Fuel Leak

[robin.richard]

Hello,

I have noticed that my (and previous) 40HP fuel pump seems to always have a little film of fuel on top of the pump after then engine has been off for an hour or more. No much, no pooling, only enough to lightly wet my finger when running it across the pointed pump cover. I thought it may have been condensation from the manifold, but it smells like fuel. I have tightened the main bolt that holds the cover on. This 40HP pump is newly rebuilt by a reputable builder from this site.

Has anyone else noticed this with their 40HP pumps? Again, it is very, very light and I never notice it when the engine is running. both this and my previous pump had the same light film of fuel on pump cover. Fuel lines in and out of pump are not leaking and pump is securely/properly bolted to engine. Could this be fuel seeping back out of the carb and causing a slight overflow back into the pump when not running? Is this a major issue/fire hazard?

Thanks.

-Rich

-Rich
_________________
Drive your bus!

[EverettB]

There should be no fuel at all.
I would look at it when it's running and rev it up a little to be sure it's not leaking while running. Gas evaporates quick so it could be worse than you think.

It's this style of pump, correct?
(Without the fuel shutoff valve)

Can you tell, is it coming from the top bolt or from the edges of the cap on top?

The top bolt has a seal that could be worn out.

The top cap has a little round seal under it.
Unless they fixed it, the rebuild kits come with a seal that is too small and could leak.
I bought a bunch of these a while back and they fit perfectly
https://www.thesamba.com/vw/classifieds/detail.php?id=1661682
_________________
How to Post Photos
Everett Barnes - [email protected] | My wanted ads
"Water is the only drink for a wise man" | "Communication prevents complaints"
Stop dead photo links! Post your photos to The Samba Gallery!

[robin.richard]

EverettB,

Thanks for the response.

Yes, a 40HP like the one in your photo. The pump was a newly rebuilt pump from a samba member. I took the cap off to check to make sure the seal and screen was seated properly; It was. It has the red cardstock style seal just like the small red seal for the bolt. It appears to be leaking from the edge, but very little and never while the engine is running. I only notice it when the engine is cold, in the morning before heading off to work. Again it is very, very little fuel residue, not much at all. But the last thing I need is to have my bus go up in flames...

I think I'm going to buy some of those seals you suggested just to make sure. Any sources for the small seal for the bolt?

-Rich
_________________
Drive your bus!

[Eric&Barb]

You can get gasket material from your FLAPS. Just make sure the stuff you buy is good for fuel, and about same thickness. A little thicker is OK, but not so good to go thinner. Then use a knife like Exacto to cut it out to size.

Another thing to try is to lightly sand the underside edge of the top cap on a flat surface like a piece of glass with sandpaper laid over it. This will help to flatten that edge so it may seal easier.
_________________
In Stereo, Where Available!

[robin.richard]

Thanks Eric&Barb,

I'll give that a try. I have been checking the pump many times throughout the day. It only appears in the morning when all metal parts are covered with morning dew here in humid VA. It is fuel, not condensation, but it is very light and only when the engine is cold in the mornings. Never during the day or when the engine is operating.

I ordered some new seals as suggested by Everett. I'll give that a try and see if there is any difference. I will also use the sandpaper trick suggested by Eric&Barb. Makes sense.

Has anyone tried the Permatex sealant specifically designed for fuel fittings? It comes in a small white tube. I have used it on threaded fuel line fittings before with great success.

-Rich
_________________
Drive your bus!

[robin.richard]

Okay, I received the new NOS 40hp fuel pump top seals. They are the metallic silver/gray seals on the left. On the right is the red seal I replaced. The NOS seals appeared a little thinner but firmer. The replaced red seal is paper and seemed to have been slightly indented with the pump top creating a slight rim along the outer edge.

I haven't driven the bus for about a week while waiting for the new seals to arrive. During initial inspection before replacing the seal I noticed a large pooling of fuel on top of the pump around the top's edge. Wow, that could have been bad. I believe what was occurring was fuel seeping out of the top edge/seal when the engine is not running and the fuel is not freely flowing. This I believe is causing a buildup of fuel that seeps out of the bad seal along the top's edge. Path of less resistance. Well, that's what I think may be happening.

I used the sand paper trick to make sure the pump top's edge was flush. Placed the screen down in the pump first, making sure it was properly seated, then placing in the new seal, and finally the top and bolt with a better small seal. I ran the engine for 15-20mins reviving the engine several times to make sure there were no leaks while running. The true test will be in the morning after the engine has been at rest overnight. If there is a pooling of fuel then I don't know what to really think.

By the way, that is a 'no-name' German 40hp pump in the photo that is identical to my original German VW pump in my bus.

Wish me luck.

-Rich

_________________
Drive your bus!

[EverettB]

I hadn't noticed the thickness but were they the same diameter?

The problem I noticed is the red seal in the kits was a tiny bit too small.
_________________
How to Post Photos
Everett Barnes - [email protected] | My wanted ads
"Water is the only drink for a wise man" | "Communication prevents complaints"
Stop dead photo links! Post your photos to The Samba Gallery!

[robin.richard]

Well, no issues this morning. The true test will be over a period of time that then engine stays cold, three or four days. But for now it seems to be bone dry.

EverettB,

I'll check diameter when I get home tonight. The diameter being smaller may be the cause for the indentation and formed lip on the red seal.

-Rich
_________________
Drive your bus!

[robin.richard]

EverettB,

I checked the diameter of both and they seem the same, although the red seal seems ever so slightly larger due to the deformation/slight ridge created by the top. Perhaps the top bolt was tightened too tight?

Drove home. All still seems good, but as before the true test will be when the vehicle sits for a few days. Not sure when that will happen now that the weather changed for the better.

- Rich
_________________
Drive your bus!