HP pump: 6+2 or 5-piston?

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white exec
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HP pump: 6+2 or 5-piston?

Post by white exec »

Can anyone help with this one?

Parts appears to list (for my VIN) the "1905L" HPP as 6+2.
In this case, it wouldn't have an FDV (flow divider valve), as the 6+2 pumps provide separate outputs for susp/brakes and steering.

The pump on the car looks like a 5-piston (and also might be a used replacement, being 'old green')...
DSCF3813r.jpg
Is that pump a 5-piston, and if so, where is the FDV mounted?

Or did any of the 6+2 HPPs look like the 5p, instead of this...
DSCF3815r.jpg
Were all 6+2's on the BX driven off the Aux (alternator) belt, or did they also get driven from the diesel camshaft?

Tad confused, especially by the Parts listing, and what's actually on the car.
Chris

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Re: HP pump: 6+2 or 5-piston?

Post by rutter123 »

Flow valve is mounted on front of gearbox with the pressure regulator. I thought standard diesel hp pumps had 6 pistons and the 6x2 was from a Xantia??
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Re: HP pump: 6+2 or 5-piston?

Post by xantia_v6 »

6+2 pumps go with anti-sink suspension, so should not be found on a BX.

[Edit] maybe Citroen did fit the 6+2 pump later to save the cost of the FDV, but it would make the suspension rather slow to rise.

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white exec
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x 48

Re: HP pump: 6+2 or 5-piston?

Post by white exec »

From a quick bit of browsing, looks as if XUD9 and XUD9 TD got the 6+2 July 1994-ish, so presumably for Xantia.
The pix I found showed one (4007 F8) with a ribbed pulley, so must be for the Aux belt.

Intrigued with Parts listing a 6+2 for my BX VIN...
.
Parts 6+2.JPG
...although it shows a 5-piston in the diagram, and 4007 T5 is also listed a Xantia pump (for anti-sink) but with a ribbed (Aux drive) pulley!

Perhaps just a parts anomaly.
So BX never got 6+2 then?
Chris

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Re: HP pump: 6+2 or 5-piston?

Post by rutter123 »

I've never seen one on a bx diesel and I've had several from F/88 to K/93 and they have all had the same single port pump driven via the cam
90 BX Tzd turbo 294k SORN undergoing major surgery
90 BX Tzd turbo estate 46k awaiting surgery
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white exec
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Posts: 426
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
2003 Toyota RAV4 2.0 D4D
x 48

Re: HP pump: 6+2 or 5-piston?

Post by white exec »

Makes sense - early XM didn't get them either. Think first appeared on later XM and Xantia.
Parts! :roll:
Chris