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AN832-4D on T1003B-R/L, Wing page 18-06

J

JDA_BTR

Well Known Member
I think I know the answer.... but!

I've fabricated the vent line and am trial fitting the parts before mixing proseal and riveting the end on. I'm finding that the AN832-4D is ever so slightly bigger than the anti-rotation plate already riveted onto T1003B-R. There is no proseal in the way, the plate just is a hair narrow.

Rather than work on the plate and maybe mess up the rib, can I just buff down the edge of the union to get clearance? I can't see why not but it is blue, and maybe there is some sort of corrosion reason not to mess with that?

Secondly, I think I have to proseal this union into the hole. Then apply the nut to the union to hole it in from the outiside. ? Any tips on ways to not make a huge mess here?
 
Tom023 said:
just to clarify, the only torque chart that I can find is on page 5-18 and that is for AN fasteners (bolts) not fittings. If a torque chart for fittings is in section 5 I'm not seeing it.


Thanks for the link Jim, I didn't know that was there.
Click to expand...

I think Scott is talking about 5.27 (currently on page 5-32). Am I correct in that you need to use permatex or some other sealant on the threads themselves? Looks like the torque is 1.5-2 turns past finger tight according to the text. I will wait for a response, I am at the same stage here. I am just about to do a leak test of the tank prior to putting on the baffles.
 
It is my understanding that no permatex is used on fuel line compression fittings. And after reading it seemed that for the compression fittings that going to finger tight followed by 1/4 turn (1.5 flats) is correct. I did 1/4 turn and a tiny bit more. I'm pretty sure if I went 1-2 turns it would ruin it terribly.

I didn't find that the hole was too small. Buffing down the flats on the fitting made the thing fit in the anti-rotation plate nicely and a little proseal on the buffed edges will cover the place where the anodizing is gone. I got an email from Vans saying no foul in buffing down the flats to fit the plate.

For the larger nut that holds the fitting onto the rib from the outside, I tightened it down very snug but didn't torque it. It seemed to go a certain amount, and then no more; with the fitting in the rotation plate and proseal on it I don't think it is going anywhere.

I think the Vans manual on this topic needs a little clarification rewrite. If you have never done this before what is said isn't adequate and it takes reading here and other places to get it right.

For the NPT fittings (drain line, plug) I will use permatex or such.
 
Hoping Scott will come back and clarify for us all, I agree for a first timer the instructions are unclear. I will back the nut off tonight and hopefully did not torque the flare off, not sure how I would reflare that. I am not sure if the gap at the end can be too much vs the 1/4" that is specified.

It does say 1-1.5 "turns" but I agree that is too much.
 
JDBoston said:
I think Scott is talking about 5.27 (currently on page 5-32). Am I correct in that you need to use permatex or some other sealant on the threads themselves? Looks like the torque is 1.5-2 turns past finger tight according to the text. I will wait for a response, I am at the same stage here. I am just about to do a leak test of the tank prior to putting on the baffles.
Click to expand...

Actually I was talking about paragraph 5.14 in manual Section 5 (most recent rev level can be found HERE)
It lists torque values for "B" nuts with aluminum tubing. The specs can also be obtained from the standard aircraft handbook.

5.27 is talking about installing tapered pipe thread (also refered to as NPT fittings) fittings.

THIS previously referenced document is for aluminum hose end fittings only. I realize the document is a bit confusing because the title just says torque specifications for aluminum fittings (it is Aeroquips document that they provide for use with there brand hose assemblies). To try and aleviate confusion, the file name on the web site was recently renamed to Torque Specifications for Hose End Fittings.

Now having said that, it appears that some people posting to this thread have been talking about two different issues. When joining flared fittings (hard aluminum lines or hose ends), you do not use any thread sealant. When installing a fitting with a tapered pipe thread you do use thread sealant on the threads. It is only the tapered pipe threads that get turned 1.5-2 turns to tighten. All other connections are done based on a torque value or sometimes a number of flats. Tightening two flats would be a third of a turn (two flats on a six flats hex nut).

More simply... if a joint has a flare, that is the sealing surface and no sealant is used. If the joint has fine pipe threads as the sealing surface, then thread sealant is used.

Other info on tightening flared fittings in a post I made a few months back found HERE
 
James,
What did you finally do with your anti-rotation plate? One of mine is about .015 smaller than the other and the "B" nut won't seat into it. The hole thru the rib is fine, but the nut catches on the plate. I really don't want to take it off of the rib, but I don't want to scratch up and mess up the rib underneath, trying to make it bigger. I think I'm resigned to taking it off, but want to know if there is an easier fix someone thought of.
 
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