Upgrading Dexta rear end

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malcolmg
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Upgrading Dexta rear end

Post by malcolmg »

I have a 1959 Dexta, and have just acquired the rear end -( back axle and transmission) from a later one.
I want to swap over the necessary bits to give my old Dexta, the diff lock, hand brake assembly, and upgraded hydraulics with draft control.
Just wondered if anyone can offer me any advice regarding swapping the bits over.
For example my old Dexta has had new inner and outer seals replaced on the half shafts. Will I be able to retain either of these half shafts when I add the diff lock.
Can I retain the LHS (Handbrake side) axle housing, obviously I will need to change to side where the diff lock pedal goes.
It has been mentioned to me that I may need to swap some some transmission bits as the new diff may have different gear ratio to what I currently have.
Will I be able to swap over the hydraulic bits without major problems.
I will probably take the opportunity to renew the pump components, as my existing one is a bit iffy and the new one unknown.
Appreciate any advice, thanks malcolmg

Brian
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Re: Upgrading Dexta rear end

Post by Brian »

You already have draft control on your Dexta and there were no changes other than minor ones on the lift itself.

You can use both your half shafts but the R/H housing will need changing to take the dif. lock pedal and fork. You will need to change the crown wheel and pinion, these are matched pairs and cannot be interchanged. You may find that the splines on the junction tube may not match the ones on the later pinion.

Sometimes it is better to swap the engine onto another gear box/rear axle assembly.

Dextas from July 1962 had a different ratio gear box.
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malcolmg
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Re: Upgrading Dexta rear end

Post by malcolmg »

Brian many thanks for the info.
I know my Dexta is '59, but have no info about the age of the 'rear end' I have acquired.
Re: hydraulics there are some external differences, and I have no idea if that would indicate any internal hyd differences.
Mine has a single raise/lower lever, attached to the valve block by a 4 bolt plate
The newer one has the linkage rod which is adjusted by a small knob. The linkage rod presses onto the raise/lower lever. This is what I had referred to draft control.
The raise/lower lever is also attached to the main valve block body by a 2 bolt plate, not 4 bolt.
It also looks as though the trailer tipping pipe takes off on the side of the block whereas mine would come off the top.
I would also like to have whatever is needed to give me two hyd take offs for a double acting ram.
As I will have the opportunity, do you suggest I automatically refurbish the hyd pump? Apart from lifting eg my plough, I have no way testing mine or of course the new possible donor one.
I will be replacing all hyd lift linkages, lift arm bushes, and lift arms.
All suggestions welcome!

Brian
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Re: Upgrading Dexta rear end

Post by Brian »

Image

OK, What you have is the earlier type lift with the old type Auxiliary Service Chest with a single port on top.

Image

This is the valve you have on the other lift, it is the later style ASC which includes a flow control to adjust the flow rate in the hydraulics to improve the correction rate when ploughing or using implements with Draft Control. The link to the main control lever is so that, when using a slowed down flow rate, when the main control lever is moved to the fully raise position, the flow control is automatically move to maximum flow. You will find a little wheel device attached to the main control lever which has to be moved outwardly to contact the flow control override linkage.

Image

The four bolt lever attachment is the earlier version, the two bolt one is the later one. Apart from the housing and the top cover there are no other changes internally in the lift, all the main linkage parts and ram cylinder parts are the same and will interchange. The hydraulic pump on the later tractor will have the improved cylinder relief valve.

Image

To be able to work DA rams you will need this, a Double Acting Ram Valve (DARV). They are very rare and expensive, the last one I saw up for sale went for £500.00. What might be an option would be to get a modern valve and mount it on the wing (say). Then take the oil flow from the ASC and return it to the filler cap. A lot of equipment like wood splitters come with their own DARV and will just plug straight into your trailer pipe, again with a return to the filler cap.
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malcolmg
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Re: Upgrading Dexta rear end

Post by malcolmg »

Brilliant, I had taken some pics this afternoon to send you, but you seem to have beaten me to it - exactly correct.
Points noted about the DARV - I was initially looking at a double acting cylinder for the top link, to enable me to positively tip my transport box, but a wood splitter might well be the next tool to follow.
Plenty for me to be getting on with thanks,
Final questions for the present:
I have not quite worked out how to disassemble the flow control valve that works the lever onto the main raise lower lever.
I will need to source a knob and no doubt any 'O' rings.
Would you happen to know if I can still get all the various hydraulic bits such as 'O' rings, gaskets, and pump refurb kit.
I will also need to get - the spring, with cover, and connector lever for the diff lock pedal, mine is severely corroded and the lever is snapped, (as is the connector lever from the flow control valve). Worst case will have to try and get then brazed up.
I have not as yet, checked with my normal supplier Agriline.
Greatly appreciate your help and experience,
Regards Malcolm

Brian
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Re: Upgrading Dexta rear end

Post by Brian »

You may have to find a flow control knob etc. on e-bay. I do not know of any aftermarket people that do them. "O" ring kits are available but some are of dubious Quality and incorrect size and thickness. Think I would try my Case/New Holland dealer, most of the "O" rings were the same on later tractors. If you need to go inside the lift, the unload valve "O" ring MUST be a CNH one as it is made of a special rubber compound. Normal rings will swell and cause the unload valve to stick.

Dif. lock links are out there, there are some people breaking Dextas ( :cry: :cry: :cry: ) on e-bay and Dextas after 1962 may have dif. lock. It will be the same link as a Super Dexta as they all had the same back end.
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malcolmg
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Re: Upgrading Dexta rear end

Post by malcolmg »

Many thanks, will proceed and see how things work out.
Hope I can get back to you if necessary,
Regards, Malcolm

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