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Hydraulic Winch Questions


samwilk200

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Been reading some of the hydraulic winch builds of members on this forum, seem very informative and interesting to read.

A couple of small questions I hope someone can answer.

1) Will a standard H12 milemarker cope with a pto pump at 25 LPM @ idle or so, or does the motor need to be changed?!

2) Is it basically the higher the LPM the faster the winch will go?! Is 25LPM a good figure to aim for? What line speed would this give?

3) Are the pto pumps fairly standard fitment. If i bought a housing for the transfer box, could i pretty much bolt any pump to it within reason?!

4) Is the dog clutch part of the pump, or the housing that bolts to transfer box?!

Just interested as my 8274 is causing me a few probs with electrics, and MM seem so reliable and powerful! And i can source hydraulic parts for reasonable money.

Cheers

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I think the motor is ok, its the standard UK supplied MM control valve that has a flow restriction.

More fluid = faster, yes, I'm not sure what max flow the standard motor will cope with though. May depend on whether it is the UK or US spec motor?

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I assume that your pump is 25 cc p/rev and you are using the 1000 rpm figure …….. but what is the max rpm of the pump ? 25Lpm is not a lot …… yes its better than the standard 13Lpm, but to really make the winch move you need about 40 – 60 Lpm.

The standard motor is fine …………. They are usually a Whites Hydraulics from the states ……… cheap and cheerful but it does the job.

To mount the pump on the Transferbox You will need a PTO adaptor and this has the dog clutch built in. These are made by superwinch (mega uber expensive) or Maxidrive (still expensive …. £350 ish) :rolleyes:

There are two types of fitment ………… SAE A (IIRC 2 bolt 9 spline :unsure: ) and SAE B (IIRC cant remember :D ). Maxi drive now do both (SAE B is a recent addition to their product range), but the SAE A type is more popular on the pump capacities that we use.

Ian

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I havnt got the pump yet, but was looking at your figures from your write up. 25l/min @ 1000, and 60l/min @2500rpm (if that was max rpm) would be about right for some decent speed i take it?!

surely you need a pump that will match the max rpm of the engine?! Or is it that you will VERY rarely use it over 2500rpm?

I'm guessing pto pump housings second hand are fairly rare?!!

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They're fairly rare but do crop up reasonably often, you're usually more likely to find one with a winch, either a 525 or H14. eBay is the place, and a PTO on its own will usually fetch just as much as if there's a winch & bumper & tank & pipes with it.

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5000's, 525's and H14's can all be shaft or hydro drive, they just stick a stubby driveshaft end onto the hydro motor that engages in the dog on the back of the winch.

Beware of what you're buying though, as 5000's are originally for Series vehicles so any PTO with those will likely not fit a defender unless someone's found a PTO separately and built the system up.

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I havnt got the pump yet, but was looking at your figures from your write up. 25l/min @ 1000, and 60l/min @2500rpm (if that was max rpm) would be about right for some decent speed i take it?!

surely you need a pump that will match the max rpm of the engine?! Or is it that you will VERY rarely use it over 2500rpm?

I'm guessing pto pump housings second hand are fairly rare?!!

The PTO pump does not need to match the engine revs ……….. the pto is driven directly from the gearbox (via the input shaft into the transferbox) so with hydraulic you will normally winch without drive assist (i.e. the transfer box in neutral). Yes, the 2500rpm is the max pump speed.

To see why drive assist does not really work with transmission coupled pumps, see my post here (there is a minor calculation error in there and nobody noticed it, but its not important)

http://forums.lr4x4.com/index.php?showtopic=10646

40 – 60 LPM is more than adequate. Remember that you will also require a large tank (mine is 33L)

Second hand PTO adaptors on their own are like finding rocking horse carp…….

Ian

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