CX prestige hydraulic clutch

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Real cars have hydraulics
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Hi All,

well SWMBO has said she wants to start driving the stinky old CX if she needs to.... So I'm again on the lookup for a CX prestige hydraulic clutch. All I'll need is the slave cylinder. The master can be purchased from CX Basis/western hemispheres and probably Andre Pol. I can do the hydralics and clutch pedal myself most likely.

I just need that slave cylinder though ................... Anyone here ever wrecked a CX prestige with a manual gearbox?

seeya,
Shane L.
 
The clutch maybe similar to the SM ?? The Maserati with the LHM hydraulics also has it. It's not a "standard" hydraulic clutch (were talking Citroen at it's peak here). It taps into the high pressure hydraulics and uses them to do the "hard work" of dis-engaging the clutch... There is quite a lot of plumbing to be added in order to retro-fit one. The clutch pedal assmebly is also different.

I'm not sure if it's similar to the DS BVH... This clutch will also work (but be much heavier) if there is no hydraulic pressure in the system.

Ted Perkins has done a pretty good writeup on it:

http://www.tedperkins.com/hydraulic_clutch.htm

seeya,
Shane L.
 
Master cylinders do come up on eBay occasionally but I have never seen a slave cylinder for sale. I asked Peter Raffels about the slave cylinders. He says they are NOT the same as SM / Maserati ones.

I did harbour ideas of making a slave cylinder - even started doing drawings. But it is a lot of work and the project didn't get far. It would require some high precision machining and honing and selection of the right materials for each component.

If I was to do it now, I would be using a concentric slave cylinder. There are plenty available commercially and at reasonable prices. Commonly used in race cars and quite a few current production cars. A trip to your local clutch specialist should give you some clues on how best to achieve a simple install with commonly available parts. Unfortunately they will all be designed for brake fluid so the seals will not be compatible with LHM. Seals are likely to be made specially for these so it is not likely to be a simple matter of just replacing the seals.

You COULD make your own concentric cylinder. They are pretty simple and there is a vast range of seals, wiper rings, back up rings, wear rings and O-rings available for hydraulic oil. Adding power assistance from the hydraulic system adds a whole level of complexity, but I doub't that you would actually NEED the power assistance. Although it does have a certain amount of nerdy citroenesque appeal...

The simple solution would be to slavage an existing sytem from the wreckers and use it with brake fluid.

The following links were some that I found tonight...

Wilwood unit on eBay

LUK unit

A few photos on a british-cars.net

RAM Clutches

AP Racing

GMP Racing in Melbourne
 
Thanks Rod,

the willwood unit looks interesting, though I doubt it would fit .... and if it did, how would we fill the reseviour ?? ....

I think I prefer the external slave cylinder for simplicity of install (and it keeps brake fluid out of your bell housing). I think the hydraulic clutches fitted to PSA era Citroens are just standard master/slave systems too. ie: NOT using LHM, most likely brake fluid.

Do you know of any LHM citroens that use a hydraulic clutch ? It's such a shame we can't find a slave cylinder for the proper clutch setup :(

I wonder what is different about the SM setup ?? I'm sure we could buy in SM slaves from the US ?

seeya,
Shane L.
 
Xantia CT Turbo and Activa use a hydraulic clutch and so do C5 manuals, but I believe they are sealed units and would use brake fluid. They are not powered units. The DS BVH cylinders are just a simply slave unit and controlled by the engagement control on the manifold.
 
Thanks David,

I was wondering about the SM unit as it appears to tap into the main hydraulics ... I've asked on the SM list about it. Even if it's nothing like the CX's, at least it'll use LHM and the main reseviours hydraulic fluid.

Strangely enough I've possibly been guided to a source for the CX hydraulic clutch fitted to a prestige that's currently being wrecked. Someone else in kindly finding out for me... You see I don't speak the lingo to request it :clown: Fingers crossed, I may end up with a slave cylinder. Best case, master/slave and pedal. We'll see in time :)

seeya,
Shane L.
 
I'm virtually certain that the SM is the same fitment as the CX. I seem to remember being told this some years ago, by a well known source of SM spare parts.

I have right here in my bedroom a brand new CX clutch master cylinder, as I too am hoping to put a hydraulic clutch on my car...(when I get round to fixing it)
 
I would keep looking for a CX slave cylinder. I would not think a SM slave cylinder much more common than a prestige one? I got hold of a complete set from a danish source several years ago for my -78 GTI that I am very slowly doing up. It cost me as much as the car :crazy: but then again the car was not very expensive. The rubber boot of the SM slave is listed as the same part as the D slave (well, where I found it on the net), if that is correct then it is not the same slave, the CX slave boot is 50mm at the base, the D is 32 or close on that. I bought one, and it is too tight.
 
Shane, even if CX Basis don't list the prestige slave cylinder it would still be worthwhile starting an e-mail conversation with Jochen Heusel about the issue as he's bound to have needed one at some time. If they are unobtainable, he would know if there was an alternative. Petermelb, president of CCCV, has a prestige and may be persuaded to at least photograph his or give you some dimensions.
 
