Hey guys,checking out moms 86 T/A a/c.New GM compressor 5 years ago changed to R134 by shop back then,worked pretty good.Now mice destroyed it in winter storage and had to completley restore dash/interior.When I put the system back together with a new dryer and white orifice tube,in the correct way,the low side pegs the gauge high.Vaced for 90 mins with Snap On machine,no prob,added 80% of original charge and a little oil.When running today high side was around 225-250 at 80 degrees outside.Low side was pegged.Did all over again and only put in a little under 2lbs,same.Recovered system,took apart orifice to look for crud,its clean.All parts except 5 year old compressor are original.Clutch is engaging as it should,but never did cycle,stays on.Ideas to check???Mom wants her baby back soon or I might have to lend her my 88. theyre twins.Thanks Allan

 

Almost sounds like an internal leak with the compressor or the orifice tube o-ring is not sealing properly. You are positive you installed the orifice tube in the correct direction? The short end below the o-ring goes in facing down.

Other possible cause is the system is overcharged but for the low side to be pegged I would think the high side would be well over 300psi if that was the case.

 

Sounds like the compressor isn't working right; most likely has a broken reed valve.

 

Tube was put in with the arrow on the orifice facing the evaporator,large screen end facing condensor.system does seem clean also.When it was running the first charge the low side was a little high and it never could get down below 50.Then found it leaking out the low side adapter port I just put on it.Reclaimed and vaced new adapter put on,charged and then everything really went haywire!! Thank you for the help,anymore???