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240 Trying to fix AC on a 93 244

Prime240

Prime240

240 addict
Joined
Feb 8, 2009
Location
Canada
Hi there
I posted a wanted ad but I want to see what are my options
I want to fix the ac on my 93 244 but there is a major hole in the condenser to evaporator AC line and the high pressure switch is missing
Now the part numbers for the 93 are 3540702 and 3540657 respectively they are a 93 only part and are NLA
I found a brickyard post about the switch:
The high pressure switch (3540657) at the condenser is supposed to ground the fan relay to turn on the fan when the engine fan doesn't provide enough air flow across the condenser. It fails often, and most of us, I believe, just wire around it, which causes the aux fan to cycle with the compressor. That may be an alternative your tech can provide you, if you're willing to make that compromise.
Within the 240 series, this switch has a different part number for each of the three years using the orifice tube AC. The 93 is unique because it is set for discharge pressures expected with R134a, but the 3540227 (91) and 6848584 (92) perform the same function at lower pressure levels, so if you used one of those you might wind up with the fan on just as often as if you eliminate it altogether and ground the wire. I'm quite happy with that arrangement, but where I live, AC is a one- or two-month thing.
Click to expand...
So I understand the older switch can be used

What about the line? can I use 3522877 which is the line for 91 and is stil the only one being sold?
Thank you for your help
 
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See last picture (click for bigger) and comments here: http://forums.turbobricks.com/showpost.php?p=5994144&postcount=63

Currently, I don't have a front A/C electric fan in my '85 (mechanical fan only), but I do have a cabin LED wired up to turn on if I ever hit high AC pressure. So far, it hasn't turned on, but I also haven't been stuck in stop&go traffic (low airflow) on a really hot day with the A/C blasting. If it ever turns on, I'll devote some time to finding an aftermarket fan that fits behind the original '85 J-shaped hood latch support bracket (the '93 fan is too big).
 
bobxyz said:
See last picture (click for bigger) and comments here: http://forums.turbobricks.com/showpost.php?p=5994144&postcount=63

Currently, I don't have a front A/C electric fan in my '85 (mechanical fan only), but I do have a cabin LED wired up to turn on if I ever hit high AC pressure. So far, it hasn't turned on, but I also haven't been stuck in stop&go traffic (low airflow) on a really hot day with the A/C blasting. If it ever turns on, I'll devote some time to finding an aftermarket fan that fits behind the original '85 J-shaped hood latch support bracket (the '93 fan is too big).
Click to expand...

Thank you for your reply
I do live in a big city where traffic can be preatty heavy at rush hour so I better have a working fan

Your picture comparing the lines gave me hope but then found out this:
The 134 sensor will be Acme threads and the R12 will be 1/4 flare
Click to expand...
So I guess this confirms I could not use a 91 line on my 93 system?
 
The sensor determines when the fan turns on. From your brickboard post, a '91 R12 sensor will turn on sooner (at a lower pressure) than a '93 R134a sensor. The fan turning on earlier won't hurt anything. If you were going the opposite way, R12 in a R134a system, the fan would turn on late, which is bad.

Those pressure sensors do fail, and the cheap fix is to jumper across them. This means that the fan turns on whenever the compressor is running. This won't hurt anything either, but will be noisier and might get annoying.
 
If you can't get the new lines, have your local a/c shop make them for you (not the cheapest, but they won't leak like mine did from all hose), high pressure switches are generic, so you can search or ask your a/c guys what pressure should be cutoff and have a new hose plumbed in with a fitting for that cutoff, or you can add a safety vent like the pre-91 systems. definitely replace all your hoses, it's ancient rubber that WILL leak. Check other posts for everything you'll need but make sure that pusher fan works! Good luck!
 
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