No air pressure buildup wabco air compressor installed 5hours ago

The 'units' referenced correspond to the markings on the cup supplied with the Bendix BASIC test kit. No specific volume is noted in Appendix A.

 

Is the purge valve releasing pressure at 120 psi? Those can go bad and prevent build up.
So no leaks now in hoses? Or fittings?
Also is governor new and working?

 

When nasriza gets back he may be able to answer that. He has extensive knowledge of these trucks.
The point about parts is I have encountered defective replacement parts before. Assume nothing is good test them. I usually check the compressor outlet lines on the truck as mentioned. Then remove the air line between the governor and compressor. Retest. Then connect an air line from the air compressor outlet to a Cheetah tank ( an air tank laying on the ground with a gauge on it ). The compressor builds air or it does not. Most any leak large enough to cause o psi can be heard right after the engine is turned off. Two exceptions are the air line mentioned and a free flowing dryer exhaust port.
I would go back to the basics and use the second air compressor in place of a Cheetah tank.
If the new compressor is regulated to 120 and connected to the wet tank the truck air system should operate. If it does not he has something else going on.

 

That small 1/4 inch black line with the shut off valve with a blue knob looks like it goes under the floor mat, might be to the drivers seat air bag. Just a guess. If he has a major leak, like can't build up air at all, he wont hear it when the truck is shut off. With the truck running if he builds up some pressure he can use a soapy water solution to look for bubbles. I like using the bubbles solution that are sold in the toy dept. Soap solution is corrosive, the bubbles solution sold in toy stores is safe for kids eyes must be safe to use on truck

 

Yes it's line to inside the cab driver seat, passenger seat and air blow gun. Other end of this line connected to the air pressure protection manifold. Located inside the frame rail in area where is battery box. Hard to see and work due to there is almost no room between transmission and frame.
This line can drain pressure from secondary supply tank but will not prevent air compressor to build up pressure.
All compressor governor lines connected to the wet tank

 

I am going to remind you to drain that wet tank if at all possible.

If you do not drain that tank the slurry built up in it will migrate to inside your air service chamber on at least one of your braking wheels opposite the spring with the rubber divider in between. The slurry is capable of eating through the diagphram. There is no holding pressure after that point especially after a brake application.

I generally don't know where the gauge input sits on the wet tank, but its possible that there isnt meaningful volume of air in there at all to build pressure. You might have too much liquid slurry in it.

IF you try to drain the wet tank and nothing comes out then your airdryer has been doing a good job. I have had that particular problem on a farm truck that never had a air dryer on it. Employer thought it was a unnecessary expense when he ordered it long ago. You can bet he has air dryers on his newer trucks now.

I have also had compressors fail. When they do, you get nothing. Replace the whole thing with a quality factory replacement. Not some cheapo after market compressor.

 

If truck is not building pressure he has to have a huge leak or compressor not working. If its a new compressor, or rebuild, I don't know the set up on his truck, but it could be the gears that turn the compressor gear are loose. In other words the compressor is not turning there for not making air. With compressor on truck and all air lines disconnected he should be able to tell if compressor is making air. Put hand on compressor outlet fitting and you should feel air pressure. If he doesn't than compressor is not making air, check compressor or gears, if he does feel it then he needs to look past the compressor for a large leak. If that small black air line was leaking that wouldn't be enough to stop system from building air pressure.

 

Have my A/C working again. Blower motors do not work well in water and a lot of dust related problems. Did your dad get that worked out?