M998 HMMWV Frozen Tailgate Hinges

[knighthawk]

I just picked up a 1987 M998 in good condition but needing some work. I am new to the M998 and need some advice on dealing with the problem of corrosion between the aluminum and steel parts. In particular the tailgate hinges are completely frozen. The tailgate , hinges , and frame are in excellent unbent and undamaged condition but the steel hinge pins are frozen in the aluminum hinges. I have tried heat , PB Blaster , Kroil , ATF and various combinations of the previous with no movement whatsoever. Does anyone have any experience with this problem? If so what worked? I am about ready to unbolt the tailgate and drill the pins out but would prefer an alternative. Thanks in advance.

 

[Skrilex]

Dang, well you’ve tried everything I know of. More heat!

 

[TOBASH]

I just picked up a 1987 M998 in good condition but needing some work. I am new to the M998 and need some advice on dealing with the problem of corrosion between the aluminum and steel parts. In particular the tailgate hinges are completely frozen. The tailgate , hinges , and frame are in excellent unbent and undamaged condition but the steel hinge pins are frozen in the aluminum hinges. I have tried heat , PB Blaster , Kroil , ATF and various combinations of the previous with no movement whatsoever. Does anyone have any experience with this problem? If so what worked? I am about ready to unbolt the tailgate and drill the pins out but would prefer an alternative. Thanks in advance.

Remove them and wash away the oil and then try 2-3 minutes in DILUTED plumbers acid?

Not more than 3 minutes as it will DESTROY the Aluminum.

 

[knighthawk]

By diluted plumbers acid do you mean hydrochloric acid ?

 

[cwajciec]

Unbolt them and submerse them in a mixture of atf and acetone. Worked for me to unfreeze an old set of leatherman pliers.

 

[TOBASH]

By diluted plumbers acid do you mean hydrochloric acid ?

Yes. You're using the correct term. Most people outside of the chemistry world use the term "plumbers acid" and not hydrochloric acid, so I apologize if I confused you.

EDIT - The other term is Muriotic Acid

 

[tage]

HCL eats al. I would advise strongly against using a strong acid for this purpose. Especially if you have a high molar HCL product it will immediately chew apart the al. To even suggest this is astonishing. It's extremely dangerous, and will produce hydrogen gas and vigorously "boil".
I have an under grad degree in chemistry.

Now take them off and soak them in a solvent. If you want to use an acid I would suggest a weak acid as in acetic, citric, or even vinegar. Which is commonly found in soda pop. heck you could even use electrolysis, but that's more involved.

 

[TOBASH]

HCL eats al. I would advise strongly against using a strong acid for this purpose. Especially if you have a high molar HCL product it will immediately chew apart the al. To even suggest this is astonishing. It's extremely dangerous, and will produce hydrogen gas and vigorously "boil".
I have an under grad degree in chemistry.

Now take them off and soak them in a solvent. If you want to use an acid I would suggest a weak acid as in acetic, citric, or even vinegar. Which is commonly found in soda pop. **** you could even use electrolysis, but that's more involved.

With all due respect to your being on this forum longer than me:

Maybe you didn't see I said diluted and less than 3 minutes, or maybe you took chemistry but don't really know how to apply anything you were taught. Your tone in your post implies a bit of disrespect, so let me give you my credentials:

I was a Chemistry major who aced basic chem and then honored in Organic Chemistry. I was considered gifted, kind of a prodigy. Currently I'm an Orthopaedic Surgeon, also considered gifted. Previously I worked as a mechanic to get through school after my dad died and moneys dried up. I later was a part owner of a auto shoppe. Maybe, I might have worked on one or two cars over the years, maybe a few thousand more than that. If I was a betting man, I would bet that I've faced stuck aluminum hinges and such, as I worked on rare cars and even planes and boats over the years. I live by the ocean in an area that uses road salt for snow, so we get a crap load of frozen hinges made of all combinations of Aluminum and Iron and steel. As such I'm giving solid advice.

