Firewall Discoveries....1964 Riviera

[alex bonino]

Well, it was nice (yesterday, anyway) in Denver, so I decided to bite the bullet and remove the hood so I could get at the wiper/washer motor assembly per earlier posts on this board. Someone had tapped into the existing wiring and mounted a K mart aftermarket washer, so I wanted to remove the existing stock wiper/washer, fix the washer pump mechansism, and get back to original.

Its amazing what you can see when the hood is off. Along with the jury rigged washer, I discovered a couple more oddities (see pics below).

So my questions are:

1) It looks like someone replaced the dual stage vacuum diaphram for the heater/evaporator door with an incorrect (albeit Delco) single port diaphram. I couldn't find the part ## for the correct dual diaphram in my part book. Anyone know the part #? Or a Source? Don't remember seeing too many of these on ebay.

2) Appears to be some sort of switch wired into the A/C compressor clutch coil circuit (green wiring). According to the manual, looks like instead, this should go directly to the main A/C switch in the interior of the car.

3) Last, on the wiper/washer assembly, I assume once you've contorted to remove the fastening bolts (and not loose them into fender oblivion), that the wiper linkage retainer is accessible so you can remove the assembly? I refuse on principle to remove the entire front clip to get at the damn wiper motor.

thanks in advance,

alex

roa# 11550

[Jim Cannon]

Remove cowl vent and wire screen on drivers side to get to the wiper transmission linkage. Reach down in there to remove keeper and wiper motor will slide out going toward front of car.

[Bill Stoneberg]

Are you sure they haven't rigged the STV valve to be electric instead of vacuum powered ? Its a fairly common fix from what I hear.

Do you still have a bunch of vacuum lines going to the STV valve ?

What is on your compressor ?

[johnrex]

Your AC has been updated using an Old Air Products kit (50-2500P). This kit modifies the Suction Throttle Valve) STV and adds a control relay that cycles your AC compressor as the temperature varies in the input to your evaporator. The function of your old STV is eliminated.

I installed the same kit three years ago and am totally happy with the AC operation. Your evaporator will never freeze up and you should get a little better mileage.

For more information, contact:

Old Air Products

8744 Forum Way

Fort Worth, Texas

76140

817-531-2665

www.oldairproducts.com

John Hellmuth

[alex bonino]

Thank you guys for the responses. This forum continues to be a consistently valuable and helpful source of information.

Bill, the vacuum hose was cracked but still connected to the STV. The compressor had the green clutch coil wire intact (the relay from the kit John makes reference to was wired in the circuit at the firewall)

I frankly am not sure of what I want to do with the A/C long term ie, conversion, etc. First, is to get the Heater/AC vacuum circuit plumbed properly, squared away and leak free. I want the system to work as designed with regard to airflow.

The more I got into it, I was really surprised at how sophisticated the A/C vacuum system was in a vehicle of this vintage. I'll bet alot of folks spend time tracking down the cause of poor performance not realizing the problem cound be due to vacuum leaks from cracked/hardened hoses somewhere wihin the A/C system.

thanks again

alex

roa# 11550

[1965rivgs]

Hi Alex,

Just a few observations....the component pictured is not a relay but a temperature switch. It interrupts voltage to the compressor clutch when the outlet temp of the evaporator gets too low. There is a sensing bulb at the end of the metal tube which originates at the switch. The bulb is most likely affixed to the outlet tube of the evaporator under the sticky tar-like wrap seen in the photo under the STV valve. The temp switch basically turns a constant run compressor into a cycling mode. Good news is you remove the load from the engine when possible but the bad news is the cycling can cause less consistent evap pressure and hence outlet temp.

Be certain there are no vacuum leaks in the control system as any leaks will cause other parts of the system removed from the actual point of leakage to be non-op.

Good luck,

Tom Mooney

[alex bonino]

Thanks for the additional info, Tom.

Now that I understand how the system has been modified, it will help me bring it back to original. The benefits of cycling the compressor notwithstanding, I'm not really into incorrect stuff like tar wrap and and non original compressor switches hanging off the system.

The plan is to first fix the basics, like the vacuum circuit - so the air doors open and close when they should, and then dive into the r12 vs r134a, etc issue and try to use original A/C components where possible (eg, rebuilt STV valve) which I've seen a few threads on.

I've ordered replacement dual stage vacuum actuators and am investigating sources for the narrow diameter striped vacumm hose needed for the A/C ciruit.

thanks

alex

roa#11550

[Bill Stoneberg]

Alex, I was able to buy a roll at my local auto parts store.

Take a piece in and see if they can match it. It took a roll of 50' to do the whole car.

Now, if you follow the directions in the shop manual, it has one pair of hoses reversed, so just follow the wires.

You may want to check the vacume switch on the dash panel to as I found mine was leaking. Also if the car has not run for awhile, you may need a new expansion valve up under the dash as it gets full of crud.

I went through what you are doing last year and its not hard, just tedious tracing all the hoses.