help with rear suspension shocks

[waynerp]

Hi guys.I'm in urgent advice for changing my suspension and shocks on my z.
I'm starting on the rears and am at the stage of having removed the original shock.
I'm not sure what parts to take from the original to put on the new.
Also any ideas on how I remove the spring
Plus where the heck foez the blue adjustable bracket go???
Any tips very much appreciated

[BladeRunner919]

Doesn't look like you need anything from the old shock. Do you not have new top-mounts, though?

[waynerp]

No.can i not use the old ones

[BladeRunner919]

You can, but they wear and are the cause of rattles and knocks. New ones are only about £13 for a pair. Not replacing them is a false economy.

[waynerp]

OK thanks will get a new set. So does anyone know if the blue adjustable thing goes on top or bottom of the spring

[gookah]

OK thanks will get a new set. So does anyone know if the blue adjustable thing goes on top or bottom of the spring

It can go on either way, but if you put it on the bottom, it will collect dirt and grime and make it harder to adjust in future.
Best at the top imo.

[Del]

I assume you have opted for independent coil springs and shock absorbers and that the blue ring on the left is a ride height adjusting “pad” for the new coil spring?

The shock absorber appears to come complete with its own dust cover and presumably has its own bump stops etc. underneath the dust cover – Bilsteins come like this also.

I suggested already, it is a good idea to replace the old mounts as they are a “sandwich” of steel and rubber which has degraded on most Z3s. It really would be good practice to replace the old ones as yours look quite rusty.

In my view you would need to reuse the “dished washer” at the top of the new shock absorber. A slight query I have is that the existing OE Sachs shock has a spacer at the bottom that is fitted so that it faces the road wheel – this presumably keeps the suspension/axle geometry at a certain angle. I note that the picture shows no similar spacer?

[gookah]

A slight query I have is that the existing OE Sachs shock has a spacer at the bottom that is fitted so that it faces the road wheel – this presumably keeps the suspension/axle geometry at a certain angle. I note that the picture shows no similar spacer?

Del's correct, the spacer is part of the old shock absorber, and the new shock absorber will need packing out with a new spacer or large washer, otherwise the bolt will bottom out on the threads and allow the shock absorber to move side to side on the bolt.
I know....

[waynerp]

Hi Guys.
Many Thanks for all your advice.

SOOOOOO.....

That was probably the most stressful afternoon I have had in a VERY long time. I now know why i never pursued a career as a mechanic.!!

I have managed to get everything back on, but i need to get some new mounts, plus will any washers /spacers do to fill out the gap where the new shocks dont have the as per the original ones?

The next BIG problem is. i watched a video where someone did the same thing and they said it was optional to put back the original rubber mounts that go on top and bottom where the spring fits.
As i nearly broke my back getting the spring back on i didnt put the top one on, as firstly the rubber would not fit into the hole of the adjustable part. secondly the extra couple of mm would have made it near on impossible for me to get the spring on.
Now i think because of this the adjustable part is just spinning round, and well... wont adjust.
Any ideas / tips as what i can do to resolve this????

[Joycey]

How does the car sit with the adjuster like that? I bet its still high at the back. unfortunately that's how those coilovers work. They dont really get the rear any lower.

If you aiming to get the rear higher i would try tapping it round under tension.

Lee

[waynerp]

yes its really high, the complete opposite of what i want, but when i try to adjust it, the whole adjustable caliper spins round so it wont adjust

[waynerp]

This is the adjustable part for the new spring, and the rubber gromit is what was origianlly on the car. Although the gromit will fit nicely into the adjuster. they wont go over the knob bit of the car, which is why i didnt put it back on.
Can anyone suggest how or if i should put it back on, and if this is the reason the adjuster is turning when i try to adjust it

[Del]

You're supposed to still use an upper and lower spring pad (you call gromit) to avoid any metal-on-metal knocking or grinding noises.

Disconnecting the drop-link on the anti-roll-bar will give you more wriggle room to fit a coil spring. I'm guessing that there needs to be some load on the spring to stop the whole adjuster unit spinning.

