I think its more correct to say that the rear helper spring "controls" the front ride height rather than compensates...

By adding front height (washers or whatever) you effectively lift the whole car. The rear height would increase except that the spring tension remains the same and so keeps the rear at the same height. So, fluid is then transferred forward and front ride height will increase.

Doing the opposite ..ie removing length from the rear strut does not have the same effect. Any lowering of the overall height will just be transferred to the front. While ride overall height will reduce the front to rear balance will be unchanged...

If you increase the front ride height but disconnect the rear spring the car will still tip forward until it sits on the bump stops. Only with the spring removed and the front sitting on the bump stops will reduction in rear strut length affect rear ride height. To me this demonstrates that rear spring tension is the sole determinate of front to rear ride height.

Cheers, Ian

I know you can't fit hilos on the front of a hydro car, but how about the rear? There's a lot more room. So when you have the suspension deflated and are putting your washer on the strut [or sawing a bit off to make it lower], bung a couple of hilos on the back. Then, when you have pumped up the suspension, and if you have got the front right you can fine tune the rear without having to deflate the suspension. If that doesn't fix the front/rear relationship, it’s time to look at the springs.

Looks to me like stronger rear springs would be the best way to level it.

Or a few bags of cement in the boot

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1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

But for the same reason as before, the springs need to come up to tension, shortening the struts mean the bags push out further, but at the same height as you haven't changed the spring length.

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SooperDooperMiniCooperExpertEngineering

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

People put too much thought into the springs and not enough into the basic static heights of each end.

My car (a Morris 1100) had no springs for a couple of years and all it did was upset the pitch. It didn't sit bum high or nose down.

I too shortened my rear struts. I went through the suspension in and out so many times to get it right that I lost count but when I cut the rear struts down 7mm in length it worked a treat. I remember reading this as a BMC suggested method for suspension enhancement.

_________________
"Investing my Super in a Cooper" &
"Re-living my Surfing Past in a Woody"

I'm going to have to think about this some more...

thanks

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SooperDooperMiniCooperExpertEngineering

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

According to my memory there were 2 rear strut lengths and 2 different springs. 2nd spring type colour coded orange.

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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.

There is also two different size cups that are in the bottom off the hydro bags
the steel one in the cooper s bag is about a 1/4 inch shorter than the cast alloy one
in the other bag , this is what I have found .




Mark

Just backing the truck up a little...why?

A perfectly flat stance on a Mini looks unnatural IMO...leave it alone and let the dubbers go slam their cars is my advice

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"Show me the Mini!"

I'm with Morris 1100. My K has spacers front and shortened rear struts to help lower the rear. This has no effect on suspension behaviour.
The length of the rear strut has no effect on the the bag- if the strut was 10mm long, the bag would still respond to the load it is supporting.

They were nearly level when new but 45 years later the front rubber springs have sagged and the cars are now around 1" to 2" lower in the front than they should be.
This means there is a lot less suspension travel. Instead of floating on fluid you are bouncing on bump stops.

People try to inflate the suspension to the correct height but end up with a fluid higher pressure. This creates a harsher ride than normal.
The correct height is a combination of strut length and pressure.

yes, shortened rear struts,,, & pack up the fronts,,,

we also try to find the strongest rear spring (to help pitch & dive motion) & also fit front shocks ->( to help pitch & dive motion)

I have often also fitted restrictor washers in the join of the hose & the pipe at the front,, also helps slow the fluid movement (to help reduce pitch & dive)

yes all this takes time but well worth the efort to help maintain the hydro ride quality

the front bags are squished from years of pounding,,,
they (all hydro bags) have a rubber spring inside --->>>>>just like a dry donut
once it`s been squished from years of the power unit pounding on them,,, well,, it`s just like an old dry donut--> squished

swapping front bags to rear & rear to front is one way to stuff a kitten but you`ll then need to pack the rears & shorted the front struts

& around & around it keeps going

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Are the rear springs still avaiable? New of course

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The best part of fixing your mini is the test drive

Minis..

1976 van daily drive
1975 van
1968 deluxe in the shed
1967 deluxe high strung 1310
1959 austin healey sprite

+1 for Morris 1100's & Matty's posts - many are surprised when they finally realise this ->



The fluid just sits in between the bag outer & the rubber spring, but acts like a lossy spring, with the "loss" going to rear displacer. Once the little flap valves on the bags wear out, well that's when you need the restrictor washers etc like Matty mentioned to stop the "riding the sea" feel

cheers,

Jacob

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'72 Clubman Van - 1022cc, 295 head, 731 cam - Daily Driver
'69 Morris 1100 S - Dinged by a bus, in shed under repair
'64 Morris 1100 - Early 1100, long term project