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55 Fuel Pump Cover Leak


KAD36

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Took the Buick out today for a short trip - its been out a few time this year, and its been run in the garage also. It was about 70 out here, and a few miles down the road the engine started surging - kind of like a vapor lock symptom on a hot day. I hit the electric pump and it went away. Turned the pump back off - and shortly thereafter the problem came back. Turned pump back on. Hmmm - not typical, dont see vapor lock unless its like 85-90 out, turned and headed for home. About a mile from the house, picked up a faint smell of gas. Got the car home, popped the hood, and saw water pouring through the front of the radiator. Water? Coolant leak too? No way, that was gas. Jeepers cats - shut everything down. Don't do anything to make a spark.

Gas had been shooting from between the top of the housing and the top cover. It was probably dribbling when the electric pump was off, and flowing freely all over the radiator when the pump was on. This is the second time this has happened. The first time, upon removing the top cover, it looked like the cover gasket had shifted and gas leaked out. I had taken the cover off back then, ran it over a piece of sandpaper on a flat surface to make sure the cover was perfectly flat - which at that time it was not. The gasket is rubber and was in good shape - pliable - no rips or tears. Applied some fuel tolerant sealant and glued the gasket to the cover, put it all back together, torqued all the screws evenly in a pattern. That was about 2 years and 1500 miles ago. And here we are again. This time, the gasket was still in place, and I am not sure what went wrong. I reran the cover over a piece of sandpaper on a flat surface and noticed there was a new "low spot". Hmmm - thought we took care of that last time. Ran a few more strokes until it was flat, the gasket looks good, still pliable with an indentation showing where it sealed to the housing - and have just resealed it to the cover. Its drying now.

Any advice before I bolt it back to the pump housing? This is supposed to be simple like dirt. What do you torque the cover screws to (I have the early fuel pump with 6 screws on the cover vs the dome with 1 screw in the middle). Am positive there are lockwashers on there. Am I missing something subtle?

Perhaps for a fail safe, one could install a pressure switch downstream of the pump that would prevent the electric pump from turning on if the line could not hold pressure, that might complicate things though when the pump is used to prime the system after the car has sat for awhile unless a bypass switch of some sort was added.

Lesson learned - if your car acts up with what seems like a fuel delivery problem during a time when there shouldn't be one, think twice before hitting that electric pump switch to rescue yourself. Pay attention and KNOW YOUR CAR. If something seems odd, pull over and check the pump and line integrity first. And carry a fire extinguisher. Boy oh boy if that leak were spraying into the generator or the hot manifold - poof! - you guys could have a field day buyin tasty crispy fried 55 buick parts on eBay.

Edited by KAD36 (see edit history)
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Thanks for the quick response guys - Mike I did just as you said. Got some small stainless washers down at the parts store. This pump is about 12 years old - I got it rebuilt on exchange from a well advertised Buick parts supplier. I have replaced all the guts once myself a few years back (thanks Willie for that bent nail trick) - there were never any lockwashers and I didn't think to add any - this is how it came. Long story short, I made a new gasket from some rubber/fiber material (one of my better creations actually), re-assembled dry, and hit the electric pump. No joy. It seeped a fine ribbon of fuel out the back.

Humpf.

When in doubt, use two. Made a second, stacked em up, and being experienced and skilled at cracking 50 year old cast parts and stripping fine pitch threads, took it as snug as I dared starting with the 2 center and cross tightening the perimeter then back to the center. Ran the electric ump for a few minutes with the engine off and it held. Its been idling in the garage for about 30 min with the pump on and looks good. Willie - you got me wondering if that pump housing is off true. I have wondered about this pump since I got it - especially if that boss in the center was true so there isn't any leakage from the suction chamber to the pressure chamber. BTW - is that Permatex anaerobic sealer fuel tolerant? I hesitated using any sealer this time.

Well, better fixed now than on the way to Indiana. Odd how it just "went". Jeese. Gotta sit down and have a talk with that car...:cool:

Edited by KAD36 (see edit history)
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Ken

I would not use or count on sealer for this application. Rebuild a spare pump to take along and/or use a pump bypass:

post-30648-143141875335_thumb.jpg

connect to the steel line at the frame and the top of the pump....this bypasses a slobbering pump, but preserves the vacuum assist portion and is quicker and easier than changing on the road and risking a stripped flare fitting.

Willie

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Duly noted on the sealer and thank you! I like your jumper line better. Mine is just a piece of hose with 2 spare clamps - picks up the hose barb on the frame line, bypasses the pump and then goes over the flare on the feed line to the carb. My original looking flexible line fell by the wayside 30 years ago. I couldn't seem to find a fitting for my jumper line to mate up with the flared line that goes to the carb - will try again. The pump sure is a b**** to change on a hot engine.

On another note - this mechanical pump is driving me nuts. Just came back from another drive and now the car runs like crap - uneven miss at the exhaust up to about 1500 rpm. Its usually solid. The glass filter bowl is now at about the lowest level I have ever seen it when hot, even with the electric pump on. Dont know if the low fuel level in the bowl is an indicator of pressure or maybe the cars picking up the junk gas at the bottom of the tank as its almost empty. Enough for one day. This will be the end of the "winter" gas blend - will put in fresh gas with some Techron, and if that doesn't help will pull and check plugs another night. Any other ideas?

I did ask the car what the heck its problem was. Heard something like "overdue for new paint and trim polished - get on it bucko".

Must be springtime!

Edited by KAD36
Fixed bad Englis! (see edit history)
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