6748 hydraulic problem

Hi all,
New here, so a quick intro: we bought a rather funky 6748 a few years ago. The owner before the one we bought from had removed the cab and modified the remains with some quality workmanship - reason being it was going to work in a low shed.
Anyway it's been very reliable for the limited but vital use it gets around our patch, maybe apart from the brakes (reputedly a Zetor issue?). And even the horn works.
It's kept in a good dry shed when not in use, so has a pampered life.
Anyway, yesterday after filling the trailer with a load of brush, I tipped it on the bonfire pile.... But then the trailer wouldn't go down.
Now in the field causing concern to spy satellites.
Spent rainy day in the shed trying all I could think (have a concrete mixer for testing the ram function) with no luck. Works on the up, makes noise but nothing happening on the down.
Any comments greatly appreciated.

Hi,

It sounds like a quick release coupling problem. Have you pulled the coupling out to test the ram? If so, put it in the other fitting on the back of the tractor. You'll need to support the trailer to release the pressure on the coupling to get it in. Be careful under the trailer - don't get squashed. !!

Mike

Quick couplers can screw you nuts. Sometimes they work sometimes they block. They cost sbout 7 euro so dont hesitate...

you can always get the trailer body down by carefully loosening the coupling off the end of the tipping pipe... crack it slowly to let the oil dribble into a container.

youll probably find you cant connect the line to a tractor to let it down because its pressurised by the weight of the trailer body.

thanks folks.
It's actually a dowty connector, same as my ancient David Brown - which lowered the trailer no problem when connected up!
Had the seat off and then the banjo to give myself an oil shampoo.
Filled with oil, pressed the lever to down and it all disappeared back inside. Put on a new dowty connector, works fine on the up, but no go on the down.
Just can't figure it - naturally trying everything before lifting the lid.