Lifton LS850 wont drive uphill

[CaptLimey]

Stock
"It appears to these tired old eyes that on the front motors you have forward port, reverse port, hand brake, and case return. Do you know which axle it is binding on?
Wonder if the pump is bleeding pressure on the hand brake circuit ??

Just another thought............they are the same as tracking hubs...so you have you have two feeds forward and reverse ........the case drain is the return .........and the third port on the front hub for the hand brake.........."

Hi Stock

The motors with the fwd/rev/handbrake/drain ports are the rear ones. The front ones have three ports but only two in use, one for fwd HP and the other the 'serial link' to the rear motors. Like you, I at first assumed that the front didn't have reverse drive but my recent experimant dispelled that theory and they must receive their reverse HP flow via the serial links from the rear motors. I still don't get how it by-passes the NR valves and the return link to the pump?
The 'binding' happens on the front RIGHT wheel - BUT - when I swapped the front serial lines over it hapenned on the LEFT front wheel. So the problem it flow/pressure somewhere in the the serial line circuit.

Thanks guys for all your input. I'll press on nibbling away at the pressure tests and logical steps we've established and keep you updated.

Rgds CL

[CaptLimey]

OOOPS! Operator error!!!

Having taken the advice from y'all and the Wacker Neuson expert, I decided to go back to basics and start again from the beginning, with a full pressure test at the forward, reverse and pilot pressure ports.

I was astounded when I found that forward and reverse pressures were both only around 200 bar!!!

It would appear that I mis-read the first pressure test I did with the new gauges. The guages are partly filled with glycerine which can distort the image and like Stock, I'm a little 'visually challenged'. The gauges are calibrated in both psi, in bold black and in bar, in less distinctive red, all on a white background. My guess is that I read 3000 psi for 300 bar.
Sorry guys.

Whatever? - all your useful input has helped me achieve an understanding of how the machine works and I'm now better equipped to deal with any future problems thanks to you.

We now have to find a company that can refurbish the pump to where it can provide the design working pressure of 360 bar. I've done some preliminary research here in France but the prices quoted for 'worst case scenario' are frightening. Does anyone know a UK firm who specialise in reconditioning hydraulic pumps, in particular the Bosch Rexroth A10VG?

BTW I used the machine today and it works OK even on it's low pressure but it did have a problem getting a loaded skip up a one in seven gradient - only just made it, not surprisingly. Best I go find a place on a more even keel!

Rgds CL

[Muz]

I was astounded when I found that forward and reverse pressures were both only around 200 bar!!!

It would appear that I mis-read the first pressure test I did with the new gauges. The guages are partly filled with glycerine which can distort the image and like Stock, I'm a little 'visually challenged'. The gauges are calibrated in both psi, in bold black and in bar, in less distinctive red, all on a white background. My guess is that I read 3000 psi for 300 bar.
Sorry guys.

Right ... well these things happen ...

Does anyone know a UK firm who specialise in reconditioning hydraulic pumps, in particular the Bosch Rexroth A10VG?

Theres a specialist guy up here outside Glasgow who I've used ... who would do it .. he's not expensive, but these guys are so in demand it could take months to turn your pump around. heres another company that specialise in this stuff cos you would be faster getting a new 'un

http://www.whitehouseproductsltd.com/default.aspx


They should get it for you and their prices are good ........ofcourse all assuming yours cannot be adjusted and its definately worn ?

[jackpreacher]

Sorry to be sceptical, but going on the previous symptoms of a labouring engine, well....at 200Bar the engine wouldn't labour...or would it?

Over to someone who know!!

[CaptLimey]

Sorry to be sceptical, but going on the previous symptoms of a labouring engine, well....at 200Bar the engine wouldn't labour...or would it?

Over to someone who know!!

Good point Jack. The labouring was more noticeable when trying to mount an incline and the front right wheel would lock with the others slipping. Under test conditions more recently, when chained to a tree, pedal on metal and no wheels slipping, the engine would rev, clearly under load but not to the point of stalling - strange. It might be that my tinkering with the pilot pressure adjustment has made a difference, it's certainly improved the power take up which is now a lot smoother.

Muz could you let me have the contact details of the guys near Glasgow, I'll be there visiting family in a few weeks and maybe a prior chat twith them might be useful. Thanks for the link to White House I'll give them a call but I suspect a new pump might cost more than the machine is worth?

