The Myth, The Legend, The Citroën BX 1.9 Diesel Meteor 4x4!

[barry badger]

Which parts of the zx driveshaft can be used and from which model? My nsr one has a lot of play in the outer joint, not sure if its the joint or the splines on the shaft, it needs stripping to investigate further. Although none of this is apparent when driving it.

Mines off the road at the moment for a bit of welding/rustproofing, I had a feeling there was something going on under the osr wheel arch so i kept it garaged over the winter. I was right there was a small rust hole about 20mm x 20mm. I noticed a wet patch on the bottom of the sill at the rear when the rest of the car was long dry. It was water kicked up by the wheel getting into the box section and draining down into the sill.

Have you ever stripped a bx transfer box?

[David]

Well, What a busy few weeks it's been with the BX.

I found that I had another leak from the octopus & that leak from the engine, so rather than struggling to try to get behind the engine & transfer box, I just pulled the engine out to make things easier to get to.

I have replaced the octopus & return hoses with nylon air tube, which I have seen recommended on this forum, which are a better fit than the previous one I made, and they don't rub right up against the transfer box, drive shaft, subframe & front height corrector now. The actual "octopus" (if you can call it that now) lives right next to the LHM tank now & it is all easily accessible.

That oil leak from the engine turned out to be another crap crankshaft oil seal, which was replaced (again) when I put the A/C system in the car, but yet was still leaking. It has been replaced yet again, and while I had the car apart I resealed the sump, spacer plate & main bearing cap just to be sure that it wasn't leaking there.

The hardi-disk has also been replaced as it looked like it was on the brink of splitting in half, and as it was easier to get to with the engine out, it seemed like a great time to do it.

I then reassembled the front end. It's also had new diesel pipes as the rubber was starting to perish.

I have also fitted it a new A/C compressor as the other one had a leak. I found one for a Lamborghini Diablo which fits perfectly. I just need a condensor now.

Once the front end was together & the engine ran, I moved my attention to the rear diff which... Guess what... Had oil leaks from the drive shaft holes. This time I've replaced the oil seals with some with tighter lips so I'm hoping that it's finally sealed them.

This time I also got some pictures when it was apart.

I've driven the car around 20 miles over the last two days, so I need to have another look underneath now.

Oh, the car finally hit 200000 miles yesterday! What a milestone.

I've tried to contact pleiades about a new hydraulic pipe for the rear, but they haven't got back to me yet, so I'm assuming that they're closed for the lockdown, so that leak hasn't been touched. Yet.

Red color makes it faster!

Not really, it's only a 1.9 diesel engine. I was just bored with everything being black and rusty, and as I had a tub of red paint lying around, I painted it red.

Which parts of the zx driveshaft can be used and from which model? My nsr one has a lot of play in the outer joint, not sure if its the joint or the splines on the shaft, it needs stripping to investigate further. Although none of this is apparent when driving it.

Have you ever stripped a bx transfer box?

I sent you a detailed pm on this.
The drive shaft was a fiasco as the seller didn't measure it properly, so it was smaller than I expected, but I'll be able to use its parts somewhere else.

No I've never pulled a complete transfer box apart, only the speedo drive, prop shaft drive & the left plate that bolts to the gearbox.

Here are the pictures that I managed to get.

[David]

More pictures.

Showing the clutch, flywheel, oil seal, another of the engine & testing the thermostat.

[Kaapelimies]

That blue colour in the flywheel doesn't look good. Is that the original flywheel? I think I have never seen that lightened model in my hands.

[David]

It's funny that you mention that; It's not visible to the eye, but it's there in the pictures, unless it's the light on it? I'd just washed it with brake cleaner when I took the picture.

No, it's not the original flywheel, it's the 3rd one I've had on it; The original was the automatic driveplate. This one is off a Peugeot 205 1.6 GTi. I needed it because the 1.7 diesel one I had fitted before wouldn't fit with the A/C sump; it needed the cut out in the back, which this one has. An added advantage is that the clutch is the same size on both flywheels.

[Kaapelimies]

Yes, camera sees more than human eye, so it's probably just infrared light added to the picture. And also flywheel explained, this is new info for me that the A/C sump is longer than the tinplate one (: .

[David]

Well lockdown is now over, so work on the BX has slowed again, but hasn't completely stopped.

One of the replacement struts that I put on last year was pouring oil out of the return leak offs, so I've sourced a replacement off a forum member (thanks Kevin), and fitted it. So far it seems to be behaving.

Knock Knock, or Drip Drip. Who's there? Octopus. Again!

Yes! Can you believe it? I went out to the car after it had been driven and then sat for a week to find this.

