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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 2108
Experience:  Owner at DJ Wilson
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I am working on a Mack Roll Off Truck. I work on so many different

Customer Question

I am working on a Mack Roll Off Truck. I work on so many different ones that I don't remember the year or motor. But the good news is I have a AC question.
I have replaced 1 AC pipe and 1 hose to this AC system. the Vac and Leak Test age good. My problem is I can not get it to take more than 0.16 lbs of Freon. I have tried to charge it from the hi side and the low side. I have also tried to charge it with the AC compressor engaged and also with the compressor off. I also have blown through the system and air does go through it. I have thought that the Valves may be faulty, but I took off a pipe after the truck sat about 2 days and there was a little pressure in the system.
Please help.
Submitted: 2 years ago.
Category: Medium and Heavy Trucks
Expert:  spankyjr1 replied 2 years ago.
Hi Joe, my name is ***** ***** you for your question.

This is a 134 system correct?
Was it converted to 134 from 12?

Are your low/high side gage ports on compressor or lines?

With the amount you are able to add it sounds like the ports are not opening.
.16lbs is about enough to fill gages and hoses of gages.
I would start by checking schraeder valves.

On your gage set are they just quick disconnect or do they also have screw knobs you turn in to push on valve?

Upright or radial ac compressor?

Let me know
Customer: replied 2 years ago.

I have not been able to work on this truck again up to now. I have it scheduled for Tuesday but you know about "the best made plans of mice and men," don't you.

I am the lead tech and we are busy and short handed last week on the days it was scheduled.

I will get back to lyou as soon as I can.

Thank you.


BTW it is the normal AC system with a rad. comp. not an up right.

Also, I would add I was able to get it to take 2 oz. of oil.

Expert:  spankyjr1 replied 2 years ago.
Thanks for info Joe,
I will be around Tuesday so just let me know when you get a chance to check schraeder valves and what your gage readings are?