Need help with a leaky fuel pump

Gert3116 · 09-18-2007, 09:01 PM

My fuel pump went out a couple months ago and I replaced and it started leaking. I took it back off and replaced the gasket and cleaned it all up and it still leaks. If anyone has any tips I could use some.

dynamic88 · 09-18-2007, 09:52 PM

maybe try some black silicone to see if that helps seal it up

Oldsguy · 09-19-2007, 05:15 AM

leaking fuel or oil? I think you mean oil. Then the pump itself really isn't leaking the mating surfaces between it and the front of the block are. The block surface must be free of any old gasket debris or old silicone, etc. That area is hard to get to when the engine is installed with everything in the way, sort of a tight fit. I use a small mirror and flashlight to reflect light directly onto the surface and allow me to see how clean the surface is. Use a small scraper, small bits of emery cloth on the ends of my fingers etc to clean it off. If you have room (I doubt it) use a dremel tool with a buffing attachment, that is the one that is made of layers of white cotton pressed together. I did this but the fan and alternator and all the other stuff was off the engine. It turns fast enough to provide enough friction to clean the surface. Then clean with denatured alcohol or your favorite solvent. It really has to be clean. The same goes for the fuel pump mating surface but usually if it is new that isn't a problem. I pre-apply the gasket to the pump first with silicone and let it set up. That way it won't slip on me when I install it, a little silicone on the other surface and on it goes. If it still leaks, you may have a bad gouge or someone in the past has really worked on that surface and given it a depression so it isn't flat.

Gert3116 · 09-20-2007, 09:03 PM

My brother is a mechanic and he helped me install it and he said the block might be warped. have anyone ever heard of this.

Oldsguy · 09-21-2007, 03:24 AM

No I haven't experienced that or heard of that but I guess it would be possible. That area of the block is pretty strong with not many large flat areas. I would think more that the surface has been made uneven by excessive "cleaning" with abrasives like sandpaper or a heavy scratch from a scraping tool, etc. But like your brother has mentioned, if it is warped that would cause difficulties getting a good seal.

ozoneblue · 09-21-2007, 06:10 AM

Are the Olds blocks like the SBC blocks? .With a 5/16 threaded hole above the fuel pump If so this bolt is known to leak, It is made for access to the fuel pump rod.use thread tape on this bolt when re installing. CAUTION if bolt is missing do not use one too long

Oldsguy · 09-21-2007, 08:24 AM

They use a stud on the bottom and a threaded hole on top, not sure about the size. On the Oldsmobiles, the fuel pump has an integral armature that rides against the eccentric on the front of the camshaft, I don't think the hole is all the way through for access to a rod.

Olds64 · 09-21-2007, 03:32 PM

I don't think the block would warp in that area.

Maybe if it was a Chevy engine. I hear that GM used Crest toothpaste in the late 60s to mid 70s as a material for Chevy engines. They would inject it into a mold and let it harden. You know, the way toothpaste gets hard on the sink when you forget to wash it off in the morning. That is why Chevy had to use four bolt mains. The metal wasn't really metal at all, just hardened toothpaste.

ozoneblue · 09-21-2007, 04:53 PM

Dont know what Olds used ,But my 54 dosent have many cavietys

Gert3116 · 09-21-2007, 10:33 PM

alright. i guess i'll take it off again and try a new gasket and clean it some more. thanks for the info.

88 coupe · 09-22-2007, 02:29 AM

Quote:

Originally Posted by Gert3116

........ he said the block might be warped ........

Not a chance.

If the mating surfaces are clean and the gasket is new, the leak is elsewhere. Ask yourself: What changed when the leak started?

Clean the pump with brake cleaner so it is good and dry.

Get an athletes foot spray power (like Desonex), and spray any suspect areas with the spray powder. Take it for short ride. The power should change color showing you exactly where the leak is coming from.

Thanks, to oldsmobile1915, for this one.

Norm

texasred · 09-22-2007, 05:06 AM

Quote:

Originally Posted by 88 coupe

Get an athletes foot spray power (like Desonex), and spray any suspect areas with the spray powder. Take it for short ride. The power should change color showing you exactly where the leak is coming from.

Thanks, to oldsmobile1915, for this one.

Norm

I like that one!

C.J.

Olds64 · 09-22-2007, 05:54 AM

That is a good idea, and it is alot cheaper than buying some of that Zyglo leak detector from the auto parts store.

