Same problem again, tapers and bolts

[Golden Gate]

Well here I go again, y'all may remember I had just replaced the two tapers and bolts on my 185 used less then 20hrs since taper replacement and the bolt broke on the 1 side yet again. I have yet to tear it apart, I am hoping the taper at least is not broken. I was using a grapple on some brush at the house no strenious lifting. When put back together there was no slop etc and I did replace both sides with all new parts and every time I get on the machine I check the bolts on both sides. Does anyone have a clue as to what is going on? Is it possible I've gotten a bad bolt direct from bobcat?

 

[waggles]

Im wondering if the tapered pins are parallel with each other . So no twisting of the bobtach is taking place putting a side load on the pins and bolts each time the bucket is crowded back and forth. You shouldnt be breaking these just using the grapple on some brush. Are both stops making contact at the same time on each side on full forward crowd ? One might be touching before the other and placing a side load on the pins. The bolts should be grade 10 high tensile or better .

 

[Fishfiles]

Im wondering if the tapered pins are parallel with each other . So no twisting of the bobtach is taking place putting a side load on the pins and bolts each time the bucket is crowded back and forth. You shouldnt be breaking these just using the grapple on some brush. Are both stops making contact at the same time on each side on full forward crowd ? One might be touching before the other and placing a side load on the pins. The bolts should be grade 10 high tensile or better .

I know you don't want to here this one , but you are most probally over working the machine , a grapple bucket and stumps can casue problems ----------- I asked the guy at the place that I get nut and bolt from about an harder bolt not long ago , as I see a lot of broken Bobtack pins and asked for somethingharder and his theroy is that a harder bolt is more likely to sheer off than a softer one he says that a bolt is made to hole things together , the load is between the head of the bolt and the nut and not to used as a pin which holds the load on it's side , he says if you use a softer bolt it will bend before it breaks , I never took him up on that one but it seems to make sense------------- there was some changes to the bobtack pin bolts over here a few years back , the newer pins have the threads on the back side of the pin and longer bolts are used , is that what you have or is your pin threaded on the front side with a shorter bolt

 

[Golden Gate]

I know you don't want to here this one , but you are most probally over working the machine , a grapple bucket and stumps can casue problems ----------- I asked the guy at the place that I get nut and bolt from about an harder bolt not long ago , as I see a lot of broken Bobtack pins and asked for somethingharder and his theroy is that a harder bolt is more likely to sheer off than a softer one he says that a bolt is made to hole things together , the load is between the head of the bolt and the nut and not to used as a pin which holds the load on it's side , he says if you use a softer bolt it will bend before it breaks , I never took him up on that one but it seems to make sense------------- there was some changes to the bobtack pin bolts over here a few years back , the newer pins have the threads on the back side of the pin and longer bolts are used , is that what you have or is your pin threaded on the front side with a shorter bolt

no it is definitly threaded on the larger end of the pin. Gotta figure this out, I will be taking it apart today hopefully I'll be able to figure whats going on. Is there anychance I have over tighted the bolt just wondering

 

[Golden Gate]

no it is definitly threaded on the larger end of the pin. Gotta figure this out, I will be taking it apart today hopefully I'll be able to figure whats going on. Is there anychance I have over tighted the bolt just wondering

I have feared since putting this back together of it coming loose it did the first time of it doing it again that I constantly crank on it

 

[Golden Gate]

Im wondering if the tapered pins are parallel with each other . So no twisting of the bobtach is taking place putting a side load on the pins and bolts each time the bucket is crowded back and forth. You shouldnt be breaking these just using the grapple on some brush. Are both stops making contact at the same time on each side on full forward crowd ? One might be touching before the other and placing a side load on the pins. The bolts should be grade 10 high tensile or better .

this is possible any clue as to how to figure such a scenerio out

 

[renopker]

this is possible any clue as to how to figure such a scenerio out

Are the tapers true? if there not holding the pin will tip causing the bolt to stretch and brake.

