I have a Bobcat T190. the lower pivot pins for the bobtach mount into the boom on a taper. One of the pins broke off in there before i bought it and wore the taper real bad. I found a company called Construction Tool Parts that makes a repair kit. They say to drill out the boom to 1 3/4" and then they have a bushing to install? Has anyone ever used this kit? I'm trying to figure out how to drill such a big hole! A machinist buddy of mine says that he can't even drill this big with a magnetic base drill. Any thoughts would be appreciated.
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Bobcat boom taper worn
- Thread starter RQRents
- Start date
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- Tags
- bobtach boom taper pivot pin
willie59
Administrator
In my experience with Bobcat machines, pin bosses such as that tapered pin boss that attaches the bucket pivot pin are available from Bobcat, I've replaced them before myself. They're simply a machined pin boss that is set in a hole in the end of the loader arms then MIG welded on either side. Take a grinder and grind it down flush, set a tapered bucket pivot pin in the inside and wail on it with a sledge to knock it out. Clean the hole in the loader arm with a burr and set your new Bobcat pin boss, then weld it in. Done it a number of times, no drilling required.
willie59
Administrator
Typical Bobcat Loader arm, item #17 is the weld in tapered bushing for the bucket pivot pin.
willie59
Administrator
If I recall correctly, on that bushing, you simply take a gas axe and cut away, clean it away from the tip of the loaders arms, not a hard task if you're handy with a torch. Once you get it cleaned away, set the new bushing and weld it all the way around where it contacts the loader arm. I've done this repair before, it's not that hard, and it doesn't require setting up a drill to drill a proper perpendicular hole to set some kind of aftermarket machined bushing.
willie59
Administrator
HOLY CRAP, looks like willie was totally wrong and needs to be took to the woodshed. I found some pics where I did this repair on a 753, and yes, it's a specialized repair that requires certain tools to do proper, and in this case, a mag drill. First I had to set up a mounting plate to accept the mag drill so the hole would be square and then used an annular cutter bit to bore out the worn bushing.
After boring out the old bushing I set the new bushing from Bobcat.
Then weld the bushing in with a MIG welder.
Lastly, grind it down smooth.
After boring out the old bushing I set the new bushing from Bobcat.
Then weld the bushing in with a MIG welder.
Lastly, grind it down smooth.
Thanks for your help! I'm pretty sure there is not bushing welded in mine. So whether I do the bobcat bushing or the aftermarket repair. i need to drill it. Willie, what kind of bit did you use for that in the mag drill?
I think the aftermarket will be a little simpler if I can just drill the hole.
I think the aftermarket will be a little simpler if I can just drill the hole.
05sprcrw
Well-Known Member
Can you take a picture of the attachment that is worn. On my S300 I had the lower pivots on the arm wore out as well, but they sell the ends and I just cut them off finger tightened the pins into the boss to use the bobtach to keep them concentric. And re-welded the new bosses to the arm. It was a pretty easy project if you are handy with a torch and welder, took less then 3 if I remember right to do both sides. After I tack welded them I ran the tilt both directions several times to check for any binding adjusted if needed. This sounds like what willie said in his #4 post.
The bosses were reasonable under $100 a piece if I remember correct, but I am not sure how the T190 compares on the loader arms.
The bosses were reasonable under $100 a piece if I remember correct, but I am not sure how the T190 compares on the loader arms.
willie59
Administrator
Yep, the 300 machines, even the older T300, used a different type of pin and pin boss for the bucket pivot, made a little different at the tip of the loader arms. Every T190 I've seen looks just like the one I posted above. It wasn't a hard job, but it did require some specialized tools and set up. Once the hole is bored out it's easy down the back stretch.
willie59
Administrator
Your typical T300 bucket pivot pin boss. Like you stated, this is what I first thought he would be dealing with until I pulled up the pics of the similar repair I had done. On that 300 one simply whittles the old pin boss off with a torch and fits a new one. The T190 arms are a bit different.
Wytruckwrench
Senior Member
I have done a number of the aftermarket drill out and install the expando pin. I weld a plate to the boom and set up my mag drill. Seems to work pretty well.
kshansen
Senior Member
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We had a similar problem with a 743 years ago. Wish I could say how it was repaired as we took the easy way out and because the boom needed other work we sent it to a machine shop we were dealing with and they fixed it. Not sure if they welded up the bore and then bored it out or if they just bored it out and made a tapered ID bushing and welded that in.
Many years back we had a Terex R-35B truck that the tie rod ends had come loose and wallowed the tapered bore out in the axle. That one we fixed by boring the hole out about 1/4 bigger than the large end of the tapered hole but leaving a step at the bottom of the small end. I then went to work on the old lathe in the shop and made a bushing with the taper on the inside to match the tie rod end and the outside a good press fit in the hole our welder/linebore guy had put in the worn part. As I recall we just pressed the repair busing in and then assembled without welding anything. Truck was used for a few years after that repair with no further problem.
Many years back we had a Terex R-35B truck that the tie rod ends had come loose and wallowed the tapered bore out in the axle. That one we fixed by boring the hole out about 1/4 bigger than the large end of the tapered hole but leaving a step at the bottom of the small end. I then went to work on the old lathe in the shop and made a bushing with the taper on the inside to match the tie rod end and the outside a good press fit in the hole our welder/linebore guy had put in the worn part. As I recall we just pressed the repair busing in and then assembled without welding anything. Truck was used for a few years after that repair with no further problem.
That type of bit is an annular cutter if your buddy doesnt already have one it takes a weldon shank adaptor to the mag drill Ebay is an excellent source for an adorable cutter they like to walk around in bigger sizes so the drill has to be secure
Any chance you have some pictures of how this setup?
Wytruckwrench
Senior Member
I can’t find any pictures of it. I’ll keep looking as I’m sure I took some. The last one I did was about a year ago.
colson04
Senior Member
Looks like I'm going down this rabbit hole on my Dad's 753. I went to move some dirt and couldn't believe how much slop was in the bobtach.
Last pic is dump cylinder pin. Not as bad as the ends, but bad enough.
Pins and bushings are ordered. We'll see how this project goes.
Last pic is dump cylinder pin. Not as bad as the ends, but bad enough.
Pins and bushings are ordered. We'll see how this project goes.
I just did mine recently and highly recommend using a torch to cut the bushings out. The harden steel just kind of explodes and it is pretty easy to cut a line in them. Just be careful to keep moving so that you don't get into steel underneath the bushing. Once the line is cut the bushing will will come out easily. Try to salvage at least one bushing and weld it on to one of the the old pins to use a tool to drive in the new bushings. That worked well for me.
Wrightmachining368
New Member
Here is what i came up with today with the 740 bobcat . At first we thought it was a inset then we found that it was not and that it was a cut taper in the arm . I first drilled it out then because it was so bent i line bored it and the welded in the inserts. I welded them in when the bobtach was bolted on and tapers sucked in ( not shown in pics ) this step kept it straight And aligned .
Attachments
Wrightmachining368
New Member
Done 
dirtyernie52
New Member
did you have to mag drill through both sides? or was the bit able to go all the way through? also do you know what size annular cutter you had? Thanks