NH T7030: yellow brake line issue.

[PSQ]

As per the title. Tractor hasn’t had anything with brakes attached since last harvest. Serviced in the winter by local dealer.
Just picked up a hired 18t trailer and the brakes are locked solid. Pressure from the red line is fine, tractor air tank showing 90psi, but no noise from brakes when either foot or hand brake applied.
Trailer brakes were working fine last week on previous hire I am told, trailer looks tip top.

Any ideas of what it could be? Electrical? Mechanical? Fuse?

Got a ‘shed’ load of muck to shift, starting 1st thing, and would rather use air than oil for braking on some long descents.

Cheers.

 

[del_boy]

We've had this on our t7210. Check the fuses 1st. If not a fuse
take the plastic cover off covering the air fittings behind the cab where the air fittings are and behind there are 2 electrical switches. I believe one is for the handbrake and the other the break pedal. Our one had failed. Check you have power coming there. I cant remember if the switches can be swapped or not.

 

[vario]

you might have a bad relay valve
put a gauge on the signal line and if your getting pressure with your brakes and hand brake not applied it could be relay valve

 

[Zebbedee]

When you pull off yellow line is there pressure in it ? With no park lock/handbrake or foot brake applied there should be no pressure in yellow line Edit too late I think Del Boy above is on right track

 

[PSQ]

Yes, constant pressure on the yellow line without the brakes applied...

 

[PSQ]

Fuse no. 16, trailer brakes, blowing.

 

[timmyboy]

Fuse no. 16, trailer brakes, blowing.

Do the brakes come off the trailer with just the red line connected?