Newbie help please - Kubota finishing mower hitch/linkage height

[siwilson]

Hi,

Hoping someone can help please. I'm a new owner of a Kubota B7100HST (old type). Along with it I've got a Kubota finishing mower that I have been rebuilding (bearings etc.)

As the mower has only got two jockey wheels to the rear it's important that I get a constant height with the rear linkage.

My question is, with the engine not running, should the rear link stay at the height I set it? With the mower attached, it drops back to the ground after a couple of minutes. Or, should it only stay at the height I set with the engine running (I haven't tried this yet, so don't know what happens). Or is there something to 'lock off' to hydraulics somehow? There's nothing mentioned in the user manual.

If it should stay put, does anyone know which could be the likely faulty parts please? I'm guess some seals somewhere, but I really don't know where to start to look.

TIA

/Simon

[art]

When a cylinder settles down when the engine is off then you have a leak in the circuit. There is a valve that could stop it under the seat but that would only lock out the valve end, if it still settles after that then it would be the cylinder leaking.

[siwilson]

Thanks. When you say valve under the seat, do you mean the 'implement lowering speed adjuster', or do you mean the 'directonal control valve' (I think this diverts oil pressure to an external control valve?).

The hitch definitely drops over a short period, engine running or not. I guess I'll have to take a look at the cylinder, which I think is under the directional control valve.

Can anyone verify please? Any hints or tips on taking this apart?

TIA

/Simon

[ozzie tractor]

yeah the lowering speed adjuster. turn it fully slow. if it still creeps the seals in the piston have gone. take the roundish cover off the 3pl lift sover (under the seat facing forward (3pl all the way down first). then lift the 3pl arm up real fast, the lift piston will usually come flying out. replace to o ring on it.
i also had a feeling the old 71's had a chain from the top link to the lower lift arm which you could shorten to set the low position.

[ozzie tractor]

Originally Posted by ozzie tractor

then lift the 3pl arm up real fast, the lift piston will usually come flying out.

woops sorry all. technical stuff up here. it may prove more successful if you lift the arms all the way up and push the piston back as far as it goes, then drop the arms to pop the piston out. i sort of had it backwards before. my most humble apologies, so whats the fine for miss information on here, 6 lashes o the whip???