Hi guys,
It has come to my attention that there are variations in Cooper S rear suspension displacer strut lengths. This is the rod that fits between the displacer and knuckle joint. I would be grateful to hear from anyone who has one handy they could measure the length for me.

I see there are two Mk1 versions listed in my book, one is 21A1497 and the later one is 21A1805 and it seems this one is 9 3/8" (about 238 mm). Comps may have had some alternatives too.

Kindest regards
Al

To throw another one in to the mix there is also a 21A2276, which appears to be the only one fitted in the UK and was used (at least) in the last of the Hydro cars in Oz. Sorry, I don't have any data on them (yet).

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Shall I wait up?

Any information you can find will be appreciated. It also seems there is a later S/GT helper spring too and I've popped an advert on the wanted board for a set of them.

Thanks
Al

The 'later' struts where P/N 21A1805 and according to the UK Factory, these were 9 3/4" (247.6mm) long. They should be used in conjunction with helper springs P/N 21A1806 and the entire set was to be used with Hydro Displacers 21A1804, 21A1811, 21A1872 or 21A1874 (depending on how hard or soft was the difference between these displacers).

It appears (not 100% sure) that the early displacers (front and rear - not those above) used a seperate spacer of 0.180" where as the later ones did not.

I'll see what else I can find.

No, don't wait up.

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A wealth of knowledge is our GT.

I never realised before there were struts of different lengths. If you made the mistake I did and use different ones on each side, it really has an amazing effect on the cornering.

Suffice to say I needed a change of underdaks on occasions.

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1967 Cooper S - new front bearings to do.
1965 Cooper S shell - Slow progress. No time or money!
1966 Deluxe- next rustoration!
Mk 2 & XJ6 Jags. Less said the better.

Hi Guys,
Thanks for your help, one and all. This is what I've found. Later cars (early '66?) all used a 21A1805 9 3/4" strut and it seems that it may have been colour banded to match the displacer. Modifying was acceptable by reducing the length by .300" to lower the car for circuit racing or adding spacers up to .150" to increase ride height.

From this same date (early '66), the rears suspension spring changed to the 21A1806 and it was also used across the entire range of Mini's and derivatives.

So, it seems that Cooper S's differed from the factory in only the displacers and one of the displacer differences was the piston height (the part the strut rear, or knuckle front fits to). From what I can see, the displacers may well have been built with a heavier wall on the hose end and thus the different dimension from the top of the hose end ledge, down to the rubber. This would allow higher pressures and stiffen the ride.

Anyway, thanks again and I hope someone else benefits from this.

Regards
Al

I'm still looking in to all this, but the change over date I have was actually March '67 (TBC) and yes, the struts and helper springs were common across the range (ie not unique to the Cooper S) and changed over at the same time. It was only the Displacers (both early and late) that were different between the models.

There was also 'another' later helper spring used on the Oz built Minis from about 1969 / 1970. It went under P/N AYG7060, however from what I am able to determine it is the same as the 21A1806. I think it was locally made in Oz (to get the local content up) with that 'type' of part number. I seem to recall that these had a coloured band of tubing (orange?) at the top end to ID them.

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The dates I quoted are based on UK build serial numbers and that possibly explains the introduction delay in Australia.

Regards
Al

My 1970 car's helper springs have orange paint.

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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.

Kev, orange seems to indicate a standard Mini part and the strut had orange band midway if it was used in a standard Mini. It seems it may have bands in other colours if used with red or blue bags (NOS struts exist with these two colours) , not sure about the other colours. The later 21A1806 spring seems to be only marked in orange.

Al

My 69 S has orange band on the helper springs.

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S

I had a bit of time today to dig some Hyrdro stuff out.

The Strut is an Ozzy one, colour coded Orange, P/N 21A2276. It is 9 3/4" between seats.

Of the 2 springs, the Black One with the Orange Tubing is the matching Spring P/N AYG7060.

Both these items above are for use with Displacers P/N AYA4090 ('Mini') or AYG7061 ('GT'). The AYG7061 is the same as the Late Cooper S (P/N to follow)

The other spring I am unable to positively identify, however from mount to mount, in a relaxed state was 1/4" shorter than the AYG7060.


By gtmowog

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There's been heaps of conversation about springs and displacers of late, its good to see some facts come out.

Would it be possible GT to see the early and late springs and struts side by side?
I'm wondering if early springs match to early struts and late springs to late struts of all models and that if that is the simplest explanation? Or is there more to it?

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I think the best way to describe that is as 2 different 'sets' and in each set there where a number of different displacers.

Early (~<67)

Springs P/N 22A1566
Struts P/N ????? (The short one in the pic above is this spring)
Displacers;
Mini P/N 21A1477 Fronts
P/N 21A1703 Rear
Stiff P/N C-21A1705 same F & R
Hard P/N 21A1819 Front - Note these are 0.0180" Higher
P/N 21A1821 Rear

It was the 21A1819 & 21A1821 that were fitted to the Cooper S.


Late (~68>)

Springs P/N 21A1806 also AYG7060
Strut P/N 21A1805 also 21A2276
Displacers;
Mini P/N 21A1804 Front & Rear, Also P/N 21A2008 F & R
Stiff P/N 21A1811F & R, Also P/N AYG4090 (as fitted to Oz Clubman )
Hard P/N 21A1872 Front, Also P/N 21A2012, Also AYG4113
P/N 21A1874 Rear, Also P/N 21A2014, Also AYG7061

It was the 21A1872, 21A1874, 21A2012 & 21A2014 that were fitted to the Cooper S, and for the historians, the AYG4113 & AYG7061 that were fitted to the Oz Clubman GT.

So, the helper springs and struts are interchangable only as all early or all late. It appears displacers need not necessarily be kept in same early / late sets, that is (according to the factory) one example they used was the late helper spring and struts but with the early hydro displacers to raise ride height for rally work and where extra weight has been added.

I don't have any early struts in our parts bin to measure ATM but should have by Friday.

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