 

[Golden Gate]

Are the tapers true? if there not holding the pin will tip causing the bolt to stretch and brake.

actually I think the arms are out of true as one taper seems to be around 3/4" higher then the other

 

[Tazza]

actually I think the arms are out of true as one taper seems to be around 3/4" higher then the other

Even if the pins aren't dead straight, i never thought it would snap the bolt, the pin yes, not the bolt.....
Was the pin and taper clear of all oil and grease when you installed it?
I like the idea of the stops, make sure both are making contact at the same time.
I'm not sure how you would go about checking if the pins are running true. All i can think of is: remove the linkages to both tilt rams, install the new pins and bolts. Tip the bobtach all the way forward and all the way backward. Does it run smooth? or does it bind up? if there is no binding, i would believe the pins are running true.
I rebuilt my 743 and machined my own bobtach pins, they are 1" diameter heat treated 4140. I have pulled stumps with my 4 in 1 bucket, i was hauling on it so hard that i tore a ram off the bucket, my pins and bolts are still perfect. The pins on your machine are far bigger, they should not break with this load.
Is it only the one side going? could it be something to do with your tilt ram on that side? if it was modified, it could be over extending for some reason?

 

[waggles]

actually I think the arms are out of true as one taper seems to be around 3/4" higher then the other

When you remove the bobtach , insert both tapered pins in the arms and measure them with a long straight edge to see if they line up with each other. If they are good then check that the bobtach touched both stops at the same time, and as Tazza said are both rams the same ? one may be different and have a longer stroke that twists the bobtach everytime .

 

[waggles]

When you remove the bobtach , insert both tapered pins in the arms and measure them with a long straight edge to see if they line up with each other. If they are good then check that the bobtach touched both stops at the same time, and as Tazza said are both rams the same ? one may be different and have a longer stroke that twists the bobtach everytime .

How did you go? What did you find ?

 

[Golden Gate]

How did you go? What did you find ?

Here is what I found. First when I added the 2 new tapers, 2 new bolts and 2 new flat washers I also added 2 new 1/4" (T) stainless steel split lock washers. What I didn't know is that the proper torque would eventually and did cause 1 of the lock washer to fail allowing flex thus destroying the sleave inside the Btech boss. Till I decide how to handle this through those on this forum(yeah u guys LOL) In my mind that is an inserted sleave inside what I refer to as the boss. Am I right can anyone tell me?

 

[waggles]

Here is what I found. First when I added the 2 new tapers, 2 new bolts and 2 new flat washers I also added 2 new 1/4" (T) stainless steel split lock washers. What I didn't know is that the proper torque would eventually and did cause 1 of the lock washer to fail allowing flex thus destroying the sleave inside the Btech boss. Till I decide how to handle this through those on this forum(yeah u guys LOL) In my mind that is an inserted sleave inside what I refer to as the boss. Am I right can anyone tell me?

Yes there is a sleeve inside the "boss", it is a hardened bush that is usually replaced with new tapered pins at the same time. Do you mean the boss, the bush pushes into is damaged as well ? If this is so it can be either line bored and a sleeve inserted into it or the "boss " can be cut out and new one welded in place. A "belleville" spring washer should be used on the bolts to ensure the bolt does not come loose. A split washer will separate under the heavy torque and come loose.

 

[Golden Gate]

Yes there is a sleeve inside the "boss", it is a hardened bush that is usually replaced with new tapered pins at the same time. Do you mean the boss, the bush pushes into is damaged as well ? If this is so it can be either line bored and a sleeve inserted into it or the "boss " can be cut out and new one welded in place. A "belleville" spring washer should be used on the bolts to ensure the bolt does not come loose. A split washer will separate under the heavy torque and come loose.

So that hardened sleeve as you put it is available and therefore replaceable? no the sleeve is still intact just scared. I guess I will call my dealer order the bushings and another pair of tapers and start over again

 

[waggles]

So that hardened sleeve as you put it is available and therefore replaceable? no the sleeve is still intact just scared. I guess I will call my dealer order the bushings and another pair of tapers and start over again

Yes the hardened bush is available, I will typically grease those pivots every1-2hrs of operation to keep them lubricated.

 

[skidsteer.ca]

Yes the hardened bush is available, I will typically grease those pivots every1-2hrs of operation to keep them lubricated.

