BC753 Bob-Tach Pin & Bushing Waller'd Out

[Cannon]

While I was supervising the 14 yo, I noticed the bucket was becoming loose so pulled out the breaker bar to tighten and wasn't able to put any additional torque on the bolt because it had sheared off. So time to shut down and perform surgery....

-Detached the bucket.
-Detached the hydraulic cylinder.
-Removed the Bolt, washer, cup & seal from each side.
-Separated the Bob-Tach assembly from the Lift arms.

Inspection.
-One pin had shattered due to the bushing had disintegrated (1804 hrs on the machine).
-The Bob-Tach mounting hole straight bushing that the pin sat in had to be chiseled out (no I don't have a cutting torch). No longer straight, but waller'd out.
-The Lift Arm had 'egged (not round - tapered), and that tapered bushing is WELDED in (no torch), so can't remove.

CHECK LIST/REPAIR STEPS (Please comment).
-Pickup/install straight bushing into waller'd out Bob-Tach mounting hole. Coat with JB Weld slow hardening compound & leave overnight.
-Install pins by 'whaling on (seating) with a big hammer.
-Oh, and the lift arm has egged enough to also have the bolt washer start to wear out the exterior side of the lift arm, so... I've ground a small amount of the tapered side of the pin so that it fits flush with the outer side of the lift arm, as well as snug with the welded-in lift arm bushing.
-Double up on large galvanized washers on the outer side of the lift arms (approx 1/8" thick).
-Reassemble and torque to 180+ lbs.
-Apologize to the wife (somewhere in here) for tracking in, dirtying up, taking too much, or spending too much.

Comments/experience welcome. Thanx in advance.

 

[willie59]

-Apologize to the wife (somewhere in here) for tracking in, dirtying up, taking too much, or spending too much.

Comments/experience welcome. Thanx in advance.

Not much more one can add. :notworthy

Can't help you with the wife, your on your own there. :Banghead

 

[hardy]

I have a BC 753 , only owned it for a couple of months & noticed recently that the bucket has a bit of play, it can slide back & forth about an eighth on either liftarm. Is this normal or should the liftarms always be tight against the bobtach? I tried tightening the bolts on either side with a breaker bar & then with an impact wrench but they seem tight & didn't move at all. Does that mean something? How else can I tighten them? Thanks in advance for any help!

 

[BIG D]

The normal repair is to use a tapered ream and make the hole deeper. Most Bobcat dealers have these reams and make this type of repair very often BIG D

 

[KSSS]

I never understood why BC insists on using that Cantilever design on the lower bucket pins. Its weak and problematic.

 

[hardy]

So I take it that the play is not normal... If my impact wrench can't tighten or loosen the bolts how else could I try removing them/ is there something I'm missing? Is the ream something I could conceivably do myself (I have most of the basic tools & workshop just not the experience)? Thanks

 

[BIG D]

the play is not normal when bolts and nuts dont come loose heat and heavier tooling will be your next move. the ream is a special Bobcat tool and cost I am guessing 2 to 300.00 there are other repairs used like boring the holes and have a machine shop make a tapered bushing and press them in and then weld them in place good luck Big D this is for the loader frame. and not the bucket bores

 

[bobcatmechanic]

the reamer i heard a price one day on it in the 800.00 range. have used them on the lift arms basically just insert use 1/2 breaker ratchet ream holes. then insert pin if not tight on the taper ream more if the pin is too long cut off the taper end of the pin a little with a chop saw or method of choice. then replace bobtach bushings in bobtach usually cut them out and weld the ring at the top of the bobtach to hold them in if not tight in the bore. replace both lower pins bolts and washers tighten the **** out of them. Then grease the new pins really well before rotating. it is possible that if it has had a heavy load life and they are just weak that the arms have spread it is common on those to spread if run hard and just in general.

 

[hardy]

I have been able to remove both bolts, I cleaned everything out & tried to tighten with some pressure from a pry bar, but it seems it will not tighten more ie; the force I put on it with the pry bar just pushes the bobtach the other way... If the arms have spread due to wear is there anything else I can do? extra washer on either end, or something? what happens if I just leave the play there, will it get worse or will it effect something else? thanks

 

[cps]

Im not very familiar with the Bobcat set-up (or bobcat in general) can some one post picture or a parts diagram so in can follow abit better?

Thanks CPS

 

[Bumpsteer]

As far as the bobtach assembly "floating" between the lift arms, I wouldn't worry about it. The loader arms could be spread slightly allowing this to happen. At least you know it's not binding and causing excessive wear.
Mine will "float" around 1/4" total, I've never had an issue with it.

Ed

 

[bobcatfixeruper]

Pin Float

As far as the bobtach assembly "floating" between the lift arms, I wouldn't worry about it. The loader arms could be spread slightly allowing this to happen. At least you know it's not binding and causing excessive wear.
Mine will "float" around 1/4" total, I've never had an issue with it.

Ed

Greetings all! If your pins are floating or your bobtach assembly knocks when you jostle the drive sticks, that means everything is not binding and you have at least a little bit of grease in those ever so critical pivot pin points. Personally on my 843 (Awesome machine!) I have about a 1/4 inch too, I like to hear those points knock or make a clacking noise when moving around.

