Hey Guys,our 70 chevelle has had the A/C system apart now for about 3 years,we taped up all the fittings when we took it apart,also,it had no charge in it when we dissasembled it.We dont know for sure if it is in working condition but the system is complete and there is no reason to believe it wont work when we have it charged,my question is: A friend told me anytime you have a vintage A/C system apart you should always replace the drier.Is this true?Are there any other "must" replace items in an old A/C system?We were just going to get it charged but if some items should be replaced first we would rather do it right the first time.

Dean, I agree the moisture removing desiccants in the drier do not last forever, especially when the system is exposed. I would also replace all the o-rings on the compressor, hoses, etc.

Other than that, pull a vacuum, make sure it holds overnight, then charge.

Mike

I would also replace all the o-rings on the compressor, hoses, etc.
They will dry out and not hold if not used on a regular basis.

Well i went ahead and ordered a new receiver /drier but now I want to make sure we have the correct amount and type of oil in the compressor before we get the system charged,any ideas?

Well i went ahead and ordered a new receiver /drier but now I want to make sure we have the correct amount and type of oil in the compressor before we get the system charged,any ideas?

That depends on what refirdgerant you have available. R12 was used originally in these cars, but is a lot more expensive than it's newer counter part R134a. The 2 refirdgerants DO NOT take the same oil. If you don't have the equipment to do so, I recommend letting whoever you are taking it to to charge it, do it.

Im pretty sure we ar going to put R 12 back in the car,the a/c guy didnt know how much oil to put in.

Check your chassis service manual. My 1966 Chevelle AC system calls for 11 oz. of 525 viscosity oil. Your 1970 probably uses a similar amount, but check the manual for the specs.