RFJohnston

I just replaced my sending unit and it leaks past the rubber O ring. The cam lock isn't tight at all. I can move it side to side about 1/4". It rotates very easily to the the limit of it's rotation. (lock)

Are these things made to stay centered? Do I need a new cam lock? I don't want another gas bath...

GUSTO14

Unless the tank retaining flange or cam is damaged and the O-ring is good, the cam should be very tight. As you tighten the cam, it has tabs that incline making them press the cam tighter against the O-ring and tank. At the limit it actually has a notch it "climbs" over to lock it in place.
Fuel Sending Unit Cam ~ $2.00

FUEL SENDING UNIT O-RING SEAL ~ $2.00

They even have a tool for under $20 if you don't want to risk the new cam with a cold chisel...Fuel Sending Unit Cam Tool


I would get a new O-ring at least and maybe a new cam and see if this doesn't fix the problem. These parts are not unique to the Corvette, so it's likely you can find them locally.

Good luck... GUSTO

PinkVetteLady

Great pics.. I used a bronze drift instead of buying the tool.. Had the drift and not the tool so I made it work.. LOL

RFJohnston

Dunno guys... I got all those things.... still leaks. I have a new gasket and cam being overnighted to me from Paragon. stay tuned....

mysixtynine

When I replaced my tank in my 69 I also purchased a new sending unit. Both the tank and the sending unit came with a new cam ring and O ring. I tried using the cam ring from the sending unit and it was way too loose. I could install it almost by hand. I grabbed the bag with cam ring that came with the new tank and you can see a definite difference in the two cam rings. On the loose cam the 3 edges that ramp up to put pressure on the O ring were almost non existent. On the tight cam you could really see the 3 edges (ramps) that put pressure up against the sending unit which applies pressure to the O ring. To make it easier without the tool I use a little silicone grease on the cam so it will turn easier against the sending unit plate. I then use two big pliers to grab the cam tabs and turn them together to get it to lock in. I then fill the tank only enough to get gas over the sending unit with the front end of the car jacked up so that I can drop the front end in case the tank leaked.

6T7L71CPE

The factory soaked the seals in oil for a few hours before installation. You might give this a try. However, my old tank/ring and the new tank/ring were what I would call snug. I did the same thing as mysixtynine, I tested the seal slowly.

DansYellow66

The new cam lock I used on my replacement tank was too small and if not carefully kept centered could slip and become disengaged on one side. By installing it carefully to keep it centered, I got it to seal up fine. Do you have your old cam lock? You might want to use it instead. That's what I did on my GTX's sending unit this last weekend. Course I first spent an hour trying to install the sending unit upside down before I figured out my mistake.

RFJohnston

I ordered a new cam lock and a new o-ring from Paragon, and had them overnight it to me. O-ring was very slightly larger. New cam lock had a very slight more 'incline' to the cam ramp. These two new items seemed to solve the leak problem.

Purists will hate this... I also used a thin coat aviation non-hardening gasoline impervious Permatex. Sorry, but this baby is now sealed.