 

[hardy]

here's a pic... everything else seems fine, if a bit dirty. Mind you I don't know much about this at all, just learning as I go. I like your advice Bumpsteer, the machine was owned by an equipment rental place before I got it so I can imagine it received a fair amount of wear...

 

[bobcatfixeruper]

Hardy if you have a little side to side play that is okay. It there is excessive play perpendicular to that bolt axis your pointing at then you either have pin or bushing wear with the pins that go into the end of the bobtach assembly. This could be because of lack of maint / greasing the zerk fittings. Now the bolt you say is tight.. all that does is pull the tapered portion of the pin assembly into the boom arm. Kind of like a tapered shaft on the end of a lawn mower engine with a female thread in the end of the taper. The more you torque it the harder it drives the pin into the boom assembly up to a certain point, then the threads give out. Hope this helps

 

[hardy]

Sounds good, thanks everyone. Just being an overprotective parent I guess!

 

[willie59]

Im not very familiar with the Bobcat set-up (or bobcat in general) can some one post picture or a parts diagram so in can follow abit better?

Thanks CPS

Hey CPS, go down to the pic that hardy posted at post #13. The pivot action happens at the bucket pin boss, that's where the pin bushings are and the reason for the grease fitting you see installed on the bucket, the pin remains stationary. Imagine the bucket is not there. What you would see would be a straight shaft pin about 4 inches long. That's what fits into the bucket pivot hole. Just about the area where the dust cup is (where hardy drew an arrow on the pic that says "play") the pin becomes tapered to fit into a tapered pin boss socket welded into the end of lift arm. The pin is hollow and threaded to accept the bolt you see on the outside of the lift arm. You simply insert the tapered pin into the lift arm tapered socket, install bolt, and tighten. You now have a very firm and rigid pin for the bucket to pivot on. When removing the bucket pins on a Bobcat; 1) remove the grease fitting to allow grease to escape. 2) fully remove bolt and remove flat washer. 3) re-install bolt stopping 1/8" from being set. 4) place hardwood block on bolt head and knock the snot out of it with sledge. This will unseat the tapered pin. Screw the bolt out slightly and begin tapping the bolt head with hammer until you can fully push pin into pivot hole of bucket. This is where the grease has to escape. You can push the pin fully into bucket which will allow you to remove bucket from lift arms. Hope this all made sense.

 

[sierradmax]

AH, thanks atco. Last night I removed the bolts and scratched my head. I figured it was a tapered pin and tried a piece of pipe, but to no avail, I was unable to remove the bobtach. I'll try your method tonight.

 

[Cannon]

Well, it's happened again (400 hrs later) & every time I'm operating I've ensured tightened.

I'm assuming reaming the cantilever hole on the 'tach is what I'm left with. Any other suggestions before off to the Machine Shop would be appreciated.

 

[weaktea]

While I was supervising the 14 yo, I noticed the bucket was becoming loose so pulled out the breaker bar to tighten and wasn't able to put any additional torque on the bolt because it had sheared off. So time to shut down and perform surgery....

-Detached the bucket.
-Detached the hydraulic cylinder.
-Removed the Bolt, washer, cup & seal from each side.
-Separated the Bob-Tach assembly from the Lift arms.

Inspection.
-One pin had shattered due to the bushing had disintegrated (1804 hrs on the machine).
-The Bob-Tach mounting hole straight bushing that the pin sat in had to be chiseled out (no I don't have a cutting torch). No longer straight, but waller'd out.
-The Lift Arm had 'egged (not round - tapered), and that tapered bushing is WELDED in (no torch), so can't remove.

CHECK LIST/REPAIR STEPS (Please comment).
-Pickup/install straight bushing into waller'd out Bob-Tach mounting hole. Coat with JB Weld slow hardening compound & leave overnight.
-Install pins by 'whaling on (seating) with a big hammer.
-Oh, and the lift arm has egged enough to also have the bolt washer start to wear out the exterior side of the lift arm, so... I've ground a small amount of the tapered side of the pin so that it fits flush with the outer side of the lift arm, as well as snug with the welded-in lift arm bushing.
-Double up on large galvanized washers on the outer side of the lift arms (approx 1/8" thick).
-Reassemble and torque to 180+ lbs.
-Apologize to the wife (somewhere in here) for tracking in, dirtying up, taking too much, or spending too much.

Comments/experience welcome. Thanx in advance.

Ok... So, I'm having a similar problem. I've never had the Bob-Tach assembly off my T190 or any other Bobcat, so I'm not understanding the way it's all attached. I've had the bolt and possibly pin shear off on one side and it's dangling from lift arm. I took the bolt off the other side but it seems stuck in place. Do I need to detach the hydraulic cylinders first and then will all be solved. Or, do I need to do something else to get the non-sheared pin to release? Any help, would love to see a parts diagram of this attachment point. I don't have one. Thanks for any help.

 

[Delmer]

to quote ATCO above:

When removing the bucket pins on a Bobcat; 1) remove the grease fitting to allow grease to escape. 2) fully remove bolt and remove flat washer. 3) re-install bolt stopping 1/8" from being set. 4) place hardwood block on bolt head and knock the snot out of it with sledge. This will unseat the tapered pin. Screw the bolt out slightly and begin tapping the bolt head with hammer until you can fully push pin into pivot hole of bucket. This is where the grease has to escape. You can push the pin fully into bucket which will allow you to remove bucket from lift arms. Hope this all made sense.