Rear end not raising.

BX Tech talk
シトロエン
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Location: Bournemouth
My Cars: 1987 BX 19 RD
Mk3 Mondeo
XJS V12
x 3

Rear end not raising.

Post by シトロエン »

After 6 months on stands with no rear subframe, Last week my BX finally was partially reassembled and had LHM flow through its veins again. It even fired the moment I turned the key!

The first thing that happened was it blew a rear strut supply line after a few minutes of running. After replacing that one, it's finally holding LHM for the first time since I got it almost a year ago!

The first thing that happened was the back raised up into the air, and the front was stuck on the floor. I set the height lever to full height, then the front went up and the back dropped. Since then, the rear has been stuck on the bump stops, no matter what position I try out. The front goes up and down just fine now *. I've raised and lowered the lever a good 6 or 7 times, and it's made no difference.

The height lever is vaguely adjusted about right as far as I'm aware With it in the driving position, it's within middle area of the slot. It is able to actuate the height corrector lever when moved to either end. It's not perfect, but close enough I'd have at least expected something to happen in one of its positions.

I understand that the brakes are going to be full of air (they do still work somehow, at least on the front!) However in order to bleed them, do I not need the rear suspension to be pressurized?

*I've noticed that the regulator doesn't really make anywhere near the noise it used to. A faint wooshing noise, but not the really noticeable clicking on and off it used to when it was last driving. It also seemed to bring the stop light on when changing heights that would only go away with some gentle revving, although the last couple of cycles up and down it didn't do this.

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white exec
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Location: Sayalonga, Malaga
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- LHD, NA, AC, RP_5800
1996 XM 2.5TD Exclusive
x 61

Re: Rear end not raising.

Post by white exec »

The system needs bleeding. It sounds like it's full of air in unhelpful places.
As the front has been rising, the pump looks as if it is getting a decent supply of fluid from the reservoir.

Citroen recommended bleeding procedure is as follows:
- Support the car securely on stands, all four wheels off the ground, and remove the wheels.
Thrown an extra 1L of LHM into the reservoir, and with engine running, set the suspension to Highest.
- Lightly wedge the brake pedal down (length of wood between pedal and seat front does it).
- Bleed the brakes at the bleed screws in this order: RR, RL, FR, FL - until air-free fluid emerges from each.
Expect to draw off around 1L+ at RR, much less at the others.
- Keep an eye on reservoir level, and check it afterwards.

Steering is self-bleeding, and a few full slow turns from lock to lock will push any aerated fluid back to the reservoir.
A good idea to do this first, before bleeding the rest of the system.

Let us know how you get on.
Chris

thorter
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Re: Rear end not raising.

Post by thorter »

Sound like you might have feed and return pipes swapped, though it should then raise for the height lever right down assuming it is correctly adjusted. Another possibility is a blocked height corrector damper nozzle.

tom
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Re: Rear end not raising.

Post by tom »

With a correctly jacked up and supported car, check the linkage to the height corrector first. I live in Poole so can potentially assist.
I bled brakes using my own technique. I took two lengths of washer pipe, (clear!) and placed them on the bleed nipples. I routed these pipes over the roof and into the reservoir. With the bleed nipples open, I ran the engine and operated the brake pedal until no air was visible in the pipes. Works perfectly and takes a couple of minutes.
Vive les UX.

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white exec
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- LHD, NA, AC, RP_5800
1996 XM 2.5TD Exclusive
x 61

Re: Rear end not raising.

Post by white exec »

Now that's thrifty! O:)
Chris

シトロエン
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Posts: 13
Joined: Sat Feb 27, 2021 8:37 pm
Location: Bournemouth
My Cars: 1987 BX 19 RD
Mk3 Mondeo
XJS V12
x 3

Re: Rear end not raising.

Post by シトロエン »

thorter wrote:
Thu Nov 25, 2021 9:36 am
Sound like you might have feed and return pipes swapped, though it should then raise for the height lever right down assuming it is correctly adjusted. Another possibility is a blocked height corrector damper nozzle.
Bingo! Thank you.

I'd taken a load of pictures, been extra careful and still somehow got them the wrong way around. The pipework is a bit of a mess to be honest, I made the new pipes much too long, and with no way to re-flare them while they're under the car, I'll just have to work with it. At least one of them is the correct length!

I swapped them over yesterday and now it seems to be pressurizing at front and back. I didn't have the time to bleed the brakes, so will get on with that this weekend if I don't freeze my nuts off and its dry enough. Hopefully I'll be able to finish off what I can over the weekend and get it booked in for the rest and MOT.

Next problem is going to be how to support the exhaust. It lost it's backbox hanger due to rust, and while there is nice new floor there now, the hanger is MIA.

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white exec
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Joined: Sat Sep 12, 2020 4:04 pm
Location: Sayalonga, Malaga
My Cars: 1992 BX19D Millesime
- LHD, NA, AC, RP_5800
1996 XM 2.5TD Exclusive
x 61

Re: Rear end not raising.

Post by white exec »

Re: the missing exhaust tailbox hanger, I've had to deal with just that a month or so ago, where the body-welded rod hook had detached from the body.
Will post a photo of my alternative hanger in the morning.
Chris