How the heck do you guys torque a cylinder nut to 600 ft lb? Rebuilding Bobcat combo bucket cylinder.

[Semper Paratus]

Years ago we used to use "Turn of the nut" and a slugging wrench on metal to metal steam joins torque to 2000 ft-lbs+ to obtain a nominal 2/3 yield. If you new the grip length, fastener diameter and thread pitch you went into the tables and found out what angle of advance (number of flats) you needed after an achievable initial torque like 200 ft-lbs. So long as we got all the fasteners tight, in a couple of increments, in a Kriss cross pattern it worked well. Problems if you took it to full torque sequentially around the bolt circle.

 

[mo1]

I am putting new seals in and apparently I need to get the bottom nut to 600 ft lb. I do not have that kind of torque wrench. How do most people achieve this? Thanks.

Torque multiplier and a torque wrench that will go to 600 ft/lb divided by the multiplication ratio of the torque multiplier. I had to torque a nut on my rotary mower about 650 ft-lb and this was very easy to do with a 3:1 torque multiplier and a 4 foot long 3/4" torque wrench that goes up to 450 ft-lb. I set the wrench to 1/3 of what the required nut torque was and tightened until it clicked. The added bonus of a torque multiplier is that the handle on the multiplier (slip a piece of pipe over it and wedge it against something) takes the counteracting torque so I didn't have to try to jam something in the blades to keep the pan from turning as I torqued the nut as I would if I was just using the torque wrench by itself. Probably the worst thing was finding the correct size metric socket for the nut.

 

[4570Man]

Well, I will have to do more homework. My manual for my bobcat s150 has 600 ft lb for the lift cylinder and only 100 for the plate tilt and 90 ft lb for the bobtach wedges. So.... I need to find the proper torque for the bobcat combo bucket. My guess is it is below 600.

600 pounds sounds pretty high for a nut that size.

 

[CalG]

If I recall correctly, and have done the maths. correctly..

600 pound feet requires a 30 inch long , 3/4 " drive breaker bar and a two foot length of water pipe over the handle.
Three "ugga uggas" and a grunt is the EXACT the conversion equivalent.

 

[IndyJay]

This is an application where you don't have to be dead nuts accurate. RickB's method will be fine.

I needed to set the bearing preload on the steering head bearings on a motorcycle. This required a spanner wrench which I had, but no way to use a torque wrench with it. So, I measured from the centerline of the spanner 6" and ground a groove. This held the hook of my fish scale. A pull of 3 lbs on the fish scale yielded the required 18 inch pounds of torque.

A little ingenuity and math will get the job done in many cases.

Agree. Often these specs are a very precise number for a ballpark requirement. Engineers are funny that way. But how else would you describe "really, really, tight without breaking or stripping anything"?

 

[clydesdale]

I understand. Where I am stuck is that there is a huge difference between 600 ft lb and 90 ft lb. I specialize in breaking sh*t. So, I would feel more comfortable if I could find the service manual. But, so far, no luck. I may have to call the Bobcat dealer. My guess is that they will just say make it tight.

 

[clydesdale]

Well, I just took the nut off and all I had to do was turn it with a regular ratchet. Not only that, I put almost no torque through it. It was "snugged" at best. Either that, or it loosened up. It took zero effort to remove the nut.

 

[WranglerX]

Well, I just took the nut off and all I had to do was turn it with a regular ratchet. Not only that, I put almost no torque through it. It was "snugged" at best. Either that, or it loosened up. It took zero effort to remove the nut.

Does it have a "O" ring seal?

 

[wdchyd]

Well, I just took the nut off and all I had to do was turn it with a regular ratchet. Not only that, I put almost no torque through it. It was "snugged" at best. Either that, or it loosened up. It took zero effort to remove the nut.

You did good to catch it before it backed off on its own. The 6’ of pipe and 100 lbs is the best way to retorque if no other means avail.

 

[Smily0]

I'm not sure if you are open to spending any money, but I bought a 3/4" digital torque adapter for this purpose. I knew my brush hog called for that level of torque, trailer lug nuts were 200, and the new gooseneck hitch I was installing on my truck needed 375. I would have probably settled for several ugga-duggas from my Milwaukee high torque 1/2" impact if it hadn't been for the Gooseneck hitch. That was the most important in my eyes, so I started looking and found this adapter. It may or may not be the most accurate item on the market, but I'm sure it was better than me guessing. For $80 or so, I haven't regretted it one bit, and have used it more than I expected.