CX power assisted clutch - mad task...

palyasm

palyasm

Member
Fellow Frogger
Tadpole
Tadpole
Joined
May 5, 2011
Messages
253
Location
Adelaide Hills, SA
I have probably just pulled the trigger on a maddening task... Given the impossibility of finding a Prestige power assisted clutch slave, I did manage to find a used unit, including master cylinder, from a '79 Maserati Merak.

Unfortunately it is different insofar as the mounting lugs and port positions are different, but perhaps I can do some (lots of..) mods and make it work... Once it arrives from UK, so I have some reprieve!

Hours of frustration!
 
I'm looking for one too if you have any leads I can followup.

Cheers, Ken
 
Hi Ken, this was an entirely random find. I've been turning the problem over in my mind for months, coming up with various ideas utilising existing Citroen hydraulic valves. The secret is in the dual diameter slave cylinder design. Ted Perkins' page gives the clues..

Anyhow, I was approached this week to sort out a hydraulic issue on a local Maserati Merak, which got me thinking again - so I searched eBay and just so happens a bloke in UK was converting his Merak to a conventional Dot 4 master/slave and brakes too (wtf, surely a significant downgrade?).

There is nothing special about the master - I think it is the same as the SM unit, which is pretty much identical in design to any conventional master, except mineral. The slave on the Merak unfortunately is a bit different to the CX in terms of mounting. I'm taking a bit of a financial risk based on faith (!) in my inventiveness (and a couple of photos...) that I might be able to adapt.

I don't know if the Maserati world commonly goes the Dot 4 route (probably?)so if this experiment pays off it may be of some interest to the many many millions of CX Turbo owners, hey?

Cheers, Steve
 
The Merak has the LHM system for at least the brakes so I think it would be used on the clutch as well.

We were showing the SM and GS at a Cars and Coffee at Samford early one Saturday last year and a chap came over and wanted to see under the SM Bonnet. I then learned that he had a Merak down at the other end of the lineup that had an HP pump, regulator and accumulator sitting a a very familiar looking accessory stage and the back of the engine bay.

Cheers, Ken
 
I'm yet to have a look at the Merak I'm to work on, probably next week. The owner has absolutely no idea, mechanically.

He says it lost all braking and clutch and the HP warning light came on - could be as simple as a belt on the pump. He didn't mention any major leaks. He ordered a new accumulator, which of course won't be the problem..

For some reason they appear to use two brake accumulators (DS/SM style) and use the hydraulic system for pop-up headlights, seat adjustment (wtf) and other stuff but not suspension (could be another wtf here?). Not sure about steering? But certainly brakes and clutch.

I guess it is possible that one or both the brake accumulator diaphragms busted and filled the system with gas...
 
palyasm said:
I'm yet to have a look at the Merak I'm to work on, probably next week. The owner has absolutely no idea, mechanically.

He says it lost all braking and clutch and the HP warning light came on - could be as simple as a belt on the pump. He didn't mention any major leaks. He ordered a new accumulator, which of course won't be the problem..

For some reason they appear to use two brake accumulators (DS/SM style) and use the hydraulic system for pop-up headlights, seat adjustment (wtf) and other stuff but not suspension (could be another wtf here?). Not sure about steering? But certainly brakes and clutch.

I guess it is possible that one or both the brake accumulator diaphragms busted and filled the system with gas...
Click to expand...
That Merak sounds like it would be well worth a thread of it's own - I've heard the name, but that's about all!
 
palyasm said:
I'm yet to have a look at the Merak I'm to work on, probably next week. The owner has absolutely no idea, mechanically.

He says it lost all braking and clutch and the HP warning light came on - could be as simple as a belt on the pump. He didn't mention any major leaks. He ordered a new accumulator, which of course won't be the problem..

For some reason they appear to use two brake accumulators (DS/SM style) and use the hydraulic system for pop-up headlights, seat adjustment (wtf) and other stuff but not suspension (could be another wtf here?). Not sure about steering? But certainly brakes and clutch.

I guess it is possible that one or both the brake accumulator diaphragms busted and filled the system with gas...
Click to expand...
I've worked on a Khansim before. it had been contaminated with brake fluid. the headlight switch inside the car (and the seat adjustment from memory) is hydraulic as well ..... and can leak. I never got the Khansim working as it was at a mechanics and he said he'd removed the reseviour and flushed it ..... he hand't though, and I fitted up the new accumulators and tried to bleed the system. when I found all the sludge/brake fluid mix in the bottom of the revesiour, I told the owner they would need to work there way downstream. the priority valve probably had gunk blocking it .... you'd have to just keep going until you had pressure everywhere it was needed.

