2 * 2.1 SD

[Dieselman]

Time to address the gearbox leak.
I only became aware the ME5T gearbox does have a fill/level plug on the side of the box recently. I have always used the taper plug on the front and filled with 1.85 litres, which I will do again, as it is convenient, though if one needs to check the level the fill/level plug should work. You will need a new 10mm copper washer for the seal.



This gearbox has a slight weep, just enough to wet the underside so new drivehsaft seals are being fitted.

Right side is easy, clean the surface, lever out the seal, clean then drive in the new seal.



When the seal is removed you can see the speedometer drive gear.



The left side was the one weeping, so more dirty. It has also been catching the crankshaft oil weep and due to being near the left wheel, road dirt.



I gave the area good clean to not transfer dirt and grit into the gearbox. The visible wet oil is Lhm dripping down due to the reservoir being removed and the filter unit dripping.



The seal is installed into a plate and appeared resistant to being levered out and has a bearing tight behind the plate, so I checked the Haynes manual. It says to remove the plate and remove/install the seal from the inside.

When you remove the plate the differential bearing moves and the differential drops a bit. I didn't want this to happen so wedged a slip of plastic into the oil drain channel which held the bearing in position.



As I hadn't been expecting to remove the plate I didn't have the, 70.2*1.9, O ring that seals it, so acquired one from a local seal supplier.

The plate appears to be a straight bore without any lip, however I think removal is necessary so there is no risk of damaging either the differential bearing, or the new seal on installation.
I applied sealant to the outer rim of both new seals before driving them in.



I refitted the hydraulic pipe support and Gnd cable to the top of the gearbox and the clutch cable and mass to the clutch release arm.

I pressed the clutch pedal which so far exhibits extremely light operation. Quite different from the old clutch that over a period of time snapped a brand new new cable bell-crank, the upper pedal clip and the upper cable.

[Dieselman]

A bit more re-assembly and then onto the pressure regulator, which I had removed as I intended to re-seal it as it has been wet on the underside, from the bottom seal.

To access the seal the base plug has to be withdrawn. The plug is held in by an internal hog-ring/circlip which the plug pushes down against.
To remove the ring push the plug in against the spring pressure, prise the ring out of the groove and withdraw it from the body.

I used a G cramp to push the plug into the body but couldn't hook the ring outwards, so went for the inwards approach. I used a sharp pick to prise the ring out of the groove and further into the body, inserted a junior hacksaw blade under the ring so it couldn't fall back into the groove, then hooked the ring out .

G cramp with block of wood and plastic sheet, to stop any wood particles entering the regulator body.



Hog-ring pushed inwards, hacksaw blade inserted



The ring pulled out, the G cramp released and the workings removed.



I didn't bother removing the slide valve, but cleaned the rest of the components, noting there is a single shim mounted on the plug for the spring to press against.
I installed a new 29*2.7mm O ring. I used 29*3mm @90 shore. I then lubricated the components and O ring and re-installed it.
Refitting the circlip was fairly awkward, have the start of the clip in the groove pressing down towards the bench, I held the clip in position with my left thumb at about 10 O-clock, then used snipe nosed pliers to push the free end of the clip into place, then released the G cramp.

Next was the O ring under the plastic cap.
G cramp the unit so the plastic ears don't break off when the screws come undone. One side will undo first and the cap will twist, breaking off the other tab.
Also You won't readily push the cap back on by hand, while starting the screws.



Remove the spring and pressure plate. I noted two shims inside the cap.



The O ring fits in the bottom of the regulator housing, so the plastic cap pushes down on it.



I cleaned up the rust, fitted a new 33*1.9mm O ring. I used 33*2mm @ 70 shore, then rebuilt this part.

I then replaced the 12mm bleed screw O ring.

Remove screw and I recovered the 8mm ball bearing also. Make sure you have the means to retain this ball bearing if you decide to remove it, as this is the pressure relief valve...no ball, no pressure.
I fitted a new 6*1.9mm O ring. I used 6*2mm @ 90 shore.



I then removed the 6mm one way ball bearing valve from the upper side of the regulator, which is just a case of unscrewing the flap that retains it.
When re-assembling, ensure the screw is tight, otherwise the ball can come out and will pass into the accumulator.
This ball stops fluid flowing back into the input port, so it can only pass towards the output side of the regulator.



View down, ball on left, screw thread on lower right, shuttle valve pintle central: the plate retains the ball and the pintle.



I then refitted the regulator and pipework back onto the gearbox. I Couldn't make the 6.35mm pipe engage into the socket with the regulator bolted to the bell-housing, so had to remove the bolts so as to be able to manipulate the regulator for exact alignment, start the back-nut thread, then refit the regulator.

Refitting the pipes took quite a while.

I had already removed the Lhm reservoir, so cleaned it and the filters to receive fresh Lhm.
I was surprised how dirty the filters were, though did run this car in Hydraurincage about 30,000 miles ago, so maybe the Lhm has picked up more dirt then normal.

[Dieselman]

Today was a rebuilding day.
When refitting the pressure regulator I had noticed the main pressure pipe, with the pigs tail, had some rust poking out from inside the rubber clamp where it is mounted onto the subframe.
The clamp bolt, clamp and rubber were very corroded and the bolt had to be cut off. The rubber/grit/rust had rubbed the pipe. I had a pipe which was from the same type of engine, but an automatic, which means the regulator is mounted the opposite way round.
I gently reformed the pipe bend to invert it, then installed the pipe. The pipe is annealed soft steel, so should have survived the bending ok.

