Ok guys, I am not a mechanical type person. I kinda like it, and I’ve replaced brake pads and a few little things to cars over the years, but I’m a true novice. That’s one of the reasons for my purchase of the C3. I wanted something that I could learn on and tinker with over time and “upgrade” a thing or two.......over time. Well, my “over time” has come much too quickly. I’ve had the car for about a month (I’ve driven it approximately 250 miles) and I came home yesterday to a seriously strong odor of fuel, a puddle under the car, and an apparent leak of some kind. I opened the hood, started the car and saw fuel spraying from under the fuel pump. I couldn’t tell if it was a hose or the pump itself, but I ran the hoses with my fingers as the car was running and couldn’t feel a split of any kind. I’ve removed the pump, plugged the fuel line to the gas tank and have ordered a pump from the local Autozone. I’ve decided to take this opportunity to replace the filter, the pump, and all the rubber fuel hoses and hose clamps. I’ve purchased so far a:

Pump
In-line filter
adhesive for the pump seal

I need to go back and purchase some rubber fuel line and hose clamps. A couple questions. Am I missing anything or is there anything else I should consider? Also, what is this third fuel line that goes to the bottom of the pump and seems to run parallel to the main fuel line back to the gas tank?

The Carb is newly replaced this last fall before I purchased the car. The car hasn’t been driven much over the last 8 years, but I’m planning to make it my daily driver after I get it up to snuff. My father-in-law is a whiz with engines and he is a great resource over the phone. Unfortunately he’s 6 hours drive away or he would have had this apart and back together in a fraction of the time it is taking me.

Thank you in advance for any helpful hints or advice.

The fuel pump




The extra fuel line that seems to run back to the fuel tank. The main fuel line is underneath it. Please correct me if I’m wrong. I just don’t know the function of this extra line. It didn’t appear to be the fuel supply because I didn’t have to plug it like the main fuel line.



This is where the extra fuel line was attached on the bottom of the pump.

 

The mystery line is the "return line". It returns unused fuel to the gas tank, thereby cooling the fuel somewhat, then is pumped back to the carb if needed. Just like a closed loop. Some models take a detour through the vapor canister on the way to the tank.

So, your replacement pump must have not only three ports, but the ports should face in the correct orientation. I would recommend another Delco for stock or moderate H.P. application. If that original Delco made it 50 yrs, a new Delco should . . . . . .

You will also need a fuel pump gasket, a fuel pump mounting plate gasket + Permatex Black. Go ahead and change the plate gasket while you're in there. Apply goop on both sides of both gaskets also.
By placing the engine in the #1 TDC the pump pushrod will be the farthest away from the pump arm. This makes it a lot easier to install. The rod will try to drop down but there are ways of holding it into position, but I have had success by just being faster than the pushrod. Once you get one bolt started you have it made.

 

The extra fuel line is a return line to the tank. I would order the preformed lines from someone like Willcox Corvette. Get an AIM (Assembly Manual). It will be a major help with this repair and other future work.

Bob K.

 

Jason, it looks like the feed line from your pump to the carburetor is a rubber line. Is there any reason you can not replace it with the correct metal line?

You mentioned replacing the inline fuel filter. What type of inline filter does your car have?
What carburetor are you using?
What engine do you have?

Your engine should have a Quadrajet unless it is an LT-1 which used a Holley. Both left the factory with a metal fuel line.

When replacing the fuel line, be sure to use hose specifically designed for fuel. The feed line that goes from the frame to the fuel pump, is a preformed hose specifically for your car. Many have tried to replace it with ordinary fuel line and soon discover that it will kink and restrict fuel flow or fail prematurely. Be sure to purchase the correct hose to avoid this problem. This is what the frame to pump hose (Molded "S" Hose Kit) should look like...



https://www.paragoncorvette.com/p-35...-hose-kit.aspx

The return hose is more straightforward, but is 1/4" fuel line and looks like this...

https://www.paragoncorvette.com/p-35...-hose-kit.aspx

Good luck... GUSTO

 

S fuel hose ... pre-formed ... yes, you Might get a length of hose cut exactly right ... but maybe not ... then the hose partially or fully collapses and you're left scratching your head ...
they're pre-formed for a reason.

https://willcoxcorvette.com/corvette...it-front-70-82

 

Also, since you're new to the C3, you may find this Vehicle Information Kit useful. It is filled with lots of specific data related to your 1972 Corvette. Save it to your hard drive for a quick and ready reference.
https://www.gmheritagecenter.com/doc...t-Corvette.pdf

These kits are available at the GM Heritage Center website for most GM vehicles.

