Monday, January 6, 2020

Installing a New Fuel Pump on a C3 Corvette

Replacing the fuel pump on a C3 Corvette is not necessarily difficult, but it can be a messy job, so you have to plan your work and then work your plan.

Over the years. I've replaced many components on my Vette, and have to keep reminding myself that the best ones are those made by reputable companies, which 99.9% of the time means American-made. Yes, there are exceptions to that rule, but I have gotten to the point where I refuse to take my chances with components made elsewhere.

Now, to be clear, when I say "American-made" that includes parts manufactured in Canada and Mexico, as well as the USA.

And when it comes to finding the right parts, don't just click the "Add to Cart" button the moment you find what you're looking for.

I've found many great deals on eBay and Amazon in the past, but there are a lot of fly-by-night sellers on both platforms with prices all over the map, so search and compare prices before finalizing a purchase.

I found the right fuel pump for my 1976 Corvette on CarID.com (link at the bottom of the page), even though the listing did not include my model year. However, from my research, I knew this was the right pump for my car.

As a matter of fact, it may be the same fuel pump for Corvettes (and maybe other Chevrolets with small-block V8 engines) from the late 1950s all the way to the late 1970s, so always take the time to do your research.

Total cost, including delivery charges, was $36.12. A great price when compared to other part vendors.



You will need to lift the car in order to be able to comfortably and safely remove the old fuel pump and install the new one. And regardless of the lifting method, make sure the car is secure so it won't roll (if you use ramps or a jack), as well as supported by jackstands.

You will also need regular tools such as screwdrivers, pliers, crescent wrench, standard sockets, extensions, and a rachet, to name a few. Plus a basin or bucket to catch some of the gasoline that will inevitably come out once you disconnect the fuel lines, and as the photo above shows, you will need to remove the right-hand side wheel.

Needless to say, having a fire extinguisher handy is mandatory.

As a side note, you may also want to take this opportunity to replace the pump's fuel line flex hose and the vapor return hose.

Depending on the age of these hoses, this is the perfect time to take care of this task.

Just make sure to order the correct lines since they are molded to exact factory specifications. Using an off-the-shelf straight hose will result in a kinked line and the car will not run.




As the two photos above show, you will need to reach one of the pump bolts with a socket and long extensions. Chevy engineers made a provision for the removal of the bolt. The remaining bolt you can easily reach from under the vehicle.

But before you take the pump out, you will want to disconnect the lines. At this point be prepared ahead of time with a way to plug the lines as fuel will spray out. And even though mechanical pumps are gravity-fed, you may be surprised at how much fuel gushes out of the delivery line. So have a bucket or basin of some sort at the ready.

You can get rubber hose pincher pliers, which usually work great as they minimize the amount of spilled fuel. But since I did not have any handy, I used my next favorite method to plug fuel lines.

I used drill bits. A 3/8" for the fuel delivery line, and a 5/16" for the vapor return line. A little messy but they work far better than old bolts. Just make sure to plug the lines with the shank portion of the drill bit, not the cutting edge.




Once the fuel pump is out, you have to remove the pump base plate since—in order to install the new pump—you will need to grease the pump pushrod so it remains in place and out of the way so you can install the new unit properly.

Yes, there is another way to hold the pushrod in place during installation, so keep reading.

You will also need to have a new fuel pump plate gasket or the proper gasket material to make one. I found the correct gasket at the local Advance Auto Parts store for a few bucks.

Alternatively, and based on how the original pump baseplate looks, you may opt to order a new plate and gasket. I just cleaned mine since it was in perfect condition, albeit dirty.



The picture above shows the fuel pump pushrod as well as the bolts that secure both the baseplate and the pump itself to the engine block.

If the original hardware is there, you may clean the threads by running them through a chaser tap or, better yet, invest a couple of dollars by installing new grade-8 bolts and lock washers. I purchased mine from Tractor Supply Co., but you can also find grade-8 hardware at ACE Hardware and other building supply stores.



In order to keep the new pump from corroding, I gave it a couple of coats of clear paint before installing it. Alternatively, you can paint it. Personally, I prefer the factory-look which is maintained by the clear paint.

You must also remove the 90° brass fitting from the old pump and install it on the new unit. If the fitting is cracked or damaged in any way, get a new one.

Incidentally, like many other fittings used on passenger vehicles, most are NPT or National Pipe Tapered thread items sold at many hardware stores for a lot less than auto parts vendors (click here for an example).

Just because something is labeled as a "Corvette part," it does not make it exclusive or unique, so do a little bit of research before parting with your hard-earned dollars.



Before installing the new fuel pump, I glued the base basket with High-Temp Red RTV Silicone and allowed it to cure for several hours. The purpose of doing this is to keep the gasket from shifting and not sealing properly during installation.

The gaskets between the base of the fuel pump and the baseplate and engine block are there to prevent oil leaks from the drip that lubricates the pushrod. Fuel is delivered to the pump only through the mainline.


I cleaned the baseplate mating area of the block before gluing on the new gasket with High-Temp RTV. The photo above shows remnants of the old gasket before I scraped it off with a razor blade.

Once the area is clean, you may want to install the pump pushrod before gluing on the new gasket.

In order to keep the pushrod out of the way, I like to use a gob of grease which keeps it all the way up so the actuating arm of the pump goes in without the pushrod blocking the way. Sometimes it is necessary to manually rotate the crank a bit so the lobe of the cam that actuates the pushrod is not pushing it down which may also cause some interference.

Alternatively, you can also remove one of the block bolts next to the pump base (usually sitting right behind the lower radiator hose), and replace it temporarily with a longer bolt which will help keep the pushrod in place.

Just make sure you snug it by hand to avoid damage to the pushrod.

See photo for the location of the bolt.

For more details on this procedure, visit the 67-72 Chevy Trucks forum, 67-72chevytrucks.com for an excellent tutorial with photos.

Either approach will work well, but I prefer the glob of grease option since it makes this step a lot faster and it works just as well.



When the new pump is installed, reconnect the fuel lines and clamps and use a flare or line nut wrench for the line that connects to the brass fitting.

At this point, you're ready to start the engine and check for leaks. If each step was done correctly, there should be none.




I hope you found this article helpful, and thank you for following my 76 Vette blog!



Product Links... (#sponsored)

Carter Mechanical Fuel Pump Part No. M6955
Fuel Pump Mounting Gasket #6579 by Fel-Pro
SB Chevy V8 Fuel Pump Mounting Plate w/bolts by Spectre Perf.
Carter Mechanical Fuel Pump Part No. M6955
Permatex 81160 High-Temp Red RTV Silicone Gasket Maker
Hose Pincher Pliers 3-Piece Set
First Alert Standard Home Fire Extinguisher


Additional Resources

CARiD: ACDelco Mechanical Fuel Pump
CARiD: Spectra Premium Mechanical Fuel Pump
Eckler's: Corvette Fuel Line and Vapor Hose Return Kit 1970-1981
• Eckler's: Corvette Fuel Pump Fitting, 90° Outlet, 1963-1966, 1970-1981

1 comment:

  1. Oh man....not sure this is something I want to tackle right now....maybe just the old leaky hoses for now! :) YIKES!

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