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Main Area => General GS500 Discussion => Topic started by: 1034am on December 01, 2015, 11:50:40 AM

Title: leaking petcock at tank
Post by: 1034am on December 01, 2015, 11:50:40 AM
Does anyone have any advice or ideas on installing a tank petcock? My old one was leaking so I purchased a new one, and it is also leaking. Surface seems flat/clean, I sanded it a little. New one had a slightly thicker gasket (I thought that was the issue.)
I torqued down pretty good, didn't want to snap the bolts. Is it like a valve cover and over-torquing will distort the seal?

Any help is much appreciated.

Title: Re: leaking petcock at tank
Post by: ShowBizWolf on December 01, 2015, 11:56:45 AM
I am trying to remember what I did when I replaced mine... I'm pretty sure I just tightened them snug and then a lil more.

It's been perfect since then! I don't know if there is anything more to it but... that's what has been working for me. It's been about 2 and a half years since I replaced mine.

I wonder what it could be, causing your problem... I hope someone else will reply and help. I am now curious too. Boy would that be frustrating.  :technical:
Title: Re: leaking petcock at tank
Post by: 1034am on December 01, 2015, 12:13:04 PM
Well it's funny, as this is a project bike, I finally got it all together. And that's when I saw it dripping. So I had to clean up the garage and take the tank back off (and stand it up.)
I ordered a new petcock and tested it before putting the tank back on the bike and same thing. The new one did have a slightly thicker gasket than the old one. At least this time I had a pan under it.
As far as torquing it down, I can't get a torque wrench in there, so I'm going by 'feel.'  Probably about 25-35 ft lbs.

Weird.


Title: Re: leaking petcock at tank
Post by: 1034am on December 04, 2015, 07:30:13 AM
Okay, so I re-surfaced the tank side down to bare metal. Looked smooth and shiny. I double-checked the new petcock w/the old one, same size/model. The new rubber gasket is slightly more proud than the old one (prob original '89).
I also checked the bolts/bolt holes, didn't seem stripped, was very clean. And i torqued it to what I believe is just short of snapping the bolt heads off (very tight.)  Still leaks!

At this point I am going to believe that it's a faulty petcock.  Can anyone recommend a reliable source for a new tank petcock?

Thanks!
Title: Re: leaking petcock at tank
Post by: The Buddha on December 04, 2015, 10:39:25 PM
I have a tank that has a tiny ripple in the metal between the 2 bolts for the petcock. Will never stop leaking till you slap a inner tube in-between as a gasket.
Cool.
Buddha.
Title: Re: leaking petcock at tank
Post by: 1034am on December 05, 2015, 07:48:04 AM
Inner-tube? I was thinking silicone/gasket maker, run a bead along the outside of it.
If I go with a rubber seal/gasket should I remove the existing rubber ring? Will rubber seal against rubber?


(The other thought I had was to paint the tank w/something that might enhance sealing. Not sure what exactly.)

I'm so close to getting this together. I was hoping to have it running in time for the first snowfall.   http://gstwins.com/gsboard/Smileys/New_Smile/confused.gif
Title: Re: leaking petcock at tank
Post by: 1034am on December 07, 2015, 11:12:19 AM
Just spoke to a fellow rider and he recommended Pliobond. Says it seals everything and it's fuel-proof.
I'll update when I get it installed.
Title: Re: leaking petcock at tank
Post by: 1034am on December 18, 2015, 07:50:27 AM
Ok, so it seems that the expoxy tank liner had gotten onto the mounting threads for the petcock, preventing the bolt from creating a tight seal. It looks like the gas is leaking through the bolt.
I tried thread sealant, but it didn't help enough.
I want to chase out the threads, but w/the threat of spark, I decided to empty the tank. When I get the tank empty I will use a tap to clean-up the threads.
I also noticed that the brass bolts are very soft. First go around they fit very tight, unscrew and screw back in and they go in easily by hand.

Anybody have any advice on this? Would plumber's tape be better than fuel-resistant thread sealant?

thx.
Title: Re: leaking petcock at tank
Post by: Suzuki Stevo on December 18, 2015, 09:41:59 AM
I have tapped literally thousands of holes in my manufacturing career spanning over 40 years, I have never seen a tap make a spark, even on the end of a reversable pneumatic tapping gun. Fill the tank with water if you are still worried about a spark.
Title: Re: leaking petcock at tank
Post by: 1034am on December 18, 2015, 10:17:55 AM
thanks stevo.  i was pondering this as i looked at the brass bolts thinking, they're brass for a reason!
tank is mostly empty, i'll let it sit over a pan to try and get it completely empty, but good to know that sparking is not very likely.
Title: Re: leaking petcock at tank
Post by: The Buddha on December 19, 2015, 05:17:55 AM
Brass bolts ? where ? What are you working on ? A Dusenberg ???
There aint no brass bolts this side of 1950 grampa.

Jets are Brass cos its cheaper to make than aluminum and easier to get precise holes in it. To get that in aluminum you need to have 60 or 70 series which is far more $$$. That's about all that's brass on the bike. BTW I have seen nylon jets, dunno if that's newer tech, and going to take over for brass.

There maybe a brazed weld here or there, but even that I doubt on a stock GS. Some enterprising clown (like me) could have done it in its past I guess.

Cool.
Buddha.
Title: Re: leaking petcock at tank
Post by: 1034am on December 19, 2015, 08:10:27 AM
Really?  Are you positive? I suppose, the previous owner might have switched them out, but in the automotive world it's pretty standard to have brass components on the gas tank (fuel pump, etc.)

The bolt holes go completely through to the tank side, so I didn't think it was weird. I've got some on order from Bikebandit, I guess I'll find out...

The brass is pretty soft, I could probably get a better torque w/standard ones.
Title: Re: leaking petcock at tank
Post by: The Buddha on December 20, 2015, 11:12:45 AM
Well Suzuki clowns have been painting steel bolts in gold. Carb float bowl screws were that way on 89-00. Past it, it usually is not, but I've seen the ocassional gold screw in post 00 carbs too.
Cool.
Buddha.
Title: Re: leaking petcock at tank
Post by: 1034am on December 21, 2015, 02:13:24 PM
Since you mention it, the two bolts I pulled out did seam to be 'coated' w/ brass coloring, w/bright silver underneath. I just figured it was due wear/aging.

I'll have to check to see if they're magnetic...
Title: Re: leaking petcock at tank
Post by: The Buddha on December 21, 2015, 08:35:56 PM
Yea some thing called parkerizing or anodizing or some other crapolaisation.
Cool.
Buddha.
Title: Re: leaking petcock at tank
Post by: 1034am on January 09, 2016, 09:04:21 AM
New bolts received and they are not brass. Standard silver/whatever.
Can anyone tell me if the 'o' ring between the petcock on tank needs to be glued to the petcock? Seems like the old one was, and I don't want to be doing this again.

thx.