How a few simple steps can extend the life of your PTO
This Tech Tip, one in a series we publish for engine professionals, is aimed at helping people get more life out of their Rockford or Twin Disc power takeoff clutch assemblies.
Other PTO Tech Tips include
- Tech Tip #95: Removing a Troublesome Pilot Bearing (Part 2),
- Tech Tip #113: Prolonging the Life of Your Twin Disc or Rockford PTO, and
- Tech Tip #116: Curing Excessive Side Load Problems with Twin Disc and Rockford PTOs.
Experiencing short pilot bearing life in your Rockford or Twin Disc® clutch? Most of the time problems with pilot and other bearings can be traced back to three causes.
- Bell housing misalignment. The bell housing (for a quick overview of how to identify your bell housing size see Tech Tip #41: SAE Bell Housings Made Easy!) connects your Twin Disc or Rockford PTO to the engine. If the bell housing isn’t square on the back of the engine block and in line with the crankshaft, your PTO input shaft will twist in the flywheel and the pilot bearing won’t last. (For a quick tip on how to remove a troublesome PTO pilot bearing see Tech Tip #67: How to Remove a Troublesome Pilot Bearing (Part 1)). Dr. Diesel™ suggests that you use a dial indicator to ensure that the center bore of the bell housing is concentric with the engine and correctly aligned.
- High side loads. Does your Rockford or Twin Disc power takeoff have several pulleys installed on the output shaft? If you are putting heavy side loads on your output shaft, your bearings might not last. Installing a rear support plate will result in a longer lasting PTO. Many Twin Disc clutches already have predrilled holes in the back of the housing to accept a support plate. If you are running a Rockford PTO, you won’t have these holes, even though the Rockford might still be side load rated. But that’s not a problem. Simply fabricate a rear support plate that would resemble a cradle to install at the back of the PTO. This will prevent side movement and deflection. Your pilot bearing will thank you. See Tech Tip #47: Running a Twin Disc/Rockford PTO? Want It to last Longer? for more details on how to build a support cradle for your Twin Disc/Rockford PTO.
- Chinese pilot bearings. Most bearing distributors have good computer-based bearing part number interchanges. The problem is when a guy calls his local bearing house for a pilot bearing, they’ll take the number you give them, run it through their computer and come up with an off-shore substitute. Their parts guy thinks he is doing you a favor by saving you a dollar or two with a no-name bearing. Now, we’ve got nothing against Chinese pilot bearings. After all, they make good sinkers on a codfish rig. Please though make sure that you aren’t replacing a sealed, double row bearing with a single row bearing in order to save a couple of bucks. We stock a premium, US made line of pilot bearings and would be happy to supply you with a pilot bearing that will give you long service life.
Trouble with your pilot bearing? We stock custom made pilot bearing holders for the Ford 300 and Perkins 4236. For more information on pilot bearing holders, see our Tech Tip #131: Perkins 4236 Diesel and Ford 300 Industrial Pilot Bearing Holders.
For a quick overview on how to adjust your over-center clutch, take a look our at Tech Tip #48: Maintaining Your Rockford and Twin Disc Power Takeoff Clutch. We have Workshop Manuals for both Twin Disc and Rockford power takeoff clutches in stock and ready to send to you by Express Mail.
Manufacturers names, symbols and numbers are for reference purposes only and do not imply manufacturing origin.