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Servo pump for hydraulic winch


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Hello!

Been reading this forum with great interest for a while.

I live in Denmark, and own a couple of different Land-Rovers. My main vehicle is a HiCap 200tdi.

I am considering changing my winch (which is a Warn 8000) to a hydraulic winch. The hydraulic winch would either be a homebuilt project (have both hydraulic motor and the control valves, - just need to sort out the gearing) or a milemarker (read a lot of really good reviews of these winches)

Now, I know that people will say that hydraulics is slow (Unless you go to extremes in your setup), but line speed is of almost complete irrelevance for my use. I do not compete, but use my Landrovers for what they were built for! When I get stuck it is mostly in really muddy terrain, normally with a heavy load and probably with a heavy trailer behind...

Therefore the slow longevity and security of a hydraulic winch would be just fine.

Main problem is: I need to find some suitable hydraulic pump for the setup. Everybody seems to be talking about the ZF74 pump; but if I were to buy such a pump from new in Denmark it would be ridiculously expensive. Therefore I would like to find one from a scrapyard or similar. Does anyone know which cars the ZF74 pump has been used in? (The ZF74 is a normal servo steering pump, and is manufactured primarly for that use). Some say BMW and Mercedes, but only certain models. Does anyone know exactly?

The milemarker states max flow at 13 liters per minute and max pressure at 120 bar (1740 psi), but the Saginaw series 7 pump (fitted on the Hummers equipped with milemarker) has a max pressure of just 100 bar (1450 psi). Does anyone know of another servo pump with similar characteristic? From which car?

Hoping for some answers!

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Fitted to some BMWs and VWs, if you get stuck for one let me know and I will track one down for you, Buy one from England and have it posted over?

Many thanks for the reply!

I suppose the best move then would be to go to the scrapyard and start looking at the differnet BMW, Mercedes and VW...

I know - from pictures on the internet - the generally look of a ZF74; but is there any identification numbers (or similar) stamped on the casing of the pump?

Btw... Thorougly impressed by your Ladoga effort. I suppose you have one of Milemarkers chain-driven "Competetion" setups?

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Thanks Kim, Ladoga is a team effort - Im just the monkey that moves the wheel and pulls the levers, this year was a test and train session but next year though we go out to race :) , Im afraid my winch is one of the comp setups with a chain but the ZF is good, reliable setup.

I will have a nose for any I/D marks tonight on the ZF pump (I use one to power my steering) but I know a brand new one is £130+vat (17.5% in the UK) from Alfred Murray if that helps at all

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Again thanks for the reply!

It could probably be a viable option to have one sent form Alfred Murray or similar. Will have a go at locating one from the scrapyard first.

Will post a couple of pictures and description when I finally get it sorted out!

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  • 1 month later...

Kim,

Hell…… where do I start this post……… :)

1) The MM supplied to the UK market (and maybe EU market) has the different Hydraulic motor than that which is supplied to the USA market.

Unless something has changed very recently (I don’t think so) the hydraulic motors supplier to MM are Whites Hydraulics Inc, which are cheap but reliable motors. The US version usually has the 17.9 Cu/in which is the Whites RS300. The UK market is supplied with the Whites RS200(12.5Cu/in) ……….. the biggest differences are in flow and Maximum pressure. I guess this was done due to the difference in steering pump arrangements between LR and US trucks…….. UK- Low flow and high pressure ……. USA – larger flow and lower pressure.

The specs of the motors can be found here http://www.whitehydraulics.com/pdf/catalog/UScat04_rs.pdf

2) MM have limited the max flow to 13L/Min (3.5 US Gal) due to the carp / cheap solenoid valve that they use :angry: . This is the Maximum flow rate through the valve and therefore the limiting factor of the system. This is easily rectified by replacing the valve with a larger solenoid valve or, like me, using a manual spool valve.

3) Using the ZF74 pump is for sure better than running from the steering box ……… but it will still be slow due the fact that very much more then 13L/Min is required by the motor.

As Jez rightly states, the ZF74 is a very common pump used on Cars & vans (Merc. VW, Audi).

I looked at many options and in the end decided that a PTO driven pump was the best solution for me ……. my limitation with continuously driven engine pumps was the max RPM of the pump would be very much exceeded by the max RPM of the V8 engine. Before any smart arse comes back with gearing comments …………. If you gear the pump down then the flow at low / reasonable engine RPM is poor.

You can see the calculations and detail of my installation here ….. http://forums.lr4x4.com/index.php?showtopic=6086&hl=

HTH

Ian

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  • 4 weeks later...

Hi,

probably too late, but -

In my hydraulic workshop press project I used Citroen BX hydraulic pump I got for about 15EUR.

I believe that Citroen knows car hydraulics quite well. I also like the simplicity. I have no exact numbers, but I am sure it is able to make more than 120 bar, and I believe it can deliver your required 13l/min, perhaps more.

You can also use a pump from XM, or Xantia. Newer cars have dual pump in one body - one pump for steering, another one for suspension and braking.

Martin

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Ian - I've got the standard valve block and motor, and a ZF74 on my Tdi. From your post it looks like the ZF74 is 13l/min, so it's well matched to the solenoid block but a poor pairing with the motor. If I upgrade the valve block, there's no immediate benefit, but would it get better with an electric-hydraulic PAS pump to decouple the flow from the engine speed? Or are we talking big-thick cables and many many amps? Has anyone tried dual pumps, using an electric unit to augment flow at low engine speeds, or is there a good reason why not?

Martin's dual pump arrangement sounds interesting for more flow...

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