How do I release the pressure in the air brakes from the tractor to the trailer?

[Hazza6930]

Massey Ferguson 6715s
14 tonne bailey trailer
Having trouble getting the air lines of the tractor !

thanks

 

[AJR75]

Daft suggestion maybe but is the collar of the coupling lined up with the little pin?

 

[Farmerdunk]

Let the air out of the tank, releases the pressure.

 

[Green&Steam]

Try rotating the collars on the couplings they will only move to release in one place.
You should be able to see notch on collar that line up with a peg

red on rear of tractor push forward (Mail coupling on trailer)
yellow F/male on end of trailer hose (to tractor) pull back

 

[KB6930]

Usually have bother getting them plugged in they always come apart no bother

 

[JeremyD]

Eat more spinach.

 

[JCB_JCR]

Bit of lube slide in easier then.

 

[marcot]

Or just spit on it .....

 

[Lakesdigger]

Cheap fittings or different makes on tractor and trailer. Despite being a standard fitting it's surprising how makes of fitting can be at opposite ends of tolerances. If o rings in fittings are dry it'll make them tight.

 

[Cowabunga]

What fittings are on there these days? Bayonet or pancake style?

 

[Lakesdigger]

What fittings are on there these days? Bayonet or pancake style?

Whichever these are called. O rings can go hard over time as well might just want changed

 

[Cowabunga]

Whichever these are called. O rings can go hard over time as well might just want changed

Bayonet. Originally MF were importing tractors with palm/pancake couplings. They must have woken up and changed the spec, unless dealers still do the conversion themselves.
This is a Wabco palm coupling...

 

[Lakesdigger]

Bayonet. Originally MF were importing tractors with palm/pancake couplings. They must have woken up and changed the spec, unless dealers still do the conversion themselves.
This is a Wabco palm coupling...

I'm just guessing mind as i thought by now all tractors used bayonet couplings.

 

[Andrew]

Whichever these are called. O rings can go hard over time as well might just want changed

I’d call them C or CA couplings.
As formthe OP, Never had to release pressure though,but if you really need to then turn the engine off and empty the air tanks.
Connecting can be a bit stiff, but a bit of spit and twist the coupling as you connect makes the world of difference.
They always uncouple easily though Maybe they’re seizing up, try a bit of oil sprayed under the sleeve.

 

[Sheep]

Bayonet. Originally MF were importing tractors with palm/pancake couplings. They must have woken up and changed the spec, unless dealers still do the conversion themselves.
This is a Wabco palm coupling...

These are the couplings still used in Europe. The 'Bayonet' style couplings are standard in the UK - far superior.

 

[Cowabunga]

These are the couplings still used in Europe. The 'Bayonet' style couplings are standard in the UK - far superior.

Which is presumably why MF sent their tractors over with palm couplings. Since the UK AGCO organisation has been absolutely decimated over the last two decades, nobody seemed to have persuaded them to factory fit UK style air brake couplings until relatively recently. I don’t mean ‘a few months’ though.

 

[warksfarmer]

Massey Ferguson 6715s
14 tonne bailey trailer
Having trouble getting the air lines of the tractor !

thanks

Little bit of grease inside the coupling will sort it.