When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I replaced all components of the AC system in my 97 7.3L F350 and am doing a leak test by pulling vacuum before I charge the system. I read that it should pull 29 inches of vacuum after about 30 minutes but mine only pulls about 26-27 in. It holds firm when the valve is closed, so it appears that it does not have a leak, but I’m concerned about it not ever getting to 29 in when the vacuum is pulling. What do you guys think?
Thanks. It won’t pull more than 27 with this pump. But it’s definitely holding at 27 without losing vacuum after shutting off the pump. Think that’s ok to charge?
Originally Posted by tjc transport
could be a miscalculated gauge, or a weak vacuum pump.
either way, if it is pulling 29 inches vacuum and holding it, i would call it good to charge.
Holding vac is not an indicator it is not leaking. Agreed, gauges look inexpensive so do not expect much accuracy. Verify your schrader valve cores are fresh.
if if have any doubts about leaks, i will draw vacuum and them remove gauges. after 24 or 48 hours put gauges back on and see if it stays the same.
if not, i will vacuum it, put a enough charge in to keep the compressor running, and start going over the whole system with a sniffer looking for the leak.
Vacuum held nicely, so I added a couple cans of refrigerant. The (new) compressor wouldn’t kick on, so I jumped it to force the clutch to engage while i added the rest of the can. Plugged the compressor back in and it still won’t engage automatically. Low side pressure is 50 in. Any ideas why the compressor won’t engage?
Did you check the connections to the pressure switches? The low pressure switch is on the receiver/dryer, the high pressure switch is in the line behind the compressor. The 96 C&C truck's compressor wouldn't engage, turned out the connector to the high pressure switch was loose.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