Thanks again guys for all your input. Rgds CL

[jackpreacher]

Under test conditions more recently, when chained to a tree, pedal on metal and no wheels slipping, the engine would rev, clearly under load but not to the point of stalling - strange.

That's good then Hopefully when the pump is putting out 310 Bar the engine still revs, albeit under heavy load. ...........have you changed the fuel filters recently?

[Muz]

Muz could you let me have the contact details of the guys near Glasgow, I'll be there visiting family in a few weeks and maybe a prior chat twith them might be useful. Thanks for the link to White House I'll give them a call but I suspect a new pump might cost more than the machine is worth?

You might be surprised .. it wont be cheap though

The guys name is John Bell .. and the shop is called Servetech hydraulics 01698 826960. He just operates out of a tiny wee unit just out side Hamilton. At first he comes across a bit curmudgeonly, as a lot of these boffins do, but he's a decent old guy once you get to know him .. but I tell you this .. what he doesn't know about hydraulics aint worth knowing, that guy eats and sleeps ball bearings pump members and timing gears ... he'd probably give you a few pointers about the dumper too if only you could remember all the stuff he will tell you

Another point I thought I'd mention, if you check my post about my pump pressure test, even with a 310 Bar pump, I was able to slowly raise the revs on mine whilst the dumper was secured, and get the engine to maximum revs, the dumper was empty, It had good grip, but none of the wheels would spin .. so its not an indication of a lack of power just cos they dont turn.. if you see what I mean ? But I dont think theres any doubt , if youre sure 200 Bar is all it will give, it isnt enough.

Be sure though that you had full revs AND the wheels were LOCKED, when you read the pressure ... IMHO If any of the wheels turned, its not given you maximum pressure,

[CaptLimey]

That's good then Hopefully when the pump is putting out 310 Bar the engine still revs, albeit under heavy load. ...........have you changed the fuel filters recently?

Hi Jack, I don't know about engine maintenance i.e. filters etc., Stevey did all that stuff before he brought it over to France but, knowing him, I'd suspect yes. I'll check with him but if not we'll do all that when we get the pump fixed. I have to say the engine sounds sweet, no probs starting and smokeless except, like all diesels, when working very hard.
Rgds CL

[CaptLimey]

You might be surprised .. it wont be cheap though

The guys name is John Bell .. and the shop is called Servetech hydraulics 01698 826960. He just operates out of a tiny wee unit just out side Hamilton. At first he comes across a bit curmudgeonly, as a lot of these boffins do, but he's a decent old guy once you get to know him .. but I tell you this .. what he doesn't know about hydraulics aint worth knowing, that guy eats and sleeps ball bearings pump members and timing gears ... he'd probably give you a few pointers about the dumper too if only you could remember all the stuff he will tell you

Another point I thought I'd mention, if you check my post about my pump pressure test, even with a 310 Bar pump, I was able to slowly raise the revs on mine whilst the dumper was secured, and get the engine to maximum revs, the dumper was empty, It had good grip, but none of the wheels would spin .. so its not an indication of a lack of power just cos they dont turn.. if you see what I mean ? But I dont think theres any doubt , if youre sure 200 Bar is all it will give, it isnt enough.

Be sure though that you had full revs AND the wheels were LOCKED, when you read the pressure ... IMHO If any of the wheels turned, its not given you maximum pressure,

Muz again my thanks for the info.

Re a new unit, my preliminary and very cursory enquiries suggest that a new unit will be far inxcess of 1500 quid, whereas a refurbishment might be max that or less? I don't know for sure as all the folks I've contacted say, not unreasonably, send it and we'll give you an estimate. So we're between a rock and a hard place but still researching. I'll give John Bell a call and see what he says.

Re raising the engine revs under test conditions; my test yesterday was done with the dumper chained to a tree on a good tarmac surface and the wheels definately did not turn. On that test the peak pump HP was, forward 210 bar and reverse 195 bar, way below the design 360.
I sense that there is a governor limiting the maximum revs as (without a rev counter) I estimate that it does something around the engine data spec maximum of 2200 rpm. Apart from putting the throttle pedal to the floor how else can I raise the revs?

I'll do another test to confirm the data soon but at the moment I'm using it and it's working satisfactorily providing I don't load it too heavily and attempt any serious hill climbing.

Rgds CL

[Muz]

I sense that there is a governor limiting the maximum revs as (without a rev counter) I estimate that it does something around the engine data spec maximum of 2200 rpm.

