Wheel pant bolts coming out regularly

[Ben2k9]

We have a CTLS with the Tundra wheels. We recently replaced some bolts on the inside that had fallen out (about a week ago). Since then, they have fallen out again. You can see the missing bolt on the side with a single bolt. The same bolt is missing on the other wheel pant as well. Are we supposed to put a nut on the bolt or is there something else we are missing here to help these stay on?

 

[AGLyme]

So, this happened to me too.  In fact, the single larger bolt on the other side of the pant came out as well.  I was fortunate that the pant didn't break upon landing.

First point:  The pant bolts are a pre-flight item for sure... do it every time.

Second point:  Get the blue Loktite at the auto parts store... NOT the red colored... review Youtube for Loktite application, like everything there is a trick to the application.  The "Blue" is designed to hold the bolts, and can remove the bolts easily for maintenance.  The red Loktite is designed for hold fast (glue).  

Once I applied (the blue) Loktite, the bolts have never reversed.  Suggest calling FD USA for bolt specs... or order from them.  

[FlyingMonkey]

I have had a few of those screws get loose on my CTSW, but never when I use blue Loctite on them.  I think that's the cure.  They are subject to a lot of vibration and will shake loose without some form of retention.  The other more hard-core potential fix is to get some thin Nord-Lock washers or something similar.

[Ben2k9]

Yeah I think that’s the missing link. Did not realize it needed  loctite. Thanks guys!

[Roger Lee]

Never use Loctite on Rivnut screws. many times it will cause the Rivnut to loosen and then the screw and Rivnut just turn. Then you usually strip out the head of the screw too. Then you have to take a Dremel tool with a cut off blade and put a slot in the head of the screw so you can use a straight screwdriver. Then you have to get a pair of pliers on the back side of the Rivnut to hold it while you try and turn the screw. Sometimes you can't get to the back. prevention is a far better way to go.

These screws should not be coming out if tightened down. If they do then the Rivnut is too worn out and needs to be replaced

[BravoFoxtrot]

This is what I use on the outside screw a CTSW wheel pant. It has a nylon patch on the screw thread which helps keep it in place when there is vibration.

https://www.mcmaster.com/screws/socket-head-screws/vibration-resistant-socket-head-screws/18-8-stainless-steel-thread-locking-socket-head-screws/system-of-measurement~metric/

Haven't had them come loose since I've started using them.

[Skunkworks85]

3 hours ago, Ben2k9 said:

Yeah I think that’s the missing link. Did not realize it needed  loctite. Thanks guys!

You really should consult the maintenance manual before you work on anything on you aircraft.  

 

 

[Roger Lee]

The quote comes from a CTSW manual of Nov. 2008 page 4-21 section 4.2.2.5 and not the LS manual. His picture is of the LS and it isn't in the LS manual. They didn't put it in the LS manual. Even some of the numbers are wrong in the drawing, but the screws they are talking about that hold the wheel fairing on for both the SW and the LS use Rivnut's and this makes applying Loctite 243 hazardous to their removal. You will either strip the Allen head out or cause the Rivnut to turn inside its mount. I have seen it dozens of times and always have to slot the head of the allen screw and or hold the back side of the Rivnut so it doesn't turn. Does this happen all the time. No and you may get away with it for a while, but enough that fail that I hate going through it. Since I have been doing this since 2006 I haven't ever used Loctite on these small wheel pant Allen head screws and I have never had one come out. You just have to torque them down. This to me is old advice from a 2008 manual and isn't needed when done properly. Just like an oil filter. It won't come loose when torqued properly. 

An easier fix is to take a pair of pliers and give the back of the Rivnut an easy squeeze to allow some friction on the screw threads.

[AGLyme]

I’m not saying you are wrong Roger.  But I have removed the screws successfully Because I had to remove the pants a couple of times... after I used the blue (not the red) locktite.  As you know one uses very little locktite on the bolt... 

in the past i have tightened the bolts but with zero success.  They kept coming out.

[Tom Baker]

1 hour ago, Roger Lee said:

The quote comes from a CTSW manual of Nov. 2008 page 4-21 section 4.2.2.5 and not the LS manual. His picture is of the LS and it isn't in the LS manual. They didn't put it in the LS manual. Even some of the numbers are wrong in the drawing, but the screws they are talking about that hold the wheel fairing on for both the SW and the LS use Rivnut's and this makes applying Loctite 243 hazardous to their removal. You will either strip the Allen head out or cause the Rivnut to turn inside its mount. I have seen it dozens of times and always have to slot the head of the allen screw and or hold the back side of the Rivnut so it doesn't turn. Does this happen all the time. No and you may get away with it for a while, but enough that fail that I hate going through it. Since I have been doing this since 2006 I haven't ever used Loctite on these small wheel pant Allen head screws and I have never had one come out. You just have to torque them down. This to me is old advice from a 2008 manual and isn't needed when done properly. Just like an oil filter. It won't come loose when torqued properly. 

