Brash grab

[Peter]

The all in one type fittings with the big lever should be better for this, anyone used one?

[openspaceman]

The all in one type fittings with the big lever should be better for this, anyone used one?

 

Link?

 

I've only used the Dowty, quick fits with a teat like protrusion and the flat faced drip proof ones, these latter are the hardest to fit IMO.

[dent]

Yes that de pressurises the tractor hydraulics ( but JCB controls don't do this as they are electro hydraulic controls so engine has to be off and time allowed for oil to drain) but the oil is locked in both sides of the grab ram so if someone has disconnected it with the engine running or if the oil trapped has pressurised by change in temperature it has to be bled off a tiny bit.

The drip free couplings are worse at this, in the good old days screw on Dwoty couplings over came a certain amount of pressure.

 

Every jcb i have ever driven has had the ability to dump the pressure if they are electro hydraulic turn the ignition on and move the controls you will hear clicking from the pannel by your right foot as solenoids move or behind you if in a tm

Pressure will be dunped this is the by the book way of doing it on all jcbs up until a couple of years ago then they fitted a depresurise button under the steps and on the latest ones moved it to under your elbow

[dent]

Link?

 

I've only used the Dowty, quick fits with a teat like protrusion and the flat faced drip proof ones, these latter are the hardest to fit IMO.

 

Screw Connect Couplings - Holmbury UK

 

Not cheap

[openspaceman]

Every jcb i have ever driven has had the ability to dump the pressure if they are electro hydraulic turn the ignition on and move the controls you will hear clicking from the pannel by your right foot as solenoids move or behind you if in a tm

Pressure will be dunped this is the by the book way of doing it on all jcbs up until a couple of years ago then they fitted a depresurise button under the steps and on the latest ones moved it to under your elbow

 

I didn't know that, Once the engine was off none of the controls did anything and the check valves kept all the rams locked so I'd just wait a minute. As I said the problem was hydraulic lock on the allbutt grab more than the machine.

[dent]

I didn't know that, Once the engine was off none of the controls did anything and the check valves kept all the rams locked so I'd just wait a minute. As I said the problem was hydraulic lock on the allbutt grab more than the machine.

 

Yeah the check valves lock out the main system but the type of valve used on the jcbs aux line is such that it can be depresurised with the ignition on would make for a very tiring day on the farm waiting to change implements

It is recomended this procedure is followed before attatching or removing an implement it will also help sometimes to turn the little red handle if you have hydraulic pins as this can become sticky when warn

[dent]

These are albutt options

[monkeybusiness]

No I tried that. Only way round I found was to switch JCB off and leave for a few minutes and then bleed a bit of oil out of the grab connector, there was too much pressure to push the centre of the quick connector in.

 

I did wonder about jacking the grab up and down but it was easier to lose a bit of oil.

 

Do it on the grab fittings too. Make sure it is closed before removing (so gravity isn't adding to the issue) and turn the machine off, then ignition on and operate open/close to dump any pressure in the grab. Remove. On refitting, dump pressure out of the grab service lines as already stated and couple up. If it won't go together jam the pointy hydraulic undoerer device into the fittings on the grab to release any temperature induced pressure issues. Plug in and go grabbing!

[openspaceman]

Do it on the grab fittings too. Make sure it is closed before removing (so gravity isn't adding to the issue) and turn the machine off, then ignition on and operate open/close to dump any pressure in the grab. Remove. On refitting, dump pressure out of the grab service lines as already stated and couple up. If it won't go together jam the pointy hydraulic undoerer device into the fittings on the grab to release any temperature induced pressure issues. Plug in and go grabbing!

 

Thanks for the explanation but I doubt I will be doing it again, also it will be affected by whether the person removing the grab unloads the hydraulics as you suggest.

[monkeybusiness]

Thanks for the explanation but I doubt I will be doing it again, also it will be affected by whether the person removing the grab unloads the hydraulics as you suggest.

 

I think that's most likely your issue. I've got a timber grab that is a pain to drop off and I thought was best left attached to a log. Getting it back on the machine and detached from the log is almost impossible because of the issues you're having.