IMG_3229[1].JPG

The new "octopus" that I've just put on it was leaking from the quick release unions! Considering that they're supposed to hold high pressure, this is very disappointing. So I've had to alter it slightly. I didn't want to pull the engine out again to get behind it, and if the pipes themselves are holding OK I decided to just put some different connectors on the pipes to link them together. I've used small, short rubber hoses with plastic connectors this time. Will it hold? - Time will tell. I'm just glad that they're next to the LHM tank and not hidden behind the transfer box.

Most of the oil seems to have come from the pressure regulator leak off. Does everyone else's return a lot of LHM from the small return on the bottom of the pressure regulator?

I've also found a radiator specialist locally, so I've just bought and fitted a brand new air conditioning condenser. I've also had the A/C system vacuumed out to negative pressure and so far it seems to have held it. (6 weeks now, so I'm hoping that the A/C mechanicals are finally fixed).

I've also replaced those 2 copper pipes on the rear axle that connect the suspension cylinders to the sphere supports. I got a friendly local mechanic to make them, and he was nice enough to show me how they're made properly, it was just a case of shaping them and fitting them to the car afterwards.

I've been enquiring about getting an estate rear wiper switch as I'm thinking of doing the rear wiper mod to make it stay on next.

I think I might need a black A/C control box for it too. Currently it's wired up with switch and LED, but I've read that the evaporator will turn into a block of ice without the control box. When I fitted the air conditioning, I couldn't get the control box to work.

This is new info for me that the A/C sump is longer than the tinplate one (: .

The sump isn't longer, but it has an alloy spacer that comes down lower from the engine than the steel ones do, so unless the flywheel has the larger cut out, they will bump together and not allow fitting of ether the flywheel or sump.

[Jaba]

Well lockdown is now over, so work on the BX has slowed again, but hasn't completely stopped.

I think I might need a black A/C control box for it too. Currently it's wired up with switch and LED, but I've read that the evaporator will turn into a block of ice without the control box. When I fitted the air conditioning, I couldn't get the control box to work.

That black box is just an electronic relay. If it isn't working then did you check that the two temperature regulating inputs that it needs to see are working from the evaporator temperature sensor and the temperature adjuster slider. The black box should only turn off when the sensor opens which shouldn't be below about 5deg.
Also bear in mind that a vacuum test is not the same as a pressure test as the system can get over 20bars when really hot

Most of the oil seems to have come from the pressure regulator leak off. Does everyone else's return a lot of LHM from the small return on the bottom of the pressure regulator?

If you mean the return, clear plastic, that loops up over the gearbox (on 2wd anyway) from the small domed doobery then I have never seen any leakback at all there.

[David]

That black box is just an electronic relay. If it isn't working then did you check that the two temperature regulating inputs that it needs to see are working from the evaporator temperature sensor and the temperature adjuster slider. The black box should only turn off when the sensor opens which shouldn't be below about 5deg.
Also bear in mind that a vacuum test is not the same as a pressure test as the system can get over 20bars when really hot

I honestly don't remember how I tested it as I couldn't get much information at the time, I just remember that I couldn't get it to work. I tried putting the wires in every different position, but nothing would work. I'll have to pull the centre console out again and have another look.

If anyone has any information about what does what, it'll come in very handy. From what I remember, there are 5 wires that come out of the black box 3 wires that go into a plug, and 2 more that go to the evaporator tempature sensor.

Yes, I know that the pressure and vaccume tests are completely different. Before I replaced the condenser, I gave it the vaccume test, which it lost in 2-3 days, so I hooked an air line to it and put 50 psi in it, at which point it actually went "pop" and started hissing loudly. Once the condenser was replaced, I did the same thing again, and it held the pressure, but with the method I used to to put the air in it, I had no way of knowing if it had lost any of the pressure, and as the compressor would engage with even compressed air in the system I got it vaccumed out so it couldn't be ran accidentally.

If you mean the return, clear plastic, that loops up over the gearbox (on 2wd anyway) from the small domed doobery then I have never seen any leakback at all there.

Yes, that's the pipe. Not long after I first bought the car, the rubber pipe that connects the transparent pipe to the regulator itself snapped, and it emptied the hydraulic tank in no time. I did find it strange that a low pressure return would do this, and stranger still, the hydraulics seem to be in very good condition. For example, last time I gave it a "tick test" in the garage, it was ticking between every 45 seconds (just after it had just been disturbed) up to around 3 minutes thereafter (I can't remember the exact figures), with the suspension pressurised, me in the car and the engine running.

Maybe I'll have to see what the return does on the parts car.

I'm not really worried about it at the moment as it's just how it's always been, but I'll just have to make sure all the returns are oil tight to stop it losing LHM anywhere.

