1965 Suction Throttle Valve

[Don H.]

I am starting a rebuild of my original 1965 suction throttle valve. I have the '65 Shop Manual which has a detailed procedure. Does anyone have tips or comments to add to that procedure? Thanks, Don H.

[Gary J.]

Re: 1965 Suction Throttle Valve

Make a mark on both halves to get it back in the right position when reassembled. Also be careful as if my memory serves me right it is spring loaded.

[Harry S.]

Re: 1965 Suction Throttle Valve

Make a mark on both halves to get it back in the right position when reassembled. Also be careful as if my memory serves me right it is spring loaded.

Don, to start, assume the adjustments (screws are correct) for your altitude. Yes, it is spring loaded, so take it apart slowly.

I took mine apart, cleaned it with alcohol, let it dry and installed a new diaphragm. Reassembled the unit. I believed it had a hole in it. I also rebuilt and/or replaced the compressor and expansion valve. Installed R12 and it been fine for 5 years.

Good Luck

[Robert W.]

Re: 1965 Suction Throttle Valve

Are there any tricks to installing a new diaphragm? Service manual discusses inserting a 3/8" rod to depress the piston a bit prior to reassembly to avoid pinching, but doesn't say how far... Is it obvious?

[Don H.]

Re: 1965 Suction Throttle Valve

I finished mine and installed it, so far it has held vacuum and took a charge. The '65 Corvette Shop Manual Supplement has good drawings and procedure. I found the mating surfaces (where the two halves join) of my valve were bad. I used longer screws to align when assembling and did depress the piston as it said. Good luck, Don H.

[James W.]

Re: 1965 Suction Throttle Valve

Don,

Where did you source your rebuild kit?


Thanks,

James

I finished mine and installed it, so far it has held vacuum and took a charge. The '65 Corvette Shop Manual Supplement has good drawings and procedure. I found the mating surfaces (where the two halves join) of my valve were bad. I used longer screws to align when assembling and did depress the piston as it said. Good luck, Don H.

[Don H.]

Re: 1965 Suction Throttle Valve

Hi James, I bought a kit with diaphragm from Classic Auto Air. Also Long Island has a new piston with diaphragm available. Don H.

[Robert W.]

Re: 1965 Suction Throttle Valve

For what it's worth, That's where I got my "parts" too! LIC has NOS piston/diaphragms in stock (I just picked up a spare). I plan on doing the install this weekend. Thank You!

[Gary J.]

Re: 1965 Suction Throttle Valve

For what it's worth, That's where I got my "parts" too! LIC has NOS piston/diaphragms in stock (I just picked up a spare). I plan on doing the install this weekend. Thank You!

keep us posted on how well it goes. I have one to do when I get back home from the convention.

[James W.]

Re: 1965 Suction Throttle Valve

Don and Robert,

Thanks for the info on parts sourcing.

James

Hi James, I bought a kit with diaphragm from Classic Auto Air. Also Long Island has a new piston with diaphragm available. Don H.

[Robert W.]

Re: 1965 Suction Throttle Valve

Hi, I just charged my 1966 AC with r12 (after flushing and rebuilding STV) and it only took 2# 7oz to get a clear stream on the drier window? Is this unusual? I'm getting ~44' air at the vents, which is really nice! Gauge pressures are: LP 34 (no vacuum attached to AVR), HP 185 (OAT ~75')

[Larry M.]

Re: 1965 Suction Throttle Valve

Robert:

Capacity of your system is 3 lbs 4 oz.......or 52 oz. The sight glass should clear up about 12 oz before this point.......or 40 oz. You saw this at 2 lbs 7 oz or 39 oz. So I would say you are "right on the money" as far as total refrigerant charge.

Your LO side pressure is a bit high, and I believe you can adjust the STV to get it down to 32 psig. Or perhaps just hooking up the vacuum will also accomplish this. That will improve cooling in the cabin by at least 2-3 degree F. The HI pressure is just about ideal for summer temperatures.

Congratulations.

Larry

[Robert W.]

Re: 1965 Suction Throttle Valve

Do people use an expansion valve screen on newer (four seasons I think) replacement expansion valves? There isn't enough length (about 3/8" shorter) to fit an original screen (GM 15-512), but I guess the top collar could be removed to fit in the available space?

[Larry M.]

Re: 1965 Suction Throttle Valve

Do people use an expansion valve screen on newer (four seasons I think) replacement expansion valves? There isn't enough length (about 3/8" shorter) to fit an original screen (GM 15-512), but I guess the top collar could be removed to fit in the available space?

Short answer is NO.

Larry

[Robert W.]

Re: 1965 Suction Throttle Valve

As an update: My rebuilt STV was weeping a bit of oil, so I vented (I have a Robinair RG3 recovery machine) and rebuilt it again. It looked like the diaphragm was slightly pinched. I reinstalled, recharged and now have (vacuum disconnected) LP: 33psi HP: 233psi vent temp 41' (OAT 73' 80% humidity). I charged with 3# 4oz this time, but it was too hot in the garage, even with the turbo fan on high, so I'll recheck pressures and sight glass again tomorrow. After charging, It was actually ICE COLD in the car when I shut it down. Unbelievably, I now have parts from 3 different STVs, an original expansion valve I'll get rebuilt (its too dirty to do myself), a partial r12 tank, refrigerant recovery equipment, and enough spare parts to last a very, very long time! I am having fun though...