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  #1  
Old 03-15-2017, 07:27 AM
pa38112 pa38112 is offline
 
Join Date: Mar 2008
Location: Clarksboro, NJ
Posts: 357
Default Andair Gascolator O-Ring

There is that old saying about "fool me once..." - I am rally tired of the O-rings for my Andair gascolator. If you purchase the correct O-ring they do not fit tightly against the bowl grove, making it almost a sure thing that the O-ring will be damaged during assembly. I am tired of replacing it every year only to find that the new O-ring fits as poorly as the one I am replacing. From searching the forums I do not think I am alone with this problem. I use Fuel Lube on the O-ring, so that could be causing drag as I assemble it. Regardless, I have decided that I am going to replace it with a "proper" fitting O-ring. After taking all of the measurements I have determined that an AS568-29 should fit properly. I have ordered Viton O-rings from McMaster-Carr: https://www.mcmaster.com/#9464k291/=16rjar5 I may also try a -129, but think it will be too tight.
I will report back here my initial and on-going experience with these.

If anyone else has replaced their O-rings with a different size, please let me know what you used, and how it has performed.
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  #2  
Old 03-15-2017, 07:40 AM
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Bob Martin Bob Martin is online now
 
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Location: Richmond, Virginia
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Default Grease

Just a thought.
I use the DOW silicone grease on my o rings.
Same stuff I put on the oil filter gasket.
DC-4 is what it is called, I just looked and it is recommended for oil filters but not fuel....but DOW has other silicones that are.

Fuel lube is very sticky....wonder if that just makes a not so tight fit worse?
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  #3  
Old 03-15-2017, 09:06 AM
pa38112 pa38112 is offline
 
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Location: Clarksboro, NJ
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Default

Yes, I am sure the fuel lube is not helping with the install, other than it does help keep the O-ring in the grove.
I use Dow Molykote 55 on my other O-rings, but did not want to use it on the fuel system.
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  #4  
Old 03-15-2017, 10:37 AM
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swisseagle swisseagle is offline
 
Join Date: Feb 2005
Location: 20km outside of Zurich, Switzerland
Posts: 347
Exclamation Does you follow the maintenance instriction?

Hello pa38112

Does you follow the maintenance instruction?

There it is mentioned, that you should use a NEW O-Ring, when you take the bowl of. This has a reason: The fuel will swell the o-ring over time. When you take the bowl of, the o-ring has now space to grow. After you cleaned the filter and bowl, your o-ring does not fit anymore, regardles which grease you are using. If you now force the bowl into position, you will damage your o-ring and generate a big risk, that the gascolator leak fuel and/or even greater risk, that your engine is sucking air ... and loose power soon.

I have found this situation by myself and two other buddy's ... I will do my two gascolators next weekend and will take a close look and make photos. I also have two o-rings from the last change, one year old on the shelf. I'm pretty sure they have again the original size ... they where swollen and dryed now. But I will not use them again.
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  #5  
Old 03-15-2017, 11:44 AM
pa38112 pa38112 is offline
 
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Location: Clarksboro, NJ
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Default

Yes, I do replace them every time - that is my frustration. The new O-rings are not a good fit right out of the package.
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  #6  
Old 03-15-2017, 12:13 PM
simpkinsona simpkinsona is offline
 
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Location: Vacaville, CA
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Default O-rings

This is what I use.

2mm X 39mm V75 Viton O-ring Black

I order them through the o-ring store online. I tried 40mm, but they fit too loose.

-Andy
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  #7  
Old 03-16-2017, 03:17 AM
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swisseagle swisseagle is offline
 
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Default Let me check

Hello Keith

I understand that this is frustrating.

Let me check the situation next weekend, I have a few new o-rings from Andair here on my desk. Also the one that where in until next weekend and those that I took out last time.

I will report here.
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Last edited by swisseagle : 03-16-2017 at 03:18 AM. Reason: spelling
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  #8  
Old 03-16-2017, 06:56 AM
pa38112 pa38112 is offline
 
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Location: Clarksboro, NJ
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Default

Thank you. I will be interested to hear how the different O-rings from Adnair compare. My son has my plane until next weekend. When I get it back I will try a few and see what fits best. I have the following to try:

- Stock O-ring from Andair
- AS568-029
- AS568-128
- 2mm X 39mm
- 2.5mm X 39mm

For full disclosure, the "Andair" O-rings I have are from ACS; however, I think it is a safe bet that they get them from the OEM.
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  #9  
Old 03-19-2017, 04:12 PM
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swisseagle swisseagle is offline
 
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Location: 20km outside of Zurich, Switzerland
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Default No problem to change the bowl ...

Hello Keith

Today I opend one gascolator and cleaned the filter, put a new o-ring on and installed it again.

It was no problem at all! Also the old o-ring did not look'd bad/bigger!?

Old one:



New one:

Its difficult or nearly impossible to measure the o-ring size, because of the big diameter, you need a cylinder with the exact dimension to try and find out.

Toolshop is far away, so no quick trial.

I wonder if your o-ring that you purchased came like this or if your vendor buy them by himself someware else?


I made a video where I install the bowl ... buy my iphone dont want to share it ... give me time to find out. https://goo.gl/photos/tV9XNosfGaXG5mJD7

I also was whiping around the seat of the o-ring on the cascolator-housing, with the finger that I was putting a small amount of fuel lube. Not a visible amount, just to not have it dry there.
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Last edited by swisseagle : 03-21-2017 at 05:46 AM. Reason: video-link placed
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  #10  
Old 03-19-2017, 04:46 PM
Tom Martin Tom Martin is online now
 
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Location: Ontario, Canada
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Default

I would suggest replacing the filter at around 500 hours. On the threads there is a bit of a coating that, along with the pipe thread, seems to hold the filter in place. Mine got a bit worn and at the next annual I found the filter in the bottom of the bowl! There is no way of knowing how long it was like that during the year.
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