Air brakes, wagons

[Louby]

Can anyone tell me if its a fault if the brakes keep releasing air. My last wagon never did it. I think its a safety mechanism to release air but it did it quite a few times on a shortish journey?
Havent mention the H word

 

[foraday]

The compressors that build up the air automatically release when they have got more than enough in there

To do it on a short journey though would be strange!

Make sure there isn't any water in the air tanks-you should be draining the tanks after every run anyway to prevent any water building up

See how it is tomorrow-start the truck up and see how many times the air tanks release their air

 

[Louby]

Thanks, sorry didnt explain properly, it isnt my wagon, just one I was viewing today. It did it after the air built up before setting off, then about 5 or 6 times on a 30 min test drive. My last wagon never did it, except when the mechanic built the air up to test it did release.
Thanks for answering.

 

[moneypit1]

I was told by my fitter that it is fine. Its called "blowing off", can't think why! My older Ford Cargo never did it but my newer lorry does it all the time. It shows that the air is building up very efficently apparently.

 

[perfect11s]

Thanks, sorry didnt explain properly, it isnt my wagon, just one I was viewing today. It did it after the air built up before setting off, then about 5 or 6 times on a 30 min test drive. My last wagon never did it, except when the mechanic built the air up to test it did release.
Thanks for answering.

Did it make a farting noise? were the air gauges right at the top its hard to say but it could be the unloader valve u/s and so a safety valve is blowing
off.. is it a leyland daf ? or it could be normal as you use the brakes or before you drive off the compressor builds up air then the valve opens which sometimes makes a wooshing sound ...