I will be replacing the low pressure AC hose on my son's 94 Toyota Celica either tonight or tomorrow. Do I need to worry about using a vacuum pump to get the air out? Also, do you have any recommended tricks if I do?
Thank you,
--George
It is best if you pull a vacuum on the unit, since that helps remove moisture and air from the system, and allows you to check for leaks by observing ability to hold vacuum.
It isn't absolutely necessary though, especially if you plug off the rest of the system when you remove the hose. You can flush the system with refrigerant and remove almost all the air.
Are you crazy? The ONLY way to get the air out of the system is to pump it down with a vacuum pump. The vacuum allows the moisture to "Boil" out of the system. Just flushing with refrigerant is not going to do that. (legally of venting issues aside). If the system has been open too long, you might have to change the desiccant too. If you go to all the trouble of changing a hose, do it right. Change out all the O rings while your at it. Do it right and pump it down for up to an hour. Then see if the vacuum holds. Your going to need a gauge set and vacuum pump. Some tools usually not in most DIY garage. Is it R134 or R12? What happened to the old hose?
BOB
The old hose is pretty rotten and has a pinhole leak somewhere. I think the refrigerant is R134a, we converted the system last summer and all the refrigerant leaked out over the winter. We can recharge the system, but the pressure slowly goes down over several weeks.
I may be able to order a gauge set and vacuum pump in from Harbor Freight. I remember looking at them once there some time back. I can have my son wait until they come in if need be.
--George
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