Leaking fuel pump

[JOS]

My 1966 230 SL has developed a fuel pump leak, a constant drip out of the over flow tube.

Things I have done so far.
Replaced fuel filter
Checked return line. clear.
Checked fuel line from fuel pump to fuel filter, clear.
Checked hoses inside trunk to canister. Clear.
Checked hoses from gas tank to fuel pump, clear.
Replaced fuel pump, second pump doing the same thing.
Any Ideas? 

Thanks

[mdsalemi]

Where exactly is this leak?  You say overflow; are you talking about the overflow that comes from the canister in the trunk, and exits via a metal tube on the right rear of the car?

Where are you?  The current heat wave in much of the USA will cause fuel expansion and cause this to drip.  On the way to PUB last week in the heat, I filled up about 80 miles out of Columbus, and soon after started smelling gas...when I got to the hotel, the overflow was dripping.  I simply removed the filler cap, relieved the pressure pushing the fuel out, and problem went away.  It was the heat.

[George Des]

If this is the original, long style pump and it is leaking from the small leak off pipe, you have an internal seal problem and the pump will need to be rebuilt or replaced.
There are many posts covering this in the forum.
George

[JOS]

I do have the old long fuel pump.
I live in North Carolina USA last tree week temperature average 95 degrees.
my problem started when the temperature average was 75 degrees.

What are the chances that two pumps are having  all of a sudden the same problem?




"The reason Politicians try so hard to get re-elected is that they would 'hate' to have to make a living under the laws they've passed."

[George Des]

With these old style pumps, the chances are very good depending upon how much service they have seen and how dirty or clean the fuel was that were run through them. I do not think that the temperature is a factor, but you are correct in ruling out a restriction somewhere in the line. These pumps have a mechnical seal that seals the shaft, preventing fuel from going from the pump section to the motor section. The seal is not always perfect and the leak off pipe allows any that gets by the seal to drain off. A drop every now and then is not any real cause for concern but a few drops per minute or steady stream is. A build up of fuel in the motor can result in development of a paste once it combines with the brush dust and this will eventually choke off the motor. You could possibly rule out a bad seal by testing the pump off the car with a small device that would allow you to run fuel through the pump to determine if the feed and return lines are truly clear and are not causing a back pressure in the pump. It is also quite possible that the pump check valves located on the pump outlet fitting may be blocked. If so, this would cause enough back pressure in the pump that fuel would blow past the seal. If the pump still leaks after checking these issues, then it is almost certain to be a faulty main seal in both pumps. Hope this helps.

George

[JOS]

Thank you George.

Where can I buy the parts needed to rebuild a fuel pump?

Thanks

John O. Salazar


The reason Politicians try so hard to get re-elected is that they would 'hate' to have to make a living under the laws they've passed.

[George Des]

John,

My advice is to pull the pumps apart to assess whether they are a good candidates for a rebuild. Usually they are even if the commutator is worn-they can be rewound with a brand new commutator if need be by a firm in CA called Eurton. If your comm is ok, then a typical rebuild would include new bearings, o-rings, brushes, rubber seals and a new tab washer. I have put kits together for several folks in the past that include these parts. Take a look at the tech manual to see what all is involved and then contact me with a PM if you would like a kit. Hope this helps.

George