Hydraulic top cover swap

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Bounce
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Hydraulic top cover swap

Post by Bounce »

Hi, this is my first post on this forum. I’m a month into restoring a 1963(?) Dexta that was in a pretty sorry state and I could do with some/lots of advice!

The hydraulic quadrant assembly, diverter valve, lift arms and the spring/plunger assembly for the draft control are corroded beyond repair so I’ve been looking for a complete replacement hydraulic top cover. As it’s a later Dexta the top cover has the quadrant assembly that is held on with the 2 bolts and has the flow control valve as well, but I cannot track one down. A few breakers claim to have them but when I ask for a picture to see the condition of the cover they never get back to me.

There seems to be plenty of the older type with the 4 bolts holding the quadrant and the more straightforward diverter valve for the aux service, would one of these top covers be a straight swap for the cover on my Dexta? If it is a straight swap, and I was able to get my diverter/flow control valve to a workable condition would this then fit back onto the older type hydraulic top cover?

Thanks in advance.

Billy26F5
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Re: Hydraulic top cover swap

Post by Billy26F5 »

I'm afraid you will need to be very careful, as the early top cover might well have some tiny difference in performance that doesn't work well on the later tractor. I think it will fit, but you'll loose the flow control. I recommend you try to find the right cover so you can work better once your Dexta is running.
Sandy
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Re: Hydraulic top cover swap

Post by Bounce »

Thanks for your reply.

I would like to get the correct top cover but that’s proving to be a bit tricky, and if I don’t find one soon I’m going to be at a standstill. My thoughts were to put the old style top cover on so I can get the tractor useable again (if it will fit & work), it won’t be doing much more than a bit of trailer work and maybe the a bit of topping, no ploughing for now at least! Then once I’ve got the tractor going again I can focus on finding a new cover or at least the parts I need to rebuild my top cover/flow valve.

Would the older style cover be up to the job of lifting the odd implement and tipping a trailer? Just looking at options to get the Dexta up and running again.

Donnie

Billy26F5
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Re: Hydraulic top cover swap

Post by Billy26F5 »

It should be fine for that.
Sandy
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Re: Hydraulic top cover swap

Post by Bounce »

Excellent thanks.

If anyone knows of a later hydraulic top cover with the 2 bolt quadrant assembly and flow control, please pass the details my way!

Old Hywel
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Re: Hydraulic top cover swap

Post by Old Hywel »

How about the 3000? Certainly similar, perhaps you could find one to compare.

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Re: Hydraulic top cover swap

Post by Bounce »

Seems to be a few of the 3000 tops about, might be worth a shot.

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Re: Hydraulic top cover swap

Post by Bounce »

After not being near the tractor all summer, I finally got back to it and I have managed to source all the parts I needed to repair my hydraulic cover/controls. The new bits have all been installed exactly as it was dismantled, but I now have no hydraulics.

If I remove the diverter valve and turn over the engine there is plenty oil being pumped to the cover, but no movement from the linkage, and no oil from the aux service when the tractor is running, no matter what position the controls are in. During the rebuild of the cover, the lift cylinder, control valve and check valve all remained untouched. Any suggestions?

Billy26F5
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Re: Hydraulic top cover swap

Post by Billy26F5 »

Looks like the unloading valve is siezed (Item 11 in the exploded diagram, pdf page 4 and 5 in the manual).
Here's the manual: http://www.smallholderservices.co.uk/si ... hydraulics
Sandy
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Re: Hydraulic top cover swap

Post by Bounce »

Thanks for that Sandy.

I’ll get a look at that tomorrow.

Bounce
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Re: Hydraulic top cover swap

Post by Bounce »

Sure enough the unload valve had seized. Once I got it out, cleaned up and replaced the o ring, hydraulics are now working perfectly. Thanks once again Sandy for the invaluable advice.

Now time to start painting….

Billy26F5
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Re: Hydraulic top cover swap

Post by Billy26F5 »

Glad to see you got it sorted easily. A siezed unloading valve is very common, the o-ring tends to stick, giving the symptoms you had.
Sandy
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