# 1959 Dexta not lifting weight



## NeilP (May 16, 2017)

Finaly put the wings and electrics back on my grandfathers 1959 Dexta the other day, ..have been slowly working on it for the last 17 years. It went in to storage in 1994 or therabouts, due gearbox failure.

Fixed up the gearbox and have done bits of body work and sorted out all electrics slowly, since about 2004.

But she wont lift any weight.

Lift arms go fully to the top, and drop just fine.
Trailer hitch lifts just fine and can tip a trailer on the Aux Service valve.

But put a transport box on the back, and with a light load of 20 or small garden paving slabs, it will not lift.

If I give it some help, with the forklift lifting the box, then it will hold it in the air with the engine stopped. 

It drops a little, 5-6 inches in about 30 minutes, so that seems to show that the piston rings and lift cylinder bore are servicable. 
Also seems to show (to my mind ) that the check valve and the lift cylinder safety valve are also passable.


This tractor has the most basic ASC control, no speed control, just push in for three point linkage and out for aux services. 

So where could the lifting problem be? where should I look first... 

I do have a 3000psi pressure gauge on its way to me, so will be checkgin pump output pressure this weekend, once the gauge is piped up.

rear axle oil is clean, not milky at all.

Any hints on where to start? Guess it will need to be a lift cover off job..which will not be easy due the 4 main pins of the trailer hitch being seized in to place


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## sixbales (May 18, 2011)

Howdy NeilP,

Start by checking the pump pressure, as you are planning to do. Pressure should be 2000+ psi.


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## NeilP (May 16, 2017)

Well pressure at the Aux service valve is no where near 2000.

My old 3000 psi gauge was desd/frozen, so found a scabby old 1500 psi one in a box, covered all sorts of muck, cracked glass, no glycerine in it... and that read a brief pulse up to about 1200, settling to 600 at tickover with the quadrant fully up. 

New gauge arrived, so piped it up yesterday, and it confirms what the old gauge reads, 1400 or so, then rapidly dropping to about 650 on tickover, and up to about 1000 at full revs.

Do these pumps really get so tired as to be this bad ? I don'g believe they do. This tractor has been in our family all its life, and apart from very occassional trailer tipping, its aux service system never used. 

Has lifted weight very often on the 3 pt linkage, it will have done lots of work with a Vicon fertilizer distributor, lifting /carrying/spreading 600 kilo of fertilizer st a time. 


The Aux service selector does move in /out very easily, possibly too easily. Wonder if leaks inside there are allowing oil pressure loss back to the sump ?

I have a x2 spare pumps, x 2 Aux service valves, and x2 complete lift top covers, might just stsrt with a pump swsp and see whst happens.

The aux service selectors I have, one is the speed control type, totally seized up, and the other , no selector sticking out... looks like it has snapped off while pulled out, then been pushed back inside again, can see a shaft stub down in the hole.


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## RC Wells (Dec 26, 2008)

Do you have the service manual?

If so take a good look at the exploded view of the lift cover assembly, paying particular attention to the pressure and return pipes and the O rings. If they are in good shape, then pull the flow control valve and inspect the components and the spring on the flow control valve. Pressure build and drop can be that spring has failed, or the flow control valve linkage spring has failed and as soon as pressure builds enough to force the broken spring back it dumps the pressure. That is generally seen as a rise and sudden drop in pressure.

The selector valve itself only has seals on the outboard end (knob end) and on the inboard end and is easily inspected and consists of a machined rod that slides in or out to change the pressure output ports. If the inside O ring fails you end up with uniform low pressure.

My approach to the symptoms you describe would be to pull the lift cover assembly and then inspect every valve and spring along with the pressure and return pipes and O rings. Obviously the lift cylinder assembly should be inspected to verify the piston control linkage is sound and no broken springs are resulting in it being fooled into dumping back and releasing pressure.

As for the pump I would rule out the most common age and wear items in the control linkages and valves first, then do the pressure test. Pump failure generally do not result in an initial pressure rise followed by an immediate drop.


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## NeilP (May 16, 2017)

Hi yes, I do have the pdf manual and have been browsing its pages trying to see an easy place where this oil maybe leaking passed.

I at first did wonder about the cylinder safety valve blowing off, or the valve in the pump. I have not yet got around to inspecting the pump safety valve. I have three pumps, so I'll swap one of them over first.

Springs.... ummmm... the only springs are the big ones on the control lonkagrs... had not considered that, but yes, could cause weird results if they were damaged.

I'd have taken the top cover off before I put the wings and foot plates back on, I had wanted to strip down and replace worn pins etc on the 3pt linkage, but the 'big 4 ' pins on the trailer hitch are sll extremely seized in. I tried to remove them 15 years ago with freeing oil, brute force, levers, drifts etc, but they were not coming out. Don't have the oxy acetelyne torch for heat anymore  so gave up and decided to forget the top cover service and repaint...sunce 'the hydraulics were perfect!' or so I thought!


Have been looking at it all and it appears I'll be able to get top cover off along with all the trailer hitch linkage, then get the whole lot to a mates farm, where he still has oxy torch.


I have just dragged an old rotten 3.5 ton trailer in to the shed, and started stripping that to painf and fit new boards, so this hydraulic job is back on the back burner . I will order the complete top box o ring kits and a few spare ware parts so I am ready to go.


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## NeilP (May 16, 2017)

i have bought a copy of the hydraulic repair video from the site below. 

One of his first few comments mentions my exact problem of lift arms not lifting weight... generic tired /s 'O' rings 

The video also gives details of setting up the draft and position linkage settings, WITHOUT the official service tools.

Draft (Qualitrol) selected , lift arms ½ inch up measured at the yoke eye, quadrant ½ inch off the top stop
0.396 inch between face of lift cylinder and land on control valve
Adjusted at the control valve turn buckle 


Position adjustment:
Lift arms in same ½ inch up,
Quadrant lever all the way to bottom

0.449 inch between face of lift cylinder and land on control valve, but adjusted on sprung adjusting nut /shaft on linkage.
Pin sticking out liable to snap, so hold the flat plate 'nut' with spanner

So I am now not worried about the top cover settings.... it is just getting these damned trailer hitch linkage pins removed ☹


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## NeilP (May 16, 2017)

These are the buggers that won't shift

Will have to get the trumpet houding studs out in order to lift the whole linkage system off in one.... grrrrrr


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