Gas Leaking When Filling

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randymir
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Gas Leaking When Filling

Post by randymir » Fri Sep 18, 2020 1:03 pm

I just joined the Pinzgauer family after purchasing a 74 710K.

So the journey begins . . .

When I first filled the gas tank, there was gas leaking and dripping onto the ground. It appears to be the seal between the tank and the filler tube. I'm trying to remove the boot to get down inside to determine where the leak may be. Is there an easy way of removing the boot, or is this something I should drop the tank for? If I need to drop the tank, any suggestions, or things to avoid before starting (I know, drain the tank first. :-) )?

Thanks

Randy
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'74 - 710K
Randy
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rmel
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Re: Gas Leaking When Filling

Post by rmel » Fri Sep 18, 2020 1:34 pm

There are a few places that gas can leak from the top of the tank -- if filled to the tip top.

1. Fuel level sending unit -- there is a plate covering this in the rear cabin area. Easy to
remove and inspect.

2. Similar seal for the pick up tube, you have to drop the tank to address that.

3. The filler tube which is what your digging into now. Assuming the hose is good
two hose clamps for that.

While your at it, inspect the lining of the tank, any flakes you see is not a good sign.
These tanks can be relined if that's an issue.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

whitesik
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Re: Gas Leaking When Filling

Post by whitesik » Sat Sep 19, 2020 8:00 am

And since Ron missed it, let me be the first to say WELCOME!

Let us know your location. Maybe someone is close that can help.
75 Swiss 710K
Not so new owner but still a novice

randymir
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Re: Gas Leaking When Filling

Post by randymir » Sat Sep 19, 2020 9:58 am

Thank you both.

I will check the different areas to try and narrow it down, but there is gas by the boot area, so I think it's leaking prior to hitting the tank, so my thinking is the seal in the filler tube. I will tighten what I can and check the sending unit seal.

I live in Fallbrook, in north San Diego county.

Randy
'74 - 710K
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rmel
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Re: Gas Leaking When Filling

Post by rmel » Sat Sep 19, 2020 10:18 am

By the looks of where the gas is leaking from I think you are on the right path.
Either hose or clamp. The other possible sources for leaks are informational.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

randymir
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Re: Gas Leaking When Filling

Post by randymir » Sat Sep 19, 2020 10:55 am

Thanks again Ron.

Looks to me like I will need to drop the tank. It doesn't look difficult.
'74 - 710K
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rmel
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Re: Gas Leaking When Filling

Post by rmel » Sat Sep 19, 2020 11:23 am

Well, now your thinking -- once I get that leak taken care of next up will be
to fill up that K with some decent HAM gear and an antenna farm on the roof -- Eh!

cheers, 73's

The good thing (or bad thing) about a Pinz is the projects never stop :lol:

ron
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

randymir
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Posts: 13
Joined: Wed Sep 16, 2020 8:05 am

Re: Gas Leaking When Filling

Post by randymir » Sat Sep 19, 2020 12:55 pm

Already has radios, just need to put in some newer technology around it. I just turned them on and they all seem to be in working order.
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rmel
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Re: Gas Leaking When Filling

Post by rmel » Sat Sep 19, 2020 1:47 pm

At the risk of going off topic. It would be interesting to get the history on your truck.
Typically the radios are stripped out prior to export. Two pieces appear original kit;
The RT524A/PRC transceiver (usually 2 were installed on a K) and the receiver R442A/PRC.
The unit on the right is a PRC-47 transceiver, US issue circa 1974 as a 2 man portable unit.

Swiss tactical Radio system

https://en.wikipedia.org/wiki/Mobile_ra ... G_1547.JPG

This is going to be a whale of a lot of fun to play with :mrgreen:
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

randymir
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Joined: Wed Sep 16, 2020 8:05 am

Re: Gas Leaking When Filling

Post by randymir » Sun Sep 20, 2020 12:07 pm

The gentleman who owned it prior to me had it for about 4 years. I bought it from his wife, since he recently passed away. She did not know the history of the vehicle. I think the truck had all original gear in it when he purchased it. He had several large rooms full of old military radio gear. His wife believed he had all the original radios, but she couldn't verify which one it would be. She's in the process of selling them, plus the Patton museum is interested in some of the radios.

I could have spent days in those rooms going through all his radios and gear. My kind of pack rat.
'74 - 710K
Randy
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randymir
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Re: Gas Leaking When Filling

Post by randymir » Tue Sep 22, 2020 4:07 pm

I dropped the tank, so I'm going to replace the gaskets. I'm not really seeing where the gas may have been coming from. It was when I was filling up, so I'm going to assume it was from the filler tube.

When I removed the boot and then the filler tube, I was expecting to see a sealer ring around the filler tube coming from the tank, but there wasn't anything, only the rubber tube connecting the filler tube to the tank. Is the seal required? I'm assuming that may very well be the problem, but it really doesn't make sense as to why someone would remove and not replace it. It's number 6 in the image.

Also, when I was trying to remove the drain plug, it was stuck good. I gave it a couple of good whacks and it started leaking very slightly. I finally was able to get the drain plug out, but now I think I may have caused a leak at the drain plug. The drain plug didn't have a seal either, which it should have, so maybe that's it. I guess I will find out. Not sure how I could pressurize the tank to check for a leak, so I think I will replace everything hoist it in and fill slowly to see if it leaks.

So two questions out of this . . .

1. Do you need the filler tube seal (6 in the diagram) or not?

2. Is there a way to test (pressure or otherwise) the drain plug to ensure it doesn't have a leak before putting the tank back in? Not sure how I could seal the filler tube to pressure test.

Thanks!
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rmel
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Re: Gas Leaking When Filling

Post by rmel » Tue Sep 22, 2020 7:22 pm

I have dropped my tank on a 712 to get it relined.
The filler hose had a hose clamp at both ends. So
I don't have first hand experience with seal P/N 6.
I'd be curious to know for future reference.

With respect to the drain plug, there should be a 22mm x 27mm x 1.5mm
brass crush washer in there. This is a common washer for the diff, trany and
engine drains. Get yourself a huge handful of these, they should not be
reused unless they are tempered first (somewhat of a PITA vs just a new one).
I've gotten them on ebay and Amazon in the past.

If the Plug and shoulder on the tank are in good shape the washer will do the trick.
Last edited by rmel on Sat Sep 26, 2020 7:05 pm, edited 2 times in total.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

randymir
United States of America
Posts: 13
Joined: Wed Sep 16, 2020 8:05 am

Re: Gas Leaking When Filling

Post by randymir » Tue Sep 22, 2020 7:26 pm

Thanks again Ron!!
'74 - 710K
Randy
WB6OSK

whitesik
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Re: Gas Leaking When Filling

Post by whitesik » Tue Sep 22, 2020 7:50 pm

Is part 6 just a grommet type ring as the filler tube goes through the metal body? it would not play a role in preventing a fuel leak. Just throwing this out.
75 Swiss 710K
Not so new owner but still a novice

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pcolette
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Re: Gas Leaking When Filling

Post by pcolette » Tue Sep 22, 2020 7:54 pm

As Ron mentioned, I also had a hose clamp at each end of the filler tube but I've never seen seal #6. Interestingly, although the parts diagram shows one clamp, the parts description indicates that 2 clamps are needed.
Paul C.
_________
'73 Swiss 710M
'89 Puch 230GE
2002 MB G500

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