orphan part dilemma

cgrab

cgrab

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cgrab
I can't find a supplier for the cork seals (s350) used on my fuel sender bolts [Cessna Cardinal]. MacFarlane sells a bolt with a rubber in steel washer they say is better. I can't find a source for just the washer since I can't use the MacFarlane bolts as they aren't drilled for safety wire. Can I use the bolt and loctite it in? How does the mechanic sign that off?
Like the old commercial says: "What's a girl to do?"
 
cgrab said:
I can't find a supplier for the cork seals (s350) used on my fuel sender bolts [Cessna Cardinal]. MacFarlane sells a bolt with a rubber in steel washer they say is better. I can't find a source for just the washer since I can't use the MacFarlane bolts as they aren't drilled for safety wire. Can I use the bolt and loctite it in? How does the mechanic sign that off?
Like the old commercial says: "What's a girl to do?"
Click to expand...

You go down to the aviation parts department at Auto Zone (or O'Reilly's, or whatever you have in town) and buy a sheet of cork gasket material. You take your aviation approved kitchen scissors and cut a cork seal. You install the cork seal one of two ways. You tell your aviation mechanic that you are making an owner-produced part in accordance with 21.303 (b)(2) OR you let the maintenance fairies install the seal with no notice.

Do NOT under any circumstances use loctite on the bolt or the mechanic that comes along later trying to remove it will use language on you not generally acceptable at Sunday morning church.

Jim
 
Safety wire on bolts for a fuel level sender? Why? I'd update to the MacFarlane bolts.
 
Or, instead of scissors, you can make an ACME aviation approved set of gasket punches by buying appropriately sized pieces of steel pipe and grinding a nice sharp cutting bevel on one end. A quick tap with a swing press makes for a nice, clean cut and a perfectly round hole sized appropriately.
 
Stewartb said:
Safety wire on bolts for a fuel level sender? Why? I'd update to the MacFarlane bolts.
Click to expand...

You see, this stuff called "safety wire" is designed to stop a bolt, or a nut as required from backing out under vibration. The designer of the plane/fuel system decided that the fuel sender was to be held in place with a bolt prepared for safety wire, so it has safety wire locking it into place.

The use of chemical glue on threads is a reasonable alternative except in cases where the chemical glue might be affected by surrounding solvents, say - gasoline. So, back to the safety wire. :D
 
cgrab said:
I can't find a supplier for the cork seals (s350) used on my fuel sender bolts [Cessna Cardinal]. MacFarlane sells a bolt with a rubber in steel washer they say is better. I can't find a source for just the washer since I can't use the MacFarlane bolts as they aren't drilled for safety wire. Can I use the bolt and loctite it in? How does the mechanic sign that off?
Like the old commercial says: "What's a girl to do?"
Click to expand...
Step one would be to go to the A&P that you think is going to sign off and ask him/her/it what they want you to do.

Then, you will drill the holes in the bolts as directed. http://www.amazon.com/Aircraft-Tool-Supply-Safety-Safblock/dp/B005VR4BG6
 
Small screw holes in gasket material are easiest made with a leather punch plier.
 
cgrab said:
I can't find a supplier for the cork seals (s350) used on my fuel sender bolts [Cessna Cardinal]. MacFarlane sells a bolt with a rubber in steel washer they say is better. I can't find a source for just the washer since I can't use the MacFarlane bolts as they aren't drilled for safety wire. Can I use the bolt and loctite it in? How does the mechanic sign that off?
Like the old commercial says: "What's a girl to do?"
Click to expand...

What on earth are you talking about? There are no seals on the bolts themselves nor do they need any. The bolts thread into an encapsulated nutplate ring and the threads are dry. DO NOT LOCTITE those! If you do it may strip the threads out the next time they are removed making even more headache.



The only thing I have ever found under the sender attach bolts is a star type lock washer. The big rubber seal with the 5-bolt hole pattern that McFarlane sells is all that is needed.