09-18-2007, 09:01 PM	#1 (permalink)
Gert3116 Red69CutlassS Join Date: Sep 2007 Location: Billings Posts: 35	Need help with a leaky fuel pump My fuel pump went out a couple months ago and I replaced and it started leaking. I took it back off and replaced the gasket and cleaned it all up and it still leaks. If anyone has any tips I could use some.

09-19-2007, 05:15 AM	#3 (permalink)
Oldsguy Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 2,775	leaking fuel or oil? I think you mean oil. Then the pump itself really isn't leaking the mating surfaces between it and the front of the block are. The block surface must be free of any old gasket debris or old silicone, etc. That area is hard to get to when the engine is installed with everything in the way, sort of a tight fit. I use a small mirror and flashlight to reflect light directly onto the surface and allow me to see how clean the surface is. Use a small scraper, small bits of emery cloth on the ends of my fingers etc to clean it off. If you have room (I doubt it) use a dremel tool with a buffing attachment, that is the one that is made of layers of white cotton pressed together. I did this but the fan and alternator and all the other stuff was off the engine. It turns fast enough to provide enough friction to clean the surface. Then clean with denatured alcohol or your favorite solvent. It really has to be clean. The same goes for the fuel pump mating surface but usually if it is new that isn't a problem. I pre-apply the gasket to the pump first with silicone and let it set up. That way it won't slip on me when I install it, a little silicone on the other surface and on it goes. If it still leaks, you may have a bad gouge or someone in the past has really worked on that surface and given it a depression so it isn't flat. __________________ Dan '46 2 door

09-21-2007, 03:24 AM	#5 (permalink)
Oldsguy Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 2,775	No I haven't experienced that or heard of that but I guess it would be possible. That area of the block is pretty strong with not many large flat areas. I would think more that the surface has been made uneven by excessive "cleaning" with abrasives like sandpaper or a heavy scratch from a scraping tool, etc. But like your brother has mentioned, if it is warped that would cause difficulties getting a good seal. __________________ Dan '46 2 door

09-21-2007, 08:24 AM	#7 (permalink)
Oldsguy Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 2,775	They use a stud on the bottom and a threaded hole on top, not sure about the size. On the Oldsmobiles, the fuel pump has an integral armature that rides against the eccentric on the front of the camshaft, I don't think the hole is all the way through for access to a rod. __________________ Dan '46 2 door

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09-18-2007, 09:52 PM	#2 (permalink)
dynamic88 Senior Member Join Date: Oct 2006 Posts: 147	maybe try some black silicone to see if that helps seal it up

09-20-2007, 09:03 PM	#4 (permalink)
Gert3116 Red69CutlassS Join Date: Sep 2007 Location: Billings Posts: 35	My brother is a mechanic and he helped me install it and he said the block might be warped. have anyone ever heard of this.

09-21-2007, 06:10 AM	#6 (permalink)
ozoneblue Senior Member Join Date: Jun 2006 Posts: 404	Are the Olds blocks like the SBC blocks? .With a 5/16 threaded hole above the fuel pump If so this bolt is known to leak, It is made for access to the fuel pump rod.use thread tape on this bolt when re installing. CAUTION if bolt is missing do not use one too long

09-21-2007, 03:32 PM	#8 (permalink)
Olds64 Landyacht Club President Join Date: Jul 2007 Location: Lawton, OK Posts: 1,242	I don't think the block would warp in that area. Maybe if it was a Chevy engine. I hear that GM used Crest toothpaste in the late 60s to mid 70s as a material for Chevy engines. They would inject it into a mold and let it harden. You know, the way toothpaste gets hard on the sink when you forget to wash it off in the morning. That is why Chevy had to use four bolt mains. The metal wasn't really metal at all, just hardened toothpaste.

09-21-2007, 04:53 PM	#9 (permalink)
ozoneblue Senior Member Join Date: Jun 2006 Posts: 404	Dont know what Olds used ,But my 54 dosent have many cavietys

09-21-2007, 10:33 PM	#10 (permalink)
Gert3116 Red69CutlassS Join Date: Sep 2007 Location: Billings Posts: 35	alright. i guess i'll take it off again and try a new gasket and clean it some more. thanks for the info.

09-22-2007, 05:54 AM	#13 (permalink)
Olds64 Landyacht Club President Join Date: Jul 2007 Location: Lawton, OK Posts: 1,242	That is a good idea, and it is alot cheaper than buying some of that Zyglo leak detector from the auto parts store.

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