1997 753 Bobcat Bob-tach Problem

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Joe288

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I'm having trouble with my bobtach left side where it is attached to the boom it keeps losing up and when i try to tighten it the bolt just spins not like its stripped, threads are good its like whatever the bolt goes into is just spinning, i got the bolts back out of left and right side of the bobtach and i cant get it off to see whats in there am i missing something here looks like there is some kind of bearing in-between the boom and bobtach it looks bad allot of play only on the left side, can someone help me get to the bottom of this thanks Joe
 

Tazza

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Hey there Joe.
Ok, here is how the pins work.
The lift arms have a tapered hole machined into them that a matching taper on the pins fit into to lock them in place. The pins have a tapped hole in the middle that a bolt goes through to pull the pin sung into the taper on the arm. If its not tight enough the taper will not hold and will spin and it will eventually un-do.
Now for the secret of removing them. Have a look at the bobtach, where the pin goes through. You should see a grease nipple at the opposite end, in-line to where the bolt is. Remove this grease nipple. You will need to do both sides to get access to the pins as you will need to drop the bobtach down to get to them. With the grease nipples out, use a long punch or a long metal bar to go through where the bolts used to be to lock the pins in and knock them into the bobtach. Grease will be pushed out of where the grease nipples used to be. Do this on both sides and the bobtach should just fall down, be sure to put a piece of timber under it as they are quite heavy. Just let it drop a few inches you don't want to damage your tilt cylinder.
While its off, you can replace the bushing in the bobtach and install new pins. You may need to run a small bead of weld on the bobtach bushing to get it out but deal with that if you need to. To re-install the pins, insert them into the bobtach first then pift into position (2 people make this ALOT easier) then using a long punch or metal rod knock the pins in place through the grease nipple hole. If you pump it up with grease, this will also help as the hydraulic effect will push the pin outwards and into the lift arm. Tighten the bolts up nice and snug and it should be all good!
If anything is un-clear just let me know. I'm assuming they haven't changed the basic design of later machines to my 743 but its essentially the same. The grease nipple may be in a different location.
Any problems just yell. Good luck!
 

Eric

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Jan 19, 2005
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I believe this machine has tapered pins that hold the bobtach in place.
Are you using a impact wrench to tighten the bolts that hold the pins in place???
If you are not using an impact wrench then that may be one of the problems.
Another issue is if the pin and the bushing are worn out, it will have a very hard time staying tight.
Another issue is grease. If grease gets in the threads of the bolt that holds the pin it will have a hard time staying tight.
So how do you get the pin out??? Remove the bolt until there is some thread left to hold it in place. Then push the bolt inward and this will push the pin ou of the loader arm and into the bobtach. Inspect the pin and bushing for wear. If they are worn, then replace them.
How to reinstall, remove all grease and oil from pin and threads and bolt threads. Stick pin back into bobtach so that it clears the loader arm. Then add semi perminent loctite to bolt threads. Stick bolt through the lift arm and thread the bolt into the pin. Make sure no grease or oil get onto the new or clean parts. Then use an impact wrench to tighten it up. For extra security I then use a breaker bar to get the bolt extra tight.
GOOD LUCK!
Image1.jpg
 

Eric

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I believe this machine has tapered pins that hold the bobtach in place.
Are you using a impact wrench to tighten the bolts that hold the pins in place???
If you are not using an impact wrench then that may be one of the problems.
Another issue is if the pin and the bushing are worn out, it will have a very hard time staying tight.
Another issue is grease. If grease gets in the threads of the bolt that holds the pin it will have a hard time staying tight.
So how do you get the pin out??? Remove the bolt until there is some thread left to hold it in place. Then push the bolt inward and this will push the pin ou of the loader arm and into the bobtach. Inspect the pin and bushing for wear. If they are worn, then replace them.
How to reinstall, remove all grease and oil from pin and threads and bolt threads. Stick pin back into bobtach so that it clears the loader arm. Then add semi perminent loctite to bolt threads. Stick bolt through the lift arm and thread the bolt into the pin. Make sure no grease or oil get onto the new or clean parts. Then use an impact wrench to tighten it up. For extra security I then use a breaker bar to get the bolt extra tight.
GOOD LUCK!
Combine what Tazza and I posted and you should be done in no time.
 

