New Rear spring needed - E46 M3

[Andrew Coates]

Hi guys

Noticed today that the off side rear spring has broken on my E46 M3; a common problem I know.
Does anyone know of a good supplier in the Sheffield/South Yorkshire area where I can get one and roughly how much it would be?

Also, I understand that they are pretty simple to fit; what needs to be disconnected to do it?

Any help would be appreciated.

Thanks

[Nedz]

Best to replace them both. They are a bmw only part so you would have to go to your local bmw dealer.
I paid £170 for both rears.

To fit,the car needs to be up on a four poster ramp.Remove the rear wheels,unbolt the shock absorber from the suspension arm,pull the arm down,take the old spring out and put the new one in.Its as easy as that.
A mate did mine and it took little more than 10 mins to do both sides,so dont let anyone try and charge you silly money coz you drive an m3 and dont even bother asking the main dealer for a price to fit them,unless you fancy a laugh!

[henrycrun]

You can get a rough idea of BMW prices from www.realoem.com just enter the last 7(?) digits from your VIN
(for $ read £)

Edited by henrycrun on Saturday 27th March 19:49

[Broaders]

Does the car need to be up on 4 axle stands? Can you do the back springs with the back off the ground only?

[sjj84]

Broaders said:

Does the car need to be up on 4 axle stands? Can you do the back springs with the back off the ground only?

Only need the back off the ground.

[mat205125]

Broaders said:

Does the car need to be up on 4 axle stands? Can you do the back springs with the back off the ground only?

Only the back needs lifting, and you can do it on the driveway .... As stated above, however, the job takes seconds with a ramp and an air gun

[Frik]

Nedz said:

Best to replace them both.

I've heard this repeatedly and never understood why.

[mat205125]

Frik said:

Nedz said:

Best to replace them both.

I've heard this repeatedly and never understood why.

Over time, the rate of a spring can change as the material is moved and is worked. They may sag a little too.

It's very unlikely that the majority of people could notice a dynamic difference, however a slight difference in ride height will accelerate tyre wear at best, however could cause a "slew" or other peculiar handling trait in the event of an emergency manoever.

For the sake of a few quid, avoiding the above (admittedly unlikely) scenario is a price worth paying.

[Frik]

Why would they sag if the material hasn't yielded?

[mat205125]

Frik said:

Why would they sag if the material hasn't yielded?

Depends what you mean by "yielded"????

If you have two springs the same static length, with the same weight on each, however one is softer than the other, the softer spring will compress more under the load.

In the real world, the spring rate on an older spring may only drop by a few percent, however (whilst the static, unloaded length may remain constant) this may be enough to mean the car willsit lower on one corner, and the balance of the car will be upset.

We're talking about minor changes, and small percents that daily "shopping" driving will never be effected by, however an M is a performance car that might (should) occasionally be driven properly.

[Frik]

mat205125 said:

Frik said:

Why would they sag if the material hasn't yielded?

Depends what you mean by "yielded"????

I'm no materials scientist but surely a coil spring shouldn't go beyond it's elastic limit in compression before it becomes coil-bound (unlikely in this application anyway), so why would there be a change in its properties over time?