Landseer

Need some advice.

84 5 speed. New Bilstein shocks. Not sure of spring origin.

Am at 210mm in rear (per Tony
s writeup ) after winding the adjusters (was 225+).
Have about 16mm of threads remaining below rear shocks. Can wind the adjusters down that additional amount.

Doesn't seem like I will achieve 170mm ride height.
How do I get down additional? Cut the springs?

GlenL

The rear motion is close to 1:1 (front 2:1) so you're not going to get there...if you're measuring it right. Do the sides evenly, a few cranks at a time.

Maybe give the car a few bounces or a short drive. The rear doesn't need time to settle like the front but it will stick a bit.

Assuming you've got regular 928 springs, or 928 aftermarket bits, you should get it to 170 and below.

A trick I use is to cut a stick to the target height. I've got a few, actually. Makes measuring easy.

mark kibort

Glen, where did you get that motion ratio for the front? no way its 2:1. I atually measured 5:1 for the front. 1" on the shock is 5" on the wheel. I dont know what the rear is, but its more than 1:1

if you are at 210mm, you might want to think about cutting a spring or half of a spring coil out, if lowering the adjusters doesnt work.

Landseer

Am measuring correctly, I think: from garage floor upwards to the flat on the lower control arm mount (the inboard ones, with the adjustment cambolts) per the write-up below.
http://members.rennlist.com/v1uhoh/checkingRH.htm


Will wind-down the rear the rest of the way and see where it ends-up. Springs have blue paint markings / they might be replacements of some type.

Front is also way-high. That's next.

Mrmerlin

look in the WSM for spring colors it will tell you what the colors mean and where they are used

Jadz928

Chris,
Those are the M474 sport springs, but not sure of the color dot. I know for a fact that same setup was set low. So my guess is you will get there... or something is assembled wrong, or you're measuring at the wrong place (which I doubt)

For reference:

LT Texan

replacing the boges on mine with Bilsteins turned it into a 4x4!!!

I cut the springs.

Landseer

So a few pictures.

Springs are 3 green paint splotches on front; 3 blue splotches on rear

First, the rears.
Am now out of adjustment. Got down to just under 210 mm.

Then the front driver's side.
Used a spring compressor to try to relieve a bit of tension, to no avail.
Can't seem to turn the adjuster either up or down. Its soaking in penetrant right now.

Does any of this look out-of-ordinary?

Tails

Chris,

Are you measuring the ride height with the correct size tyres fitted. If not then you will have to make some allowance for the ride height taking into account the outside diameter of the tyres to ensure that the ride height attitude is correct and within specifications allowing for the +/- allowance and the maximum specification difference between each tyre. There is a record sheet in the WSM that allows you to record the different adjustment, heigth and tyre pressure and the maximum difference in measurements. I take a recording at each yearly service as well as measuring the average tyre tread thickness to gauge wear and its relationship to ride height.

Another point to take account of is how flat is your floor you are measuring from.

To get a quick gauge of the flatness of your garage floor, get a clear plastic drum/can and attach a length of clear plastic hose near to the base. At the free end of the hose attach a 12 inch rule to the tube by zip ties.

To start the measurement fill the drum to about 6 inches whilst holding the rule vertical adjacent to the drum until you get the "U" tube reading on the rule. Place the drum adjacent to a front wheel and take the "U" tube measurement on the rule. Now move the vertical rule to each corner of your car next to each wheel and you will see how level your garage floor is and how much you should adjust the ride height measurement at each corner to compensate for any out of level measurement.

It is interesting to note that I have seen some post stating that the measurements have been taken to the top of the tyre arch in each fender-very inaccurate way to measure the ride height as the front fenders can be different heights at the arches.

When you look at what happens when you do a wheel alignment, ever little bit of "out of level" at each corner can make a difference to your wheel alignment.

In addition if you really want to get technical, then measure the corner weights or the vehicle (corner balancing) at each wheel with the correct amount of fuel on board and some sand bags equal to your weight in the driver's area, as well as all the tools and other removable items you usually carry.

Hope this helps,

Tails 1990 928S4 Auto

Landseer

Thanks! Am just trying to get in the ballpark grossly at this point. Interesting.

Here is a photo from the Tony writeup. Its where I'm measuring rear ride height.

Tires are low profile 18" radials and are slightly, but not appreciably, taller than factory 16's.

Not sure why the rear is still tall. Its bottomed out now at 210mm, which is 40mm > target.

Maybe I need to disassemble the fronts to break-free the adjusters.

Does the front identification number translate to the correct front shock fitment?

Jadz928

For a visual reference, here are those exact wheels/tires on Perl....

Jadz928

Hey man, I just found this post. I'd checked the ride height on Chewy after having the new Bilsteins installed.

Check your measuring technique and environment.

Reference pics of one front and one rear... (man, I can't believe I save all this stuff)

Jadz928

Stole this measuring technique from JPTL...

Landseer

OK, will review. Am using a ruler marked in mm for rear measurements. Could be me.

This rear wheel/tire set is about 30mm diameter larger than a similarly-treaded 225/50/16.
So, there's potentially 15mm, essentially bringing us to 195mm.

The front wheel/tire set is just about dead-even in size.

GlenL

5 to 1? no way.

On the rear the shock mounts on the pivot pin next to the bearing carrier. Moving the spring u/down the shock will lift/lower the body almost the same amount. There are some subtle differences but it's real close.

On the front the shocks mounts roughly half-way between the hub and pivots at the body. 2:1. In practice these have been good estimates. With 1.5mm threads you'll get 3mm change for each full revolution of the nut.

To the issue: did you assemble the hats right?