Anonymous-0
Well-known Member
Took the stick cylinder off the backhoe on my Cat 931B to see what happened inside. It's a 4" bore x 34" stroke cylinder. It uses a large bolt that threads into the rod to hold the piston on. It was too big for me to work on in the field so I took it in. Bad news! The bolt came out and took 2/3's of the internal threads with it.
That cylinder always creeped a little so I think maybe the bolt was a little loose. The guy from the shop said that can happen over time and the shock loading causes the bolt to loosen off. They don't make heli-coils large enough to fix it. The rod itself has a .058" bend in it that they could probably straighten but might leave a small mark on the rod.
They said they could try put a new bolt in with loctite and hope the remaining threads hold. They also said they could just leave the bend in the rod. I think it's worth trying to straighten the rod. That part's minor as far as I'm concerned. I hoping one of the experts on here has ran into this and has a cost effective solution. Welding up the threads would would cause greater problems. They can make me a new rod but it would cost close to $1000! The seal kit isn't bad at just under $100 but for everything including honing the barrel and testing it, I'd be looking at around $1600!!! Anyone have a solution that's not so expensive? This shop specializes in heavy equipment repair but it's not cheap. $142/hr. and $152/hr. for the machine shop. This is in Alberta where you don't find $50 or $75/hr. shops.
That cylinder always creeped a little so I think maybe the bolt was a little loose. The guy from the shop said that can happen over time and the shock loading causes the bolt to loosen off. They don't make heli-coils large enough to fix it. The rod itself has a .058" bend in it that they could probably straighten but might leave a small mark on the rod.
They said they could try put a new bolt in with loctite and hope the remaining threads hold. They also said they could just leave the bend in the rod. I think it's worth trying to straighten the rod. That part's minor as far as I'm concerned. I hoping one of the experts on here has ran into this and has a cost effective solution. Welding up the threads would would cause greater problems. They can make me a new rod but it would cost close to $1000! The seal kit isn't bad at just under $100 but for everything including honing the barrel and testing it, I'd be looking at around $1600!!! Anyone have a solution that's not so expensive? This shop specializes in heavy equipment repair but it's not cheap. $142/hr. and $152/hr. for the machine shop. This is in Alberta where you don't find $50 or $75/hr. shops.