Rear Suspension Coil Spring Replacement

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Joined: Fri 14 Nov, 2003 00:24
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  M roadster S54
Location: Sunny Yorkshire

Rear Suspension Coil Spring Replacement

Post by NorwegianBlue »

This is to replace the rear coil springs on a 2002 ///M Roadster (S54) but should be similar to other models.

Firstly I looked for some aftermarket springs, maybe something to spice things up a little. I didn't want to lower the car, it's low enough but herein lies the problem. That's because I couldn't find anything that didn't lower the car! Also, the likes of GSF and Eurocarparts and Motormec didn't stock replacements. So after some sound advice, I stuck to the BMW ones and called around for some prices. I found it was worth being a little cheeky and asking for a discount, so got a new pair (yes they come as a pair, with replacement rubber pads) for £144.

Being a bit of a miser I decided to do it myself, so started off by buying some spring compressors, this turned out to be a waist of time, as you can't get them in, plus as you'll read I didn't need them.

At this point you may want to measure the ride hight of the car. This is not an exact science but will give you a general idea. Stand the car on level ground. Use a tape measure to take a reading from the floor, throught the centre of the wheel to the underside of the wheel arch. Do this on both sides and write it down.

To replace the springs I chocked the front wheels and jacked up the rear of the car and stood it on axle stands. Removed the wheels. Removed the bolt from the bottom of the shock and also the bolt holding the anti-rollbar to the suspension arm. This allows the suspension arm to lower further. Then by applying a little pressure to push the hub down, I could wiggle out the old spring.

Replacement was pretty much the reverse but you'll need a jack under the hub to push the suspension arm back up, so you can locate and fit the two bolts for the anti-rollbar and shock. The tightening torque for the shock bolt is 77nm, not sure about the other.

In retrospect it may be best to buy new pads for the top of the spring, the springs came with pads for the bottom only. Mine were not bad so I'm not going to fret over it.

Take the car for a quick test drive and ensure all is fine. This also may the time to check the ride hieght again. If your lowering the car, take a few measurments over a few days as it does vary. You can buy pads to adjust the ride hight, if it varies too much from side to side.

Sorry I forgot to take any pictures!

This all took at tops 90 minutes but could be done in an hour or less.
Last edited by NorwegianBlue on Tue 30 Oct, 2007 14:47, edited 1 time in total.
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  M roadster S50

Post by c_w »

Yea, the key is to undo the anti roll bar nut which allows the trailing arm to drop down a lot more than it otherwise would. After doing it a few times I can now change them in about 10minutes; the longest time is taken jacking the car up and removing the wheel!

Why did you replace them though?