A buddy has a Cat 216B with some loose drive chains in it. I'm going to open it up to inspect and tighten them but I don't have any service information. What does Cat recommend for tensioning these chains? Any things I should be watching for once I have the inspection covers off? Thanks, Jon.
Well, we got into the chaincases for our Cat 216 yesterday, intending to tighten the chains. Well, maybe not. One chaincase was filled with water and the bolts for both hydraulic motors were loose. The chaincase that was filled with water had the sheared heads of 7 bolts where presumably a previous owner had the same problem with loose bolts but didn't catch it in time. So here's my question: I will change all the bolts and see if I can torque them up to whatever Cat recommends. The bottom 5 bolts are awful awkward to get to... I think I have to drop the belly pan to get at them. I suspect that this isn't an uncommon problem. Is there any secret to keeping the motors tight? The bolts look like grade 2 agricultural grade crap but they are metric, marked 10.9. Since the motors have rattled around in their mounts, are we faced with remachining the mounting spigot so the motor is tight so the bolts only hold it from torquing? I'm not asking about changing the chains because this machine will only be used a couple hundred hours per year. The sprockets are still good so we will clean up the chaincase and run it for a while before changing the chains. Jon.
Those "bolts" are actually studs. Just like a wheel stud the first inch or so of the shank should be splined so it has to be hammered into place. The thread is metric M12 coarse and the nuts on them are the self-locking type. Regarding quality the fact they are stamped 10.9 means they are rated 1000MPa (145,000 psi) so that would make them the same strength as a Grade 8 bolt of the same size. I would say that not only are you looking at somehow remachining the motor spigot so that the motor is a good fit in the housing but also reconstructing the holes for the studs so that they have to be fitted into position using a hammer.
Studs?? Nige, In looking closely at the bolts and bolt holes for the motors on this machine, the holes are square holes in the machine frame. The bolt heads are a standard carriage bolt head with a matching square under the head. No wheel studs here! I wonder if Cat went to the wheel stud idea after fighting with this carriage bolt stuff for a while? Jon.
Jon, You're absolutely correct. Not knowing your Serial Number I picked one at random, it's the later design with the "wheel stud"-type fasteners. Sure enough the earlier design shows your carriage bolt with the square head and refers to it as a "Bolt". The carriage bolts are still 12mm metric 10.9 (Grade 8 equivalent) though, and the torque at 90ft.lbs. remains the same. I guess it's a fingers crossed deal how much wear has taken place in the square holes while the bolts have been loose and the motor's been moving, plus how much metal has been worn away from the hole in the frame where the motor fits. I think that even if you replace the bolts and clean everything up as you had originally planned I think you might struggle to keep the motors tight.
Your chain cases look horrid. On the top, under the cab you will find your breathers are plugged. The right one is a PITA to get to! I have had a problem with this until I vented them with a nipple and hose. Also look out for the chain rollers cracking. They should be one seamless piece.
If you have only a little slop in the square mounting holes on the frame. I would not use the m12 bolts that Cat calls for. I would recommend ordering qty. 20 of each of these numbers. Cat part # 220-8163 (bolt), # 8T-4223 (washer), # 1K-6872 (locknut). This is slightly larger hardware and will allow you to avoid costly welding repairs. Upon reassembly, both sides of the mounting surface need to be buffed to the bare metal along with the mounting flange on the drive motor. Apply a thin bead of rtv to the face of each new carriage bolt before you hammer them in the frame (they will be a tight fit). Reinstall the drive motor with new washers and locknuts (I also use red loctite) and torque to 90ftlbs starting with the center bolts and alternate top to bottom working your way out. Once its its tight I apply a bead of rtv on the inside of the chain case around the drive motor face. This keeps any splash oil from getting out and any water from getting in. Cat spec on the chain tension is 1/2" deflection up or down. Good Luck