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Shortly picking up a mk 2 with Hydrolastic , but im going to run it dry , can i put all the hydro stuff into my mk3 S which is dry at the moment but should be wet ( will have subframes, hydro unuts, pipes etc)

and can you stiffen up the hydro units if need be ??

New to all this hydro stuff so excuse the stupid questions youre gonna get

pad

Yes is the answer. It would fit. Unless you have been very lucky in finding a mk2 S or S spec. hydrolastic units I wouldn't change from the dry set up.

Getting standard hydrolastic firm enough for a fast road car will be fun.

pad, I agree with Iain, stiffening hydro is a challenge, back in the 70's we tried many things, but I think the most effective was to add front shock absorbers. Hope this is helpful.

So making a std set stiffer is i guess impossible then, what actually makes them stiffer then ?

So you could run a set of shocks on the front ... and on the rear ?

are all hydro units interchangable , say i eventually picked up a set of S units would they be easy to swap over ?

pad

Working on the fluid side, restrictors can be added into the the front-to-rear lines but the common way was to fit gate valves in the lines so that the front displacers could be pumped to the desired pressure, the valve closed and the rears pressurized independently, operating closed with more pressures front than back. Another method used was to shorten the displacer pistons and then increase the operating pressure so that the displacer grew to the same overall length but was running more psi and therefore, more firm.

Perhaps the most common method was to increase the bumpstop heights (competition bumpstops). All this really did in practical terms was to change a hydro car to something closer to a rubber one.

Front shock absorbers help hugely and there are more options today than there ever were. The addition of these is simple and I reckon, once fitted, a hydro car can be quite a sharp handler.

Ultimately, rubber suspension is lighter than hydro and easier to set up so was the preferred choice way back when. I have a hydro S road car that I have modified and apart from the work involved, was a very worthwhile project.

Al

A decent set of shockers on a "Standard" hydro system will transform the handling & IMHO Makes it comparable with a decent dry setup.

Definitely worth doing in your situation i.e a MK3 S with no hydro at all.

I agree with Mark a pair of front shockabsorbers would be a must. But shockabsorbers and bump stops front and rear and it will still not be all that firm.
Its not so much getting the car to feel firm, its the pitching and tossing on accelaration.

I have a mk3 S with the original S hydrolastic units and it drives very similar to a dry car, just slightly softer over bumps.

I also have standard Hydrolastic cars and there is no comparison.

Yes you could fit all the hydrolastic pipes and change the units later but they are very hard to find.

There is one way to find out.

Mark that's exactly what I'm thinking - the MK2 I'm getting, the hydro system and subframes will all come off it as I'm going to use the bloody thing for some rallying - My road going MK3 S I would like to put back on hydro as it should be (plus I'm over 40 and need a bit of comfort ) and while i have all the parts I'm thinking I might as well do it.

Gives me time to scout round for a set of S hydro units as well

Mark do you have any info on the workings and differences in the hydro units - so i know what to look for and have an idea how they work ?

Cheers

PD

Hi PD,

Sorry, I don't have any specific info on the Hydro units. I have only ever worked on 2 hydro cars & the only one I have ever owned is the speedwell car.

I am sure that someone will know what to look for though.

M

The following may help in your quest for the hydro units.

Although primarily a road car, I used my Mk1 'S' many years for hillclimbs, still with hydrolastic suspension but modified with competition bump stops, front shock absorbers, very slight negative camber and rose-jointed. Its handling is precise, it stays quite flat and is very comfortable on the road. Far superior, in my opinion to the dry suspension of my other Minis.
Garry.

pad4 wrote: do you have any info on the workings and differences in the hydro units - so i know what to look for and have an idea how they work ? PD

Most displacers had the part number stamped into the body but they are often hard to locate and to read now. If the colour bands have gone, there are no remnants on the bodies or hoses and the stampings can't be found, the only way I have been able to identify S displacers is to measure from the top ledge of the hose end, down the the rubber on the inside. On regular displacers, this is around 7/8" and on S ones, it seems to be around 5/8". I suspect there is more rubber in the rubber bag within the displacer. S pistons may also be shorter. There are internal differences but by the time you have found them, the displacer will be useless !! One last thing, don't rely on the (21A?) 1477 number on the rubber. This is a very early displacer number but all UK made displacers have it.
No Australian made displacers that I have seen don't have the number stamped into them.

Al