Leaking fuel shutoff rod

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Mark44
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Leaking fuel shutoff rod

#1

Post by Mark44 »

I swapped carburetors on my Panhead, and in the process, overhauled my fuel shutoff rod, as it didn't completely cut off the gas flow. I did the same operation on my WL with successful results -- shutoff cuts off the gas flow, and there are no leaks in the gas line.

For the Panhead, the results aren't as good, no doubt in part because the connection is more complicated, with a banjo fitting for the crossover pipe.

For my first attempt, I put the rod back in the tank using new brass flat washers - it leaked.
For my second attempt, I re-used the flat washers, but did a better job of cleaning the threads of the bung and where the rod goes up into the gas bung -- still leaked, even after getting the fuel rod in just about as tight as I could get it.

Third attempt, I used the copper crush washers that are used on the Linkert float bowls. I put the fuel rod in not so tight -- not as much of a leak, but still weeping, which tightening the fuel rod didn't fix.

I looked through the KB, and one member (mbskeam) said he had gone to a plumbing supply house and gotten some fiber washers, and had used some sort of pipe compound on the threads of the fuel rod, with excellent results.

My next step is to take off the left tank, and make sure the bottom of the gas bung is nice and flat, which is difficult to do from underneath when the tank is still on the bike. I'm tempted to see if some kind of O-rings would work better than the flat washers or the carb bowl crush gaskets. I believe that there are some O-rings being sold that are impervious to gasoline. The viton tip of my Linkert's needle valve has been in the bike for maybe three years, and it hasn't swelled at all.

I'm also tempted to use some "Right Stuff" sealant, carefully applied on the bung thread and to the banjo fitting.

I've had the crossover fitting off, and used sandpaper on the flat surfaces. I'm pretty sure I'm not getting any leaks from it, but I'll test it again.

Mike Beam (mbskeam - he used to post here but hasn't lately) lives close to me, and I have his number, so I'm going to try to get in touch with him for details of what he used, and if it's still working for him.

In the meantime, do you have any advice for me. It's a PITA to put things back together and find that each time, it's still leaking, so I have to siphon the gas out again so I'm not leaking gas on the floor of my garage, which is where the furnace is.

Mark
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Re: Leaking fuel shutoff rod

#2

Post by panz4ever »

I use the copper crush washers with good results. Are you sure that the shut off rod is getting a good seal at the tip and that the shut off rod has a good alignment. Carl's Cycle Supply will sell you a shutoff rod with a Peak Seal Tip on it. I did the tank alignment procedure for the shut-off rod per the manual. That plus the Peek rod works like a charm.
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Re: Leaking fuel shutoff rod

#3

Post by james »

First, everything must be perfectly clean, no paint, dirt or corrosion. That goes for the gas tank opening, the banjo fitting and the fuel shut off rod seat, bolt.
Use new brass gaskets with Permatex Industrial Hydralic Sealant #81802. Tighten it down and let it sit overnight. I don't recommend that "Right Stuff" stuff.
Also 9 out of 10 times the copper crush washers from the float bowl work. but,
Just make sure you are showing clean metal on all mating surfaces before reassembly.
Let us know what happens.
Jim M
Mark44
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Re: Leaking fuel shutoff rod

#4

Post by Mark44 »

panz4ever wrote:I use the copper crush washers with good results. Are you sure that the shut off rod is getting a good seal at the tip and that the shut off rod has a good alignment. Carl's Cycle Supply will sell you a shutoff rod with a Peak Seal Tip on it. I did the tank alignment procedure for the shut-off rod per the manual. That plus the Peek rod works like a charm.
I don't think the rod is making a good seal against its seat. I've dressed the end of the rod, but I didn't do much in the way of burnishing the seat. My main difficulty is getting the damn rod assembly to stop leaking/weeping out the bottom.
The rod assembly wasn't leaking before I took it apart, so in retrospect, I would have been better off leaving it alone. I've been pretty careful in removing it (each time), so I don't think the rod is misaligned.
james wrote:First, everything must be perfectly clean, no paint, dirt or corrosion.
This might be the problem. The mating surface at the bottom of the tank bung shows different colors. I can't feel anything, but when I take the tank off I'll have a better view than when I'm underneath shining a flashlight up at it. I'm planning to take a rubber stopper of the appropriate size, attach a circular piece of sandpaper, and dress that surface of the tank bung so that it's all bare metal and nice and smooth.
james wrote:That goes for the gas tank opening, the banjo fitting and the fuel shut off rod seat, bolt.
Use new brass gaskets with Permatex Industrial Hydralic Sealant #81802. Tighten it down and let it sit overnight. I don't recommend that "Right Stuff" stuff.
Also 9 out of 10 times the copper crush washers from the float bowl work. but,
Just make sure you are showing clean metal on all mating surfaces before reassembly.
Let us know what happens.
Jim M
The banjo fitting and the rod seat and screw in part, plus the threads of the shutoff base are nice and clean. I'll pressure test the banjo fitting to make sure I'm not getting a leak from that. I'll pick up some of that Permatex sealant - 81802.

Thanks, all (and Cotten) for replying! I appreciate your help.
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Re: Leaking fuel shutoff rod

#5

Post by james »

You may not be able to find the Permatex 81802, probably outdated. Try the Permatex 54550.
Good luck with the assembly. Once everything is clean, I feel confident with the repair.
Jim M
Mark44
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Re: Leaking fuel shutoff rod

#6

Post by Mark44 »

Even the Permatex 54550 isn't that easy to find. I went to a local O'Reilly's - no luck. I then went to a tractor supply place that opened recently. When I asked where they kept the Permatex, none of the three employees I talked to (including the lead) had ever heard of Permatex -- bad sign.

After than, I checked Autozone's online catalog - no go. Finally I did a web search for Permatex 54550 and found an outfit in Arizona (I think) that carries it. Should be here tomorrow.
Mark44
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Re: Leaking fuel shutoff rod

#7

Post by Mark44 »

panz4ever wrote:Carl's Cycle Supply will sell you a shutoff rod with a Peak Seal Tip on it.
They don't show it on their web site, either with or without the PEEK seal. Did you have to call them on the phone and ask for it?
I don't think they've updated their online catalog since 2012, so it could be that this is something they added to their product line after that time.
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Re: Leaking fuel shutoff rod

#8

Post by kfelt »

I have found that a little "Seal All" in between all the washers etc. on the fuel rod on the bottom of the tank before tightening prevents it from leaking. l also use it on the little screw that attaches the float to the arm in a Linkert to lock it in place. The stuff is impervious to gasoline. Had a crack in the plastic fuel inlet on the carb on my Softail and was leaking pretty bad far away from home. Stopped into a hardware store and picked up a tube of "Seal All" and smeared it on the crack until I could replace the part. It is still there with no leaks 2 years later!
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Re: Leaking fuel shutoff rod

#9

Post by ultrapan »

Mark44 wrote:
panz4ever wrote:Carl's Cycle Supply will sell you a shutoff rod with a Peak Seal Tip on it.
They don't show it on their web site, either with or without the PEEK seal. Did you have to call them on the phone and ask for it?
I don't think they've updated their online catalog since 2012, so it could be that this is something they added to their product line after that time.
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Re: Leaking fuel shutoff rod

#10

Post by jpd298 »

Carl's Cycle supply does still sell the PEEK shutoff rod assembly. Just bought one less than a month ago. Just call or email, very nice to deal with.
Mark44
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Re: Leaking fuel shutoff rod

#11

Post by Mark44 »

I sprang for the shutoff from Carl's Cycle Supply. With that and the Permatex 54550 sealant, no more leaks.
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