Good luck... GUSTO

 

In your first photo it looks like the upper control arm bushing is bad. Evidenced by some rubber squished out and the fact that it is off center. This job is probably best left to a professional.

 

The "S' Hose. Often imitated, never duplicated. The C3 "S" Hose.
Not available in any store. Don't be fooled by other knock-offs.

But wait! Call in the next 10 minutes and receive two offers for double the money. Plus we will throw in four clamps. Absolutely free. (plus shpng / handling fees)
And in addition, receive a pair of micro-fiber towels to first five customers. Act Now!

 

A few things come to mind. When changing the fuel pump, check to see if there is a bolt at the front of the engine. There should be a bolt about two inches up. Remove it. It should be very short. Once the pump is removed and the engine is at TDC on the #1 piston, remove the rod inside the engine. Find a bolt about 2" long that is the same diameter and thread size as the small bolt. Start the new bolt in the hole. Put the fuel pump rod into the engine and when it is all the way up, thread the long bolt in until it contacts the fuel pump rod. Hand tighten only. The bolt will hold the rod in place while you install the pump. Once the pump is installed, remove the long bolt and replace it with the original small bolt. I add a bit of gasket seal on the shoulder of the bolt to prevent any leaks. I would also change all fuel lines as they may be original. Don't forget the line from the tank to the steel fuel line at the back of the car. Lastly, change out the oil in your car in case the rubber diaphragm on the pump leaked fuel in your crankcase. Be careful with all the fuel around. Jerry

 

One other tip....pack the cavity where the lever goes into the pump with grease, so the lever where it pivots stays lubricated. Just make sure that the battery is disconnected while you do this work..

 

Jason

When changing the fuel pump on my 69 350 with A/C I found I had to remove the lower radiator hose to get at the fuel pump bolts. Also, removing front tire helped.
I used Tampa Jerry's method for holding the fuel pump rod up. It works!

VS

 

The S hose is a must for any stock early C3.......in fact, order two of them and stick one in the box for the future....

Jebby

 

Guys, thanks for all the links and the helpful hints. I’ll tell you how it goes.

 

You guys are a plethora of knowledge. I appreciate it so much. Someone tell me about the original fuel line from the pump to the Carb. Where was the fuel filter? I have a generic rubber line with a generic in-line filter that cost $3.99.

 

It was on the pressure side, where yours should be....never put a filter on the inlet side....
The original fuel filter was in the housing screwed into the Q-jet carb body.

Jebby

 

Old cars don’t tolerate ethanol in the gas very well. Use 100% gas if you can.

 

Just a little update. Yesterday, my 17 year old son and I were finally able to get the new fuel pump installed. I did ultimately have to take a hose loose from the radiator to the water pump to be able to get enough room to get it back in place. I watched a YouTube video of a guy installing one, and picked up a couple tricks....... but it was on an old Chevelle and there seemed to be way more room to work.

Anyhow, it’s back in place and the radiator is full again. The car started right up, and it runs WAY BETTER now. Before (with the old fuel pump), the car would cough and sputter and would choke-out if you even touched the gas peddle right after startup when cold. Now? It starts cold and purrs like a kitten from the start.

I’m very happy with the results. Now on to the next project. Thanks guys for all the helpful information.

 

Jason, I apologize if I missed it, but did you ever tell us what carburetor you have?

A picture will do. If you tell us the carb, we can likely link you to the correct metal line for your engine.

Good to hear you've solved the fuel feed problem.

GUSTO

 

I didn’t ever tell you the Carb. Thank you fie your generous offer. I will take a few quick snaps tomorrow and post them. The only thing I know is that the carb was recently replaced before I purchased the car. I just wished the fuel pump would have been replaced........evidently it was not.

 

Sorry, I forgot the Carburetor pics. I’ll try and take some today. Meanwhile, my 17 year old thinks he’s a boss learning to drive a manual transmission in the C3