Joe288

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Combine what Tazza and I posted and you should be done in no time.
Wow Guys thats some really good info. I will give that a try tonight when the wife gets home.I think my pin is wore out it really sloppy
 

skidsteer.ca

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Wow Guys thats some really good info. I will give that a try tonight when the wife gets home.I think my pin is wore out it really sloppy
A tapered reamer is available from bobcat to repair the hole in the loader arm to match the taper of the pin if it is worn from the pin running loose. Hopefully yours looks round still. Be sure to retorqe the bolts a couple time after you re install and use it a bit. 100 or 110 ft lbs if mem serves.
Ken
 

Joe288

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A tapered reamer is available from bobcat to repair the hole in the loader arm to match the taper of the pin if it is worn from the pin running loose. Hopefully yours looks round still. Be sure to retorqe the bolts a couple time after you re install and use it a bit. 100 or 110 ft lbs if mem serves.
Ken
Again guys thanks for the great info!!! And for the fast and very helpful replies to my first post Just got a call from the wife working late AGAIN i will try to get to my new land tomorrow where the machine is at and let you all know how i make out Again thanks allot Joe
 

Tazza

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Again guys thanks for the great info!!! And for the fast and very helpful replies to my first post Just got a call from the wife working late AGAIN i will try to get to my new land tomorrow where the machine is at and let you all know how i make out Again thanks allot Joe
ROFL Eric, i love the “not to scale”
I agree, using in impact wrench sure makes it easier (i cheat and use it most of the time) and removing the grease from the threaded hole for the bolt. If there is grease in there it will “hydraulic lock” and you just will not get the bolt to tighten.
 

Joe288

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ROFL Eric, i love the “not to scale”
I agree, using in impact wrench sure makes it easier (i cheat and use it most of the time) and removing the grease from the threaded hole for the bolt. If there is grease in there it will “hydraulic lock” and you just will not get the bolt to tighten.
OK guys had just enough light to get it apart (Thanks to Tazza and Eric) and looked to see what kind of damage I have and it doesn't look good!!. Seems like the pin and bolt were run lose for awhile now, Ware the pin fits into the bob-tach is really sloppy but it looks its just the bushing is shot I don't think that’s a big deal if I could replace the bushing. But on the other end of the pin were it goes into the loader arm its whore out pretty bad in my book, The pin tapered end goes into the lifting boom and comes out the other side like 2/16 of a inch there is no bushing in there like Eric said its just all lifting boom (All Metal) so now how would I go about fixing this. (Skidsteer Ca) said something about a tapered reamer but wouldn't that just make the hole bigger? And here’s the other thing I Just bought this machine used off a bobcat dealer I don't think they new it was like this it was a trade in I’ve had it for two months and I put 15 hours on it this damage could not have come from my use this looks like it was loose for years looks like the original owner even put a big washer over where the pin sticks out of the lifting boom, Do you think I should make a call to the salesman that sold it to me or what do you think guys. I just bought 3 acres of land and this bobcat with my life's savings to build my new house on I really don't have lots left for repairs already this early in the game Any of your thoughts on how to go about getting it fixed it would be most appreciated Thanks Joe
 

Eric

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ROFL Eric, i love the “not to scale”
I agree, using in impact wrench sure makes it easier (i cheat and use it most of the time) and removing the grease from the threaded hole for the bolt. If there is grease in there it will “hydraulic lock” and you just will not get the bolt to tighten.
That is kinda funny. Its a habit I've developed. I used to be an estimator and project manager for a large union fence company here in Southern California. I would have to do my own submittals and shop drawings for my jobs. So this is where I learned how to perform some technical drawings of construction details. I basicaly just just wanted to say, I whipped it out pretty rough so I hope you get the idea. But shortened it to, Not To Scale.
You brought up a good point about removing the grease fitting. I forgot about that detail.
I dont see how you can realy get the bolt threading into the pin without an impact wrench. The pin is kinda floating in the bobtach. I tried just using a breaker bar to tighten those but the bolt and pin would just spin. I think you nead an impact until the pin seats into the tapered bushing.
 

Eric

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That is kinda funny. Its a habit I've developed. I used to be an estimator and project manager for a large union fence company here in Southern California. I would have to do my own submittals and shop drawings for my jobs. So this is where I learned how to perform some technical drawings of construction details. I basicaly just just wanted to say, I whipped it out pretty rough so I hope you get the idea. But shortened it to, Not To Scale.
You brought up a good point about removing the grease fitting. I forgot about that detail.
I dont see how you can realy get the bolt threading into the pin without an impact wrench. The pin is kinda floating in the bobtach. I tried just using a breaker bar to tighten those but the bolt and pin would just spin. I think you nead an impact until the pin seats into the tapered bushing.
I remember replacing the bushing on our machine but I dont remember how exactly. I cant remember how I removed the old busing. Maybe with a recipricating saw and a chisel. I think we cut the old bushing in half from within the loader arm and chiseled it out. Maybe someone can confirm this. I do remember that when we put the new busing in there was a gap at the top and bottom of the lift arm where the old pin had worn through the old bushing and into the lift arm. I think we just filled it in with a weld and it was good to go.
Did the machine come with any type of warranty?
Was it sold as is?
I would definately ask the dealer to help you out on this one. It doesnt hurt to ask, does it?
Did they perform any maintenance or inspection on the machine before reselling it?
Good Luck!
 

