Friday, November 13, 2009

Removing front coil spring

Once you get used to the suspension and steering of a Mercedes nothing else will do. The Jag's suspension and steering has always felt rather vague in comparison. The steering is horrendously over boosted and the front suspension needs to be in a "good mood" if you're to get anywhere. Having tight new polyurethane bushes goes a long way in getting the big cat handling right but having the right shocks and springs is vital. Vehicle manufacturers are faced with a compromise when installing suspension components, comfort vs performance, longevity vs cost etc.. So the stock shocks and springs are good for nothing in my book.

I installed 4 new Bilstein HD shocks and H&R springs on the IRS and it totally transformed the way the backend felt. So I decided to change the front springs and shocks too. However the front suspension does not have McPherson struts and thus removing the springs from the suspension is quite a scary affair.

To do the job, you need an internal spring compressor. Some people make their own, but I bought one from Boss Tools on the basis of an article I found on Jag- Lovers. There is a simpler one for $30 on Boss Tool right now.

Removing the front springs on a Jag is likely one of the most, if not the most dangerous DIY job. I spent months reading on how to do it first.

When free time and decent weather met a few weeks ago I decided to give it a go. The job was fairly straight forward, but the most crucial part about it is to use a set of bolts to guide the spring pan down a little, before you loosen the spring compressor. No matter how tight the spring compressor is, there will always be a little tension on the inner side of the spring pan simply because of the shape of the wishbone. This is why the guide bolts are crucial.

Once the inner side of the spring pan has dropped about 4" from the wishbone, there should no longer be any tension pushing down on the pan.

As a safety measure, I left the spring and spring compressor assembly in the spring tower while I loosened the spring compressor as far as my guide bolts would allow. Then I took the guide bolts off and set it on the ground and removed the remaining few pounds tension from the compressor.

It was the first time I had ever done anything like that before, so it took me about 5 hours to remove that one spring. Now to just POR-15 up all the bits and install my new spring and shock.