When I removed the displacers from my Sept 1970 Cooper S I noticed they were different to a set of Mini K displacers of roughly the same age in one obvious externally visible aspect. The moulded rubber component inside the metal cylinder of the S displacer was closer to the top rim than the non-S Mini K displacer. I figured this might be the method of creating a stiffer spring setting and hence a simple way to easily identify a Cooper S (and Clubman GT) displacer from a non-S displacer. Several people with much greater knowledge of hydro suspension than me agreed with my suggestion, however there's another view that all early displacers (until around March/April 1968) regardless of application (S or non-S) have the higher rubber fill and after that all displacers, regardless of application, have the lower fill.

Here's a photo that compares one of my S displacers on the left with a MIni K displacer on the right. You can see the difference in height of the rubber surface.



The displacer from my car has the part number 21A2014 and date 69 embossed in the steel case.



This lines up with the part numbers listed in a table in the BMC Australia displacer engineering drawing (YDO6 is Cooper S and YDO5 other Mini models).



In an effort to get an agreed position on this I'm asking for any displacer photos to be posted here that clearly show the embossed part number, date and moulded rubber level.

By the way, ignore the part number 21A1477 that appears on the surface of the rubber in the bowl. It's a common number used across all displacers.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

I am slightly confused with your post.
I understand you want to know the rubber spring level in the unit - will look at my bits tomorrow.
But your unit should be 21A2014 (- not 21A2104) which is for the rear, and late double silver coloured unit. Maybe just a typo from you?
Also a bit odd that a 9/1970 car would have a 1969 displacer originally.... I know there are many possible reasons... but just not common.

My 1970 Matic had the same front bags as the RH Mini K one in your pic.
It now has a complete front subframe taken from a bent 1972 GT. The bags look like the LH S one in your pic.
Sorry no idea of part numbers.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yes, typo, now fixed. Thanks for the alert.


Yes, it does look a bit early, but if manufactured in the UK and sent by ship in bulk then BMC Oz may have had a stockpile. I wonder what other cars of that era had?

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

Just had a look at the displacers from my 8/1970 S as the car is in pieces. They are all the higher (thicker) rubber style - all dated 1970.
2 mini K displacers (21A2008) dated 1969 are the deeper/lower (thinner) rubber style as in original photos.
Several displacers from my 1966 S are yellow banded (21A1693) and described as 'Early Rally'- no part numbers or dates but these are also of the deeper/lower recess style like the mini K.
To me, that means all the early displacers including early S and competition parts were all low filled. This continued with the standard displacers for Deluxe, K and matic. At some point the S displacers had the thicker rubber spring part.

My 3/70 S bags are stamped 69 too. The rubber unit is the higher type. When I finish tidying them up, I'll post some pictures. They are not as good as condition as yours. [Btw, just managed to get the old seized balls out of the fronts without destroying anything]

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1970 Mk2 Cooper S under restoration

Is it worth re-stenciling the part number on the displacer bags? You can't see them clearly when in the front sub-frame, and they do have the right # stamped on them. I was just going to seal them up, blast them and repaint in satin black. Its not a garage queen restoration, I already have one of those and don't want another.

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1970 Mk2 Cooper S under restoration

I don't remember seeing the stencilled number on any of my mk2 displacers - either the ones that are in my car or any other ones I've come across. I have seen the silver band around the middle, like the green band on the standard displacers.
It's up to you - as you say, the stencil cannot be seen once in the car.
There was a single band of silver on the hose for the front ones - 2 bands for the rears - although only the front ones are visible. And they faded quickly. I suspect the colours were for the assembly workers and not the concorse judge.

You can see part of the stencilled number on my S displacer photo at the beginning of this thread.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

Yes, I understand that 'Ausdino' and 'Winabbey' have posted photos of their displacers with stencilled part numbers. I wasn't trying to imply the stencilled numbers didn't exist but these are the first I have seen with stencils and that none of the displacers on my 8/70 S ( am fairly sure I was the first to remove them) and on a small number of 21A2012 displacers I collected in the '80s didn't have the stencilled numbers either.

I would be curious to know if any rear displacers had their part number stencilled on them. None of the ones I have are stencilled.

Bill, my rear displacers didn't have the part # stencilled on them (3/70 mk2 S), fronts per post - same car.

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1970 Mk2 Cooper S under restoration

Hi Winnabey,
It's your lucky month as I'm finally getting to that hydro leak that's been annoying me since 2006. I have taken a pic of my LHF displacer which in 2006 I attempted to reproduce the same colours and stamping to what i assumed it was when it was new. It hasn't done much work in the 14 years since so i gave it a wipe and took some pics as requested. The date stamping was not done too well on this one I'm afraid and even though my car appears to have been assembled about 10/69 the displacer is missing the "69" at the end like the one you have shown. Thanks to your publications, I now understand that the ring around the displacer body should have been white not siliver. I found that the hose on the fronts were single band near the fitting and the rears were double banded, I painted these silver as I had heard about Cooper S having silver bands although now I am not so sure if this was correct?
hope this helps you, regards Gavin

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Are they big? I like 'em big!

I don't know about white bands on any displacer. 21A2012 was silver like you have painted on your displacer - and it appears in very good condition, too.

Hi Winabbey,
Below is a pic of displacers from my 04/72 GT. They dont have any part numbers that I can find, Fronts have 1 orange "dot" and rears have 2 orange dots. Also some signs of green paint on at least one of the rear units.
They have the higher moulded rubber level:




I also have an 07/72 Clubman Mini in bits that has the lower level displacers, again no part number that I can find and no sign of any paint marks/colours:
Net=xt to one of the orange ones for reference:


edited for wrong pics

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'78 1275 LS (Under Repair, Dependant #1's car)
'72 GT Powered Clubman (Mine)... Under (re) construction

My 11/72 GT had no part numbers stamped or any colour codes.
(Not that I could find anyway)

Sent from my SM-N960F using Tapatalk

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