Next was to refit the drive-shafts.
The driveshafts are exposed and the seal journals had suffered from dirt build up and some pitting, so to give the new gearbox seals their best chance I spent some time cleaning up, then polishing, the seal journals on the drive-shafts with 400 grit wet 'n dry paper. I then lightly greased the journals and inserted the shafts.
I cleaned out the hub splines with a wire brush then brushing, added copper-slip to both the shaft and hub splines and installed them.

The fine red powder you see on splines (e.g. driveshaft, clutch) is fretting corrosion, which is stopped by using copper grease.

I filled the gearbox with 1.85 litres of oil, copper-slipped the taper plug and installed it, fitted the air intake pipes, air and fuel filters, boost sensor, etc.

I filled the LHM reservoir until the float was above maximum, ensured the regulator bleed bolt was at least one turn open then started the engine. After about 1 minute I closed the bleed bolt expecting the pressure to rise, which it didn't.
After several attempts, including filling the reservoir more, I couldn't make the pump prime.
The official method of priming the pump is to disconnect the suction hose, fill it with Lhm, then start the engine and as soon as the level falls refit the pipe to the reservoir.
I didn't want to do this as the original Ligarex banding was still in place and it's messy and hassle. Ligarex creates perfectly round clamping, which other clamps can't.

I tried blowing hard down the breather pipe, to no avail, but so connected a bicycle pump with Presta fitting to the reservoir cap, held the cap down and pumped while the engine was running.
The air pressure forced Lhm into the suction pipe and the pump primed. I closed the bleed bolt and the system pressurised, so performed a few cycles of Citrobics to purge the air.

[josh2109]

I’ve just clocked this thread and have been enjoying reading through - the pictures and descriptions of the work you’ve been doing are fantastic, thank you for sharing them.

Will cleaning and re-sealing the pressure regulator improve its operation? Mine takes a bit of time to build pressure if the system has been de-pressurised.

I’d like to clean my LHM filter too, so seeing the photo of that is really helpful. Did I read one of your older posts that suggested a litre or so of mineral based spirits can be added to LHM as an alternative to Hydraurincage, or am I imagining that?

[Dieselman]

Will cleaning and re-sealing the pressure regulator improve its operation? Mine takes a bit of time to build pressure if the system has been de-pressurised.

I’d like to clean my LHM filter too, so seeing the photo of that is really helpful. Did I read one of your older posts that suggested a litre or so of mineral based spirits can be added to LHM as an alternative to Hydraurincage, or am I imagining that?

Stripping and resealing the regulator certainly appears to have improved it's performance. This car has always dropped quickly if left on Max height and switched off, now it stays up, indicating the pressure is staying higher, for longer. I suspect this is the one way valve holding pressure for longer.
If going from normal ride height to lowest, then back to high it used to bring on the STOP lamp and take a while to rise, now it's instant with no warnings.
Some of that could be attributed to the filter now being clean.

For cleaning the filters, refer to the thread from the V6. viewtopic.php?f=19&t=10982&start=20#p131220

My advice would be for absolute surety of fluid to use Hydraurincage, but its very expensive now and other hydraulics flushing oils are available.
It stands to reason as white spirit is the recommended solvent for Lhm, that a quantity of it added to the reservoir will perform a cleaning action.
in my own car, I would probably add 0.5 litre of white spirit and run the car per using Hydraurincage. Until tested I wouldn't do that for anyone else.
Any thinning agent/flushing oil, will have reduced lubrication value, hence not leaving it in too long.

[Dieselman]

Final finishing was to refit the wheels and tighten the drive-shaft nuts.
Never tighten these nuts without the wheel on and clamping the brake disk securely. If only the disk holding screw is in place and the disk locked, it will shear the screw off.

The torque figure is 350Nm with lubricated threads.
I initially tightened them using a 600mm breaker bar until they felt tight enough to put vehicle weight on: these hold the wheel bearing together.

To converted Kg to Nm I use 9.81. 10:1 would be good enough for this exercise.
I then made a few assumptions...lets say my "kerb weight" is 95 kg (931Nm) so that meant having a bar length of 375mm would give the same torque figure: 931/350 = 0.375m.

Add a marker to the bar and stand outside the marker, applying your full weight. I did this and the nut didn't move so I marked the position of the nut, loosened the nut, oiled the thread and repeated, and the nut tightened to exactly the same position as the threads were already a bit greasy.
I had tightened the nut sufficiently just pulling it tight initially. One only needs to apply 583N (59Kg) to a 600mm bar, which is achievable.

To keep the socket and bar in place use an axle stand, set the bar to near horizontal.
Is this why they are called Axle stands...to stand on when tightening your axles...



Don't forget to install the castellated nut and R clip.



Thread torques are generally given with lubricated threads. When refitting the lower suspension ball-joint nuts I couldn't make one side grip the taper enough to be able to tighten the Nyloc nut, the thread just kept spinning. I tried jamming the taper closed, but to no avail.
I added lubricating oil to the thread and it thread tightened immediately.

Incidentally, I performed some torque tests using the Xm folding wheel brace.
Xm wheel bolts are specified as 90Nm for steel wheels and 100Nm for alloys. Steel wheel bolts have beveled seats, alloy bolts have flat seats. Don't forget to copper-slip the threads and wheel hub.

With the wheel brace folded, using my right arm only was able to acceptably apply 90Nm, 100Nm was a strong push. With the wheel brace unfolded, for loosening, it's easy to pull at least twice the torque.
It appears Citroen thought of as many technical aspects as possible.

[Julianw]

I’ve just clocked this thread and have been enjoying reading through - the pictures and descriptions of the work you’ve been doing are fantastic, thank you for sharing them.

I'm in total agreement with Josh on this.

Thanks Will!