The reaction of Aluminum with DILUTED store-bought Muriotic acid would be unlikely to generate enough Hydrogen gas to generate more of a pop than a cap gun, and the heat would be negligible.

Thanks for freaking out.

My advice stands.

[I've seen some of your other posts, and you seem like an OK person, so please consider who you might be talking to before you start spouting off about your undergraduate achievements. I'm not trying to make myself look important. I'm not important, just another cog in the wheel of life. I'm just a guy who wonders why you went off the way you did when it was not necessary. ]

 

[tage]

Not worth it.

I'll comment.
I've gone to many licensing board meetings to understand the type of person you are. Who am I talking to? A self proclaimed prodigy? you received a chemistry degree? Aced gen Chem and orgo? Not hard to do, but okay. What about physical, inorganic, solid state?
Okay you took a mcat and got into some med program. Not hard to do either. Did your 4 plus residency. Now you mention your profession as some sort of dig that you're a top 10% earner in the U.S. Which I don't care. You're in a mil wheeled vehicle forum. Want to drop subliminals on your accomplishments go to rennslist.

Want to know who I am? Look at the bottom. Ask questions if you don't know acronyms. I have my dd form 2.

 

[tage]

Remember kids, Acid to water. I would use a glass container as well.

 

[wheelspinner]

Come on guys, lighten up. You wanna argue who's hand is bigger; do it in private. JMHO for what it's worth.

 

[cwajciec]

Good reading. If the oil solvents don’t work I think dilute acid would be a perfectly acceptable way to break down the bond holding the pin to the aluminum. Start weak like recommended on the muriatic acid bottle and short time (minutes). Rinse with clean water and then neutralize the resulting salts with baking soda or soda ash. It will eat the metal so watch out. Experiment a little to see what works. I’m not nearly as smart as the others here but I am a BSChE with a Chem minor.

 

[porkysplace]

Good reading. If the oil solvents don’t work I think dilute acid would be a perfectly acceptable way to break down the bond holding the pin to the aluminum. Start weak like recommended on the muriatic acid bottle and short time (minutes). Rinse with clean water and then neutralize the resulting salts with baking soda or soda ash. It will eat the metal so watch out. Experiment a little to see what works. I’m not nearly as smart as the others here but I am a BSChE with a Chem minor.

Make sure you don't spill even diluted muratic acid on any concrete without a heavy wash down right away or you won't have a finish left on the concrete.

 

[f800]

Not worth it.

I'll comment.
I've gone to many licensing board meetings to understand the type of person you are. Who am I talking to? A self proclaimed prodigy? you received a chemistry degree? Aced gen Chem and orgo? Not hard to do, but okay. What about physical, inorganic, solid state?
Okay you took a mcat and got into some med program. Not hard to do either. Did your 4 plus residency. Now you mention your profession as some sort of dig that you're a top 10% earner in the U.S. Which I don't care. You're in a mil wheeled vehicle forum. Want to drop subliminals on your accomplishments go to rennslist.

Want to know who I am? Look at the bottom. Ask questions if you don't know acronyms. I have my dd form 2.

He can't help it. Most orthopedic surgeons think and talk this way...even the bad ones.

 

[TOBASH]

Amazes me. Oxidation and a potential galvanic reaction that has fused a hinge is not uncommon. Any dilute acid can help with this.

Muriotic is cheap and effective when diluted. We used it every day at the auto shoppe. Dilution is a common thing, as it separates things like store bought vinegar from concentrated Acetic Acid. Your own stomach uses muriotic acid to digest food.

If other posters here are so timid as to be afraid to dilute it by themselves, soak those hinges in Pepsi or Coca Cola and let the Phosphoric Acid work for a few hours.

My point was that some guy who took basic chemistry went nuts over using a dilute acid on Aluminum, as if I were asking him to throw pure Sodium into a glass of water. His response was over the top. If you feel my response was too, apologies.