[David]

Well, it's been a busy, although not really productive afternoon with the BX today.

I decided that I'd have another look at the air conditioning 'black box', so I pulled the centre of the dash out... and the steering column lower shroud... and the radio holder before I could even get remotely to it. Access is difficult.

I still haven't got any definite answers here, although my thoughts are that the temperature sensor in the evaporator might be broken and that possibly two wires might be in the wrong positions in the black box itself, although I haven't moved any of them & they're all showing to be correct according to the wiring diagram. If you can follow my diagnosis below, then all might become clear, or someone might see something obvious that I've overlooked.

Once I'd located the plug with the three connecting wires I attempted to test it by putting a circuit through it (12V live & earth). With not knowing which wire did what, I just had to guess. Initially nothing happened, no matter of what position I put the wires in. (I believe this is what I did last time to test it, and after I'd got nowhere I just put a toggle switch in & screwed everything together). I was turning the AC switch on & off at the same time as moving the wires... still nothing. I then jumpered the two wires together that go to the temp sensor in the evaporator (which are pins 1 & 2 in the box) and it clicked.

So, once I'd got this far I've now established that pins 1 & 2 are the temp sensor, pins 3 & 4 are the A/C switch, Pin 5 is live out (to the A/C compressor),
Pin 6 is earth & pin 7 is ignition live.

With 1 & 2 linked, the relay in the box was engaged, however that's it, it wouldn't disengage regardless of if the A/C switch was on or off.
With 1 & 4 linked, it was the exact same situation.
With 1 & 3 linked, it would turn on & off with the A/C switch on the dash.
It didn't do anything if 2 was linked to 3 or 4.

The wires on the three pin plug are:
1 is ignition live, 2 is switched live out & 3 is neutral.

The A/C switch itself was showing an open circuit when it was slid anywhere except from all the way to the right, in which case it was showing no resistance & a closed circuit.

The temp sensor was showing an open circuit, it didn't matter if I wiggled the wires about. They aren't obviously snapped and there's no corrosion on the connections.

So, has anyone got any idea what I'm missing here?

Surely if it was just the sensor, then it wouldn't be behaving as above once it'd been linked? And if the sensor was OK, then the box's relay would be constantly on with the way it's behaving above?

Just to add, I tried a variable resistor in place of the jumper wires, but it made no difference, it was ether on or off; no in between even when I altered the resistance between the contact points.

Here are some pictures of the box & my connections.

[Jaba]

The temperature sensor is actually an NTC thermistor, a RN3436 is a working equivalent with a resistance of 1Kohm at 25C so shorting pins 1 and 2 will not prove much. The on off switch is a variable resistance which alters the effective resistance of the sensor seen by the black box electronics and will raise above 5deg the cut off temperature.
I don't think you have missed anything circuit wise it is just that is doesn't work properly. There is not much you can do except verify the on off slider switch operation then change the sensor and or the black box. Or devise your own control circuit. I always fantasised about fitting an automatic temp control where I would set my goal interior temperature and it would come on and off automatically. Much like the climate control I have in my Skoda.

[saintjamesy89]

This is new info for me that the A/C sump is longer than the tinplate one (: .

The sump isn't longer, but it has an alloy spacer that comes down lower from the engine than the steel ones do, so unless the flywheel has the larger cut out, they will bump together and not allow fitting of ether the flywheel or sump.

This may be the one thing that scuppers me fitting a/c to my GT! Does anyone know which flywheels are compatible with the alloy sump? When I removed the alloy sump from my donor 16TRS auto I noticed that it kind of laterally went into the flywheel housing a little bit - is this what you mean by the 'cut out' David? I'm yet to try and fit it to my GT, life keeps happening and getting in the way of stuff.

Top project btw

[Jaba]

I had that sump/flywheel problem Tom.
I am not 100% sure how I solved it but I think I simply cut off some metal from the ally sump to get the clearance. That spacer mystifies too, I think I left mine off as some cars have it and others don't. You may have to leave it off. I believe it is used as a way of increasing the sump capacity.
Could you use the flywheel from your donor car ? I dont recall if it has the same engine.

[saintjamesy89]

The donor is a 16TRS auto and recipient 19 GT manual. I imagine the flywheels will be quite different, but there is only one way to find out! Im hoping i can get the sumps swapped in the next few weeks.

[mat_fenwick]

That reminds me - the first ali sump I fitted I don't recall having to modify, but I did with the second. The first was from a TD, and was a smooth casting with no spacer. The second was from a 16v, and came with a spacer (without which I think it would have fouled on the oil strainer).

The 'black box' control you could just replace with a thermostatic relay, which would stop the evaporator from freezing but leave you unable to vary the exact temperature - i.e. simply on/off control.