The International Cessna^® 170 Association

I haven't tried to replace the o-ring in my gascolator yet (cold here in the Adirondacks), but will try that first. Mine is the glass type with the brass sump valve in a '56 172. If that doesn't work or I can't find the correct o-ring/seal, can the old brass sump be replaces with a hewer type sump valve assembly available from Spruce? Does anyone know the npt size of the original?

I was told by another straight tail owner that there was more good information here applicable to straight tail 172s than at the 172 sites. Seems to be the case.

Thanks in advance. And Happy Holidays to all.

Frank

Where is the leak in your gascolator? In the valve itself, or the seal where the glass meets the top or bottom? The seals/gaskets for the glass-to-frame are superceded but readily available. I replaced mine a year or two ago. I ordered two, but only needed one. If you have trouble finding one, send me a pm.

After careful reading I see your looking for the o-ring seal that goes in the sump valve.

Looking at the 172 IPC there appear to be three different valves used. One with a remote pull that rotates a shaft to open the valve and this does use a MS 29513-7 o-ring. I think the type without the remote pull but has a wing nut like tab you twist also uses the same o-ring. The third one has a valve with a bar through it that is pushed up with a remote pull. This is the Curtis CCA-7450 and o-rings are no longer available. It is really not an o-ring but a flat ring.

If you find you have a Safe-Air valve you can get the seals from them.

Now I will caution you. The brass valves get really stuck in the aluminum base. It is very easy to twist or bow the base when you try to twist the valve out. Use all due caution. If you twist or warp the base you ruin it. The glass will not seal against it. If the valve does not come out use heat on it to get it to break loose.

The valve should have a 1/8" NPT thread

Sorry, I should have been more clear. The leak is in the sump valve assembly. The sump valve I have has a "T" shape and pushes in to drain the Gascolator. Can this legally be replaced with a sump valve available through Spruce? The gascolator seals fine. I'd like to avoid the $200+ solution if possible.

Thanks.

Frank

fshaw wrote:Can this legally be replaced with a sump valve available through Spruce? The gascolator seals fine. I'd like to avoid the $200+ solution if possible.

Thanks.

Frank

Yes. I just replaced mine with one from Spruce.

Frank, it sounds like you have the Curtis CCA-7450. No seals available. You can replace it with the same valve available at Spruce. You won't need the $200 option UNLESS you ruin your base removing the old valve.

I had a leaking Curtis gascolator valve on my 172 a couple of years ago. I just ordered an new valve from Spruce. I don't recall the cost, but it wasn't expensive and replaced it along with the two gaskets on the top and bottom of the glass itself. They were hard and cracked! No problems since. As you were cautioned, be careful removing the old valve. Mine was so tight I couldn't remove it in the normal fashion. I used a propane torch and evenly warmed the aluminum base and the valve came out quite easily.

yeah Frank, any correct size quick drain valve (curtis, etc) will work there. I don't know the size offhand though, mine hasn't leaked yet.

Bruce Fenstermacher wrote:Frank, it sounds like you have the Curtis CCA-7450. No seals available. You can replace it with the same valve available at Spruce. You won't need the $200 option UNLESS you ruin your base removing the old valve.

Reeve Airmotive in Anchorage carrys the seals 907-274-8522 (Have the valve part number available)

Someone once recommended to me that I place a little fuel lube around the leaking valve. Not sure if it was the fuel lube or just a grain of dirt finally displaced, but I have not had a leak since.

Robert Eilers wrote:Someone once recommended to me that I place a little fuel lube around the leaking valve. Not sure if it was the fuel lube or just a grain of dirt finally displaced, but I have not had a leak since.

Someone needs to get real about safety. Go flying and have it start leaking without you knowing. Just do it right