The steering looked like an upsdie down SM rack possibly ( I'm not familiar with SM's and havne't worked on them).

the main thing is, do everything your self.... don't trust anything previous mechanics have touched or looked at (unless possibly they were citroen mechanics/maserati mechanics).

seeya,
Shane L.
 
For those parts... you have to be on the constant lookout on ebay, leboncoin, but also online second hand marketplace sites per country for Prestige parts from a donor car. And hope anyone has those parts or the car for parts is still there.... I know of one, but those specific (ultra-rare) parts are reserved. I have seen a few.... (one is now in my GTi T2).
You need master cilinder, with clutch specific pedal set
and the slave cilinder to mount onto the transmission (fit/bolts right on)
The specific LHM rubber hoses, for tapping / having LHM from the existing return hose.

4719998097_da37dc2a8e_o.jpg


4720647176_473c6bc4e0_o.jpg


4720647484_6b488b879d_o.jpg


4720672856_6fd148b444_o.jpg
 
The Merak master/slave I purchased is on its way from UK. Both are different castings to the CX Prestige units. The master cylinder looks like both pipe fittings point straight up rather than out the side. The Slave has the mounting lugs at the rear of the cylinder rather than on the front / boot end, and the ports for HP and return are on the 'top' (once fitted to the CX these will be pointing to the ground) between the cylinder and the slide-valve. The master cyl input looks about the same, but there is another fitting on the opposite side which must be the bleed.

I'm looking at the Turbo (cable) pedal box and it should be easy enough to modify that...

Once the parts arrive, if it looks all too hard to make it fit the CX all is not lost because it will very easily bolt on to the SM (the Merak has the same engine, bell-housing and gearbox). SM already has the master cylinder operating a DS BVH style slave cylinder.
Screen Shot 2024-05-10 at 12.01.13 PM.png
 
Obviously he's mixed up the position of the bleed nipple in that photo, it should be where the lower banjo bolt is... where the bleed is should be HP inlet
 
I'll need to modify/fabricate the clutch fork lever, too... if someone could let me know the measurement between centres of the cast Prestige one it would be helpful? No rush, when convenient..
 
palyasm said:
I'll need to modify/fabricate the clutch fork lever, too... if someone could let me know the measurement between centres of the cast Prestige one it would be helpful? No rush, when convenient..
Click to expand...
its all external, the clutch fork is the same as far as I'm aware. I was able to just bolt it all on :) oh, you mean the throwout lever on the bottom of hte gearbox. from memory its a cast piece .... I'll need to check.
 
The box of parts arrived from UK, so I'm committed to starting the mission...

The slave cylinder seems to be in good order, no serious metal damage/corrosion. The seals are simple o-rings so I'll see if I can match locally sourced, although there is no return/dust boot so I may end up ordering an over-priced kit from OS...

The master cylinder presents a new problem - unlike the usual circlip arrangement, the piston is retained with a mechanindus pin installed in a blind hole which is also the fluid supply port... does anyone have a cool trick for extracting said pin - there is about 1mm of the pin proud of the hole, so not much to grab on to! Screwing something into it is only going to expand and tighten it?
 
Interesting project!

Regarding the pin - if it's a multi-coiled pin, then I've had success using a screw extractor set, provided it's been installed such that the extraction is tightening the coil. It's a bit of challenge getting both bite and extraction at the same time, but they're usually just a pressure fit, not an interference fit.
 
It is a standard mechanindus - "c" in cross-section; so any screwed-in extractor would expand the pin and thereby tighten it in its bore...

It is installed through a cylinder, so it grips at each end. The end of the blind hole is a boss in the casting, so I guess I could drill that through and then push the pin through, then tap a thread and seal... Annoying arrangement - there's plenty of room to have fitted a circlip instead!
 
If the owner cannot sell the damaged Prestige series 1 to a new owner for restauration, he may sell it in parts. If anyone is interested they could enquire.

This should be the correct link

The other Prestige series 2 is nice indeed. But not for parts and doesn't have the hydraulic clutch (only on series 1 Prestige)
 
You must log in or register to reply here.
Top