DS failing to rise to the occasion

Glenn Drake

Glenn Drake

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I am trying to identify why my 1974 DS is taking an eternity to rise.
Thinking it was probably sucking air, I have checked piping, LHM level and that the filter is clean etc from LHM Reservior and found nothing untoward
I think that the pump is not cycling correctly, as normally it cycles often when trying to raise the car, but the pump seems to only be cycling infrequently upon startup.
Leading me to believe my pump may be on the way out
Can any AF brains trust help shed light on this?

cheers,
Glenn
 
its got to be either the pump or the regulator, i wonder if the spring in the regulator is broken ?
 
Possibly a crack in the pump body between two pistons meaning it won't develop the pressure it needs to. Aluminium pump body? Does it start to rise when you increase the rpm but not when idling?
 
Have you given the pump circuit a good bleed to make sure all the air is out of the pump, pressure lines and regulator?

I would open the bleed screw on the regulator, start the engine and give it a rev to 3000 rpm for 30 seconds or so, then close the bleed screw and see if it pumps up any better.

Cheers, Ken
 
if you beeld it, open and close the regulator screw several times, rev the engine between each, air doesnt usually stop the pump cycling and the car rising.
 
Thanks everyone, a few things for me to check out…
I just noticed it’s a little wet underneath the pump which doesn’t look right.
Starting to think my pump is faulty…
cheers
 
Another question for our collective brains trust…
If I have a blockage in the hydraulic system (ie dirt somewhere) what would be the method of isolating where it could be? I see on a hydraulic troubleshoot guide that slow to rise could be a “blockage in high pressure lines”, with a remedy of “clear blockage”. How exactly you identify where a blockage is occurring is a mystery to me?

Glenn
 
Somewhere I saw images of the brushes on a Citroen hydraulic pump. The hydraulic fluid tends to wick into the brushes area and causes the carbon powder from wear to form a sludge. The lack of free movement can inhibit the spring pressure against the armature.

Reports of reduced pump performance being resolved by a good cleanup of the sludge were fairly common.

I am not well schooled on Citroens. Is the above problem perhaps what is causing your reduced pump action?
 
309B6D said:
Somewhere I saw images of the brushes on a Citroen hydraulic pump. The hydraulic fluid tends to wick into the brushes area and causes the carbon powder from wear to form a sludge. The lack of free movement can inhibit the spring pressure against the armature.

Reports of reduced pump performance being resolved by a good cleanup of the sludge were fairly common.

I am not well schooled on Citroens. Is the above problem perhaps what is causing your reduced pump action?
Click to expand...
May well be.
The car has been going brilliantly, and I did replace a failed sphere a month or so ago which got me thinking of possibly dirt in the system.
Weirdly the car is only really slow to rise on the first start of the day (after sitting for many hours) . Subsequent starts see it rising faster, albeit not as quick as it should/used to.
I have just returned from a 1,700km trip to STH Australia, and I only noticed the slow rising in Keith (a bit over half way).
Because the hydraulic pump is not cycling as regularly as it should when first starting the car, I am focusing at the moment on the pump.
As you suggest, it could all be related to a wear issue in the pump🧐
cheers,
glenn
 
Might be a silly suggestion but, is the regulator bleed screw tight?

It could also be a sticky priority valve. Does it take a while for all the hydraulic systems to start working or only the suspension?

If you’ve got a spare regulator or pump it might be worth putting it on.
 
David S said:
Possibly a crack in the pump body between two pistons meaning it won't develop the pressure it needs to. Aluminium pump body? Does it start to rise when you increase the rpm but not when idling?
Click to expand...
a cracked pump body usually means the pump has to work harder and runs more often. Glen said the pump is working less often, which suggests to me it is building sufficient pressure to cut out the regulator.
 
When Glenn said the pump was now cycling infrequently, I think he meant cycling off then on. I think Peter assumed he meant cycling on then off. In other words, the pump is working more often, not less often, and it is not building sufficient pressure to cut out the regulator. A DS hydraulic system in good order can sometimes have the pump build pressure faster than the hydraulic system can use that pressure to lift the car from its resting position.

A third possibility, after the pump and pressure regulator, is a major internal leak, generally in the steering rack.

A DS hydraulic pump does not contain brushes. It is belt-driven from the camshaft pulley.

DS hydraulic pumps generally fail not gradually through wear, but suddenly through fatigue cracking of the aluminium pump body.

Roger
 
" A DS hydraulic pump does not contain brushes"
How stupid of me. I have read about the belt drive from the camshaft pulley on DS. My brain failed to "join the dots"
I now recall the brush issue was while I was browsing videos about C5 being slow to rise. They have an electric pump.

Thankyou, Roger W for cancelling out the false information that I posted. Misleading advice can hang around for a very long time on forums.

Bryan
 
Roger Wilkinson said:
When Glenn said the pump was now cycling infrequently, I think he meant cycling off then on. I think Peter assumed he meant cycling on then off. In other words, the pump is working more often, not less often, and it is not building sufficient pressure to cut out the regulator. A DS hydraulic system in good order can sometimes have the pump build pressure faster than the hydraulic system can use that pressure to lift the car from its resting position.

A third possibility, after the pump and pressure regulator, is a major internal leak, generally in the steering rack.

A DS hydraulic pump does not contain brushes. It is belt-driven from the camshaft pulley.

DS hydraulic pumps generally fail not gradually through wear, but suddenly through fatigue cracking of the aluminium pump body.

Roger
Click to expand...
The DS 7 cylinder pumps were subject to a construction change IIRC. The alloy pump body does get internal cracks and the replacement was a steel jobbie ... or am I confusing this with accumulator bodies ( or BOTH ).
 
fritzelhund said:
The DS 7 cylinder pumps were subject to a construction change IIRC. The alloy pump body does get internal cracks and the replacement was a steel jobbie ... or am I confusing this with accumulator bodies ( or BOTH ).
Click to expand...

The pressure regulator body changed from aluminium to steel in the mid 1960s. Aluminium regulator bodies did split. The 7-cylinder pump bodies from the factory were always aluminium. Modern-day replacements can be had in steel, which has superior resistance to cracking. Accumulator bodies were always steel, but changed from rebuildable two-piece to welded and disposable in the early or mid 1970s (though I suspect you meant regulator rather than accumulator; I say this for completeness and for any newbies reading).

Roger
 
Okay, so my DS refuses to rise at all now, so a bit of a catastrophic
I’ve checked the accumulator bleed screw and it’s not loose.
The pump appears to cycle every 30 seconds or so, but doesn’t result in the car raising.
I played with the manual height lever…sill nothing
I thought I heard a “clack” coming from left hand side of the car when I moved the manual height level from full low to full high, so maybe an inspection of corrector behind LH guard is in order.
Quite the pickle !
I’m away until Thursday so I will have further investigation then.
 
If you haven't got the big red warning light on the dashboard, then the assumption would be that the car is building up pressure. From your latest post, it does begin to point to the height corrector and/ or it's linkage. A the very least, you need to investigate it even if it's to rule it out
 
Budge said:
If you haven't got the big red warning light on the dashboard, then the assumption would be that the car is building up pressure. From your latest post, it does begin to point to the height corrector and/ or it's linkage. A the very least, you need to investigate it even if it's to rule it out
Click to expand...
I agree with budge. Looks like it’s come adry
 
Sounds like you are getting some pressure and you say the regulator is cutting in and out?.
Obvious of course, but always worth making sure the belts are tensioned properly and are actually driving the pump...
 
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