What am I doing wrong- tailgate crack

[The Proton]

After owning my 80 series for about 10 years it developed a crack in the upper tailgate. It looks like a fatigue crack. At the time I figured it was due to me standing on it to open the RTT. I ended up finding a used tailgate and replacing it.

After the new one went on I also added a new rear bumper I could stand on, and stopped standing on the tailgate. A few years later the same crack appears…. I just replaced the tailgate again.

I don’t want to buy a third one. Any ideas what could cause this? It seems to be more fatigue than a single incident.

Any thoughts? Photos of tailgate #2

 

[Brindleboxer]

Can you take a picture from a little farther away to give perspective.

Also, do you have tailgate storage? When you open it do you guide it down or do you just let it fall?

 

[NeverFinis]

I don't think it is metal fatigue.

San Francisco?

Someone tried to use a pry bar to break into your vehicle.

In order of likelihood according to AI:

1. Pry bar
2. Dropped the tailgate onto something
3. Metal Fatigue

 

[leonard_nemoy]

Attempted theft

 

[george_tlc]

Metal fatigue = *ZERO* chance. Given the dents etc, it's either the hulk with a prybar or some hydraulic tool.

cheers,
george.

 

[jeremy j]

The pry bar makes sense but wouldn’t there be marks on the upper door? Can’t imagine thief would be careful about that.

 

[thatcabledude]

Happening to two different tailgates is weird whether it’s attempted burglary or not.

Do you ever have a hitch mounted bike rack or basket on the truck?

 

[NeverFinis]

The pry bar makes sense but wouldn’t there be marks on the upper door? Can’t imagine thief would be careful about that.

I would assume there would be marks, but the upper hatch is made from high-strength steel, unlike the tailgate. Plus, it is folded over at the lower edge of the upper hatch, increasing the strength.

 

[The Proton]

It has been parked in San Francisco, and there have been pry marks around the rear sliding window. That being said it started small and got worse, so I think it was fatigue based, I would expect a prybar or similar to leave more dents before the metal would actually crack like that.

I do not have anything that would have hit it (tow hitch, basket, etc. ) I am not gentle, however, when I open it, I tend to unlatch and let it fall, so maybe that is part of it. As it started to appear I found I really had to slam the upper tailgate to get it to latch, so that may have something to do with it as well.

I'll try being super gentle now, and the vehicle is parked out of the city as well, so hopefully this one will do better.

 

[bj70bc]

how fat are you, damn dude

 

[ajax1]

Upper hatch not adjusted correctly? What’s the upper look like in that area? More pics

 

[bttygoose]

It has been parked in San Francisco, and there have been pry marks around the rear sliding window. That being said it started small and got worse, so I think it was fatigue based, I would expect a prybar or similar to leave more dents before the metal would actually crack like that.

I do not have anything that would have hit it (tow hitch, basket, etc. ) I am not gentle, however, when I open it, I tend to unlatch and let it fall, so maybe that is part of it. As it started to appear I found I really had to slam the upper tailgate to get it to latch, so that may have something to do with it as well.

I'll try being super gentle now, and the vehicle is parked out of the city as well, so hopefully this one will do better.

Having that happen twice is definitely someone trying to get into your truck. I could see someone desperate enough telling someone else desperate enough “you just hit here with a sledge and a chisel and the tailgate opens” and then taking off when the tailgate doesn’t magically open.

 

[thatcabledude]

Having that happen twice is definitely someone trying to get into your truck. I could see someone desperate enough telling someone else desperate enough “you just hit here with a sledge and a chisel and the tailgate opens” and then taking off when the tailgate doesn’t magically open.
View attachment 4241929

I totally disagree.

 

[thatcabledude]

Visiting this thread again and thinking again. I swear this has been brought up before by other users over the years. I think it’s a “thing”.

Do some searches.

Could be what @ajax1 mentioned

 

[thatcabledude]

Screen shot from another thread. Post from @SNLC

More… @BILT4ME mentioning his had the same crack:

 

[MissahPapaJ]

Funny enough I’ve seen a 80 for sale with the same crack and was wondering if it got hit but it didn’t look like it

 

[fjbj40]

The early 80 series lower hatch is weaker than the later series.
There is extra bracing inside them, the factory swingout revealed this and all later series got the bracing.

Now, I may be going off memory on this but I’m pretty sure as I have installed a swingout on my 93 and if you slam the carrier the flex it clearly visible vs the factory equipped swing outs I’ve observed closing vs mine.

The question is does the early series crack without the carrier? Mine has +300k on it and not yet cracked even though I have the swingout installed for 10k miles.

If you are using the lower as a seat and you are say over 200lbs and sitting on the edge in the center then I can see this causing fatigue and eventually cracking.

Possible cure is more internal bracing which I’ve been planning on doing, just hasn’t happened yet.

I don’t slam my doors nor am I anywhere near 200lbs.

Looking at the pics the author posted it looks like a stretch relax failure. This may have come from individuals sitting on the tailgate, flexing it down(normal), causing stretch, and then when they get off it can’t shrink and stress cracking forms. Metal stretches easier than it compresses in the door design. The metal attempts to return to its shape but can’t and the stress stays applied until it relieves itself and fails.

The second tailgate cracking could be due to the fact it was already cracked or under the stress that causes the crack and it took awhile for it presented itself.

If you look closely at the crack it is a rise up instead of a depression at the fractured edge. I have some experience in this field with aircraft structures.

Sorry for the long winded post

 

[BILT4ME]

It's not from anyone trying to break in.
It's not from my fat ass sitting or standing on it, because I don't.
It's from repeated flexing at the latch area.

When my trunk is completely full, I slam my upper gate and it latches first try with a solid thunk.

When it's empty or not packed all the way to the back, I must slam the upper gate multiple times to get it to latch.
It also makes a difference where my hand is placed when closing. My hand must be on the outer third of the upper gate for it to latch the first time. Otherwise it will flex and reverberate and not latch.

Having more reinforcement on later models would make sense, but I'm not sure that really took place. I have another gate that needs a little body work and I have considered placing a 10 ga. Plate under the latch area across the width to act as a stiffener.

 

[fjbj40]

Have you tried adjusting so you don’t have to slam?

I don’t have to slam mine for it to latch, it latches very easily.

 

[80t0ylc]

Have you tried adjusting so you don’t have to slam?

I don’t have to slam mine for it to latch, it latches very easily.

I don’t have to slam mine either. I do have a problem, though, if I spend a lot of times on washboard roads, the tailgate pops loose enough to let dust in. My swing out is off my Kaymar bumper, so I don’t think that my swing out is contributing to anything. I can see how a factory swing out could contribute to the problem that this thread is showing. I believe the factory swing out latches on the tailgate and/or the upper hatch which could put additional stress on both, especially if slammed frequently.