Well it finally happened. My '06 435 had cracks on both sides of the boom. I have seen many of them with this issue before. My dealer always told me it was because they were being abused. That the operators would swing into banks and piles at full swing (why would anybody ever do that?) but I took his comments with a grain of salt. Anyway, I have just over 2,800 hours now and I noticed the cracks (both sides) when the machine came in for service. It is cracking along the weld where the hinge assembly, for the dipper attachment point, is welded to the boom. My welder says that he see this a lot on Bobcats. He does all the welding for the dealer. In his opinion he thinks that Bobcat does not pre heat welds and this makes them succeptable to stress cracking. This machine has been run by my employees as well as myself (I'm sure I have put the vast majority of hours) and I have been putting all the hours on it lately. No abuse when it's under my ***. Have any of you seen this issue. I have had it welded (pre-heated and slow cooled) so I hope to have this issue under control (going back into the field tomorrow). Please share your experiences. Cracking and whatever repairs (with or without success), no cracking, whatever you may have to add. BTW I really don't think that saying "Bobcats suck (which I probably would agree to) and Yanmars rule" would add much to the discussion. Please refrain from such drabble.
We have fixed alot of cracked booms and sticks on Cat equipment. I am sure the problems lies with the steel and it being made in china. We fix it unless the cracks are in the cast sections or on top in the parent metal. we air arc out the cracks or the entire plate, weld it up with backing strips and add fish plates. Here are some pics of one we did recently, at the bottom of the page.
i have this problem as well. first time it happened i lent it to a buddy and it came back cracked. end of boom, where stick attaches. probably the same place. after that we kept an eye on it and it kept cracking. finally, we ended up putting a large fish plate on it and it seems to be holding up. i think the machine has over 6000 hours so i can't really complain. good luck.. cd
I had the same problem on my BC 334, cracked in the same place. We field welded it a couple of years ago and so far so good but the machine may have had 150-200 hours put on it since then.
Cat had a recall on the 420 TLB.I forget the series.Had to fish plate the boom.
I had a crack on my 416C boom as well. It (actually they-it was two small cracks) were on the top of the tower where the boom and crowd rams attach to the boom (right above the CAT logo). They were only about 1" long when I discovered them. I did not think that it was of much concern and I was planing to gouge them out and weld them. I never got the chance to. While I was trick-or-treating with my youngest son (he was about 6 or 7) I ran into one of Quinn's service advisors as he was doing the same thing. He asked about my hoe and I mentioned the cracks. He said that Cat had a bulletin out that said that Cat would replace the boom if the machine had less than 5,000 hours on it. Anything above 5,000 hours and they would replace at 50% cost share. My machine had 4,990 hours on it at that time. It worked out well for me. They replaced the boom at no charge. While they had it off I had them install a new swing frame too. I felt as though I was treated very fairly and was very happy to have the assistance that I was not expecting. Over all my experiences with Cat have set the bar pretty high for the other dealers. So far the new boom has done well for more than 7,000 hours so far. I know that some failures can be found on most brands (even the mighty Cat brand) but IMO it should not happen so soon (2,800 hours). If Bobcat would stand behind their product as Cat did with my backhoe I would not complain but rather I would be singing their praises. I am happy to hear that the field repairs are holding so far. I hope that mine will last a few thousand hours. If not it will get some serious fish plating.
My experience with cracked booms is that when the boom is cracked at the top between the top and side plates as it rounds down...if that makes any sense......it's usually from the operators side sweeping with the bucket. Side sweeping uses the stick to twist the boom ever so slightly, and that's usually where the cracks show up. Cracking at the end of the boom where the stick pins on is a new one to me. Now, I've seen the casting crack off the end of the boom.........became a quick detach boom, but that was a bit of a special case, and was definitely operator error.....and to this day, we still haven't let him live it down...LOL.
bobcats? well, i am in the same boat. different problem though. 2300 hours and my swing brake locked up.always something cd
Mine had an intermittent issue with the swing. I think it was around 1,300 hrs on SMU. The problem turned out to be a bad seal on top of the swing brake. Oil would sometimes pass over the seal and begin to equalize the pressure on both sides of the swing brake piston. This would bi-pass the swing brake release (works with oil applied to piston any time you ask the swing circuit to function). The swing brake is located at the top of the swing motor so I'd think it's not an expensive fix. Of course it's a bit more of a PITA on a mini since the motor is under the cab floor.
i'll let you know what happens. we got it torn down yesterday in the rain. today is probably a trip to junction for parts. always something.... regards, cd
435's hope you got yours fixed. thanks for the note, ended being being the exact same problem, so thanks again!! regards, cd
So far the field welds are holding up. We will be keeping an eye on it though.