Wing bolts,... what to do now,...?

[BillSchlatterer]

Well, knew it was too good to be true. Getting ready for inspection and the last serious job is replacing the wing bolt hardware pins with the CT bolts. Was going extremely well until I got to the last of the big bolts. In my exuberance,....I got carried away and drove it about 2/3 of the way in without a washer on the head side.



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For those that don't know, on the A models, the bottom bolts get washers under the head instead of the nut because of clearance issues and possibly because you have to torque the bolt head instead of the nut. Even then, getting the right torque is problematic. Also because of the landing gear construction, there is NO way to drive a bolt out from the back.

Sooo, the problem in the picture is obvious,... no washer and the bolt is in very very tight. I see only three ways to deal with it.

1) Blocks of wood with a perfect sized crowbar and a 7/16 open wrench under the head and pry it out. Probably doable but not pretty and possibly ruin something.

2) Cut a special end for a slide hammer to go over the bolt head and then slide hammer hammer hammer it out! Also possibly ruin the bolt and not get it out.

3) Since the bolt is really loaded in shear anyway and the head face does have a washer like surface, I could just drive it on in normally, put a little of the heavy anti-seize under the head so that it doesn't scratch the spar web when I torque it, put a washer under the nut for spacing (there is room to do that) and then torque it on down. This is far and away the easy, risk no damage option.

I am leaning toward option 3 since I think I run the least chance of damaging anything, and it would be basically no different than the ones on the top except for the issue of torqueing the bolt head with no washer under it.

Is there a safety issue on this that would justify the efforts and risk to remove the bolt just to get the washer under the head? All of the rest are in and torqued properly.

If anyone has done this and run it past Vans, I would really like to hear what they said.

I would really appreciate it if someone like Mel or other A&P types could jump in with some real world advice.


Thanks Bill S
7a almost there,....

 

[L.Adamson]

Besides just getting the bolt removed, if you can't torque the nut from the front side ....

How about two thin washers with a slot ground or filed. Then put them opposite of each other. This thought just went through my head. And the slots would have to be clean & deburred, to prevent marring. Thoughts....anybody?

Other than that, I once had to remove all the bolts in my 6A after being torqued. It wasn't too tough, as I could also get something with a point on the back side to knock them out.

edit: How about a block of wood on each side of the bolt. And then drive wooden wedges down.

L.Adamson --- RV6A

 

[sbarger24]

I managed to do the same thing on one of my bottom bolts and managed to get it out. I used a pair of channel locks to grab pull and twist the bolt until it came out. I also had a helper moving the wing up and down ever slow slightly as I worked it out.

 

[jimski9]

Back in January I sent this email to Van’s about the same issue -

Re: RV7A Wing Attach Bolts

After installing the larger lower outer wing attach bolts I realize I did not put the washer under the bolt head but put it under the nut. I was distracted by reports of how difficult these bolts were to install and didn't check the plans properly. I tightened the bolts and the required amount of thread is showing beyond the nut. (The nut did not bottom out on the thread).

I note another builder did the same thing
http://www.rv7-a.com/IMG_5318.JPG
(and the picture also appears to show he has omitted the two AN4-13A bolts)

I will install the inner lower bolts and the lower smaller bolts with the washers under the bolt head. Should I try and remove the bolts? I am concerned that this may damage them (or the center spar)​

Ken Scott’s reply -

As long as the bolt is doing what it's designed to do, there's no need to remove it.
Omitting the two AN4 bolts is NOT advisable. They are there for a reason.​

Jim Talbot
RV7A ZK-JLT
New Zealand

 

[Jamie]

Getting the bolts out is no big deal. If you ever need to remove the wings you're going to have to get them out anyway so you may as well get a technique down.

Did you lube the bolts before you put them in? You should have. If you have lube on there you can put a closed-end wrench on the bolt and rotate it and work it out.

You can also take blocks of wood and place it on the center section and just pry them out, building up the wood blocks as the bolt comes out.

You really only need to do this on the bottom ones. The top ones you can just drive them out!

The trick here (taught to me by a repeat offender) for *installing* these bolts and driving them out (when possible) is a rivet gun. The bolts will go right in. Much nicer than pounding them with a rubber mallet or dead blow hammer.

 

[Walt]

Spar bolts

As far as safety is concerned its not an issue, you can just drive the bolt in and put the washer on the other side and torque it.

It would be "nice" to take it out and put the washer on like the others but if you damage or mar the bolt or spar in the process then you've just made it worse. Prying out bolts (using a pry bar under the head) can cause nicks and or gouges in the bolt head radius which would require them to be replaced.

Bottom line if it were me, just go ahead and install it as is.

 

[noelf]

Bill, from your picture...

...it looks like the adjacent bolts are not torqued down. Van's spar is composed of several layers of aluminum bar strips. When they were drilled at the factory, they were tightly held and compressed as an assembly prior to drilling the bolt holes. If these same areas are not compressed in your aircraft assembly, it allows the individual bar stock (with the attendant precision drilled hole) to move slightly and cause a difficult bolt insertion / extraction task.

I learned to compress the areas next to each bolt hole prior to installing each bolt. They went in (and could be removed) with light tapping. Large "C" clamps or "monster" long reach vice-grip type tools work well in this area.

 

[BillSchlatterer]

Actually, they are all torqued down except for the 1/4" bolt to the left of the 7/16 bolt. Top bolts were torqued on the nut per standard but bottoms have to be torqued on the bolt head. They were all lubed and went in with no real problem but they did have to be coerced a little bit Since the rest are in, there is no "jiggleing" the wing.

While I could probably get it out with some effort, the chance of damaging the wiring in the area and/or the spar seems like a lot of risk just for the sake of having a washer under the bolt head when it get's torqued.

BTW, it is taking about 5 foot pounds of torque just to turn the 7/16 bolt and about 40 inch pounds on the 1/4" bolts. That makes final torque on the 1/4 inch stuff a guess when torqueing the bolt head instead of the nut.

I like what Ken Scott said in Jim's post above. "As long as the bolt is doing what it is supposed to do, there is no need to remove it."

Lots of good ideas here. Still pondering but leaning toward the "leave it alone" option after seeing the note from Ken Scott.

Thanks Bill S

 

[Andrew M]

Use heat/cold

Heat the hole area with a space heater until it is almost to hot to touch, (it's not to hot to affect the metal see AC 43-13)then apply dry ice to bolt while prying. Do this repeatedly if necessary. The only similar experiance was driving out MLG pins from a C-207, and we used liquid nitrogen. The trick is to heat soak first, then cool the bolt.
Good luck
Andrew

 

[Neal@F14]

Can you get an air-powered rivet gun in front of the spar? if so, then you can use a smaller diameter softer steel bolt shank with threads cut off as a driving punch, and use the rivet gun as an air hammer to drive the wing bolt out backwards to remove it. I've seen this technique used successfully before to remove stubborn close tolerance wing bolts.