On my 1991 C4 I have the M030 option with the "sports" suspension. I like the hard ride, but the wife does not!

I looked at the shocks last night and noticed what appears to be an adjustment nut on them, under the nice big red spring.

Can I adjust this myself?

 

Dear Brad,
What red springs. They are not Porsche M030 springs. M030 springs are Black with two green dots. M030 springs give a 40% harder ride but do not adjust ride height. The adjustments you are looking at will raise or lower ride height by 10mm giving 5mm for levelling.
This will not give you a softer ride, only ahigher and more unstable one. I suggest that you find out what springs you have fitted and replace them with the correct Porsche ones for a softer ride.
Ciao,
Adrian
911C4

PS: Boge shock absorbers are also black.

 

I'm at work now, but from memory the red springs carry a 993 part number and have the word "sportwagen" on them. I'll have a proper look sometime, but they def. have a porsche stamp on them.

 

And yes, the Boge shocks are black (and nice and shiny after I got bored and cleaned out under the arches!)

 

Brad,

If you have red springs, sounds like you have a set of H&R lowering springs, they are also marketed by Gemballa.

The adjuster nut is the ride height adjuster, if you can move it OK (quite often seized), you can adjust your ride height.

You will need to have the geometry checked afterwards, because the caster/camber and tracking will be affected.

 

Phil, you are right! They are H&R springs, which I believe are good (I'm new to Porsche). My mechanic reckons that I need new front wishbones - if these are "worn" would that increase the bumpiness of the ride?

 

Dear Brad,
Can you confirm that you have H&R 993 lowering springs installed on your 964 C4. These are not the best springs, not even from H&R. The 1990 model lowering springs from H&R are Green. I have a set in my cellar.
Worn wishbones which normally means the bearings are gone and you need a complete wishbone, but the wishbones do crack are often the result of "Using" the wrong suspension parts. lowering too far which puts extreme stress on the wishbones and not have a proper alignment, levelling etc carried out. If the 964 is lowered "TOO" far then the geometry on the whole front end is changed. It is known that cracked wishbones often accompany 964s which have been lowered below 964 RS Specs. This point can be easily exceeded with H&R springs lowering springs. Well the ones we have here. They will lower 60-65mm. This will also trash your struts and rear shocks in short order as well if you drive hard,
Ciao,
Adrian
911C4 (lowered to 964 RS Specs)

 

Just a reminder to all C4 owners. When embarking on suspension modifications you need to remember that a C4 has a thumping great, front differential that adds just a little more weight to the front. Porsche C4 springs are slightly stiffer than C2 springs. Orange dot for C4 and Blue dot for C2.
Ciao,
Adrian
911C4

 

Adrian,

I am fairly sure that the original 964 H&R springs were green, but then later production went red.
I know that the springs that I have fitted over the last 3-5 years have been red.

We offer a conversion on the front wishbones that is a great mod for owners of 964 models that do relatively low road mileage, but do a number of trackdays. We fit a nylon bush, then spiral groove the internal shaft and add a grease nipple to lubricate. This works particularly well on RS models, but the lubrication is fairly high maintenance (2-3 times a year)

Porsche do not sell the bushes seperately so I am afraid that a new arm is necessary. If you are buying new arms, you may want to consider the RS units, they have a stiffer rubber joint.

It is common for the wishbones to develop a crack from the holes where the air deflector is mounted.