Sanden 508 compressor, how much psi?

[Houston Ben]

Hi all,
I just installed my AC (high mount sanden 508) and filled with R134a. After driving for about 45 min on highway and when I started to come to a stop with RPM's between 6-700 the sanden would vibrate so bad that I could feel it in the cab and hear it but only at the above mentioned rpm's. I am wondering if I have too much 134 in. I put in till the psi was at 250 psi high side and around 50 on the low which is 3 cans and one can of 3oz oil since I lost some the first time I tried to put 134 in.

Any help would be appreciated.

Ben

[Desert1957]

Sounds like an over fill situation, Most older A/C systems (R12)ran at about 25-30 Low Side and 175 -200 High side.

Newer stuff (134A) can run higher on the high side.

Is it a retrofit system (134A in a R12)?
Most retrofit systems only take about 85% of what the label says for R12.

There are many variables that control A/C pressures, The biggest one is air flow across the condensor. Things to check

* Clutch fan condition
* Does it have a fan shroud
* Engine cooling system temps
* Belt tension

Any GOOD functioning cooling system fan should hold a dollarbill sucked up against the condensor, If it can't fix that first.

[Houston Ben]

Hi Desert,
Yes, I am using the old stuff with new compressor and drier for 134. Everything on your list is checked and good. I guess I need to bleed it a little.