This is one of a series of Tech Tips we publish for the industrial engine community. This one focuses on power take off clutches; specifically Twin Disc, Rockford and AutoClutch power takeoff assemblies. It discusses how to get more life out of your PTO with a simple upgrade to your pilot bearing.
Earlier Tech Tips have discussed power takeoff clutch maintenance (see
- Tech Tip #48: Maintaining Your Rockford and Twin Disc Power Takeoff Clutch
- Tech Tip #93: Twin Disc® and Rockford Power Takeoffs
- Tech Tip #116: Curing Excessive Side Load Problems With Twin Disc and Rockford PTOs and
- Tech Tip #147: Running a Twin Disc/Rockford? Want It To Last Longer?)
and pilot bearing selection (see
- Tech Tip #67: How to Remove A Troublesome Pilot Bearing (Part 1)
- Tech Tip #95: Removing a Troublesome Pilot Bearing (Part 2)
- Tech Tip #118: Super Sizing Rockford and Twin Disc or Auto Clutch Power Takeoff Clutch Pilot Bearings: Prolonging the Life of Your PTO – (Part 3) and
- Tech Tip #158: Power Takeoff Clutch Maintenance: How to Remove a Troublesome Pilot Bearing (Part 3).
This Tech Tip focuses on enhancing the life of your Twin Disc, Rockford or AutoClutch power take off clutch by choosing the right pilot bearing. The pilot bearing on a power take off clutch is critical. It is inserted into the flywheel and is the important link between the flywheel and the Twin Disc, Rockford or AutoClutch PTO input shaft. Yet when servicing their PTO assembly many people either don’t replace the pilot bearing or seek the cheapest one they can find. We’ve often heard customers say as they leave our facility, “Naw, I’ll just take a new disc. I’ll pick up a Chinese pilot bearing at NAPA on the way home.”
What does AAMCO Transmission say in their ads, “Pay us now or pay us later”? People may have gotten away with using cheap pilot bearings when they were running low HP gas power units on an intermittent duty cycle. But today’s high horsepower diesels produce lots of heat and a cheap pilot bearing doesn’t last.
Big Horsepower, High Heat and Tiny Pilot Bearings
We’ve seen an increase recently in pilot bearing failures, especially in wood chippers running high horsepower engines coupled to Twin Disc, Rockford and Auto Clutch clutches. The industrial engines used in wood chippers are getting more and more powerful yet the size of the pilot bearing hasn’t changed. This is especially true of an AutoClutch PTO running behind a John Deere engine. The John Deere flywheel doesn’t allow much space for the pilot bearing. As a result it is relatively tiny. When it fails the results aren’t pretty and the owner is often faced with buying a new flywheel from John Deere. In case you haven’t priced out a John Deere flywheel recently, it could ruin your day.
We’ve seen so many John Deere flywheels ruined by a pilot bearing failure that we stock the most popular Deere flywheels used in wood chippers, PN RE25651 and PN R500219. Not only do we stock these flywheels we buy them right and can discount them to you. But here is how to avoid all that
Upgrading the Pilot Bearing
While you can’t change the size of bore in the flywheel allowed for the pilot bearing, you upgrade your pilot bearing. In earlier Tech Tips (
- Tech Tip #73: How to Make Your Twin Disc or Rockford Power Takeoff Last Longer and
- Tech Tip #113: Prolonging the Life of Your Twin Disc or Rockford PTO
we suggested that people stay away from Chinese pilot bearings sold in Chinese boxes. At a minimum, you should purchase your pilot bearings from a US bearing manufacturer. But here is new idea for longer pilot bearing and flywheel life.
We recommend that you use a Viton sealed pilot bearing in all high horsepower, high heat applications, especially in a wood chipper.