An easier fix is to take a pair of pliers and give the back of the Rivnut an easy squeeze to allow some friction on the screw threads.

I always use a small drop of medium thread locker on these screws. In 10+ years of working on CTLS's I only recall replacing 1 (one) rivnut, and only few screws.

[sandpiper]

I use a dab (this is a precise measure) of torque seal so I can tell at a glance on preflight if any of these are backing out. Mine rarely back out and I do not use loctite.

 

[AGLyme]

I squeeze out a drop on the applicator and  bring the bolt to the applicator and touch the thread to drop.  The solution covers about 25% of the thread. Again, no issues with removal and no more backing out problems.

the takeaway on this string for future readers is to pre flight these bolts on BOTH sides of the pant due to vibration.

 

[Ben2k9]

Thanks for all the input. FWIW emailed Arian at FD and he also advised to use blue loctite. 
 

Let me run one more thing by you guys...this never happened with my prior CT (2008 model) but this newer CT (2011 model) has some staining / burnishing behind the exhaust pipe.  It was this way when I got it. also the electrical wire used for jumping, the rubber sleeve part is a little melted. 

Is this normal and if not, what could be the cause?   

 

 

[Tom Baker]

That actually looks like burning. Did the airplane have any exhaust components replaced or repaired before you bought the airplane? If not I would look at the tailpipe and muffler real close.

[FlyingMonkey]

5 minutes ago, Tom Baker said:

That actually looks like burning. Did the airplane have any exhaust components replaced or repaired before you bought the airplane? If not I would look at the tailpipe and muffler real close.

Yeah, that doesn't look normal.  As Tom said, it looks burned.  Exhaust soot is black, that is a dark brown.  Can those stains wipe off the cowl/belly?  Exhaust stains wipe off pretty easily with a mild solvent.

Definitely time to remove both cowls and inspect *everything* very thoroughly.  Check the exhaust, and also look for burned wiring, damaged hoses, anything that looks "not right" or heat-damaged. 

[Roger Lee]

12 hours ago, AGLyme said:

I’m not saying you are wrong Roger.  But I have removed the screws successfully Because I had to remove the pants a couple of times... after I used the blue (not the red) locktite.  As you know one uses very little locktite on the bolt... 

in the past i have tightened the bolts but with zero success.  They kept coming out.

Like I mentioned it doesn't loosen the Rivnut's all the time at this location because of the metal mount, but it does happen. Applying Loctite to the ones that are mounted into the plastic areas like the spinner or instrument panel is a disaster. I don't like opening doors that I have to fix. 

[Tom Baker]

14 hours ago, Roger Lee said:

The quote comes from a CTSW manual of Nov. 2008 page 4-21 section 4.2.2.5 and not the LS manual. His picture is of the LS and it isn't in the LS manual. They didn't put it in the LS manual.

This is from the LS manual Page 4-20.

4.2.2.5.3 Procedure

The bolt C9996054B must be set with lock liquid of middle strength Loctite 243 and tighten 80 lb-in (9
Nm); the screws C9996162 (Screw ISO 7380 M5x16) are to be set with lock liquid of middle strength
Loctite 243 and tightened 49 lb-in (5.5 Nm).

[Roger Lee]

Hi Tom,

You're right and I did miss that last part, but I still don't think Loctite is needed when you properly tighten them. I've never had one loosen or come out in 14 years on an SW or LS and have never used Loctite on these out of how many hundreds of annuals. We have all found better ways to do things other than what the manuals say. Just like trimming the wheel pants or all the LOA's that are posted. 

Kind of like when FD wanted had all the props setup to only get 5200 rpm or Marc brakes or plastic fuel filters or springs in the front suspension, ect... Things change and sometimes we just find a better mouse trap.

[Skunkworks85]

19 minutes ago, Roger Lee said:

Hi Tom,

You're right and I did miss that last part, but I still don't think Loctite is needed when you properly tighten them. I've never had one loosen or come out in 14 years on an SW or LS and have never used Loctite on these out of how many hundreds of annuals. We have all found better ways to do things other than what the manuals say. Just like trimming the wheel pants or all the LOA's that are posted. 

