BC753 Bob-Tach Pin & Bushing Waller'd Out

[weaktea]

Thanks guys, made perfect sense and got me where I needed to go. I imagine I should replace both of these if I'm replacing one that sheared off, while I have it all apart? Any thoughts on that?

By the way, I only saw ATCO's post after I posted my question. It was weird, I actually thought I posted this onto another similar thread, but then it ended up here. Or, I am an idiot. Both possible. Thanks again. Great forum.

 

[crewchief888]

FWIW
to the OP

when the pin is seated (by hand) in the tapered bore, it should be below flush of the outside of the boom arm by at least 1/8". when you pull the pin tight into the taper you'll still have some room.

you can clean up the tapered bore with a die grinder, (i've done it in an emergency), smoother is better. then degrease everything, clean & dry
pop the pin into the bore by hand, if the taper is good, you wont be able to pull it back out, light tap with a hammer will unseat it.
reassemble the bobtach with new bushings, seals & cups, pull the pin into the bore, and snug it up.
smack the bolt head hard, and retighten, repeat as needed until the bolt is no longer loose after the hammer hit,
remove the bolt, apply red loctite, reinstall and torque to spec.

some bolts have a washered head, some do not , and use a heavy, thick washer under them

if the outside of the boom arm is worn unevenly, grind it flat so the washer or bolt head sits flush

the pin is the pivot and support for the bobtach, the bolt is there just to make sure it doesnt move

:drinkup

 

[bigboytoy]

I had to weld several beads on metal around bob tach bushing end...mostly as a percaution or insurance...it seamed to banana out the bushing on the outside end...wearing into the bushing boss ...when done I had a 1/4 of hard metal (7018) to reenforce the outside edge. I imagine the twisting action would wear it out sooner. I guess I could of bought a new bobtach ..ah but welding rod is cheap. I did get new tapered pins and grease bell holders..then maybe a washer or two to take up any slop. the fix should last many hours.