Installing a fuel pump on a 1964 Buick Wildcat 401 Nailhead

After the last trip to the body shop Sherman had developed low oil pressure at idle. My first step of troubleshooting was to change the oil, and upon draining the sump, there were 1.5 quarts of gasoline in the motor oil in addition to all the oil that was supposed to be there. Doing a quick google search, this is pretty common.

Factory service manual showing a pump made to be rebuilt. 

First step was to buy a new Carter M4553 Fuel Pump, RockAuto $22.79, plus $6.25 shipping (air filter was included in order so S&H may be higher than normal.) These newer pumps are crimped together and are non-rebuildable. This pump features a one year warranty.

The fuel pump mounts low on the passenger side front of the engine. This is probably easier on a non-AC car. While at this point the car has been in my care 11 years, the pump predates the car going to the junkyard so it was on the order of 17+ years old.

Hoses get disconnected. Careful on the one from the tank; since it is gravity fed you need a bolt to put in the hose or a clamp to keep the gas from pouring.

Both hoses disconnected.

View from the bottom. The fuel pump is held on by two bolts. Removing the motor mount to accessory bracket bracket to the right gives you the room you need to change the pump.

This is how I got the the front bolt. Back bolt came out from the bottom.

New versus old. When the old one, right, was re-installed in 11 years ago I didn't know to grease it, so the wear is evident.

Here is how the old one is suspect. If you look between the rocker arm and the body, it is really clean, where the gas has solvent cleaned the oil off.

View of the rocker arm just as clean where it shouldn't be.

The pump was leaking both directions. While I had it on the floor this giant puddle of oil came out of two vents holes which are past the oil seal.

See that gold ring in the oil pan? That was sediment that drained out of the old pump.

I was impressed that the two bolts still had a good coating of anti-sieze from 11 years ago.

Clean the old gasket off.


Another new vs. old. The outlet fitting gets transferred to the new pump. I tried to use teflon tape on it but adding it wouldn't allow the fitting to thread in, so I went without. No leaks have been detected.

Pump gets coated for the gasket.

Gasket installed and sealant added.

I had wheel bearing on hand to lube the rocker arm.

Dab will do.

Reconnected from the bottom side.

From the top.

Don't forget a new fuel filter. This one is a Wix 33040 for A/C cars. It was $6.49 at O'Reilly Auto.

Aside: This fuel pump lasted from July of 2015 until December 2019. It simply sat on the bench for 9 months while the engine was rebuilt, and upon being put back on the engine didn't pump fuel. It was replaced with a Precision Fuel Pumps M23040 (below) from O'Reilly for $29.64 after discount and with tax.