21 replies to this topic

[lunchboy]

Could someone tell me what is needed to convert Hydrolastic to Rubber suspension.Is it possible to use Hydrolastic subframes?

[dklawson]

I'm sorry, I don't know the exacting details. However, I have been told that the seats for the dampers and the seats for the rubber cones are different in shape. Again, my information is hearsay, not first hand. Supposedly you can re-shape the hydro-bag seat on at least the rear subframe to fit a rubber cone... but I don't know what the final shape is. The people who told me this were probably running Hi-Los to get the final geometry they wanted after the swap.

I'm not trying to drive you away from this forum for the answer, but if no one posts the specifics here, go to the Mini Spares web site and post the question on their board. I think it's fair to say that they have more Mk1 to Mk3 car owners on that board and someone there will know the answer.


one:
http://www.minimania...3/msgthread.cfm
two:
http://www.minimania...2/msgthread.cfm
three:
http://www.minimania...2/msgthread.cfm
four:
http://www.minimania...2/msgthread.cfm
five:
http://www.minimania...3/msgthread.cfm

After reading some of these posts I think you'll be able to identify about four people to email who will have the answers you need... assuming someone doesn't post here first.

[pdaykin]

Really, you need to change both subframes - although I believe that it is possible to reuse the front

The rear radies arms/handbtake quadrants/handbrake cables are different. The front arms are different too.
These components can be resued but you will get a firm ride/heavy steering.




Obvioulsy, you will need rubber cones, trumpets (or HiLos) and dampers

[lunchboy]

Thanks guys for the imformation. Will have to think long and hard before I do anything.

[v8mini]

i have thought about doing this myself on my Riley Elf.

i have also heared that you can fit shocks to the front to improve the handling on a hydro car, so i might try this instead as i have a spare set of top mounts and shocks. only need on front as being linked to the rear they dampen front and rear.

any one else tried this ?

[pdaykin]

Personally, I dont find hydro cars to be as bad as some people tell make out and wouldnt change to dry unless the on car system was shot

There were two principal tweaks that were done to sharpen them up
1. Add a helper spring at the rear
2. Add shock absorber at the front.

You will need the absorber mouting bracket as hydo cars didnt come with them - however, they did have the mounting holes fitted.

[Jammy]

I've always wanted to experiment with a hydro set up, so if anyone wants to get rid of a set that isn't shot, let me know!

[Steamo]

I've always wanted to experiment with a hydro set up, so if anyone wants to get rid of a set that isn't shot, let me know!

2nd dibs - they are supposed to be much more comfy - uprated I'm sure they would be great in a road car

[Dan]

They have a helper spring at the rear as standard don't they?

Progressive bump stops are good on hydro cars as well.

[Pavel]

I just cut up a perfectly good-order hydrolastic system on my mk2 spare parts car :\ if you can find (or repair) the two braided hoses by the front bulkhead, and somehow want me to send you the hydro bits, then by all means

And dan's right, they should have helper springs on the rear as standard (to compensate for the fact that the rear is a lot lighter than the front).

Most comfortable suspension ever incidentally! What I don't get is why people don't like it so much. In my mind, theoretically wouldn't a hydrolastic car have no body roll?

[Dan]

You do get roll, you don't get climb or dive (well, you do but the car stays more or less flat as it moves up and down rather than pitching). I've been known to wonder what would happen to a hydro car with front and rear anti roll bars fitted?

Edited by Dan, 21 April 2006 - 11:02 PM.

[mini1976]

"You do get roll, you don't get climb or dive"?

I thought the front suspension was linked to the rear so as the front wheels moved up for a bump the back moved down to keep the car level. So surely if you break hard the car will go down and the front and up at the back increasing the "dive". or is that not what you ment by dive?

And how do you get roll as surely you cant push both wheels up at the same time or pull the other 2 out at the same time either? so you would just get roll from compressing the side wall of the tyre wouldnt you? Ive never driven a hydro car but thats just my understanding of how it works. Can some one enlighten me as to why im wrong as i suspect Dan knows far more about it than I do.

[Pavel]

Ditto mini1976... front left is linked to rear left, right front is linked to rear right. So don't see how you could ever get any body roll. You do get a lot of dive, as described by mini1976. Dan I think you may be thinking that the system is linked side to side rather than front to back! (isn't that how metros were done?)

[Dan]

No, you get body roll. There are springs in the system as well as fluid. The fluid is water for gods sake it's got zero elasticity, it would be horribly harsh if there were no springs. The displacer is a rubber cone spring basically with a fluid revervoir and valves inside. The valves and spring control everything, but both wheels can move up together because of the springs if similar force is applied to both. You can't stop roll by linking the wheels on the same side you have to link them accross the car like the Metro does, that's what anti roll bars do.

And yes I wasn't fully clear about the dive situation, sorry. It will dive and climb with acceleration and deceleration but not with the road surface, like speed bumps.

I'll see if I can scan the pages from my BMC Mk2 workshop manual about hydro.

[Pavel]

If the fluid is incompressible though (and it's definitely NOT water, try getting it out of clothes.... and the smell isn't too nice either), how would the springs compress if they both displace water into a common system? Or is the system not charged up to the brink with fluid leavin the displacers some air to allow them both to compress at the same time?