I have a mk1 Cooper S with hydro suspension. When I pump the suspension up, the rear comes too high to get the front to a decent height. Do the front bags 'collapse' even though they hold the pressure, if so, how/why? ie when I put the recommended pressure of 282 lbs, the rear comes pretty much to the right height but the front are at least 25mm low. I already have spacers on the front.
I don't understand that if the bags hold the pressure why the height isn't correct?

Any suggestions?

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johnl

Knackered rear hydro helper springs and or stuffed front knuckle joints.

Bags are stuffed.... I will dispose of them for you Yeah get yourself a set of new hydro helpers springs.. theres a set on eBay at the moment

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I think Cooper S ones are different to normal ones though....

edit: But the standard mini springs will fit, just if your going all out for originality

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Helper springs were same for Cooper S and others of the same period.
Late springs were orange. Not sure of the change date I think was around Mini K era.
[edit] and the lengths were different.

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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.

Be nice if someone had technical data on these springs. Look like they're NLA from the usual suspects, might have to get some made up.

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I had same problem for years, took it to mini classic and got the knuckles replaced, best thing I've ever done to the car. Now it doesn't look so dumpy at the front.

The way I see it, if it is leaning over to the front that much, it can't just be the helper springs...

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Lillee - 1969 Morris Mini K

People may not be aware-
When you grease the front end top arm, no grease goes into the knuckle cups. There is no drilling to them. All they got was a smear of lithium grease when assembled.
I have a `grease needle' (is like a hypodermic with a nipple on the end)- I stick it thru the knuckle boot every year or so and give it a shot.

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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.

The whole front and rear end have been re-built using new parts. The helper springs were NOS.

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johnl

There where at least 2 different lengths of springs.

You haven't fitted Dry Arms in the front?

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Check the pressure gauge. It could be reading high.
Correct ride height at the front is 12 1/4" + or - 1/4" measured from the centre of the drive shaft to the underside of the front guard edge lip.
When you pump up the system the rear will rise to the correct height first and then the front will come up. The leverage ratios of the arms and struts are different and there is less weight on the rear. This causes the rear to rise first then the front. IIRC the ratios are : rears 5:1 and fronts 3:1. The later orange coded rear helper springs were introduced to stop the front end sag but after 40+ years they may have weakened. Also check they haven't worn the attachment shaft on the rear radius arm or the inside of the lower spring attachment loop. BMC in their wisdom used felt washers here so they will be well worn or more likely disappeared by now.

Edit: You do have S bags all round? There are at least 2 different hydro bags used on OZ built S cars. Early ones had Blue coded bags and later ones had Silver coded bags. UK built cars had even more different bags.
Don't know if that will make a difference but its worth checking.
When you replaced the ball sockets etc did you replace both the nylon socket and the ball end or just the nylon socket. If the ball end is worn it doesn't take much to make a significant ride height difference. Also check the front arm to make sure the ball end hasn't worn its way into the arm socket.

RonR

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68 build Mk1 Cooper S
72 Clubman GT project. Total restoration required

bear in mind that the Hydro does settle after you first pump it up....have you tried pumping it up then driving it for a few days???

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"Show me the Mini!"

I reckon the hydro bags still have a rubber spring in them, similar principal to the old rubber cone. The bag combines a rubber cone with the hydro.
There is a brief description of this in the last BMC Experience, written by Pottsy. I have also read this somewhere else.
Thus the front bags would sag more than the rears with age – as front donuts do.
New helper springs will assist, but it would be interesting to swap the bags front to rear – only take a few minutes.
I put additional spacers under the front of my S to overcome this problem.