Citroen XM Forum

Total Transmission 8 is not only recommended, and (down here) standard Citroen gear oil across all models, it actually works extremely well, and produces slick and smooth changes. It is the recommended GL4, correct viscosity (75W80).
On our 2.5, it has resulted in the best gearbox action we've ever had.

There was a giveaway in the specs. PSA PEUGEOT CITROEN B71 2330
TOTAL TRANSMISSION GEAR 8 75W-80 is specially recommended for PSA manual gearboxes, with extended drain interval (250,000 km) and friction modifier additive adapted to PSA manual gearboxes.

though to be fair, I used Comma 75W-80 in the Mandarin car and the gear shifts on that were very slick, probably due to that box only having covered 98k miles.

Derwent Diesels current prices for Purflux fuel filter repair kits.
31D138 - Repair kit Purflux - £7.74 - Contains Rubber Diaphragm and two spring loaded filters.
31D138L - Purflux Rep Kit + Button - £8.93 - Contains Rubber Diaphragm, Push Button, Spring with fixed washer, Metal Button Cap with 4 fixing tangs plus 2 small Rubber Mushrooms (usage currently unknown).
Prices are ex vat and postage was £6.95.

John

I've recently thought the Cobalt car was a bit "springy" when driving over dips in the road and full width speed bumps, coupled with it rocking slightly when encountering camber changes, though generally the ride comfort was pretty good, especially when a passenger, so I thought I'd check the sphere pressures. Another owner drove my car recently and thought mine was very comfortable.

I quickly checked one front one and was alarmed by the result so checked them all.

Fronts: 10 Bar instead of 50 Bar.
Front HA: 30 Bar instead of 70 Bar.
Accumulator: 40 Bar instead of 62 Bar.
Rear HA: 30 Bar instead of 50 Bar.
Rears: 28 Bar instead of 30 Bar.

What is clear is that heat plays a significant part in pressure loss.
Even on the rears, which had hardly lost any pressure, the one near the exhaust was slightly lower pressure than the opposite one.
I had some spare Citroen ones for all three fronts, a citroen "multicouche" for the accumulator, my spare rears were slightly down (26 Bar), leading me to wonder if the valprex valves weep a little, so I put the original the rears back on.
I last charged these spheres in 2016.
I intend to build a recharging rig to move away from using Valprex valves.
I was short of a rear HA, so put an accumulator sphere on, which is the same size (400cc) but higher pressure.

The ride is noticeably better now. It just glides over dips in the road.

Hi Will,

Have suspected a bit of weep, too.
Have only had one Valprex valve seriously lose gas (over 11 days), and that was because of a leaking O-ring. Replaced the ring, and OK.
Recently checked (and topped up) pressures on our corner spheres, which were last regassed 10/2016. Pressure loss was only very slight.
Haven't yet checked the HA's (next job), but ride still nice and soft.
Acc sphere was Valprexed and last regassed in 2013 (!), so well due for a check - but pump ticking is as it should be.

What I have found with Valprex is

O-ring size is same as Cit OE, ring thickness of 2mm.
This sits well down and loosely in the groove, and there isn't much squash when tightened down.
Few years ago decided to try a slightly chubbier Viton ring:
https://www.polymax.co.uk/o-rings-9-19m ... ton-75-sha
which compresses and seals a whole lot better.

Important to lubricate the ring (LHM or silicone grease) to deter it from scuffing as it is tightened.

Valprex sealing plug
Originally thought this was just a stopper, to positively prevent dirt getting in.
Seems it might be an integral part of the gas seal (guessing that the main non-return valve is just ball+seat), and so I'm now putting a smear of silicone grease on the rubbery point, and tightening down properly. Seem ok.

That is a thought regarding the O ring and plug. If it's not actually compressed it won't seal well.
With static pressure of 50Bar the dyamic pressure is 100Bar with the car at ride height and possibly 150Bar when the wheel is forced up due to bumps and undulations.

