Swing Bearing Replacement Costs in CAT 303.5E, 305.5E2, and 305.5 Mini Excavators
The 305.5E2 bearing uses reengineered internal raceway profile; an improvement CAT has been making since about 2016 to minimize the point-load stress at high swing speed deceleration. Unfortunately, prices vary a little when it comes to a factory CAT swing bearing on a 305.5E2 and I’d call it “variable” as it would depend on dealer to dealer, quarter to quarter, and margin pressures. I’ve had two different CAT dealers in the same state tell me they had the same part number selling for two different prices that you can’t really believe that they’re selling the same thing. Often times, when the dealer tells you “in stock” it means that it’s in his or her regional distribution center, but not in the parts center. Korean manufactured swing bearings are usually hardened to HRC 58-62 on the raceway surface (some of the bearings that are supplied to some of the CAT assembly plants are of this type). Still others are offered at HRC 52 which is awfully close, until you realize the difference in wear life is more in the hundreds of hours, not thousands. However, I will say this: If the supplier will not furnish the material cert with the hardness numbers in the raceway, and a dimensional inspection report, then walk away. The aftermarket bearings can be sold by heavy equipment parts distributors who charge you an additional 40% of the price as they hope you’ll pay in exchange for the convenience. Others are at less than half the price because they came straight from import consolidators, but it’s now your problem if it turns out to be dimensionally flawed, or to have a raceway which is canted.
The normal drive torque of a 1/2″drive torque wrench is about 250 ft-lbs. Too light torque on swing bearing bolts has been known to result in the bolts becoming loose at 600 hours and ripping the swing bearing bolt holes of the undercarriage frame. A good torque multiplier will cost approximately $85 a day.
The rule of thumb is, if you can see that it’s discoloured on the raceway, it’s bad. It is a requirement that the mounting surfaces are cleaned. I have a Roloc disc on my angle grinder to clean off old gasket material, rust and any high spots. Then I clean it out with Acetone and straight edge it again.
According to OEM specification, the lithium complex grease used must be NLGI 2 consistency and have a close to 220 cSt base oil at 40°C. Using a stiffer grease (such as NLGI 3) means it will not flow to the ball contact patches during low speed operation, and cause accelerated wear during start-up cycles.
According to CAT service documents a 305.5E2 needs to have swing bearings replaced at 6.5 flat rate hours (FTH). The manual is based on the assumption that everything is perfect–access is good, no corroded fasteners and a technician who has performed this specific operation at least a dozen times. Real-world clock time? I allow one day (9 hours) for a simple exchange. This includes documentation, disassembly, cleaning, installation, torque checking, re-assembly and more. I had to remove two bolts, using the acetylene torch, from one 303.5E which was operating in a tidal marsh reclamation job. Add an additional hour per hose if the hydraulic hoses are original, and the ferrules are frozen. If the undercarriage mounting surface is damaged and must be welded/machined, it is a several day project.
Real-world clock time? I allow one day (9 hours) for a simple exchange. This includes documentation, disassembly, cleaning, installation, torque checking, re-assembly and more. I had to remove two bolts, using the acetylene torch, from one 303.5E which was operating in a tidal marsh reclamation job. Add an additional hour per hose if the hydraulic hoses are original, and the ferrules are frozen. If the undercarriage mounting surface is damaged and must be welded/machined, it is a several day project.
Data sources for the table above:The 6.5-Hour Hallucination vs. 9-Hour Field Execution Board
The rates charged for the labor differ from area to area, and depending whether the mobile service truck or the machine is being brought to a brick and mortar shop. For mobile service my area is in the range of approximately $140 per hour plus travel. If it is less of a drive, trailer it in to save the difference in the hourly fee for the drive.
A good swing bearing has no perceptible play. A marginal bearing is able to provide 0.020- to 0.040-inches radial movement before the balls move into the load zone.
Now that you know why it is vital to get it right the first time, why it can be very expensive to fix and what the sound of a failing swing bearing will sound like, you’re ready to make an informed decision. When viewing used equipment listings most of them don’t state anything concerning the state of the swing bearing. Documentation is the key, such as inspection reports showing the swing bearing radial play is within specification, torque readings if the bearing has been replaced and any service history and inspection reports that would indicate the swing bearing wasn’t turned into the ground. We put on record any play that can be measured. If the bearing was changed we will also include the receipt and torque sheet. If the machine has a clean swing bearing (less than 3000 hours) we will say so.
