Why would my new fuel pump leak?

[standup303]

Have a newly built 440 with a Carter super street M6903. No issues for 400 miles and all of a sudden on the last drive I took it started leaking out of the bottom gasket. Drive was no different than any others. Any idea what would cause this?

 

[GTX JOHN]

If it is gas leaking (I assume rather than oil), I
would venture that the diaphragm might be leaking
unless the fuel line has a leak.

If not the lines, I would remove and disassemble the pump
to inspect pump if several of the screws are not loose and the
whole pump is not coming apart (Not likely) I see you have the one
with the screws whichI like better than the other pressed together style.

 

[standup303]

If it is gas leaking (I assume rather than oil), I
would venture that the diaphragm might be leaking
unless the fuel line has a leak.

If not the lines, I would remove and disassemble the pump
to inspect. I see you have the one with the screws which
I like better than the other pressed together style.

Thanks. Yeah, sounds like a rebuild is in order.

 

[GTX JOHN]

I added a bit more to my post.

 

[dano]

How old is it? Old rubber and synthetic rubber materials do not stand up to todays fuel, so if you rebuild it, use a new kit and look specifically for ethanol safe if available. Fuel lines as well, if you have old rubber lines then replace them all including the one at the tank.

 

[Kendog 170]

8 Screws? They have 6 screw as well.
Mancini Racing Fuel Pump Rebuild Kit

 

[AJ/FormS]

My First guess would be the gear clamps bunching up the hoses under the screwhead. If I have to use those, I double them up with the screwheads rotated 180* from eachother... all of them back to front. The rear jumper is higher than the tank, so it doesn't usually leak. Instead it sucks air.
Edit;
and
My second guess is that the fuel in the line is boiling because it's in close or near close contact, with the radiator hose; and then the pressure could be blowing past the gaskets.

 

[standup303]

How old is it? Old rubber and synthetic rubber materials do not stand up to todays fuel, so if you rebuild it, use a new kit and look specifically for ethanol safe if available. Fuel lines as well, if you have old rubber lines then replace them all including the one at the tank.

Spanking new from Summit about 5 months ago.

 

[RustyRatRod]

Cause they're made in China.

Beyond that, did you tighten up the screws around the perimeter of the pump? Sometimes on those type pumps, there's even an instruction sheet that says to do that.

 

[65 Cuda 340]

Whether or not it's a cause of the leak, that fuel hose is too close to the lower radiator hose. I wouldn't run it next to the block, either. I'm not sure what kind of alternator bracket you have, but on my two big blocks, I run the hose up behind the alternator bracket, between the alternator and the water pump housing.

 

[Bewy]

The screws are clamping rubber.....which compresses. Probably just need tightening. You could use Loctite on the screws....

 

[Dartvader440gt]

Unfortunately I've had new ones leak on me also. Credit to shoddy workmanship.

 

[440 Mike]

The 2 screws that hold the portion of the pump that your arrow is pointing to are inside the pump.

Here is a video with everything you need to know:

 

[GTX JOHN]

More Chinese Junk?

 

[Swinger 340]

My First guess would be the gear clamps bunching up the hoses under the screwhead. If I have to use those, I double them up with the screwheads rotated 180* from eachother... all of them back to front. The rear jumper is higher than the tank, so it doesn't usually leak. Instead it sucks air.
Edit;
and
My second guess is that the fuel in the line is boiling because it's in close or near close contact, with the radiator hose; and then the pressure could be blowing past the gaskets.

I just went through this. Ethanol and winter fuel is not a good combination with a carburetor car that has a fuel pump at the motor. A high chance of "Vaper Lock", as in this case, increase pressor at the heat source, motor, manifolds, headers as an example. If your set-up can't be corrected, place a machinal pump away from the motor. I installed one on the frame, by the fuel tank on my van.

 

[Daves69]

Bought one 1-1/2 years ago. How much do ya' believe in stickers?
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