FDV Failure?

BX Tech talk
Dominic
Confirmed BX'er
Posts: 42
Joined: Wed May 23, 2012 1:59 pm

FDV Failure?

Post by Dominic » Thu Oct 08, 2015 1:51 pm

To add to the lively debate on air in the system, here's another oddity (to me).
The power steering on my tzd offers what could best be described as 'inconsistent assistance', which is a bit disconcerting if you have to haul the car into a corner and half way through the assistance cuts in (or vice versa).
I bled the 12mm accumulator screw to the accompaniment of much whooshing followed by a click, and all is well again - full-time steering assistance. This used to be done every 4 weeks or so (2000 miles), now it needs doing every couple of days, so something is deteriorating. There are no leaks in the system, but something ain't right. Help, guidance and insight most welcome.
Dom
91 TZD
02 Picasso HDI
'12 DS5
83 Moto Morini 500
70 Fiat 850 Spider
Anything that turns money into noise...

Defender110
Over 2k
Posts: 5899
Joined: Wed Dec 16, 2009 8:02 pm
Location: Harwood, Bolton
My Cars: Citroen BX MK1 Break.
Land Rover Discovery Series 1 200tdi 3 door
Land Rover Discovery Series 2 Facelift TD5
BMW X1
x 25

Re: FDV Failure?

Post by Defender110 » Thu Oct 08, 2015 2:08 pm

Leaking accumulator sphere?

"Stiff power steering

Check the level of the LHM, clean the filters in the reservoir and renew the fluid if necessary. If the filters were very dirty, you should flush the system. If this does not help, you can suspect some failure in the hydraulics like a flat accumulator sphere, faulty pressure regulator, or even a faulty hydraulic pump.

The system is designed to maintain safety: if the pressure drops, the steering goes first, then the suspension so that you still have brakes until the last drops of LHM. And as the steering requires copious amounts of pressure, even a slight pressure drop might make the steering stiff or default to mechanical instead of power steering. This signals an ongoing deterioration of one of the components involved, so if the stiffness cannot be eliminated by simple cleaning, you'll have to replace some parts sooner or later anyhow."
Kevan
1987 Citroen BX MK1 diesel estate.(Currently in dry storage)
1997 Mercedes C230 W202 - daily driver.
2010 BMW X1 SE 2.0D Auto - Her indoors daily driver.
2003 Land Rover Discovery Series 2 Facelift TD5 - Daily driver / hobby days and camping.
1993 Land Rover Discovery 200tdi Series 1 3 door - in need of TLC

User avatar
Way2go
Over 2k
Posts: 7279
Joined: Fri Jan 13, 2006 3:15 pm
Location: RCoBerkshire
x 2

Re: FDV Failure?

Post by Way2go » Thu Oct 08, 2015 2:38 pm

Dominic wrote: I bled the 12mm accumulator screw to the accompaniment of much whooshing followed by a click, and all is well again - full-time steering assistance. This used to be done every 4 weeks or so (2000 miles), now it needs doing every couple of days, so something is deteriorating. There are no leaks in the system, but something ain't right. Help, guidance and insight most welcome.
This isn't right, once the air is bled it really shouldn't need doing again until the system is drained/refilled. If normal operation is regained after bleeding then this suggests you DO HAVE a leak in the system where it is drawing in air prior to the pump input. You may not see a fluid leak as the input lines are not under pressure but you need to check the quality of the rubber and hose joints for their integrity. If the input lines are all good then really that just leaves the pump itself possibly drawing air in though its shaft bearing/seals?
1991 BX19GTi Auto

Tinkley
1K Away
1K Away
Posts: 1495
Joined: Sat Jun 06, 2009 11:27 am
Location: N Hants England
x 6

Re: FDV Failure?

Post by Tinkley » Thu Oct 08, 2015 3:31 pm

More like a 'flat' Accumulator sphere. Normally you might get leaks at some of the Y joints, or T joints, and other parts of the return system as well. These are early warning signs that the Accumulator sphere is past best. Not sure what happens if the bladder becomes porous inside it but guess that would give a lot of nitrogen back into system. Maybe Defender's leaking sphere?

When was it last changed?

PS the 'debate' does concern my 'new' aquisition whereas my current runner and previous 2 (one written off by third party) were 'known' items which were sorted OK. Last 3 cars have identical engines though, even similar carbs, though the auto has a bit of odd stuff added.

Dominic
Confirmed BX'er
Posts: 42
Joined: Wed May 23, 2012 1:59 pm

Re: FDV Failure?

Post by Dominic » Sat Oct 10, 2015 1:59 pm

Many thanks y'all. Accumulator sphere last done a year or so ago, but I do starship miles, so worth replacing I guess. I also have a reserve pump. Is it safe to use jubilee clips on the pump?
Dom
91 TZD
02 Picasso HDI
'12 DS5
83 Moto Morini 500
70 Fiat 850 Spider
Anything that turns money into noise...

User avatar
Way2go
Over 2k
Posts: 7279
Joined: Fri Jan 13, 2006 3:15 pm
Location: RCoBerkshire
x 2

Re: FDV Failure?

Post by Way2go » Sat Oct 10, 2015 2:33 pm

It is not necessary to replace the accumulator sphere unless the 'tick' time interval has diminished to an unacceptable level.
1991 BX19GTi Auto