New to me 78 NYB on its way but please Don't tell my wife

Why not do it the right way and vac it down and see if it holds a vacuum???
 
Don't feel too bad about your cost for both cores..I spent $400. just to have my heater core rebuilt 2 years ago.
A handy tip if you're wanting to save some money fooling around with old and unknown A/C systems: Leak test with compressed air (approx 120 psi). A lot cheaper than Freon.
I disagree with using compressed air to leak test an A/C system.. it adds moisture to the system even if you have an in-line filter dryer. Nitrogen is a better way to go when pressure testing an AC system. IMO
 
As Bob said, I believe you should vac it, that way you clean the entire system of mouse for a clean start.
But I'm sure this isn't your "first jar of pickles" from what I've read
 
Don't feel too bad about your cost for both cores..I spent $400. just to have my heater core rebuilt 2 years ago.
A handy tip if you're wanting to save some money fooling around with old and unknown A/C systems: Leak test with compressed air (approx 120 psi). A lot cheaper than Freon.

Test done. Leak is definitely in the evaporator. Where in the evaporator is not the issue. That it leaked out the test can of Freon ($33) and lost the partial charge over three days ($99) is also not a cost but functional issue.

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Here’s the leak tester going crazy!!!
 
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I disagree with using compressed air to leak test an A/C system.. it adds moisture to the system even if you have an in-line filter dryer. Nitrogen is a better way to go when pressure testing an AC system. IMO
I agree compressed air is a meatball method, but if the system is empty and you've got no idea of how long and why it's empty, why waste freon? As for moisture in the system, an hour or so at a 30" vacuum should boil it out. Nitrogen would be nice but not everyone has it. Most people have a compressor of some sort available.
 
Heater valve was stuck open. I got t it to pop closed only with 30inches of vacuum.

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New one moves with as little as one inch of vacuum.

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Here it is in place.
 
Headlight switch and system check:

Here is the old switch with the lead to activate the headlight doors obviously loose from overheating.



New switch in for testing while I wait for replacement plug to come in.


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That the switch comes out the front is a godsend!!!!


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Problem with melted lead traced to headlight relay/motor.

Power good to relay with no short. Power for miter drive is through ignition.... which answers question of needing ignition in to operate headlight doors. Commentary below.

Power clean to motor..... check motor.

Internal motor relay checked partial open manually. Snaps closed (noisily). Cantens nurse to open (noisily) with ignition circuit energized.

Checked operation of door.


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Bingo. Right hand door was damaged which explained two things.

One: the passenger side door must have jammed in opening or closing cycle which back fed the system and overloaded the switch connector to the relay.

Two: explains the extra headlight door in the trunk.

Commentary: I don’t like that the headlight doors do not open only with the ignition circuit enegized. Should be run directly off main buss for non ignition cirquits. Bad design. Cheap solution to allow for use of same wiring harness only. Saved one power run. Dumb!!! Will need to run fused direct power to main buss.
 
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My NYB doors make a hell of a racket closing and opening. That is 1970's technology and a pretty strong headlighr door motor.
 
since I’m planning the drive this beast in Florida, I need to do a little preventative maintenance.

Just noticed some bulges in the high side lines I don’t like. Will pull and replace these while waiting for evaporator.

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More than likely you will have to have your original hoses rebuilt. Any hydraulic hose shop can repair it. They will reuse the original fittings/ends.

I had mine rebuilt with a 24 hour turn around at Benz Hydraulics in Bear, Delaware.
 
More than likely you will have to have your original hoses rebuilt. Any hydraulic hose shop can repair it. They will reuse the original fittings/ends.

I had mine rebuilt with a 24 hour turn around at Benz Hydraulics in Bear, Delaware.
Thanks! That’s what the meant... replace the rubber part of the hoses using the original fittings. Even NOS hoses are 40+ years old at this stage of the game.

Cheap reliability insurance. In for a penny....

Speaking of pennies... we just blew past $3000 on this thing. But end is in sight.... hope to get her done under $4k. Cross your fingers.
 
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