BX dropping unexpectedly

Oscar Too · Post by **Oscar Too** » 06 Apr 2005, 15:05

Hi there
Last night I changed the oil in the BX. I put it high, switched the engine off, jacked it up and put axle stands underneath. Perfectly normal straightforward oil change ensued. The car was on stands for about 20 mins, with back section still in high position. Then I took the stands away and left the car still in high with engine switched off - nothing untoward so far.
I started the engine and put the height selector in normal. The car dropped all the way to the bottom and then came up slowly. My mate and I were nattering, enging still running, when the car unexpectedly dropped to the bottom and came back slowly, twice. When I sat on the bonnet to see how it reacted, it again dropped to the bottom before coming up slowly with me on the bonnet. When I got off the bonnet, it bounced up a couple of inches and then...you guessed it...dropped to the bottom before coming up slowly. This happened twice. There was no-one in the cabin so I can't tell you whether any warning lights came on.
I then moved the height selector between all three positions and it seemed to react normally. Took it for a spin around the block and it seemed fine. Drove home and seemed fine.
For background, the car has always been quick to come up, and quick to drop too when the engine is switched off. The front struts are sticky and the front is a lot slower to drop and rise than the rear.
Can anyone tell me what's happening? Is this just because it was in high with the engine off for 20 minutes or so or is there some other reason? How worried should I be?
Any help gratefully received.
Oscar

Kowalski · Post by **Kowalski** » 06 Apr 2005, 15:18

Sounds like the car is dumping pressure catestrophically somewhere. You'll have to check your return hoses to see where the pressure is going.
What are the FDIV / Pressure regulator / accumulator sphere like?
The car would slowly sink a bit then open a height corrector to find that there was no pressure to make the car go up so the suspension pressure would be lost until the pump could pump it up. Does that sound plausable?

alan s · Post by **alan s** » 06 Apr 2005, 15:52

Check the adjustments on the front to rear rods.
I think it's 5mm from the front of the slot and 7mm from the rear (I don't know why they don't just sat 6mm each end) and if it has ever been slackened off and not properly retightened or if someone has ever adjusted the suspension using these, they will cause some extremely weird symptoms. As you can imagine, if the arm is touching the end, the slightest movement will cause it to totally depressurise.
Alan S

bulldog · Post by **bulldog** » 06 Apr 2005, 16:12

i have a manual bx oil burner (love her) drive her as "normal" when i have my daughters in her but when i have droped them of at there mums for the weekend i like to throw her about abit and have a laugh well as much as you can with an oil burner.
on the other hand i have a freind who does acident recovery and gets fed up with gear changes so he is glad at the end of the day when he jumps into his auto granada. i dont mind his auto but thats cos im a passenger but i dont think i would like to own one im going to stick with manuals, besides autos cost alot to repair and its not the type of thing you can do at home but where as a manual you can do it at home

Oscar Too · Post by **Oscar Too** » 06 Apr 2005, 16:16

Hi guys and thanks for contributions
Alan which rods do you mean? Not as well-versed in hydraulics as I need to be, but it looks like I'm going to become an expert pretty soon [:)]

alan s · Post by **alan s** » 06 Apr 2005, 18:24

You'll see a set of rods about 6 - 8mm in diameter with a hook looking arrangement that sits in a slot and a bolt and nut that holds the adjustment (takes about an 11mm spanner from memory) and slackens a clamp that allows the adjustment.
I think Anders has a write up on this one somewhere. It's a while since I last did mine, but if you look under the car at the rods associated with the manual part of the suspension height adjustment, it's all pretty obvious. As always, get it up on a ramp or pit to fiddle as these things can let things down pretty quickly.
Alan S

oilyspanner · Post by **oilyspanner** » 06 Apr 2005, 18:27

Sounds like the linkages are "fighting" against one another, as Alan suggests getting the beast over a pit would be ideal, the BOL is actually somewhere nea real on the matter.
Stewart

jeremy · Post by **jeremy** » 06 Apr 2005, 18:46

I think you've ruptured a sphere! Well I always like to be different but I think it goes like this. Put on full height - height correctors open and suspension subjected to full REGULATOR output. - This is why they creak a bit for a few seconds after reaching high. If one (or more) of your spheres is low in pressure the diaphragm is stretched to the limit and makes contact with a clip or something in the sphere and bursts.
Gas expands, pushes out fluid, start engine, move controls and gas starts travelling round the system. Couple of operations (Citroebics) expells some of it.
If I'm right the LHM will have mysteriously dropped, you will find a hard corner etc. - easy to check!
jeremy

Oscar Too · Post by **Oscar Too** » 06 Apr 2005, 18:58

Alan you're dead right about ramps! I had a go at my mate John last night for diving underneath the car when I had selected full height, before we did the oil. He more or less laughed at me, but he wasn't laughing 20 minutes later when the car dropped suddenly in front of his eyes. Still, better than on his head...[:)]
Does anyone else have any suggestions?