is still on the original shocks, I attach a photo showing a sticker on one of them which says Sachs 82 4903 558 E85 Sport.

So it looks like it's time to spend some cash! I have seen Bilstein B6 recommended, however I have seen a B12 kit with 4 shocks and 4 Eibach springs for not much more including shipping from Germany for under £650, I guess this would be a good option?

I am still weighing up poly vs regular bushes, but I am definitely replacing the ARB and wishbone bushes at the front and then asking my mechanic to check what needs replacement at the rear and get that sorted too. Probably trailing arm and limiters as mentioned at least?