How to get lower link pin off M4500?

[JohnDB]

Well I'm baffled as to how to get this plate and pin assembly off. I've undone the 3 bolts and smacked it with a special tool, levered it with a crowbar and sworn at it but it won't budge. I want to get it off so I can free up the the drawbar assembly lower pin (smaller pin visible below the hitch pivot pin) that is seized on this plate. From the parts and workshop manuals it looks like the hitch pivot pin goes through the plate and is spigoted into the gear case, so the pin and plate should come out with a bit of gentle persuasion, but I can't get it to move. The 3 retaining bolts weren't rusty so I don't think corrosion is the problem, but it's locked solid.

Anyone got any ideas about how to get it off?

Thanks in advance!

 

[mickeyd]

Have you tried saturating it with something like Liquid Wrench? Just because it doesn't look like it is rusted doesn't mean anything.

If that doesn't help, then I would try using a blow torch on it.

 

[JohnDB]

Thanks mickeyd. I tried spraying it with kerosene intermittently over a few hours, a week ago. Maybe I should try that some more. My blowtorch is too small to have much effect on this.

 

[SidecarFlip]

P Blaster and time.

 

[rbargeron]

.....Anyone got any ideas about how to get it off?

A twisting motion might help free it from the bore behind the plate. I'd try using the biggest pipe wrench that will fit (see sketch) on the pin boss at the plate and lift up on it. I'm thinking about a 3-4 foot wrench handle. It might help to grind a couple flats on the boss. The plate and boss are very strong there so it will stand quite an up-force. Once it starts to move it should keep moving easier. I wouldn't put a big wrench directly on the pin - could wreck it.

Good luck, Dick B

 

[D2Cat]

Just a bit of additional information. This information is about 15 years old, so the work "recently" is relative!

I use it all the time, and it works. First time I mixed some up I went in and found the container my wife used for finger nail polish remover, and used it to mix a 50/50 solution.



Machinist's Workshop Magazine recently published some information on various penetrating oils. The magazine reports they tested penetrates for break out torque on rusted nuts.They are below. They arranged a subjective test of all the popular penetrates with the control being the torque required to remove the nut from a "scientifically rusted" environment.

Penetrating oils ........... Average torque load to loosen

No Oil used ................... 516 pounds
WD-40 ..................... ... 238 pounds
PB Blaster .................... 214 pounds
Liquid Wrench ...............127 pounds
Kano Kroil .................... 106 pounds
ATF*-Acetone mix............53 pounds

The ATF-Acetone mix is a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note this "home brew" released bolts better than any commercial product in this one particular test.

ATF-Acetone mix is best, but you can also use ATF and lacquer thinner in a 50-50 mix.

*ATF=Automatic Transmission Fluid.

 

[North Idaho Wolfman]

What your not seeing is that the pin also extends out the back and into the gear case and that where it will be rusted in.

Spray it down with rust breaker, and do as rbargeron suggested.

Do not hammer it up or down or you could crack the case.

 

[SidecarFlip]

I find P Blaster to be as good as the Dexron Mercon / Lacquer thinner mix. I use both.

 

[SidecarFlip]

What your not seeing is that the pin also extends out the back and into the gear case and that where it will be rusted in.

Spray it down with rust breaker, and do as rbargeron suggested.

Do not hammer it up or down or you could crack the case.

I know someone who did just that (not me). Very costly blunder.

 

[JohnDB]

JOB DONE! Thanks guys, it's first time I've used the acetone/ATF mix (I didn't have access to P Blaster or other penetrants), and the pipe wrench worked a treat.. Once I had the pin assembly rotating slightly I still couldn't get the sucker to move outwards, so borrowed a jack (keeping in mind warnings about breaking stuff) then with light tapping on the pin while inching the jack got it out.

That pin was only lightly rusted on the surface, but it extends a good 1.5" into the gear case, and it's a snug fit in the housing so with all that surface area I can see why it was reluctant to move. And why attacking it the wrong way could bust the case.

The other interesting thing for me was that I reviewed a parts drawing I had before starting out on this journey, but it was only after having another look at rbargeron's attachment that I realised I had underestimated how much would be embedded in the gearcase.

Thanks again everyone for your help!

 

[rbargeron]

Glad you prevailed. Credit to Wolfman about embedment of pin - went back to edit my words to include it. The ATF/acetone soak is a good tip too. Always nice when a plan comes together ! Dick B

 

[North Idaho Wolfman]

Excellent to hear!
Thanks rbargeron, I just feel the more information, the better the end results.

Not that you'll probably ever need to take it off again, but coating the pin with a thin coat of teflon liquid pipe dope before you put it back together will help keep it from getting moisture in there and rusting up the pin or the case.

 

[JohnDB]

Getting a better description of what can't be seen was a huge help, and drives the options for solving the problem.

A couple of weeks ago I tried adjusting the front axle pivot preload (it had nowhere near the specified preload) and made 1 mistake and possibly a second despite reading the manual, cutaway drawing and parts list. So resolved that in future I'd ask for help.

Interesting thing about the ATF/acetone mix: I applied it to a rusty nut and some spread out on the flat surface beside the nut. I noticed that there is a tiny amount of effervescence that contines for a minute or 2 after applying it. You can just see tiny bubbles bursting and disturbing the surface, but you have to be up close, and have good light reflecting off the surface to see it. Which made me wonder if the bubbles somehow aid the pentrating effect. Sort of a miniature version of the impact cavitation has on metal, maybe.

 

[JohnDB]

Hi Wolfman, I hadn't heard of teflon liquid pipe dope being used like that. Would you also use it on bolt threads that are exposed to a corrosive environment? I'm thinking of bolts under my quad bike that are exposed to cattle manure.

 

[SidecarFlip]

Happy ending are always good. I keep a spritz bottle of ATF/Acetone close by. I prefer P Blaster (available about anywhere, Tractor Supply included) but ATF/Acetone works about as good and much cheaper.

Like I said, I know someone that cracked their gearcase doing what you did and it was a thousand dollar blunder.

I like to use the red spray on battery terminal coating in lieu of never seize or teflon pipe dope whenever possible. Does as good and less messy.

 

[North Idaho Wolfman]

Hi Wolfman, I hadn't heard of teflon liquid pipe dope being used like that. Would you also use it on bolt threads that are exposed to a corrosive environment? I'm thinking of bolts under my quad bike that are exposed to cattle manure.

Yes but the problem would be how would you get it to say on.

For things exposed like that, I would use undercoating spray!