Fuel pump leak

[JonnyRock]

I replaced my water pump last weekend (PITA btw), and after I had finished I noticed that the various engine and suspension components on the passenger side of the engine compartment had a speckled look. At first I thought it was because of the large amount of rain we get up here, which of course prevents me from keeping the bay clean and dry. But the other side looked much better by comparison. But I had just gotten done bending over my fender for roughly two hours and needed to let the silicone dry, and it was getting dark so I figured I'd try to figure it out the next day.

Well when I started her up the next morning to make sure all was well with the new pump, it became immediately clear why it was all speckled in there. Gas was dripping out of my fuel pump at a prodigious rate.I'd say a drop or two every 3 seconds. And they were all flying back into the compartment from the force of the fan. I witnessed a few land on the side of the battery!

So I think I need a new pump. Maybe I just need a new gasket, or just need to clean the old pump. I'm not sure. This is my first non-EFI car. My repair manuals say how to replace it, but they don't offer any info on inspecting the pump itself to tell if I need a new one.

BTW, I am going to stick with just the mechanical pump. I don't want to add an electric one, or switch to an electric one. I like keeping the engine predominantly stock.

[JimmyZ]

You're positive it's not just a loose line or bad fuel hose right? Oftentimes people use the wrong sized hose and just clamp it a little tighter. (Reffering to previous owner) Doing this can result in a leak.

The pump is a simple diaphragm with two one way valves. When it gets old the diaphragm tears and you have no flow. If this is the case you can expect the pump to fail soon... very soon. Some pumps have a small hole which allows the fuel to drip out. Sometimes the bypassed fuel drains into the crankcase and fills the oil pan a bit. Check your oil.

Don't overtorque the new pump. You can crack the spacer.

[Zs-ondabrain]

ok, so it's an old thread but I had a question related to this area.

I too have had gasket issues and fuel pumping out at a much higher rate than Johnny. This of coarse was because I pulled the top of the pump to polish it (polished aluminum is King) anyways, if leaked becasue of a tear in the gasket. I fixed it with gasket sealer.

BUT..... My main question is this........

Every Stock mechanical pump I've had, leaks oil thru the 2 very small holes in the upper part of the lower assembly. My engine bay is typically SPOTLESS and can be eaten off of at almost any time. These 2 holes are breather holes for the oil in the pump area of the fuel pump.

So the question is this, Does anyone elses fuel pump shoot oil all over their engine bay (passenger side) and is Plugging these holes OK to do. The oil gets in there and obviously Lubes the push rod that works the pump and if oil gets too high, it'll obviously return to the front cover. So should I plug them off to keep the motor clean? Or drive to the car shows with a rag wrapped around the pump to catch the oil and reduce the cleaning time at the show(s)?

Dave

[Zforce]

The holes in the pump are there to equalize the pressure on both sides of the diapham, it so happens that when the diapham fails it will leak fuel and dribble out of the hole (no pun intended) If there is oil present you probably need a new insulator and gaskets.

[ms260z]

I am having the same problem with my 260 fuel pump. Fuel is leaking out of the port hole. So, do I need a new diaphram for the fuel pump?? I pulled the pump off last night, cleaned it, installed new gasket, and it leaked just as before when I reinstalled it. Thanks for the help.........

[Zs-ondabrain]

When you tear it apart, you'll see a pressed in ring that holds the rubber boot, that seperates the oil chamber from the air chamber. That rubber boot is the whole problem with 90% of the fuel pumps I've worked on. I found a rubber firewall bushing that is wide enough to fit in the hole but the inner hole of the bushing is just small enough to be snug against the diaphram piston.

It's not perfect but it at least slows the oil flow from the lower chamber to the top. Ont the mating surfaces, I like to use 600 grit wetsand paper on a flush surface to make sure any warpage is gone and will seal perfectly. Then clean the diaphram with brake cleaner. I use "Ultra Black" gasket goop to make sure that part never leaks again.

On Some of the pumps I've dealt with, the threads are stripped. I've gone as far as using longer screws to allow the use of a Nut on the bottom side to allow me to torque all 6 screws down without worrying about it stripping newly tapped threads. When your engine bay is as nice as mine, you'll do whatever you can to keep it that way but make it still look stock.

Dave

Use Teflon tape on the inlet and outlet nozzles.

[ms260z]

Thanks, I plan on getting back on it this weekend. Any tips on where I might find the bushing?