Did you check the bolt by looking at it or with a wrench?
It is not uncommon for the taper to seat itself further once a load is on the pin. I always re torque them a few time after putting the machine back into use.
Especially if a pin has come loose in the loader arm before and the tapered holed in the arm got a bit messed up. It needs to be torqued and retorqued until it stays that tight.
Ken

 

[7LBSSMALLIE]

Did you check the bolt by looking at it or with a wrench?
It is not uncommon for the taper to seat itself further once a load is on the pin. I always re torque them a few time after putting the machine back into use.
Especially if a pin has come loose in the loader arm before and the tapered holed in the arm got a bit messed up. It needs to be torqued and retorqued until it stays that tight.
Ken

my question did you use the reamer tool, in lift arms, not sure of bobcat part # holes n arms need to be recut when replacing pins (often overlooked) cut lift arms till seeing new metal. (it sucks takes about i hr per side really loud and annoying) but this has to be done. install tach and check for freedom of movement prior to tilt cyl being installed, straight edge good idea use it my self , line bore across two centers, if out o wack needs arms. the re weld ends thing requires a shit hot machinst, at the price for new arms (not bad) to replace.some of the guys here are capble of make a new bobtach thing/build the arms.etc personnaly i think replacement with new parts is money well spent, i can change out lift arms and tach in 4...but of corse if i could i would build beefing em up and never looking back,but i cant,

 

[Golden Gate]

my question did you use the reamer tool, in lift arms, not sure of bobcat part # holes n arms need to be recut when replacing pins (often overlooked) cut lift arms till seeing new metal. (it sucks takes about i hr per side really loud and annoying) but this has to be done. install tach and check for freedom of movement prior to tilt cyl being installed, straight edge good idea use it my self , line bore across two centers, if out o wack needs arms. the re weld ends thing requires a shit hot machinst, at the price for new arms (not bad) to replace.some of the guys here are capble of make a new bobtach thing/build the arms.etc personnaly i think replacement with new parts is money well spent, i can change out lift arms and tach in 4...but of corse if i could i would build beefing em up and never looking back,but i cant,

I know where I failed, I know what I did was using a split stainless washer thinking I was improving my chances of it not coming loose as it did the first time. After torquing it to 190 it crushed failed and allowed that taper to flex until it broke and it tore the bushing to pieces. Yeah I F'd it up and its going to cost me a lot of aggravation and my PM guy who I ragged on for the original failure (again for failing to check & tighten those tapers) well he is just enjoying this a little to much. Because of this it has become normal procedure for him to check all pivot points on all equipment and to be honest he has found other loose bolts and one split pin(split lengthwise funny) on one of our big hammers. As far as the bobcats all will be getting new tapers/bolts and flat washers(just because) and then after every thing is properly torqued the flat washer will be tacked to the arm and the bolt will be tacked to the washer yeah maybe this is a little extreme but considering what this has caused in aggravation.
Yes one of the arms are definitely bent probably out maybe 3/4" from the other. Does it bother me yeah a little because it will cause wear issues? Will we replace the arms not likely as the 185 will be replaced at around 1800hrs and it will be someone elses problem

 

[Tazza]

I know where I failed, I know what I did was using a split stainless washer thinking I was improving my chances of it not coming loose as it did the first time. After torquing it to 190 it crushed failed and allowed that taper to flex until it broke and it tore the bushing to pieces. Yeah I F'd it up and its going to cost me a lot of aggravation and my PM guy who I ragged on for the original failure (again for failing to check & tighten those tapers) well he is just enjoying this a little to much. Because of this it has become normal procedure for him to check all pivot points on all equipment and to be honest he has found other loose bolts and one split pin(split lengthwise funny) on one of our big hammers. As far as the bobcats all will be getting new tapers/bolts and flat washers(just because) and then after every thing is properly torqued the flat washer will be tacked to the arm and the bolt will be tacked to the washer yeah maybe this is a little extreme but considering what this has caused in aggravation.
Yes one of the arms are definitely bent probably out maybe 3/4" from the other. Does it bother me yeah a little because it will cause wear issues? Will we replace the arms not likely as the 185 will be replaced at around 1800hrs and it will be someone elses problem

While tacking sounds like a plan, i see an issue if the bolt does come loose, you won't see the head of the bolt move and the pincan move.
If you are going to go to this much effort, why not loctite the pin into the taper and torque the bolt up. Keep an eye on the bolt torque.
The bend in the arm i see being the main issue, but you aleady know that. Hopefully it will hold up till after you upgrade the machine.