I tried to charge my ac but once i hooked it up the pressure went up to 45 then the clutch disengaged and the pressure dropped. It did this every few seconds, any help about what is happening is appreciated

 

Keep charging it.

The compressor is cycling off on low pressure switch, you just haven't put enough in yet to keep the pressure switch closed

 

Ok thanks. Ill do that today, i appreciate it

 

dont put too much in it wont get cold... too much and it starts getting warmer not colder...

you want to put in just enough to pacify the switch at cruising speeds...

 

Pressure should be around 48psi at idle with compressor running for 5 mins straight.
If you put too much in there is "hopefully" a high pressure switch to shut the compressor off again til you remove the excess.

 

48? Hell no.

 

Pressures are directly related to outside ambient temps. There is NO standard pressure at which any 2 systems will run.

 

45 psi for r134a is 45deg saturated suction pressure. That's a good suction pressure at full load on an AC system, atleast around here.

What do you guys suggest?

 

That's probably why I keep thinking everyone is crazy. I only know what works for me here.

 

Amen Brother. Leave the AC repair to the professionals OR you can put a set of guages on and try it yourself for what might be a quick fix. Follow the chart below depending on the outside temp. Slowly add refrigerant while you monitor low AND high pressure. Make sure you have a fan blowing on the condenser. If the high (head pressure) gets too high before the low (suction pressure) reaches an acceptable level then the orifice is probably clogged. 7 times out of ten you can add the propper amount of refrigerant and be good for a couple of years. The other 3 times, take it to a good AC shop, not a brake shop that does AC.
Just my opinion.