Changing Perch heights on koni's

Speedyblue · Postby **Speedyblue** » Thu Oct 01, 2009 8:14 am

I did a check last night and my NA8 is about 5mm lower than it should be, which explains why the underside has so much speedbump love.

The car sits on king springs and koni adjustable shocks. I figured I can just lift the perch height up a rung on the shock body and it should sort it. How hard is it to change that little circlip from one groove to another. I have a set of spring compressors and what not, but I'm not sure what to use to get the circlip off.

Anyone got some hints?

StanTheMan · Postby **StanTheMan** » Thu Oct 01, 2009 8:20 am

I usually use a small screwdriver to get one end out of its grove. Push the circlip up far enough & then repeat this with the other end. It will scratch the paint work a little.

Garry · Postby **Garry** » Thu Oct 01, 2009 9:50 pm

Note that due to the lever arm ratio of the control arms a 5mm change to the spring perch height will change the ride height by about 8mm.

As Stan said, the circlip is pretty easy to prise out. Just be careful when reassembling everything that the circlip fits into the recess in the bottom of the spring perch properly.

Speedyblue · Postby **Speedyblue** » Fri Oct 02, 2009 1:16 pm

Cool. I'll have a muck around with it tonight and see how I go.

Juffa · Postby **Juffa** » Fri Oct 02, 2009 9:55 pm

Due to the short overall length of the springs, especially the rear ones on the MX-5 is can be difficult to securely attach a spring compressor. There is another way to do it.

I have used this method many times on my all three of my NAs over a period of 10 years and never had a problem.

Use your preferred method to ready the spring/shock absorber for removal, ie separate the ball joint or remove the upper A arm bolt.

Using a scissor jack to press up against the bottom of the suspension, ie on a point where you can safely apply upward pressure without the jack slipping.

Raise the jack until the spring is compressed. Be careful not to raise the jack to the point where the car is lifting off the jack stands.

Loosen and remove the single upper shock absorber nut. (do not do this unless the spring is being safely compressed by the scissor jack).

SLOWLY lower the scissor jack thus releasing the pressure on the spring. The spring will un-compress as the pressure from the jack is removed.

Once fully released the spring should be loose and ready for removal.

Pressing down on the lower suspension arm will allow the spring/shock absorber to be swung free from the upper mounting point.

At this point the spring and shock absorber can be removed.

Installation is a reversal of the above.

J