As far as the person I am, or the time I dedicate to the injured, or the free services I provide to the less fortunate, or my skills as an orthopod, I will leave that for a greater power to decide. That was never my point, and I was careful to say that despite my accomplishments I'm just another tooth in the gear of life. Sanitation workers save more lives than all doctors put together because they rid the streets of filth and illness, and it is the farmers that feed us and keep all of us alive on a daily basis. They are my unsung heroes. If you all want to misinterpret what I wrote, be aware that you're misstating what I said.

 

[CMPPhil]

Back to the original question

I just picked up a 1987 M998 in good condition but needing some work. I am new to the M998 and need some advice on dealing with the problem of corrosion between the aluminum and steel parts. In particular the tailgate hinges are completely frozen. The tailgate , hinges , and frame are in excellent unbent and undamaged condition but the steel hinge pins are frozen in the aluminum hinges. I have tried heat , PB Blaster , Kroil , ATF and various combinations of the previous with no movement whatsoever. Does anyone have any experience with this problem? If so what worked? I am about ready to unbolt the tailgate and drill the pins out but would prefer an alternative. Thanks in advance.

Hi

You present a problem that be it aluminum with steel pins or steel hinge and steel pins is still a problem various of us have or will have to deal with. How about a photo of the hinge?

When I got my drop side duce bed (steet) all the hinges were seized tight from years sitting out in the rain. After squirting them for several days with ATF and Acetone with no luck. Tried pushing the pins out with Porta Power pushing between the pins up to the point where the bed began to bend, no luck.

In the end used a air chisel with a straight punch, first pushing from one end than the other. In the end started getting a little movement. Once a little movement then soaked again and walked away for a couple of days. Then went at the pins again with the air chisel and punch and they all drove out.

Once the pins were out it was a matter cleaning the bores of the hinges and making new pins. Then treated them with Never Seize and the sides and tailgate once again worked like they should. Every two years I drive the pins out one at a time and clean reapply the Never Seize.

To make the tailgate easier I've thought about drilling the pins for grease fittings.

Please let us know how you progress.

Cheers Phil

 

[Action]

Why not just replace the hinges? Or remove the tailgate and use an air hammer with s pointed bit to drive pins out?

 

[kc5mzd]

I have a friend with a auto shop in his back yard. He has a tank with some kind of acid that only works when heated. It us used for cleaning engine parts. I would suggest taking the gate off and taking it to a local engine shop in your area and having them hot tank it.

 

[tage]

Your own stomach uses muriotic acid to digest food.

muriatic*

I have only heard that term used with construction, or pools. In all of my anatomy courses it was gastric acid. either way call it HCL Mr. prodigy. Because you're confusing a lot of people. Now if you aced gen chem. you should know that you add acid to water to dilute. And this is very important step that you should mention to people with very little chemistry background. Do you remember that when you aced gen chem? or did it slip your mind?

Now I have taken a lot more then just basic chemistry. I thought I explained that to you in my post? You are the person that supposedly only took gen chem and orgo and "aced" them. I'll ask you again. Did you take analytical, physical, inorganic, and solid state chemistry?? Just say no, and move on. It's extremely petty to keep this going with cheap jabs that are inaccurate.

BTW I wasn't going to share this. But I have seen first had what the muriatic acid from Home Depot will do. Kid comes in with acid burns over face hands and legs. Kid used Home Depot brand muriatic acid and one of those orange buckets. drops his aluminum alloy what ever it was into the bucket. starts to boil, melts the bucket, and the chaos that ensued left said kid with a lot of acid burns. luckily for him the acid didn't get into his eyes. HCL is not a toy, and it's nothing to take as a joke. Same with HF, but that is more controlled outside of a lab setting then HCL.

 

[drivebymashing]

I used heat on mine. Worked great.