Lifton dumper transmission

[Pete's]

Can anyone tell me what make variable displacement pump was fitted in the old 1990's Liften 3/4 dumper the one with a foot pedal to control the speed & a spool block to reverse direction operated by a lever by the spool valve for tipping & lifting the skip.
My problem is I have drive as soon as I engage forward or reverse on the spool block without touching the speed pedal, the small plunger is free in the control unit held on to the pump unit by 6 of 10-24 unc allen bolts, but the large piston under the aluminium cover held on by 4 of 10-24 unc allen bolts does not move, has any one had this problem on there dumper, it has been sat for about 5 years since last started?
Or does anyone have a workshop manual they could sell me or advise where I could get one?
Many thanks, Pete.

 

[Mick-the-fitter]

I might be corrected but I thought they were sundstrand!

 

[Pete's]

I might be corrected but I thought they were sundstrand!

Thank you, will look & try & find a match on the internet, never heard of them before I googled & see they are Danfoss related.

 

[Mick-the-fitter]

Thank you, will look & try & find a match on the internet, never heard of them before I googled & see they are Danfoss related.

The later ones were Danfoss but because the early ones were mechanically operated they weren’t Danfoss!

 

[Pete's]

All sorted thanks, hit the aluminium piston with a wood drift, felt it move about 1/8" it didn't want to move any more, so I tried it & working fine now, hope this may help any others with this problem, all the best, Pete.