From inside the tank:

 
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A view of the big rubber gasket tied in-place using lacing cord which was cut and removed after getting bolts finger tightened during installation.


 
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I just stick the gasket in place with Seal Lube, a little Indian Head works just as well.
 
Henning said:
I just stick the gasket in place with Seal Lube, a little Indian Head works just as well.
Click to expand...

Normally I probably would do similar but the lacing cord was no residue, no mess, quick and on hand.
 
Stewartb said:
Safety wire on bolts for a fuel level sender? Why? I'd update to the MacFarlane bolts.
Click to expand...

Cessna used both a socket head cap screw and drilled head engine bolts and seems to be a lottery which it came with. The bolts have safety wire holes. The fuel lines themselves aren't safety wired so I'm not sure what the point is on the these with lock washers :dunno:
 
bnt83 said:
Normally I probably would do similar but the lacing cord was no residue, no mess, quick and on hand.
Click to expand...

Yep, many ways to accomplish, just pointing out another in case the materials aren't on hand. Clean grease would do as well.
 
Clearly the OP needs a mechanic. I consult for a yearly fee of whatever Savvy charges. :D




 
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Yes, the bolts are threaded into an encapsulated nut. Yes, Cessna saw the need to put a seal on the bolt in case the encapsulated nut failed. Yes, the specified bolts were drilled for safety wire but have been replaced sometime in the 46 year history before I got it with non-drilled bolts. Which brings me back to my question, I can either get the drilled bolts and (finally) get the cork seals or I can get the non-drilled bolts with the improved seals. If I get the non-drilled (better) bolts can I Loctite them [Loctite 242 is for gasoline environments and will allow for removal later].

I'm asking here before I go to my mechanic as I think the new seals are better and want a coherant argument for them.
 
weirdjim said:
You take your aviation approved kitchen scissors and cut a cork seal.
Click to expand...

how do you know if your kitchen scissors are approved for aviation use? I read the label and didn't find anything. I then called the company, and she called me an idiot before hanging up. :dunno:
 
I know I would not trust a chemical product in a gas environment, particularly where there's going to be lead emulsified, and sitting for a long time. If Cessna said use safety wire, I would use safety wire. There's other places I might go off the reservation and do something different, but maybe not in this application.

I can't see anywhere that loctite 242 is suitable for leaded fuel application, but I'm not going to hunt it down either.
 
I think the way forward is to skip the loctite, buy new drilled bolts and then use a neopreme washer instead of the cork seal backed with a flat washer. Is that something a mechanic can sign off? It's not an owner made part, it's just a purchase.
 
cgrab said:
...If I get the non-drilled (better) bolts can I Loctite them [Loctite 242 is for gasoline environments and will allow for removal later].
Click to expand...

My suggestion is DO NOT use Loctite on sealed nutplates :no: You are asking for trouble if you do. Use lock washers or drilled screws with lock wire.
 
cgrab,

It sounds like you have confirmed the original S350 is a cork washer. Now that I think about it I do remember selling those when I worked at a Cessna service center. I would call a Cessna service and parts dealer and find out if they can give you a cross reference to a Stat-O-Seal type washer, or find out if the originals are still sold. The "rubber in washer" washers are called Stat-O-Seals (or something very similar) They should be available from most aviation hardware suppliers, Aircraft Spruce, Mcfarlanes, Wag-Aero etc. Do a quick google search.
 
cgrab said:
I think the way forward is to skip the loctite, buy new drilled bolts and then use a neopreme washer instead of the cork seal backed with a flat washer. Is that something a mechanic can sign off? It's not an owner made part, it's just a purchase.
Click to expand...

To clarify, it is an owner produced part, not made. You don't need to physically make the part.
 
Then, I would still purchase (or drill yours if you really want to spend the time...) new bolts, and sealing washers (be it the cork or Stat-O-Seals) and install them with a thin washer, torqued per specs, and lockwire the whole thing.

If the Mcfarlane screw assembly is approved for your application that could work as well.
 