I have some 2.5mm O rings, so will swap them when regassing, unless I have built a rig by then, so will revert back to solid plugs.

I've only just discovered this thread and been binge-reading it over the last week. What a rich source of tech data and how-tos it is! Well done, Will and thanks for documenting all this great work.

I was checking over the 2.1Sd and saw a brown stain in the wheel-house, so picked at it, which revealed a rusty patch, which hadn't yet broken through, but did after tapping it.





There was a thin bit under the car also in one of the strengthening sections, so a piece let in there also.

This car has an oil leak which leaves spots when the engine is running. Some time ago I replaced the sump gasket, but the leak persisted and has become worse.
To check if the crank seal is leaking, remove the lower flywheel cover and wipe the back of the flywheel, where it meets the crank, with your fingers. If they come out oily, the crank seal is leaking.
I've been waiting for the very heavy clutch to wear out, but the oil spots are very annoying, so I've started the job.

Firstly, remove the hydraulics regulator from the bell-housing. Remember to unscrew the sphere a little while the regulator is still bolted on firmly.



Remove the Lhm reservoir and any ducting that will be in the way, release the clutch cable, unbolt the starter motor, driveshafts, etc.
You will need to remove the gearbox mount, so sort a method of suspending the engine. I initially tried axle stands under the sump, but wasn't happy with that arrangement for a few reasons, it could damage the sump and the stands were in the way.
I made a support out of wood and a scaffold pole. The engine has a lifting eye already mounted which I fitted a D type shackle to, as this has rounded profile, so won't cut the rope.



Unclip the gear selector rods and speedometer cable, place a jack under the gearbox, then undo all the bolts holding the gearbox in. You need to remove the gearbox mount, the bracket bolted to the chassis rail and as I couldn't undo the gearbox mount pin due to it being between spanner sizes 15 and 16mm, removed the mount from the gearbox body as well, which is three more bolts.
The battery tray is partially supported by this bracket, so either remove the battery, which was now too late for me, or tie the battery box to the wooden bearer.

You can't fully remove the gearbox with the engine in so just push it over the subframe to create working space. It will sit there, but for surety I added a bolt and tied it up.



It's easiest to remove the clutch diaphragm bolts from underneath. Have bottle, or can to catch the Lhm that is pushed out of the pipes and Fdv as the engine is rotated: the hydraulics pump continues to push fluid out as it rotates with the engine.



I was surprised to find this was the original fitment clutch, that's 168,000+ miles, fitted in 1992 and showing no real signs of wear, but operation is heavy. It sometimes exhibits some judder if not used for some days.
Both the friction and pressure plates are dated '92.



The flywheel has 8 bolts holding it on and a locating dowel, so no need to mark orientation. The bolts came undone readily by using a socket with sliding T handle, taking up the slack and giving the bar a whack with a lump hammer. No need to lock the flywheel, they are only torqued to 45Nm, but do and must, have thread-loc applied.
I have purchased new bolts, which already have thread-loc, but can't really see the necessity for new bolts as they are originally 11.7 hardness (new ones are 12.9) and are only torqued to 45Nm, so won't be stretched.



Removing the flywheel revealed the leak. The bolt holes are blind holes, so oil can't be coming through there.

A partially productive day.
Cleaning the engine and bell-housing of the oil/friction material sludge took quit a while. It was everywhere and very thick and in some areas, solidified.





To remove the oil seal I drilled a hole in the face, screwed in a self tapping screw and levered the seal out, thoroughly cleaned the resulting cavity and surfaces. Be careful to drill the centre of the seal, keeping away from the crank journal. Go carefully and only just drill through.
Drill access was tight due to the gearbox being in the way, so I used a right angle drill adapter.