This video shows a similar procedure (rear adjustable coil spring) on an E46
https://www.youtube.com/watch?v=X5WrBZ8Fto0

[Mike Fishwick]

What make are your springs and dampers, and where did you buy them, and did the kit not have any form of instructions?

The blue threaded ring is an adjuster of the type used with coilovers, where it would fit around a threaded area of the damper/strut - which in your case you do not have. In spite of advice that it is a 'Ride height adjuster' it has nothing to adjust against, so all it is now doing is to act as a pretty spacer. As you say, it will turn but cannot do anything. Take it off and dump it - these items should never have been supplied to you. You know how a nut and bolts works - so just apply this principle to these adjusters and you will see what I mean - it is common sense.

In any case, even if it had been supplied with another part to form an ajustable spring pad, by reducing the height of the spring you would also be compressing the spring - preloading it - and the rear suspension would become much harder. It would also have a shorter travel, which would not necessarily improve handling, and also reduce ride comfort and ground clearance.

You will have to remove the springs anyway, to replace the rubber pads at the top of the springs, as otherwise the springs/threaded adjusters will transmit noise into the body, and cause wear on the spring abutment. Replacement of the rubber spring pads by new ones is optional - BUT throwing them away is not! The upper spring pads also carry the bump stops (the bullet-shaped pieces of rubber) which are there for a purpose - to prevent the suspension compressing too much, and so damaging the springs, dampers,drive shafts/couplings and wheel arch liners.


Z3 rear suspension showing bump stop inside spring

I also have my doubts about the steel tube in the rubber bush at the base of the damper - it does not appear to protrude sufficiently to provide clearance between the damper eye and the head of its mounting bolt. Perhaps it looks better in the metal. There should also be a square piece of thin steel fitted below the head of the bolt, in order to prevent the damper eye from sliding over the bolt head in the event of a failed rubber bush - it looks like this is still on the original dampers, and should be transferred to the new ones.

If you have learnt anything from this exercise, it is to buy a spring compressor, to find out what you are going to do in advance, not to discard items which have a purpose, and that everything which comes in a suspension kit, or is offered as advice on the internet, is not necessarily useful!

Better luck next time!

[siwilson]

OK, so your setup will look almost identical the the KWv3 setup I have.

1. Undo the anti-roll bar mounts for the trailing arm. This will help you lower the trailing arm to get enough room to get the springs in and out. BE CAREFUL the drive shaft does not pop out of the diff. See how it looks before you start and make sure it looks the same after. If it does pop out it can be pushed back in.

2. You do not use an upper rubber spring pad any more now that you have an adjuster. The Adjuster goes on top and the old upper spring pad that incorporates a bump stop goes on the bottom.

3. Normally adjusters are used with shorty springs and to adjust you need to unload the spring by jacking up the car and sometimes you also need to undo the lower shock bolt. you could try an install without the adjuster and use both spring pads as they were originally. See how it sits.

Thes pics should help.

[Del]

In the pictures of the yellow springs above it looks as though the top spring pad has been fitted to the bottom.
The writing on the spring is also upside down

[David]

The writing is upside-down on the springs I fitted 2 days ago, and I have done exactly as the instructions have said. Bad design, but doesn't mean they have been fitted incorrectly.

[Mor61e]

I went without the adjuster and kept both spring pads in to give the height as you can see in my sig if that helps you

[Mike Fishwick]

OK - I now see what the adjuster is - I did not realise it was in two pieces! It is necessary to hold one piece while turning the other, but the more it is extended the less rigid it will be against the body.

Frakly, I think this design looks pretty awful, as the top of the spring changes its angle with the body as the suspension moves, so the adjuster is not rigidly attached to the body, and you still have the problem of noise transmission.

Do you really need adjustable ride height that badly?

[Joycey]

Back to what waynerp was asking. Unfortunately those coilovers aren't a very good design on the rear. On a friends car we tried removing the adjuster on the spring but the shock kept bottoming out under heavy conering. The spring wont sit central either.

Lee