Gas Leak out of 6 Port- Dash Switch the Culprit?

[44SAA]

I was under the dash and while there figured it was a good time to replace the RH/LH switch on the dash. The driver side tank has never worked so I though it was worth a shot. Well, short version is now gas leaking out of the pollack valve, specifically what appears to be a 3” rubber breather valve. I also noticed significant pressure in my fuel tank as i unscrewed the gas cap. I understand I’d have better luck sourcing unicorn tears than finding a 1980 pollack valve. Does anyone feel re-installing the old broken dash switch will stop the leak?

[TKCR]

I would say your going to have a leak regardless of the dash switch. Did it start leaking after changing out the switch and then switching to the left side? The hoses are just dry rotted and since you haven’t been using the left side or had power to the left side.
I recently had this issue, of a leak in this area. It was leaking so bad when the truck was running, it wasn’t worth the risk of driving it. I had a buddy of mine come get the truck, on his flat bed. He has a shop about 20 miles away. He replaced all the rubber hoses. At first, we thought it was a rusty fuel line, but it was dry rot.

[44SAA]

No doubt the 40yr old hoses are shot. However, the leak is clearly coming from the 3” piece of rubber tubing. And yes, the leak started only after replacing the dash switch. Forum member Hatzie articulated GM installed a “ retained power relay to keep the valve energized in the AUX position while cranking.” Any idea where it’s located?

[hatzie]

The problem is not electrical.
Fuel hoses are no doubt dry-rotted after 40 years but they're not the problem either.
The leaking hose is the Breather for the valve itself. The seals on the valve shuttle were no doubt stuck to the inside of the valve body and when it was actually energized, after several years of inactivity, it tore the seals.
The only way you're going to fix this now is to replace the valve.
The six Port solenoid valve is made of unobtainium.
If you want dual tanks you're going to have to upgrade to the motorized valve used on the 81 to 91 systems. This requires the switch, sub-harness, and valve.

[SilverMiner]

Originally Posted by hatzie

...
The only way you're going to fix this now is to replace the valve.
The six Port solenoid valve is made of unobtainium.
...

Any reason what this outfit offers can't be used? https://www.scintex.com.au/products/...l-valve-switch

I researched this a while back for another project, but never pulled the trigger. The part is NOT cheap by any means, and unfortunately it must come all the way from the other side of the globe so who knows how much or how long shipping might take.

Another alternative I found but again didn't follow up on was Pollack themselves: http://products.pollakaftermarket.co...n-valve/42-300

No prices given, and the site doesn't seem to be intended for direct consumer buyers, but at least new replacement valves exist.

[hatzie]

RockAuto carries the same motorized valve from Pollack. No need to buy it from China.

They can be used but you need the proper 81-91 switch and wiring harness. The 73-80 harness and switch will not work with the motorized valve.

Search for my dual tanks theory of operation thread. It should answer a lot of questions.

[44SAA]

Great news- one popped up on fleabay for the meager sum of $300.

[hatzie]

Six port solenoid valve no doubt. They get a kings ransom for them and no guarantee it works... even if the seller states otherwise.

This is the dual tanks theory of operation thread....http://67-72chevytrucks.com/vboard/s...d.php?t=754061

The motorized Pollack valve is just under $50 AC Delco U7000
Standard Motor Products FV5 was a Pollack valve as well but they've been rapidly moving to China so...
If you buy just the valve you'll have to buy an AC Delco D7809C switch and roll your own harness.

Harnessworx sells a harness with the Pollack 6 port motorized valve. Not sure if he sells it with the AC Delco D7809C switch or not. Tell him that's the switch you want the harness setup to take. They were $235 in 2016 and that includes at least the harness and the 65PSI Pollack motorized valve... Probably the switch too... but don't assume. Ask him.
Here's one of his for sale threads. http://67-72chevytrucks.com/vboard/s...d.php?t=706027

He also sells EFI dual tank harnesses for LS and TBI conversions.
I've never done business with him so you should not take this as an endorsement just an FYI. Do your due dilligence.

[44SAA]

I found the good ol 6 port valve off a 1975-80. It’s compatible with my truck. I’m guessing there is a slim chance it’s functional.

Question- how can I test before installing?