Hi Guys,

well thanks to a very generous aussiefrogs member ( I'm not sure if they want to be named), this arrived earlier this week:

attachment.php


yes that's a new clutch master cylinder.

Today I had this arrive in the post from Germany.

attachment.php


Many thanks to Carsten ( a member of the Citroen SM yahoogroups list), who arranged with a friend in Germany to send me the hydraulic clutch parts and handled communications (as he can speak english). A public thanks goes to Jürgen for posting these parts to me all the way from Germany. I was a little concerned about transfering money into an international bank account.... However due to the honesty of fellow citroen owners it's arrived without a problem.

attachment.php


interestingly the throwout level is cast.

attachment.php


seeya,
Shane L.
 

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Shame you aren't coming to Cit-In. I could measure it up in a few hours. A complete set of drawings might prove useful one day...
 
Very impressive Shane. Lovely guy obviously.

I don't recall seeing anything like that from the Chevron Downunder clearout FWIW.

Good to see how Citroen have managed to keep the hydraulics simple and with a minimum of pipes and fittings!

How does it work?

Cheers
 
Very impressive Shane. Lovely guy obviously.

I don't recall seeing anything like that from the Chevron Downunder clearout FWIW.

Good to see how Citroen have managed to keep the hydraulics simple and with a minimum of pipes and fittings!

How does it work?

Cheers

It's just a master/slave hydraulic clutch that replaces the cable. However being from the *proper* citroen era, the master acts on valving in the slave, allowing high pressure fluid from the main hydraulics to depress the cluch. ie: you only control the activation of the slave.... You don't actually apply the clutch directly (much like the brakes, where you only open a valve to allow high pressure into the braking system).

All manual CX's should have been sold with this system when they had already developed it. Using the heavy cumbersome cable operated clutch when they had already designed and developed this system was crazy :(

The clutch in the car at the moment is *very* hefty. It'll be finger light with this installed.


seeya
Shane L.
 
It's just a master/slave hydraulic clutch that replaces the cable. However being from the *proper* citroen era, the master acts on valving in the slave, allowing high pressure fluid from the main hydraulics to depress the cluch. ie: you only control the activation of the slave.... You don't actually apply the clutch directly (much like the brakes, where you only open a valve to allow high pressure into the braking system).

All manual CX's should have been sold with this system when they had already developed it. Using the heavy cumbersome cable operated clutch when they had already designed and developed this system was crazy :(

The clutch in the car at the moment is *very* hefty. It'll be finger light with this installed.


seeya
Shane L.

Thanks Shane. I get it. Why indeed would they not have used it? Into the Peugeot era with money going to the 604 development (with far fewer sold) might explain it.

Cheers
 
cool !

nice item to add to a nice CX !

I upgraded my GTi T2 with one, my series 1 Prestige already has it... ;-)

you have the clutch pedal set, master cilinder behind the clutch pedal set, and the slave cilinder to dis/engage the clutch.
do you have info on how to assemble ?
haynes has some !

it uses low pressure LHM from a return line, which is pressurized by the clutch pedal/master cilinder. this activates the slave cilinder by opening up a high pressure line which in turn moves the arm.
really nifty setup !

on your pictures the was a multiway connector....... not sure I had this part installed....
you do need a T-connector somewhere to interconnect.
let me know if you need info / pictures
 
nice item to add to a nice CX !

I upgraded my GTi T2 with one, my series 1 Prestige already has it... ;-)

you have the clutch pedal set, master cilinder behind the clutch pedal set, and the slave cilinder to dis/engage the clutch.
do you have info on how to assemble ?
haynes has some !

it uses low pressure LHM from a return line, which is pressurized by the clutch pedal/master cilinder. this activates the slave cilinder by opening up a high pressure line which in turn moves the arm.
really nifty setup !

on your pictures the was a multiway connector....... not sure I had this part installed....
you do need a T-connector somewhere to interconnect.
let me know if you need info / pictures

Thanks,

he must have thought the safety valve was required. I'll probably just stick a 3way junction into the feed line to the front height corrector. If shouldn't matter where it's powered from, so I'll pick a 3.5mm line somewhere nearby. I'll need to find a bleeder for it too (possibly the front brakes on a DS will have an external bleeder I can use, I'll need to check).

Teds pages have a good writeup on it. There is no information in the shop manuals I have here, so I'm surprised the haynes manual covers it!

http://www.tedperkins.com/hydraulic_clutch.htm

You just need the diagram to work out the connections:

clutch_color5%20%20jpg.jpg


1: pressure line from the master cylinder
5: High pressure line from hydraulic system
"Vis de perge" : is the 3.5mm lines that goes to a bleeder nipple i'll need to source
8: Low pressure return.

The master cylinder just has standard connections. suction and discharge. I'll have to figure out how to attach the suction side to the LHM reseviour so that it's always immersed in LHM (the return line connections could possibly be into air inside the reseviour ). Where does the suction line from the master cylinder attach on your CX's ?

seeya,
Shane L.
 
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