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Hydrolastic: Yay Or Nay?


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#1 mmaki

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Posted 16 October 2016 - 05:02 PM

So although I am very early in my 67 MKII restoration, I need to make a decision on whether to try and keep the hydrolastic suspension or not. I need to get a new rear subframe to make sure it fits all the body panel replacement I am doing.

 

I understand the uniqueness and the nostalgia of the Hydrolastic suspension but then I think of what will I do if a bladder fails down the road. I understand they are not easy to find anymore. It may be a huge headache to go in that direction. I haven't even found really any technical articles or youtube videos dealing with the system and pressurizing it at home and all that. I am not even certain the bladders are okay, but I was told they are.

 

Then there is the performance aspect to consider. I am not sure what system is better in this regard. I want the car to be fum to drive and feel like it is stuck to the road.

 

So what would you do?

 

Mike

 



#2 Daz1968

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Posted 16 October 2016 - 05:21 PM

I am currently restoring a mk2 998 cooper and I will retain the hydro, you can test the units if you make a jig to hold them, you can then pressure test them. If any are needed they are available if you look around.
But then I like hydrolastic, I fitted uprated bump stops and lowered it slightly and found it fine last time it was on the road.

#3 whistler

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Posted 16 October 2016 - 05:34 PM

When BMC Works Coopers rallied with Hydrolastic, they fitted shocks to the front and competition bumpstops to the rear to stop the 'rearing up' of the front suspension on acceleration. Worked reasonable well.



#4 mab01uk

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Posted 16 October 2016 - 07:28 PM

Useful PDF on Hydrolastic suspension pumps, repair, etc here (Australian)
http://www.hydragas....ydroService.pdf

 

More info here:-

http://www.theminifo...it-gold-plated/

 

Some useful info on Hydrolastic units here:
http://members.tripo...erica/id63.html

 

For reference MiniMail sell refurbished Hydrolastic Units:-

http://www.minimail.co.uk/


Edited by mab01uk, 16 October 2016 - 07:32 PM.


#5 Spider

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Posted 16 October 2016 - 08:03 PM

Not an easy choice.

 

If it's a high value car that's not likely to do lots of Miles and the Displacers (Bags) are in serviceable condition, then I'd suggest to stick with it. The ride is considerably better, though I've noticed that all the Hydro Cars I have are these days way under-damped and so do nose up and down all too easily. Fitting adjustable line restrictors could be one way of dealing with this, along with front dampers as Whistler has suggested.

 

The quality of the construction of the Hydro Displacers is incredibly good, they had a design life of 5 million cycles, but, ultimately, the actual spring in the Unit is rubber, so, just as our Dry Rubber Cones sag, so do Hydro Displacers, but you can swap front to rear and this will 'reset, as since the Hydro System is front / rear connected, when the fronts drop, the rears go up.

 

Apart from the Displacer, I think all other spares are still available.

 

I made my first Hydro Pump from a Clutch Master Cylinder. It could be used for pumping the system up, but really needed a vacuum pump if filling from dry. Much later, I found a Hydro Pump on flee-bay, look a little rough, but does the job. They do (or did a few years ago) come up fairly often. You could of course make your own pump, with Vacuum Unit easily too. I did buy a Vacuum Pump that the A/C Service techs used, new off ebay very very cheap, I just haven't gotten around to using it on the Hydro Pump.

 

Dry Suspension is much more and much easier to 'tune' though, and all parts at this time are still available.



#6 Dusky

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Posted 17 October 2016 - 08:10 AM

I wonder when someone Will start to make New parts for the hydro :/

#7 cool_stu

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Posted 17 October 2016 - 09:06 AM

I have the exact problem. Fairly sure the displacers on my GT are going to be past their best, but being a '70 and it being OE i guess it needs to be put back :(

 

I guess the problem with remanufacturing the units would be demand, cant see there being sufficient call for units to justify the tooling costs let alone make a profit... 



#8 nicklouse

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Posted 17 October 2016 - 09:19 AM

, though I've noticed that all the Hydro Cars I have are these days way under-damped and so do nose up and down all too easily.

 a common trick with the Metros ,I hear, was to use Citroën LHM fluid, to add some dampening.



#9 Spider

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Posted 17 October 2016 - 09:44 AM

I guess the problem with remanufacturing the units would be demand, cant see there being sufficient call for units to justify the tooling costs let alone make a profit... 

 

Having them remanufactured has been looked at in detail and discussed at length,,, great length.

 

It seems that there's a couple of dies needed to press the main body, which would be quite costly.

 

On top of that, there's a high content of rubber and in places, that needs to be bonded to the metalwork, so there's some considerable commercial risk in putting them in to production, we also know the quality of rubber components these days too. This is further compounded by the point you've bought up and that is one of demand, especially given they likely high cost.

 

It's quite a shame really, as the original system was incredible. The guys who developed it were very clever people indeed. And the quality of the manufactured product is amazing, given that the last of them rolled off the line some 45 years ago and there's still plenty still on the road today.



#10 Haynes

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Posted 17 October 2016 - 12:20 PM

When I was in the process of buying a hydro car I had plans to replace it with dry.  I'm so used to playing with hi-los etc to get the right hide spot on, using stiffer dampers etc.  But I'm so glad I left it as Issigonis intended, 

 

On an original '67 car it has to be hydor, all the beauty, charm and value of such a car is all that originality.  



#11 mmaki

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Posted 17 October 2016 - 03:39 PM

When I was in the process of buying a hydro car I had plans to replace it with dry.  I'm so used to playing with hi-los etc to get the right hide spot on, using stiffer dampers etc.  But I'm so glad I left it as Issigonis intended, 

 

On an original '67 car it has to be hydor, all the beauty, charm and value of such a car is all that originality.  

This is sorta the direction I'm aiming in. I am think what is the purpose of restoring a 50 year old car and making it "modern"? I am on the fence about paint as well. I was thinking a modern bright orange, but again I think why restore a 67 and make it look like a 2000?



#12 Miss Piggy

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Posted 17 October 2016 - 03:56 PM

My 66 is still hydro. Great system- re piped using 3/8 copper Ac TUBING.



#13 carbon

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Posted 25 October 2016 - 06:37 PM

Mike,

 

If the original displacers are still holding pressure I would keep them, just a personal view.

 

As for performance, the wet set-up I am running using 10 inch wheels is:

- standard shocks added to front

- competition bump stops all round

- 1.5 deg neg camber arms on front

- rear arms set vertical

- 3mm toe-out at front, about 1.5mm toe-in at rear

 

Gives good predictable handling in wet and dry on 145 tyres






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