Kind of like when FD wanted had all the props setup to only get 5200 rpm or Marc brakes or plastic fuel filters or springs in the front suspension, ect... Things change and sometimes we just find a better mouse trap.

Roger,

I agree with what you are saying, But when it comes to the OP, a potential safety of flight issue could have been avoided by following the recommend procedure.

And later the OP may have been asking the question of how to repair the rivnuts or if there was a better solution than using loctite. 

Any other current solution is not approved by FD and if it came down to answering(faa?) why something was done a certain way, saying "Roger Lee does it this way" would not be an acceptable answer.

 

 

[Roger Lee]

58 minutes ago, Skunkworks85 said:

Roger,

I agree with what you are saying, But when it comes to the OP, a potential safety of flight issue could have been avoided by following the recommend procedure.

And later the OP may have been asking the question of how to repair the rivnuts or if there was a better solution than using loctite. 

Any other current solution is not approved by FD and if it came down to answering(faa?) why something was done a certain way, saying "Roger Lee does it this way" would not be an acceptable answer.

 

 

If we stick solely to the manual's exact verbiage I would bet most all Ct's and many other LSA would fail. That's just from direct observations on aircraft that come in and from a thousand phone calls over the years. I bet I can find things on your aircraft that aren't 100% FD. Little things like this a I don't usually worry about so long as they are solid fixes and it isn't a real change from factory. FAA won't sweat a screw out of the wheel pant and I've never had one come loose. There are tons of minor items that owners and mechanics do that aren't specified by FD and if they the owner wanted to deviate from no Loctite on that screw I doubt FD would sweat it or even offer to give an LOA for something so minor. You have to look at it in the FAA's eyes of how important or a flight issue is the change.

There is technically correct and functionally real life acceptable and then there's changes that have been made in the field that FD didn't have in the manual, but because of the people in the field changing things they changed too. 

The FAA told me once when I was researching a paper that if it was insignificant in nature and posed no flight or legal issues they didn't have an issue with it. I seriously doubt anyone will hold your feet to the fire for no Loctite on this particular screw.

[Tom Baker]

I would be curious about how many have had wheel pants come loose. I replaced one that came into the shop with a small piece of fiberglass still attached to the gear, and what remained of the wheel pant in the baggage. I know of an other that posted on here that they lost or had one come loose in flight. They may have been posting from the airplane while it was happening. That is 2 that I am aware of, and I bet there are others.

Also remember that when you do an inspection that you are signing that you have done it in accordance with the manufacture's maintenance and inspection procedures. If a customer does have one come loose, and it does happen. They panic and lose control on landing totaling the airplane. How are you going to defend yourself? 

[Roger Lee]

"Also remember that when you do an inspection that you are signing that you have done it in accordance with the manufacture's maintenance and inspection procedures."

Because almost all mechanic's say they did it "IAW" then almost 99%  and maybe 100% fail and especially if you were to get nit- picky. We have all done things that aren't EXACTLY like the manual or even a part difference. Everyone I have seen since 2006 would have failed and that would include myself since I try to not only do it by the factory way, but I do try to make it better. Look at all the LOA's we have listed on the site. many are from me. Then there are other LOA's that aren't posted here. I have never had an issue with folks that strive to do things better just the ones who fail to do it or make it worse. I've had companies call and ask me to review mechanic's logbooks and then question them. Several have had to refund the inspection money and the annuals were redone all because they wrote "IAW" and never used a checklist and didn't know what to do. IAW is all encompassing.

Here's another example. If an aircraft company like FD has a part number assigned to a part you MUST buy it from them and that's straight from the FAA. Who has ever bought a part not directly from FD? Ooch  (Tom have you purchased items not from FD  ) We all have. There has even been times when FD told people including myself to just buy it somewhere else with nothing in writing.

What happens when the company doesn't have that part, at all.

These are just example and if you take the argument over the edge you can make a case for almost anything.

[AGLyme]

6 hours ago, Roger Lee said:

ones that are mounted into the plastic areas like the spinner or instrument panel is a disaster.

That makes a ton of sense... thanks for the warning on that.

[Bill3558]

I took my pants off so I could see the tires. May be off topic, but am I loosing much cruise performance?   I think the airplane looks fine without them. 
 

 

[Roger Lee]

There is a blanket LOA that allows you to leave them off. Your choice.