Joe288

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I remember replacing the bushing on our machine but I dont remember how exactly. I cant remember how I removed the old busing. Maybe with a recipricating saw and a chisel. I think we cut the old bushing in half from within the loader arm and chiseled it out. Maybe someone can confirm this. I do remember that when we put the new busing in there was a gap at the top and bottom of the lift arm where the old pin had worn through the old bushing and into the lift arm. I think we just filled it in with a weld and it was good to go.
Did the machine come with any type of warranty?
Was it sold as is?
I would definately ask the dealer to help you out on this one. It doesnt hurt to ask, does it?
Did they perform any maintenance or inspection on the machine before reselling it?
Good Luck!
They did a complete service new tires foam filled and new tilt ram
 

Tazza

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They did a complete service new tires foam filled and new tilt ram
New tilt ram? if they did that, they would know about the pin wear for sure!
The reamer Ken mentioned is used to clean up the taper the pin sits in. I'm not sure how it would go with excessive wear as you mention. My old 731 was worn really bad, i just made a new pin and bolted it up tight!! it hasn't given me any problems. You may get away with just a new pin too.
As for the bobtach bushing i had to run a weld bead along it to get it to collapse to remove it.
Talk to the dealer, they may arrange something for you on this. If not free, maybee cheap.
 

Joe288

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New tilt ram? if they did that, they would know about the pin wear for sure!
The reamer Ken mentioned is used to clean up the taper the pin sits in. I'm not sure how it would go with excessive wear as you mention. My old 731 was worn really bad, i just made a new pin and bolted it up tight!! it hasn't given me any problems. You may get away with just a new pin too.
As for the bobtach bushing i had to run a weld bead along it to get it to collapse to remove it.
Talk to the dealer, they may arrange something for you on this. If not free, maybee cheap.
I went to the dealer and got just about everything i need only parts they didn't have was bushing for the lift arm. i hope the new bushing will fix the slop in arm.I got bobtach Bushings/Pins /Bolts Washers/Seals/Grease Caps For $106.00 . Lift arm bushings should be here Monday
 

140mower

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I went to the dealer and got just about everything i need only parts they didn't have was bushing for the lift arm. i hope the new bushing will fix the slop in arm.I got bobtach Bushings/Pins /Bolts Washers/Seals/Grease Caps For $106.00 . Lift arm bushings should be here Monday
Another newbe here, I've got all of the above issues as well with my new-to-me 763, but, mine also has a lot of slop in the Bobtach where the tilt cyl. attaches. The pin and bushing in the cyl. end are pretty good, but the holes are badly wallowed out in the Bobtach it's self. Has anyone tried having this part line-bored and pressed in bushings, if so what did you use? Any other ideas out there short of a new Bobtach?
 

Tazza

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Another newbe here, I've got all of the above issues as well with my new-to-me 763, but, mine also has a lot of slop in the Bobtach where the tilt cyl. attaches. The pin and bushing in the cyl. end are pretty good, but the holes are badly wallowed out in the Bobtach it's self. Has anyone tried having this part line-bored and pressed in bushings, if so what did you use? Any other ideas out there short of a new Bobtach?
I have repaired this before BUT mine was so bad i got the oxy torch and cut the bosses and attach plate out of the bobtach and made a new set and welded it in. I also modified the end of the ram that pivots and installed a hardened bushing that can be replaced when it wears out.
Honestly, i doubt there is enough *meat* to line bore this out. Depending on how much wear there is, you may get away with running a hand reamer through it.
 

140mower

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I have repaired this before BUT mine was so bad i got the oxy torch and cut the bosses and attach plate out of the bobtach and made a new set and welded it in. I also modified the end of the ram that pivots and installed a hardened bushing that can be replaced when it wears out.
Honestly, i doubt there is enough *meat* to line bore this out. Depending on how much wear there is, you may get away with running a hand reamer through it.
Thanks for the reply, I kind of figured that might be my best option. There is quite a bit of wear in it, maybe as much as an 1/8 of an inch or so. I think I'll just live with it until this winter, I just finished welding a new cutting edge on one of my buckets and weld-on tooth adapters and have had enough welding in the 40 deg. celcius heat for the time being, not much shade in my shop (no walls or roof either for that matter). ;>) Don
 

Tazza

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Thanks for the reply, I kind of figured that might be my best option. There is quite a bit of wear in it, maybe as much as an 1/8 of an inch or so. I think I'll just live with it until this winter, I just finished welding a new cutting edge on one of my buckets and weld-on tooth adapters and have had enough welding in the 40 deg. celcius heat for the time being, not much shade in my shop (no walls or roof either for that matter). ;>) Don
I heard you poor people are having a bit of a heat wave over there.
We get to 40-45 C in the middle of summer, but usually it only lasts 1 or maybee 2 weeks. Either way, its NOT fun.
 

Joe288

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I heard you poor people are having a bit of a heat wave over there.
We get to 40-45 C in the middle of summer, but usually it only lasts 1 or maybee 2 weeks. Either way, its NOT fun.
Ya Tazza Ben very hot here over 90 for the last couple of weeks Where you from Bud?
 

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