Bilstein spacer - necessary?

[speed]

Hi all,
I'm replacing my rear bump stops/dust boots on my na6 with new oem ones.

I have bilsteins from a clubman and lowered king springs.

Issue I have is that one shock is missing a spacer that sits at the base of the threaded rod. I swear it wasn't there when I pulled it apart but have looked everywhere just in case.

The other side has it.

I'm not sure what the correct name is for the part which makes research difficult but it's basically a 3 or 4mm washer that looks to be made of hardened steel.

It sits at the base of the thread.

My questions are:

1. What is it called?
2. What does it do?
3. Do I need it?
4. Where can I get just one?

Would like to get it right the first time.


Thank you very much,
Steve

[93_Clubman]

From your description I'm assuming this spacer/washer is located below the tophat when assembled? Checked my front & rears in the Clubman, but there's only a split washer & nut above the tophat.
Have a spare set of Clubman Bilsteins, but they comprise only damper & spring, which are separated, so no tophat or any of the other top end parts.
Do have another MX5 NA Bilstein with a tophat & some top end parts (large rubber washer with large cup like metal washer cap & nut, which sit above the tophat), but the tophat & top end parts are different to the original parts on the Clubman, so maybe it was used on an NB at some stage.
Perhaps contact jonosx on this forum who works for, or at least used to work for, Heasmans the Sydney Bilstein specialist: <jonathon.mckinnon@bilstein.com.au>

[speed]

From your description I'm assuming this spacer/washer is located below the tophat when assembled? Checked my front & rears in the Clubman, but there's only a split washer & nut above the tophat.
Have a spare set of Clubman Bilsteins, but they comprise only damper & spring, which are separated, so no tophat or any of the other top end parts.
Do have another MX5 NA Bilstein with a tophat & some top end parts (large rubber washer with large cup like metal washer cap & nut, which sit above the tophat), but the tophat & top end parts are different to the original parts on the Clubman, so maybe it was used on an NB at some stage.
Perhaps contact jonosx on this forum who works for, or at least used to work for, Heasmans the Sydney Bilstein specialist: <jonathon.mckinnon@bilstein.com.au>

Thanks 93,
Yes it's below the top hat.

It's like a 4mm washer at the base of the threaded rod.

Picture noting on the shock, then slide on this washer, then fit bump stop /dust boot, fit spring, fit top hat and tighten nut in middle.

On the rod where the thread ends, the rod steps up in diameter which might make it difficult to distinguish the washer from the rod.

Could I trouble you to check again for my peace of mind?

If you don't have this washer on any of your NA clubmans then I'm guessing it is not necessary.

Thanks

[greenMachine]

I don't know if these will help, they are of a (leaking) PSS9 off an NB (GM1). They show the washers and the rubber bushes, as well as the bump stops.

[93_Clubman]

Just had another look & this time below the tophat, but as the rubber gaiters are still intact in the on car Bilsteins I'm unable to see what, if anything, sits at the bottom of the thread on the damper shaft.
The other set of Bilsteins were originally from Bruce's Clubman, & I bought them after they were revalved by Quadrant Suspension the Bilstein specialist down here, hence dismantled, & so we can't really draw any reliable conclusion from them as they are not complete with tophats, bump stops etc.
Think what the intent might have been is as a 'sleeve' which slides into the top rubber bush, where fitted, ie GM's PSS9s for his NB8, to make a snug fit & avoid threaded metal in direct contect with rubber.
Apart from contacting jonosx, my other suggestion would be to check the NA parts manual as a number of JDM NA6 also had Bilsteins fitted & there are usually good diagrams.
manga_blue has linked to parts manuals a few times in the MX5 Technical Guides sub forum: viewforum.php?f=76

[speed]

Thanks 93 and greenmachine, especially for politly correcting my dodgy terminology

Called bilstein. They refer to it as a "button" that holds up the bump stop. So it's necessary.

Unfortunately they say it is specific to mazda so they can't order for me.

Fat cat motorsports in the states sell the button but they called it a spacer and it would cost $5 plus freight.

Bilstein guy agreed that I could just use anything of the same size, so that's what I will try in order to finish playing suspension this weekend.

Thanks again

[93_Clubman]

Thanks for updating - useful to know.

[speed]

I'm not convinced that the button stops the bump stop from sliding down.

In my mind, it's the top of the bump stop that holds it, as it has a smaller diameter hole.

The button (or spacer, washer, bush!) Sits snug in the base of the bump stop to prevent side to side movement.

Had no luck at the fastener place, so now waiting for mazda to get back to me re sourcing a replacement.

[93_Clubman]

From memory think Mazda Aust weren't able to assist me with Bilstein parts & suggested trying Bilstein, which you've already done. If Mazda can't help maybe try Amayama.