Changing gascolator sump

How to keep the Cessna 170 flying and airworthy.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

Post Reply
Jr.CubBuilder
Posts: 517
Joined: Thu Aug 12, 2004 10:33 pm

Changing gascolator sump

Post by Jr.CubBuilder »

I have a leaky drain sump on my gascolator. It's sort of glued in with a type of dark brownish stuff that is just a bit tacky, I can dent it with a thumbnail.

What sort of sealant should I use on the replacement valve, and does anybody have any suggestions for getting the old valve out? The old valve is in there pretty tight and I'm worried about using to much force on it, I don't want to deform the bottom of the gascolator.
robert.p.bowen
Posts: 51
Joined: Thu Dec 05, 2002 6:39 pm

Post by robert.p.bowen »

First, I'd see if I couldn't just replace the O-ring, rather than having to remove the drain valve.

If that's not your preference, then I would soak the bottom of the gascolator (with the valve) for a day or so in lacquer thinner or MEK. If that doesn't seem to soften it, repeat the soaking using acetone. The dark material you're seeing sounds like a a Permatex "gasket maker" material. Not a great idea to use that stuff!

I use Fuelube on drain valve threads before screwing them back in gascolators, fuel sight tubes, etc.
Bob-
User avatar
Bruce Fenstermacher
Posts: 10424
Joined: Tue Apr 23, 2002 11:24 am

Post by Bruce Fenstermacher »

Before soaking I'd try a little heat to soften the goop. Using a heat gun or something similar.

Be careful holding the bottom and twisting the old valve. You don't want to deform it.

If I used anything at all reinstalling I'd use a touch of the liquid teflon sealer.
Last edited by Bruce Fenstermacher on Wed Sep 26, 2007 3:53 pm, edited 1 time in total.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Jr.CubBuilder
Posts: 517
Joined: Thu Aug 12, 2004 10:33 pm

Post by Jr.CubBuilder »

Thanks guys
User avatar
GAHorn
Posts: 21297
Joined: Fri Apr 12, 2002 8:45 pm

Post by GAHorn »

I don't know what is being described presently, and I'm unfamiliar with "liquid teflon", but a dab of Permatex #2 is good for this, and it should not damage anything to remove the drain valve in the future either. It's what I recommend. (Never use teflon tape in a fuel system, however. Particles may dislodge and later cause carb failure.)
Heat may carbonize whatever is there and I wouldn't use it. If it's soft enough to mark with your fingernail, it's probably soft enough to allow you to unscrew the valve without damaging the base, I'd think.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
Bruce Fenstermacher
Posts: 10424
Joined: Tue Apr 23, 2002 11:24 am

Post by Bruce Fenstermacher »

I was referring to products like Loctite 592 Teflon PST Pipe Sealant which Continental prescribes for all pipe threads or threaded holes to an oil source with some exceptions.

PERMATEX / LOCTITE - 59214 - HI-TEMP THREAD SEALANT W/TEFLON is the same product.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Robert Eilers
Posts: 652
Joined: Sat May 08, 2004 12:33 am

Post by Robert Eilers »

I aslo had a slight gascolator drain valve leak. I used the Fuel Lube as suggested on the O ring - so far no leaks. It will be interesting to see how long the fix works.
User avatar
Joe Moilanen
Posts: 605
Joined: Sun Dec 28, 2003 5:45 am

Post by Joe Moilanen »

I'm planning on replacing my gasculator drain also, can you just replace the O ring? If so, where can you get it, or where can you get the vavle if that is the way to go. Also the bowl gastets.

Joe
4518C
User avatar
GAHorn
Posts: 21297
Joined: Fri Apr 12, 2002 8:45 pm

Post by GAHorn »

The genuine Cessna Gascolator Gasket PN is: 33-199-6 Gasket .

This is the flat, O-shaped gasket which fits above/beneath the glass cylinder/bowl of the original gascolator. Two are required.

It is now priced at approx. $10. http://www.cessnaparts.com (although I recently purchased them over the counter at a cessna dist . for only $1.50 each.)

If you know which drain you have exactly... you can probably order the o-ring, but it's not expensive to have an entirely new valve (and much more reliable.) Spruce 877-477-7823 or http://www.aircraftspruce.com
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
Indopilot
Posts: 253
Joined: Fri Apr 09, 2004 5:18 am

Post by Indopilot »

I believe the drain itself is a curtiss valve that you can no longer get the special rubber seal for due to liability.( it is not an O-ring) They will however sell you a new valve. Tite seal is also good to use on the threads when you screw in that shiney new valve. :D
52 170B s/n 20446
56 172 s/n 28162
Echo Weed eater, Jezebeel
User avatar
Joe Moilanen
Posts: 605
Joined: Sun Dec 28, 2003 5:45 am

Post by Joe Moilanen »

Thanks guys, I just ordered the bowl gastets and I'll have to take another look at my drain valve before I order one. The one that's on mine now is the kind that you twist on the side, with a shaft going perpendicular through the valve. I could have sworn the valve had female threads on it when I looked at it yesterday. I didn't see any like that in Spruce. I'll look at it again next time I get to the airport.

Joe
Post Reply
Cessna® is a registered trademark of Textron Aviation, Inc. The International Cessna® 170 Association is an independent owners/operators association dedicated to C170 aircraft and early O-300-powered C172s. We are not affiliated with Cessna® or Textron Aviation, Inc. in any way.