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This is the sixth and last of your images.

Oh boy, Winabby. I tried to do what you said below and it exploded and posted giant pictures that I cant even get on my screen. And I can't get to the edit button to delete them. What now?

Never mind. I was able to get to the edit key and delete the monster pictures. So how do I get pictures to the correct size to post? Sorry, I'm sure this is not intended to be a tutorial site, but I've not done this before.

Don't worry about the photos. Post more ace engineering work

Awesome work and doubly appealing to be able to convert the relatively plentiful standard units to S spec.
I'm home now and will be up at the hangar tomorrow to find my spare unit!

nileseh, fantastic research and work, full credits and kudos mate, lovely work.

It it also a credit and testimate to the quality of these units in the first instance too, that as we all know, after 50 years, so many of these are still in working order and those that are not are for the most part, now rebuildable.

Rubber is a natural item, and dry out over the years.

I would recommend that the rubber is sprayed each Autumn, with a thick layer of silicone - preferbly the type that leaves a thick greasy surface.

To get access to the top of the front units = just fit one of them thin pipes from a waxoil can, and insert where the Hydro hose goes in.

I would also recommend that the car is put on axle stands, when not used for longer periods (like this summer ) etc etc.

Last one is a question for the specialists = even if the car is on axle stands, are the system still under pressure,
would it not release some of the stress on the rubber, if the system was depressurised during winter ?

nileseh wrote:Oh boy, Winabby. I tried to do what you said below and it exploded and posted giant pictures that I cant even get on my screen. And I can't get to the edit button to delete them. What now?

Never mind. I was able to get to the edit key and delete the monster pictures. So how do I get pictures to the correct size to post? Sorry, I'm sure this is not intended to be a tutorial site, but I've not done this before.

I had the same problem the other day and managed to re-size some 'monster' pictures here (see link below), then re-uploaded them to Imgur for sharing:-
"Resize Photos is a free online photo tool for resizing and compressing your digital photos for posting on the web, in email or on forums. There is no software to download, just upload your pictures and begin"
http://www.resize-photos.com/

nileseh wrote:Oh boy, Winabbey. I tried to do what you said below and it exploded and posted giant pictures that I cant even get on my screen. And I can't get to the edit button to delete them. What now?

Before posting your images I resized them using some free PC graphic viewer software that's basically a cut-down version of Photoshop, called Irfanview. I'd recommend this tool to anyone needing to resize, crop, rotate, recolour or perform a bunch of other effects on an image or a video. I've been using it for over a decade.

http://www.irfanview.com/

The resize-photos online method mentioned above works well.

An alternative is this stuff:

https://www.youtube.com/watch?v=AXrGJ_D4CWg

This stuff is incredible, stronger than welding. That, combined with a circular clamp similar to an exhaust clamp would be fine - maybe three or four equidistant spot welds for belts and braces. the two halves would not be coming apart again though.

Don't mention it.

Yesterday I recovered 4 units, it's mk3 cooper s, 21a2012, dated 1970.
The 2 rear units are badly reduced, I should try to clean them inside.

Lucky you! I would flush them out thoroughly until clean water runs out freely then dry them out until you need them or fill them with a silicon based fluid. I'd use silicon brake fluid as it's got all the non this that and the other properties you need to protect the rubber and the steel internal components. Plug the open hose ends with wood bungs or BSP blank-end fittings and store upright. Others might disagree of course but that's what the chemists suggest. As for the hose attachments then if they ain't broke - or leaking - why fix them? The hydraulic loadings they're subject too are nothing in the real world of industrial hydraulics. But if you do want to rep[ace it's an easy fix so long as it's not absolute authenticity you want

geroch:

Are all 4 displacers out of the same car, and are they all marked 21A2012? The literature I've seen shows 21A2012 front and 21A2014 rear. but I've only seen documentation up to the Mk2. Is it possible that Mk3 went to the same front and rear? If they are not marked with the number, 21A2012 has one silver band on the hose and 21A2014 has 2 silver bands.

nileseh wrote:geroch:

Are all 4 displacers out of the same car, and are they all marked 21A2012? The literature I've seen shows 21A2012 front and 21A2014 rear. but I've only seen documentation up to the Mk2. Is it possible that Mk3 went to the same front and rear? If they are not marked with the number, 21A2012 has one silver band on the hose and 21A2014 has 2 silver bands.