You know you can buy the drilled head screws, no need to drill them yourself (which is much tougher to do than you might think)
 
Silvaire said:
You know you can buy the drilled head screws, no need to drill them yourself (which is much tougher to do than you might think)
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Unless you do them in a V-block in a drill press, they are next to impossible to do well.
 
Silvaire said:
My suggestion is DO NOT use Loctite on sealed nutplates :no: You are asking for trouble if you do. Use lock washers or drilled screws with lock wire.
Click to expand...

Why would anyone use Loctite on anything like this when a guy can buy fuel tank sealant such as 890B1/2 which is a pretty darn good adhesive? There are no gaskets in the top of the fuel tank at all (Other than the lone one of the fuel cap) That top access plate has countersunk screws that thread into encapsulated nutplates and a thin layer of fuel tank sealant is all that keep the whole plate and the 16 screws in each from leaking.
 
cgrab said:
Yes, the bolts are threaded into an encapsulated nut. Yes, Cessna saw the need to put a seal on the bolt in case the encapsulated nut failed. Yes, the specified bolts were drilled for safety wire but have been replaced sometime in the 46 year history before I got it with non-drilled bolts. Which brings me back to my question, I can either get the drilled bolts and (finally) get the cork seals or I can get the non-drilled bolts with the improved seals. If I get the non-drilled (better) bolts can I Loctite them [Loctite 242 is for gasoline environments and will allow for removal later].

I'm asking here before I go to my mechanic as I think the new seals are better and want a coherant argument for them.
Click to expand...

I'm pretty sure the way cessna shipped the planes from the factory don't match the parts manual. The parts manual might not even be right which happens more than you think. I've never seen the gasket anything on bolts or drilled bolts and I can assure you that one transmitter I pulled had never been removed since it was new. It was installed with a big cork gasket and black regular socket head cap screws (the NAS part # in the book) and lock washers. None of these installs (4 senders) leaked. There is no way any cork or stat-o-seal would work with the NAS1352-3-10 cap screw because they have very little shoulder under the heads.

The stat-o-seals look like they would work with the drilled bolts (the alternate MS20074 bolt) in the parts manual.
 
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See if your mechanic is ok with using the drilled head screws with proseal under the heads and safety wire them. Proseal is made to seal fuel tanks and tank fittings. It works and fuel will have no effect on it.
 
I've ordered the drilled bolts and will use the stat-o-seals and flat washers.

Thanks to all for your help
 
cgrab said:
I've ordered the drilled bolts and will use the stat-o-seals and flat washers.

Thanks to all for your help
Click to expand...

Good luck. There is a lot of inconsistencies in this area.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&sqi=2&ved=0CB4QFjAA&url=http%3A%2F%2Fmountpoint.info%2FN3212T%2FCessnaCardinalN3212T%2FManuals%2FCessna177PartsCatalog68-76.PDF&ei=KVDCVISlL4r6yASjkYHIAw&usg=AFQjCNGuDoPsL1qTSwxSgI98LMePzPxemg&sig2=U63N_chkPzDKqw-fe5ApmQ&bvm=bv.84349003,d.aWw

It looks to me like the only configuration I've seen is code T (shows applicable to 17702124 & on) which just uses an NAS1352-3-10 screw and a AN936A10 (superseded to MS35333-39 internal tooth lock washer). I've found this configuration on serial # 177000021.

Supposedly the S350 applies to 17700001 thru 17702072 but I've never seen any on 17700021. :dunno:

The NAS1352-3-10 is not drilled for safety wire. :dunno:

Serial # 17702618 supposedly should have been equipped with fuel gauges manufactured by Leigh, but I found a Leigh on the left and a Stewart Warner on the right. This doesn't match parts manual data :dunno:. This mixed bag has been found on several 177Bs (http://www.fuelsenders.com/site/898219/page/650423)

This stuff is frustrating sometimes. Sometimes it is impossible to assemble hardware as shown in a parts manual even on $Xm jets due to fastener length and interference issues.
 
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