BX Immobilized : Front Height Corrector Valve

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PeterMann
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BX Immobilized : Front Height Corrector Valve

Post by PeterMann »

The Front Height Corrector Valve has gone hard over, so the front is stuck on tippy toes. It's a BX19TRi series 2, and it's the one we take into the bush to cut firewood for the coming winter..
Bit the bullet, and started taking the valve out, only to find that the RHS high pressure line is unwinding at 1/6th of a turn for every 30 seconds of concentrated effort. And the lower RHS rubber line has a hoseclamp on it that defies my most persuasive screwdriver. Serious access difficulty. Have looked at Haynes and previous postings, but all seem to gloss over the finer details of extricating the valve.
Meantime, she's up on axle stands with a green stain on the footpath from the LHS pressure line, and I'm hoping some genius will suggest a way through that doesn't involve lifting the engine out.
[xx(]
jeremy
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Post by jeremy »

Shouldn't be any problem - the car's left hand drive isn't it? Try dealing with it on a UK TD with all the steering and turbo there!
In fact the rod going into the centre of the flat disc top has probably stuck due to rust on the shaft and I would first have a go at freeing it up with WD 40 and some carefully applied force from the top. I would have thought you could get some form of rod down behind the ehaust and gently push on it.
Having got it free plaster the shaft with some grease (use a brush?) - makes a world of difference to the ride if it works freely.
A search of this site may reveal someone's trick for getting access
Jeremy
PeterMann
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Post by PeterMann »

This is an Aussie right hand drive BX efi. The external mechanisms from cabin and torsion bar are working fine, and this is a sudden onset thing ... I reckon that a damper orifice has been blocked, which has sent the valve spool to one end of its travel, and hydraulic supply pressure is then holding it there. Tried pushing on the spool ends through the outer membrane with my fingers.
jeremy
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Post by jeremy »

Peter - sorry about LH/RH drive bit.
When the height corrector goes to max height it is in fact open and the spheres, struts etc are subject to the full force of the supply from the regulator. This is why if you have a dud accumulator causing it to tick too frequently raising the car fully often slows the rate as it in effect has 4 additional accumulators
I think if the spool valve had been sent to the open end of its travel it would in fact be in the open position. The only time its shut is in the down position when it opens up the exhaust port allowing fluid from the struts to return to the reservoir.
So if you release the circuit pressure by loosening the valve on the regulator the suspension should drop as it should by natural decay.
Bet it doesn't drop!
jeremy
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AndersDK
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Post by AndersDK »

A good trick is to remove the lower engine mount bracket. Then you can jerk away the engine from the subframe and hold it there with a wooden block. Should give you at least a couple of inch more clearance from engine.
As it is an RHD - it will also have the steering pinion right next to the HC - taking up almost all available work space.
I'd say start by removing the slotted clamp from the manual height setting rod. Then it should be possible to unscrew the HC body and pull it a bit more forwrd to access the piping.
As you are in Ozzie I fear you have very bad access to any spare pipe supplies - take care not to strain the piping !
PeterMann
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Post by PeterMann »

Too late to test whether she sinks when the accumulator is discharged, but Jeremy's suggestion makes sense ... I've already had my green shower from the LHS port. I'd been wondering about the lower engine mount and jacking the motor. When it stops raining, I'll go and have a look ... if you want to keep Citroens, a brick driveway/carport floor is a bad idea.
PeterMann
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Post by PeterMann »

Removing the bottom engine mount does indeed give improved access to the RHS connections on the front height corrector valve. The bottom of the engine swivels forward as the jack lifts it. I had started by following the Haynes instruction to remove the RHS wheel : don’t bother.
Note that the engine mount is retained by bolts with Nylock nuts : the vertical one is 18mm AF and the horizontal is 16mm AF. I mention this because these sizes are typically omitted from spanner sets and socket sets, and for the 18mm, the head of a shifter may not fit into the dished area on top of the mounting bracket to stop the upper Nylock nut from rotating.
I used fittings for ¼” irrigation systems to seal off the tubes : the end plugs fit nicely into the 2 rubber tubes, and I used a short section of plastic tube with the end sealed with hotmelt glue to fit over the end of the exposed metal lines (it makes an interference seal on the bulge).
Incidentally, the rubber insert in the bottom engine mount is cracked, and I will replace it while it is disassembled. Any suggestions on how to remove it and refit into the alloy housing ?
jeremy
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Post by jeremy »

I did the large bottom engine mount in situ by cutting through the outer ring (steel) with a hacksaw. The blade goes through the slot and you can re-assemble the saw and cut more easily than just with the blade, albeit diagonally. I think I ended up with the blade with the teeth on the inside of the saw if you get what I mean. Having released the tension on the ring I was able to hammer it out with a collection of handy objects and punches.
I'd placed the new mounting the deep freeze the night before fully expecting it for supper covered with beans. No seriously the idea was to slightly reduce its diameter so that it would go in easily and expand in situ. I put a dab of grease on it and in fact it went in without problems. The smaller one in the youke I did on the bench and pushed out with sockets etc and refitted frozen as well.
The proper way is to do it off the car which means removing the RH driveshaft and centre bearing and the entire alloy mounting plate.
If the temperatures in you part of Australia are the same as AlanS is experiencing a frozen mount should be a finger push job as the difference in the temperatures is what matters.
jeremy
PeterMann
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Post by PeterMann »

Excellent. Thanks Jeremy. I'll go your way with the engine mounts. Have been photographing the dismantling of the height corrector valve. Once the pressure had been released, I was able to move the spool by hand. Haven't found anything out of sorts so far. Just been making a tool to unscrew the brass orifice body from a piece of 1/4" steel tube, rather than just probing with a needle. That way, I should know when I find the problem.
PeterMann
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Post by PeterMann »

PS: I seem to remember something about a left hand thread somewhere on the height corrector valve, but cannot find the reference. Anybody remember ?
jeremy
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Post by jeremy »

Not quite what you're looking for but tuition notes for DS mechanics may be some use as I expect the thing is essentially the same.
http://www.citroen-ds-id.com/index.html ... ourse.html
Jeremy
PeterMann
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Post by PeterMann »

Thanks Jeremy, Yes, it seems to be identical to what I remember of the GS height corrector, which was conveniently located on the RHS wheel arch area.
DoubleChevron
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Post by DoubleChevron »

Hi Peter,
I find it highly unlikely that your height corrector will be interally seized. I've only found this once before, and that was a brake fluid ID19 that was full of black 'sludge'.
I suggest following all the linkages/connections down from the height control lever. Betcha one of them has popped out of place or is bent somehow.
If you pop the linkage connector off the height corrector does the car go and and down easily if you manually move the height corrector yourself (NOTE: Please do NOT splatter yourself trying this. These cars drop with horrifying speed when you play with the height corrector). A 4pole hoist or ramps/pit is the ONLY safe way to tinker with height adjustments.
seeya,
Shane L.
PeterMann
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Post by PeterMann »

It's working again. The valve went hard over due to a small piece of plastic lodged in the orifice disk nearest the control linkage. Have a set of annotated disassembly photos for anyone that asks.
nicolewis@optusnet.com.au
Special thanks to Jeremy, Shane, Bxbodger, Niek & Anders.
PS : Ended up grinding off some of the interference fit to insert the lower engine mount. Freezer treatment was not enuff.
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