Replacing the fuel pump in a 68

Well one more thing on Frankenvette needed replacing so here’s another short writeup in case anyone else needs the info. The following should see you through replacing the mechanical fuel pump on an early C3.

My pump had developed a couple of issues. First oil was misting out of the little vent hole in the casing of the pump and being drafted by the airflow up and onto the hood. Second there was a tiny gap in the casing (circled in the pic below) that was also venting fluid as well.

Simplest option was just to replace the pump with a new one. Total cost for me was about $50 for a standard Carter style replacement (which came with a gasket) and a metre of 3/8″ (10mm) fuel hose. You may also need some 1/4″ hose if you intend to replace the return line as well if you have one.

First step is to find someone with a lift as that will make this job a whole lot easier. Toothy Grin If not, then just raise the car up on ramps or support it with stands under the jacking points on each side of the car. Now clamp off the fuel hose at the tank as it will stop the fuel being pulled by gravity when you remove the line on the pump. Also disconnect the battery so there are no sparks while you’ve got gas dripping about. If you don’t have a A/C compressor in the way then the next bit will be a lot easier. If you do, then it’s time for a bit of contortion.

On the front of the block in line with the fuel pump there should be two holes in the block with the top one filled by a bolt. If you remove this top bolt and thread in a longer one (I used a 3/8″ x 1 3/4″) you will be able to trap the rod that drives the pump so it won’t fall out when you remove the pump. Believe me this will make life a lot easier when re-assembling things.

Next remove the soft lines to the pump. Now you may have a 3/8″ feed line and a 1/4″ return line to remove, or you may have a modified setup with only a feed line. Either way remove the clamps on the hoses and pull things off. It’s a good idea to have a tub or something to catch the gas that will drain out or you may end up lying in it when under the car for the next part. Next remove the hard line from the pump to the carb at the pump.

That’s the easy part done. Now time to remove the pump. It’s held on by two bolts. The first is nice and easy to get to from the top/front by sliding a ring spanner past the lower radiator hose onto it. More fuel will drain from the pump as it starts to come loose. Now there’s the last bold left. This you can get to from underneath with a ring spanner, just. On my car there was about enough room for about 1/8th of a turn at a time so this last bolt took a long time. Once it comes out the pump will either drop off or need to be pried off because the gasket has stuck so you are half way there and probably should go have a beer to celebrate.

Next if there are signs of an oil leak from behind the mounting play you may need to take that off too via the two bolts that retain it. I didn’t have a gasket handy so left mine for now. Either way you will need to clean up the surface as there’ll be crap from the old gasket all over it I’m guessing.

Easily cleaned up from underneath with a scraper as there’s enough room to get one up under there. Just be careful not to cut your radiator hose as it’s going to be close.

Now is probably a good time to take the hard line to the carb out and check/clean your filter and line as well. I found a whole heap of crud in my in-carb filters (from my old bad tank).

Getting the new pump on is a lot easier now you know how it all came apart. Put the gasket on the pump and feed the two bolts through it. This will hold the gasket in place while you fit the pump. Get under the car and feed the pump lever into the hole so it’s under the rod. Now you’ll need to try and hold the pump with one hand while trying to start one of the bolts with your other hand. Once that’s started try the same with the other bolt which will most likely be a lot harder due to the tight space. Do them both up tight once you are able.

Next refit the hard line from the carb, and the feed/return lines. I replaced the feed line at this point as mine looked old and was starting to crack. Apparently the original fuel line in a 68 was moulded so it would curve nicely to from the line to the pump. If you replace things with standard hose make sure you have enough so you can route it without causing a kink and pinching the line which will restrict the fuel flow.

Once the lines are on and the clamps tightened remove the clamp on the line at the tank. Also remember to remove the bolt holding the pump rod and replace it with the original bolt. make sure this is done up tight otherwise it will seep oil.

Now it’s time to drop the car down and reconnect the battery. Crank the car over a few times without pumping the gas pedal to get the new pump going and prime things with fuel. Once you think it’s right then give it some gas and try to start it. All going well you now have a sweet running car. After a minute or so stop it and go and check the connections at the pump for signs of gas or oil leaks. Tighten everything if there is and repeat the process. Now go have a beer because it’s well deserved.

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