Dexta Hydraulic Lift Piston - Help!

[DextaRab]

I am working on my Dexta Lift Cover
Decided to change the seal on the piston (gland type seal) and was surprised to find a 'O' ring under the gland type seal, I seem to have the very first type piston (part number 957E 530)
Is it still possible to get the seal kit for this piston? OR do i need to buy a replacement piston?
If i buy a replacement piston with the 'O' ring and backup ring, can you tell me which way they are fitted to the new piston ie. which ring would be towards the top of the piston?
Any help would be very much appreciated!
Thanks,
Robert.

[DextaRab]

Forgot to mention: The gland is marked RSD 65 73 8 - I'm assuming its 65 ID X 73 OD X 8mm Thick

[kiwiland dexta]

All I can help with is a parts diagram, this was from the first 1957 version
Regards
Derek

[mathias1]

Parts diagram doesnt show an extra o-ring. Maybe it was fitted by someone later on. The seal should do the trick.. put it with the lip on the oil pressure side and check if the surface of the cilinder is still alright

[DextaRab]

The gland with the 'o' ring was definitely fitted by someone as its not original - I now have a new gland seal with the lip but its 7mm thick and doesn't fill the groove in the piston, the groove is 8mm wide and the old seal was a snug fit - Does it matter that the new seal i have is not as thick? Anybody know or worked on piston seals previously?
My piston must be the very early one Part no. 957e530
Thanks.

[kiwiland dexta]

Found the receipt for the one I got as a replacement, it was from the local green tractor dealer, part no. was OH PUI300250/2 described as DA seal 3" x 2 1/2" x 1/4"

[DextaRab]

Thanks kiwiland dexta, I see the seal you got was 1/4" wide which is 6.35mm - My piston groove is 8mm (well 7.9mm)
Can you remember if your seal filled the groove or was there a gap after you fitted the seal?
I know that my old seal filled the groove as it was 8mm wide - Maybe your piston was different to mine?
Would like to know anyones thoughts on this.
Cheers.