Niles, my displacer is on it's way...hope it works. I believe all Mk3 S's and early wet 1275GT's were all 2012 front 2014 rear. Early Mk2's were 1872/1874 and later Mk2's 2012/2014 but internally they are no different. I'm not yet convinced that front and rears differ in anything other than part no. but your work should decide this.
Tim

I'm pretty sure that in the next couple of years the remanufacture of, or attempts to fix the knackered internals of hydro displacers will flounder. It's not that I am a total defeatist but rather, a pragmatist and realist. Because it's not beyond the wit of man to design and develop a rubber cone suspension rubber bonded onto a x4-way bayonet fitting as per the current hydro units. Got me so far......? Then inbed or bond into the opposite end of the rubber cone a fitting the extends forwards (or downwards for the front susp.....) so you could use your current rods still sat into their cups while the rear (or top) of the new rubber cone is locked into the sub frame..

I wish I'd taken more notice during the production engineering phase at Uni!

timell wrote:
I believe all Mk3 S's and early wet 1275GT's were all 2012 front 2014 rear. Early Mk2's were 1872/1874 and later Mk2's 2012/2014 but internally they are no different. I'm not yet convinced that front and rears differ in anything other than part no. but your work should decide this.
Tim

21A2010 was the part number for the front displacers on hydro 1275GTs. Also listed for uk police vehicles. The rear was the same as the mk3S. Whether harder or softer who knows?

Hmmm.

The internals are the same for all the displacers I've opened. The differentiation seems to be the damping valve restriction. The dampening valve serves as the shock absorber in the unit. The spring rate is the same for all displacers (the rubber donut has the same part number on all) so the difference would appear to be a stiff shock or a softer shock. It makes sense to me, much like tuning shock absorber stiffness to the weight distribution of the car. I've not studied suspension systems, but I would expect a stiffer shock up front where all the weight is. Is that correct? 21A2010 is an interesting notion. We never saw the 1275GT here; was it a performance iteration? As used in a police vehicle I would expect a stiffer dampening.

I got the tracking number from timell; we'll see what that has to offer. If I can't get the original dampening data, perhaps I can just make up some dimensions to restrict the valve for a stiffer rate.

I thought we established a while ago that part number difference from early to later was a tooling issue, rather than a performance change. On the displacers I've opened there is a slight difference in the configuration of the stamped components. I think probably a tooling upgrade for manufacturing efficiency.

I'm not sure where Peter is going. I agree that any notion of a solution for the ages is probably not realistic. But I think we can get a few more years out of the inventory of 50 year old components. The rubber does not seem to have deteriorated as much as I would have expected, even in the displacers that have completely rotted interiors. The metal falls apart but the rubber bits clean up nicely and are quite supple for their age; considerably more supple than I at my age. I think Peter is suggesting that a solution is a unit with the form factor of the displacer with a rubber spring unit to be a drop in replacement. That would work, but that would be the "..lastic' portion losing the "hydro.." bit. We could also simply change to any of the many coil spring conversions available but what is the fun in that? I think this clamping ring will work, it has worked on the bench, I'll build it and find out if it stands up to the rigors of motoring. I'll work it as hard as I can short of "Italian Job" jumps. But it will be a while because I have to put the rest of the car together first.

Nileseh, I thought that the hydro splitting and clamping idea was absolutely fantastic and a mechanical work of art. But, alas, financially beyond the scope of the average bloke with a knackered unit - or even someone like me with a reasonably sized engineering shop and facilities at his disposal. You're absolutely right about the direction I was thinking and you put it well....... A 'lastic unit....' without the 'hydra' part! A rubberised unit that would fit and lock into the space of the old HYDRAlastic unit AND use the existing sub frame, rods, cups etc etc.

You're right about the variations of hydro units. The rubber content mix was the same*. It was the valving/damping that differed between the units that made them different. And I often wonder whether the average road user or restorer would/could really tell the difference between them. Nope....., me neither!

*That's an easy test using simple lab facilities to undertake

This cooper s mk3 has all 4 factory-fitted 21A2012 units. I have the certainty of the 2 former owners. Even those I found on my cooper s mk2, 2 certainly are 21A2012, but I do not know if they are of the same car.

Don't take this as gospel, however, I seem to recall that the difference between the front & rear Hydro units (in sets) was only the internal damping between.

I think I have some info on this.