Tractor brake air leak, still can drive ?

What area of the truck can you hear the air? Easiest way for me to find a air leak. Is to run a bare hand up and down the air lines, bags and brake chambers. Its easier to feel the air on your hand.

 

Do you have a hand valve? If you do, pull the hand brake down and jump out to listen. Have to determine if it’s on the tractor or the trailer or the blue glad hand seal. If it isn’t the glad hand seal, it’s probably one of the brake chambers.

 

Yup. What they said. You can also wet your hand or if the air is really still you can try canned smoke or haze in a can. The stuff i used in hospital engineering to identify vacuum or air leaks wasn't cheap but put out significantly more "smoke" than smoke/fire head testing cans.

Personally i don't know why you would be driving that vehicle with an air leak. You're an accident/lawsuit waiting to happen.

 

Air leak = no drive. It'll be PSP points at the scale house whether they fine you after an inspection or not. Those points could be more significant than any fine.

 

You'll want to get a helper to apply the brakes while you spray soapy water around the air connections and chambers. I'd start by spraying around the clamps on the brake chamber. Some chambers you can buy a diaphragm for like $5 and just replace it. If they're old and rusty, I would just get a new chamber. The next place I'd check are the fittings coming out of the brake chamber, then follow the hoses and spray any more fittings you see. Brake hoses and fittings aren't too expensive. At this point, I'd spray the ABS modulators and any quick release valves. Those aren't too bad to replace, but they're more expensive.

 

You didn't mention if bobtail or with trailer. If with trailer, pull the blue gladhand when hearing the leak if coming from the blue line then its a backfeed (Chamber, QR/IR/SR5 valve). Some air from dash is normal as the valves drain upstream, but if continuous then could be tractor chamber. If it was a modulator you'd be able to hear/find that, and even then if air is coming from the ABS modulators then air is likely being backfed to them. Pull the line going to #2 on the modulator and if air is going to the valve then there is a backfeed.