Super Dexta Hydraulic Adjustment - help please

[Showman]

My Dexta wouldn't lift the arm up beyond halfway so I renewed the pivot pin which had worn almost through. I reassembled everything without altering the adjustments. I then found that although it lifted a little more it still wasn't fully lifting the arms. I've now taken it apart again and have checked the clearance in the Qualitrol position and it is correct. When in the Position control set up the position control spring does not press up against the lever arm so that there is no functioning of the control plunger valve. There remains a gap between the push bolt and the arm and no amount of lengthening the bolt will allow the correct adjustment to be obtained. The position control spring is 42mm long with 10 coils inn it's relaxed state, does anyone know if that is correct? Could this be why the arms are not lifting all the way? Any advice welcome -thanks.

[Billy26F5]

Not totally sure what's wrong yet but here's the manual. http://www.smallholderservices.co.uk/si ... hydraulics
I'll get back to you soon if I can think of something, check to see if you find anything else worn in there.
Sandy

[Showman]

Thanks. I would renew the position control spring but no one Ive found sells them. Local dealer says not available anymore. Plenty of draft control springs though.

[Showman]

I've measured diameter of coils and ordered from a spring supplier a spring with 10 coils and 50mm long. Worth a try.

[Billy26F5]

The manual says the position control spring has 10.7 coils and is 1.96" long under 72 lbs and 1.52" under 152 lbs. I think your new spring will still not work but see if it improves anything or not.
Sandy

[Showman]

Yes thanks for that, worth a try. Spring not arrived yet. I'm replacing hydraulic arm piston seal, there was only one to remove. Parts supplier sent two, one seal and a back up seal but there isn't enough width in the slot on the piston to get both in. Do you know if there should be a back up seal fitted. Manual shows only one seal as far as I can see.
Thanks again for your help.

[Billy26F5]

Normally only one but some do have two.
Sandy

[Showman]

Cheers Sandy.
Regards
Garry

[Showman]

OK so all sorted now. Spring I ordered still not arrived so I cut down a draft control spring to 10.5 coils and fitted that. It now allows the position control lever bolt to touch the draft lever and so allows proper adjustment. Replaced piston seal and fitted new filter. Now all hydraulics working and I have full lift on the arms. ( I had replaced the cam dowel previously which had been almost worn through.)

[Billy26F5]

Glad you fixed that.
Sandy