To install the new seal I attempted to make a seal guide, but it was very awkward, so then opted to use the plastic sheet as a lip guide by running it round the seal as I installed it. This ensured the seal maintained the correct form as it slipped onto the journal.
The manufacturers instructions are to add sealant to the outer edge of the seal and not to lubricate the inner seal for installation, presumably so the sealant isn't compromised. The sealant then has to be left for four hours before engine start.

I used a block of wood and a hammer to drive the seal in, then finished by using the old seal to finish the driving in. Be careful to keep the seal level all round and spread the driving force and it will go in.





As the flywheel bolts are originally locked in with thread-loc the holes needed cleaning out so as to not create torque when the new bolts were fitted.
I don't have an M9*1 tap, so used one of the old bolts to make a thread chaser. Clean any remaining thread-loc out of the threads with a knife blade, then cut grooves across the threads either by hacksaw, or small file. I always use this technique when replacing glow-plugs as the carbon left in the threads can cause the plugs to jam in, or not be seated fully.

Screw in the bolt and cut the old thread-loc, withdraw and clean the bolt, then repeat until the thread is cleaned out.
Keep cleaning the threads out until the bolt can be wound in and out the full depth, just using fingers, then use solvent to degrease the hole, so the new thread-loc can bond.
I measured the bolts and holes to ensure there is sufficient depth. The bolt threads are 22mm long, with 12mm projecting behind the flywheel. The hole depth is 17mm.

Time to dig out a clutch and install it.
I have a Valeo clutch from the crashed 2.1, which had done about 7,000 miles, dug it out and gave it a clean up to remove the surface rust.

Prior to my ownership that car had very premature clutch failure, which, I believe, is why it was taken off the road. It was Ok driving round town, but as soon as it was under load in 5th gear, on a motorway incline it slipped badly. I can only think someone must have ridden the clutch really badly.

The three clutches, left to right, flywheel side, which is the more heavily worn.
91k miles, heavy wear to the friction plate nearly to the rivets, the pressure plate surface still has some visible machining marks;
168k miles generally worn, very heavy operation but still fully functional with some judder; The spigot bearing and input shaft splines were dry of grease and had a fine powder of rust particles, which will have contributed to the judder.
7k miles.



I spent some time cleaning and greasing the release arm bearings. Access to lift the pivot was poor, as the external arm was contacting the chassis rail, but the end result was the complete pivot would fall under it's own weight and was very free to move. This will aid operation and increase the bushing life.
Remember the adage: If you want it to move either now, or in the future, grease it. I have taken to greasing bolt threads to stop corrosion binding them in. Never grease the seats of fixings as that is what creates the majority of the torque required to hold them tight.

I added a smear of copper-slip inside the spigot bearing and on the crankshaft-flywheel spigot. Do not grease the mating surfaces, there needs to be a high co-efficient of friction between them to stop the flywheel attempting to slip.

I installed the flywheel and torqued the bolts. The Citroen Private car books give a figure of 4.5mdaN, and Haynes Manual says 50Nm. I tightened to 45Nm, then went round again at 50Nm to see if the bolts actually tightened any more. They did turn marginally.

Just use a bar held into the ring gear to counter-hold the flywheel, to stop the engine turning backwards at all.



Due to recently acquiring one, for the first time ever I used a clutch alignment tool and even bothered to tape it for a perfect fit. Normally I've just used a pipe/screwdriver handle, visual inspection.



The clutch went on readily. To tighten the screws just hold the flywheel rim, the pressure plate fits on three dowels and the screws are only tightened to 20Nm.



If one has straight visibility, it's easy to see if the friction plate is aligned. It appears a little mis-aligned, but that is due to it being difficult to obtain a straight on image.



Add a smear of copper-slip to the input shaft nose and splines, release bearing guide and release fork. Don't put a lot on, it may fly off and cause the clutch to be contaminated.



Use a decent jack as a support, then with a bit of huffing and puffing the box should look like this.



Bolt the bell-housing back to the engine block, refit the gearbox support and mountings. Remove the temporary engine support.