T7 is keeping a small amount of pressure in the braking line. Not enough to notice with a load on but heating up the brakes, you can notice it empty on a very gentle slope of you let her roll. Brakes hold on slightly after braking but will fully release if you apply handbrake and then release again. Doing it on more than one implement. Any ideas? Have had handbrake not release because of solenoid but not sure about this
T7 air brake issue
- Thread starter jg123
- Start date
Does it have a mechanical linkage from the handbrake linkage to the air brake valve , could it perhaps be out of adjustment .
Has it been off recently or anyone working on it or around it .
Have seen the round rotary type air brake valves having the linkage put on 180 degrees out , still works but does not fully release the park brake.
Has it been off recently or anyone working on it or around it .
Have seen the round rotary type air brake valves having the linkage put on 180 degrees out , still works but does not fully release the park brake.
No not been worked on. Park brake releases fine it's foot brake that won't
Yep,same symptoms , hand brake releases as normal but holds at junctions longer than usual after normal braking If linkage on wrong. ( If NH has linkage ) I don’t know .
Just a cable to tractor handbrake. Can't see anything other than electrical for air from handbrake
Just a cable to tractor handbrake. Can't see anything other than electrical for air from handbrake
- Location
- Lincolnshire
I didnt think the air did anything to the tractor braking, only the trailer?
Ye cable goes to tractor and then electric to air but air only does trailer
davidroberts30
Member
- Location
- pembrokeshire
Brake lights arnt stuck on?
On my mf as soon as you touch the brake pedal and light the brake lights theres a solenoid that pre charges the air brake system before the hydraulics send system pressure to the trailer
cosmagedon
Member
- Location
- North Wales
I assume your talking about air brakes on the trailer here? As above, if you press the brake pedal it puts a small amount of air to the brakes to put them on first before you put the pedal right down.
There's 2 solenoids on the valve, 1 for the handbrake and the other is for this pre brake function. Check to see if that's sticking or if it's getting power it could be your foot brake switches but you would notice that as your brake lights would stay on.
There's 2 solenoids on the valve, 1 for the handbrake and the other is for this pre brake function. Check to see if that's sticking or if it's getting power it could be your foot brake switches but you would notice that as your brake lights would stay on.
Brake lights are not stuck on no. It's like a valve isn't closing fully when brakes are released. I chocked wheels and left handbrake off, there's a small amount of pressure when you pull the brake line coupling off. If you pull up handbrake then down again no pressure when you pull braking line off. Maybe it is something to do with the pre charge but it's not the switch on pedal
TripleSix
Member
- Location
- Helmsley, North Yorkshire
We've this trouble with one or 2 tractors.
Dealer never has managed to sort it despite a few visits.
Dealer never has managed to sort it despite a few visits.
cosmagedon
Member
- Location
- North Wales
Have you got a flow control valve you can turn somewhere around the air brake valve assembly? Some tractors have them and some don't but you could try turning that all the way off.
Disconnect the solenoid plug to completely rule out the electric side then it can only be down to the solenoid.
Disconnect the solenoid plug to completely rule out the electric side then it can only be down to the solenoid.
Yes had a play with the flow control although it is very stiff to adjust.
Press brakes to create the problem then disconnect plug to see if it releases pressure?
davidroberts30
Member
- Location
- pembrokeshire
or disconnect plug and see if problem doesn't appear
Disconnected wouldn't I just have permanent brakes on/off? If I can narrow it to one solenoid might be able to swap a part off the puma to test
davidroberts30
Member
- Location
- pembrokeshire
dissconnect the precharge valve or pull the brake light fuse
Had a look again today. It's a problem with the pre charge.... it's always on. We cannot work out why, tested another tractor on the yard and foot pedal sends voltage (or cuts voltage) can't remember to do the pre charge. This t7 is perminately on so is always slightly braking. We have tested both switches on the pedals and they are working, checked fuses, changed air handbrake relay and running out of ideas now without seeing a wiring diagram. Any suggestions anyone? The pneumatic brake relay by door doesn't seem to get power with the pedals either, the handbrake relay gets power from relay and there's one labelled hydrualic brakes that gets power off the pedals
davidroberts30
Member
- Location
- pembrokeshire
Are there any relays feeding that?
Can't see any. Your neighbour came after I had looked for hour or 2 and has had been here 4hrs so we have had a good search. Anyone know if it's something silly like you have to configure the dash to know the tractor has air brakes and it's wrong for some reason? The only relay we can see for air brakes doesn't have any power to it ever
- Tags
- new holland puma t7