C2 sending unit

[Larry M.]

Re: C2 sending unit

Not to alarm anyone but here is something I have been thinking about on that baby teething ring.
One might think in the future the ethanol is going to destroy them. But so far I have not heard any complaints.
Maybe some one might have to make the o'ring out of viton rubber???

John:

Who uses ethanol gas?? Not at my house. .

Larry

[Dan B.]

Re: C2 sending unit

Recently installed a replacement sending unit obtained from Corvette Central along with their replacement O ring ($4.50) and retaining ring in a 63 I was working on. You must soak the O ring in oil (as John H has explained) which will cause it to swell slightly to seal. Many people who complain about leaks skip this factory step and blame the parts. No need to pay 6 times the price. GM O rings can also leak if not properly installed. Did not like the replacement retaining ring though, it was slightly thinner and we decided to use the original which fit snugly with the replacement O ring provided. The replacement O rings work fine when installed correctly. I've used them a few times this way and we had no leaks.

NOS lock rings are fairly easy to obtain as they fit a bunch of other Chevy stuff from the era, just bought some spares for $5 each on the auction site.

[Frank D.]

Re: C2 sending unit

First off, my apologies to all. After I drove the car a bit the leak returned and that gave me the opportunity to look at it and see where it was leaking from. It turns out that when I retightened the hose clamp, the hose itself split. I will however take the advice and order a new lock ring and continue to look for the O-ring. Hopefully one will pop up on EBay soon. Again, apologies and many thanks for the support.

Ha! No need to apologize; I wish I nailed every problem the first go round....
Glad you got to the bottom of it, fuel leaks are smelly, annoying and often dangerous.
The problem with the repro "O" rings I've encountered (and as Harry noted) is that the circumference is too large by a slight amount (which you can sort of see in my pic above) in addition to being thinner. If you've ecer tried to reuse a stretched O ring in a pump or elsewhere its almost impossible to get it seated correctly and its easy to pinch it. Put it in the groove on one side and it pops out of the other side.
Having said all that, this repro looks much closer to the original form than the ones I've tried to use before:

https://www.ebay.com/itm/203578171752?chn=ps&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=203578171752&targetid=4580496732614414&device=c&mktype=&googleloc=&poi=&campaignid=418233788&mkgroupid=1230353745471221&rlsatarget=pla-4580496732614414&abcId=9300542&merchantid=51291

[James W.]

Re: C2 sending unit

I would simply use motor oil lubricant like St Louis did. See AIM for details. AIM is specific on this point.

Larry

I am looking at page E165 in my 1965 AIM and do not see where it references soaking the rubber "gasket" in motor oil. Is this referenced in another location in the AIM?

Also, I've attached some pictures of my original rubber sending unit gasket and a reproduction that I found that I had order from LIC earlier this year. My original gasket is much smaller in diameter 2.187-5"(original) 2.374-5"(repro) and thinner 0.207-5"(original) 0.235-5"(repro) than the reproduction. Is it safe to say this was caused by age and being exposed to gasoline? You can also see how much smaller in diameter the original gasket is compared to the repro when sitting on the mating surface of the sending unit. My '65 has been in the family since 1974 and is mostly unrestored with the exception of a repaint in 1978. From what I found when I removed the gas tank from the car, this is the first time the sending unit had been out of the tank. I found that the original gas tank is near perfect inside so I cleaned the outer surfaces of the tank and it going back in the car.


Thanks,

James

[Gary B.]

Re: C2 sending unit

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[Mark F.]

Re: C2 sending unit

Hi Gary,

hmmm...I wonder how they did that soaking at the assembly plant??

or, was that a subassembly operation at the tank manufacturer's plant?

[Harry S.]

Re: C2 sending unit

Hi Gary,

hmmm...I wonder how they did that soaking at the assembly plant??

or, was that a subassembly operation at the tank manufacturer's plant?

I would tend to think that if it's in the AIM it happened in St. Louis. As an example, there are no sub-assembly instructions in the AIM as I recall.

[Larry M.]

Re: C2 sending unit

Hi Gary,

hmmm...I wonder how they did that soaking at the assembly plant??

or, was that a subassembly operation at the tank manufacturer's plant?

They put them in a bucket of oil near the assembly station. Then they removed one each time it was needed. See earlier posts #18 and 21.

Larry

[Larry M.]

Re: C2 sending unit

I am looking at page E165 in my 1965 AIM and do not see where it references soaking the rubber "gasket" in motor oil. Is this referenced in another location in the AIM?

Also, I've attached some pictures of my original rubber sending unit gasket and a reproduction that I found that I had order from LIC earlier this year. My original gasket is much smaller in diameter 2.187-5"(original) 2.374-5"(repro) and thinner 0.207-5"(original) 0.235-5"(repro) than the reproduction. Is it safe to say this was caused by age and being exposed to gasoline? You can also see how much smaller in diameter the original gasket is compared to the repro when sitting on the mating surface of the sending unit. My '65 has been in the family since 1974 and is mostly unrestored with the exception of a repaint in 1978. From what I found when I removed the gas tank from the car, this is the first time the sending unit had been out of the tank. I found that the original gas tank is near perfect inside so I cleaned the outer surfaces of the tank and it going back in the car.


Thanks,

James

Can't see from the pics, buy originals all have the "JR" logo on the small tab. Look for it.

Larry

[Mark F.]

Re: C2 sending unit

I would tend to think that if it's in the AIM it happened in St. Louis. As an example, there are no sub-assembly instructions in the AIM as I recall.

Good point, Harry...like UPC 6 Sheet A2 ('67 AIM) they show the alternator ASM as #4, but they don't show you how it's put together...just how it's mounted

[James W.]

Re: C2 sending unit

Gary,

I looked in my '65 AIM and there is a flag similar to yours on the fuel meter & support sheet, but I did not see any instructions in the front pages of my AIM. I'll look again tonight in the back of the AIM also. I beleive what eveyone is saying about soaking the gasket in motor oil.

Thanks,

James

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[Gary B.]