What are people lubing new petcock rubbers with?

[Courtney]

So just assembling my new K&L kits into my special tank and was wondering what people are lubing the new diaphragms with? I'm thinking brake grease??

[crazy steve]

You want to be careful with some brake greases; if they're silicon-based, that can be pretty abrasive on rubber parts... DAMHIKIJK..

I've used some petroleum jelly in the past; easy to find, won't harm anything. There is a 'rubber grease' but it's very hard to find in the US; I got mine off eBay from a guy who imported it from Australia... but is great for this as well as assembling calipers/master cylinders (compatible with brake fluid).

[Courtney]

OK, I've read white lithium grease as well, so I'm just gonna go with the vaseline I think. I'm thinking this washes off after awhile right? The gas is in contact with it??? Trying to picture the petcock holes and rubber gasket....

[skids]

Yes, gasoline disolves grease.
If you want to add years to the rubber holey gasket, sand and polish the face of the valves with mother's milk or Eagle 1. The hole edges can be pretty sharp and you can lightly sand (with 600 grit) to dull the edges. This takes no time at all and will reduce wear.

[Rasputin]

+1 on both the vaseline and polishing the surfaces. Works for me.

[TADracer]

Yes, polish those parts!

Yes, polish those parts!

My original cocks were very shabby and just did not seem worth the $ to rebuild but like many here I was on a budget. So I sprung for a pair of cheap Alfa petcocks (I think I paid $29.00 each) figuring they would last a year or so and then I could afford a pair of Pingles (at around $100.00 each). I took the Alfa's apart and polished up the parts before I installed them.....ten years or more later the Alfa's are still on and working perfectly and have never been rebuilt (and they flow well too!)

[jetmechmarty]

Less than $10 for a big tube than will last almost forever. I use it on just about every rubber seal.

[Courtney]

Less than $10 for a big tube than will last almost forever. I use it on just about every rubber seal.

Looks like another unobtanium product in Canada. Like living in a f**king third world country sometimes. I'll find something similar, it's just rubber grease I'm thinking.

[crazy steve]

Try this..... http://www.ebay.co.uk/sch/i.html?_od...1090&_from=R40

[DAVINCI]

How 'bout plain ol motor oil? Works for me.

[Courtney]

Thanks Steve, I actually found some Sil-glyde I didn't know I had, which is a rubber lube. Someone had given it to me years ago and I found it sitting on my shelf. Go figger. Would LOVE to find the stuff that is gas resistant though.

[fredintoon]

Looks like another unobtanium product in Canada. Like living in a f**king third world country sometimes. I'll find something similar, it's just rubber grease I'm thinking.

Hi Courtney,
I'd be surprised if Bearing & Transmission didn't stock either that stuff or an equivalent.

[jetmechmarty]

The Parker Lube is particularly helpful when doing an oil change. It's thick enough to stick the big rubber o'ring to the cup. It's thick or thicker than Vaseline. (petrolatum)

[skids]

OK, most of you know that I am a bit "off-center." When I read the subject line I was sure someone would respond "K-Y Jelly!"

[jetmechmarty]

OK, most of you know that I am a bit "off-center." When I read the subject line I was sure someone would respond "K-Y Jelly!"

I think KY is probably fine for installing o'rings. In the case of the petcock, I don't think it's appropriate because it won't remain lubed and the petcock will have to move over the long term.