Dry to Wet


DSCN0242

Originally uploaded by bbarlow641

This 1966 Mini has a “wet” or Hydrolastic suspension. All Minis were supposed to have this type of springing, but it was dropped in the first few model years because of development/cost issues, introduced in 1964 (correct me if I’m wrong) and dropped again a few years later to stay with the “dry” or rubber sprung suspension until the end of the Mini’s production.

There are several aftermarket suspension systems available for the builder/modifier, and since I’m not restoring this car to original form, I looked at them all. The Hydrolastic suspension parts are hard to come by, the suspension felt a little soft for a Mini, and it has a possibility of shortening an outing if a bladder or hose gives way mid-ride.

I figured I’d convert to some sort of dry suspension, and did a lot of internet research to find out how to do it, what it would cost, and how easy it might be to accomplish. Then I went to talk to Doug, my Mini spirit guide. We went through all the options, ruled out some, talked about the problems to be encountered/avoided, and in the end, I changed my mind about converting to dry, and to keep the Hydrolastic suspension. Like the rubber springs, the Hydrolastic system is amazingly uncomplicated, and if I replaced the pipes (which I will have to do anyway) and the bladders and hoses are in good shape (which they appear to be), it would be a whole lot easier (and cheaper) to keep the wet system. And, if it completely failed to work out, I could convert it to dry later on.

So I walked out of Mini City with a rear subframe for a dry suspension car and instructions on how to modify it to fit the Hydrolastic suspension. (You can’t get new wet subframes any more – you have to modify dry ones.) Like most things Mini, I love the simplicity of design that goes into these cars. The difference between the wet and the dry subframes is just one single part. I had scavenged that one part from my old subframe before trashing it, so if I could just switch them, I’d be home free.

On the Hydrolastic suspensions,¬†instead of the dome, there’s a sort of cup-like metal piece with retainers for the tabs on the Hydrolastic displacer. That’s the part on the left. The dry suspension “dome” is the part on the right. I was able to drill out the six spot welds that held it in place, and switch it for the displacer retainer salvaged from the old subframe. Only one retainer was salvageable, however, so I had to make a version up for the other side.

I made a substitute ring that I welded in place for the displacer to fit into. Here’s a picture of the displacer in place inside the new ring.
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