Dont think so Capn ? Its a simple mechanical set up .. 10 mil bolt against the guvernor stop is about as technical as it gets


As to a refurb.. If a new un is 1500 ... john will fix it for less than half of that .. he's a canny old bird though.. and knows that peeps will buy new if he cant fix it for sensible money .. that said .. he knows when to walk away too .. if its not dooable .. which is why I like the bloke .. he will tell you that where others would just take your money ... hell .. I dont really know this guy .. but I've come across enough people in my life to know he is a helper as opposed to a rip off merchant

I think his son works in the business too .. dont know what he's like .. just make sure you deal with the auld yin

[CaptLimey]

Dont think so Capn ? Its a simple mechanical set up .. 10 mil bolt against the guvernor stop is about as technical as it gets


As to a refurb.. If a new un is 1500 ... john will fix it for less than half of that .. he's a canny old bird though.. and knows that peeps will buy new if he cant fix it for sensible money .. that said .. he knows when to walk away too .. if its not dooable .. which is why I like the bloke .. he will tell you that where others would just take your money ... hell .. I dont really know this guy .. but I've come across enough people in my life to know he is a helper as opposed to a rip off merchant

I think his son works in the business too .. dont know what he's like .. just make sure you deal with the auld yin

Hi Muz and thanks for the contact to Serv Tech, they remembered you when I said who'd referred me.

I spoke with David John's son as John unfortunately had a car accident on way to work yesterday! He is not seriously injured, just a bang on the head and he expected to be back in the shop today. David was very helpful and encouraging giving a most practical and promising response to my questions. Bottom line is he doesn't think the pump should be too expensive to repair as it is still working and putting out 200+ bar. Whatever the damage he says it will not be more than a grand (ouch!) and could be considerably less. But the machine is good in all other respects (see pic) and worth repairing if the cost is reasonable. I'm going to get the pump out and ship it to Glasgow. Any tips on pump removal anyone?

Rgds CL

[Muz]

I spoke with David John's son as John unfortunately had a car accident on way to work yesterday! He is not seriously injured, just a bang on the head and he expected to be back in the shop today. David was very helpful and encouraging giving a most practical and promising response to my questions. Bottom line is he doesn't think the pump should be too expensive to repair as it is still working and putting out 200+ bar. Whatever the damage he says it will not be more than a grand (ouch!) and could be considerably less. But the machine is good in all other respects (see pic) and worth repairing if the cost is reasonable. I'm going to get the pump out and ship it to Glasgow. Any tips on pump removal anyone?

Cripes .. I hope he gets over that ok .. I suspect the guys will check it for pressure first to confirm your findings .. hopefully they just quote high to cover them selves, if its dooable for less .. knowing him, he will only charge you what it actually costs .

Theres nothing fancy about removal .. just get the spanners out, mark your hoses, even though it seems obvious for left/rights .. its the upper lower positions that can sometimes cause bother... even if the hoses seem shaped or formed, Ive still got them fooked up... probably just me though

It should just ease off the bell housing with a shaft most likely on the pump side .. it might come off with a rubber shock bush, but thats about it IMO

[CaptLimey]

Cripes .. I hope he gets over that ok .. I suspect the guys will check it for pressure first to confirm your findings .. hopefully they just quote high to cover them selves, if its dooable for less .. knowing him, he will only charge you what it actually costs .

Theres nothing fancy about removal .. just get the spanners out, mark your hoses, even though it seems obvious for left/rights .. its the upper lower positions that can sometimes cause bother... even if the hoses seem shaped or formed, Ive still got them fooked up... probably just me though

It should just ease off the bell housing with a shaft most likely on the pump side .. it might come off with a rubber shock bush, but thats about it IMO

Thanks Muz for the input. I'll update with pics & progress when I make some.
Rgds CL

[CaptLimey]

Well - it's off!

I finally removed the hydraulic pump from the Lifton today, here it is on the bench.

Not a too difficult job and I even managed to survive with all knuckles intact! I took the precaution of cleaning and numbering each hose connection in accordance with the manual's diagram of each side of the pump and then photographing them in place. Hopefully that will help in re-assembling the unit once it's refurbished. Now I have to box it for shipping to Glasgow, it's pretty heavy for a little machine - 37kg!

Thanks for all your help and advice.

Rgds CL

[jackpreacher]

Well Cap'tn, look at the bright side - there's nowt to faze you now...you and Stevey know that machine backwards. Best of luck - I hope it's a much cheaper job than you're expecting