Tips on curing excessive side load problems with Twin Disc and Rockford PTOs
This Tech Tip, one of series that we publish discusses how to address the problem of excessive side loads, which results in short service life with NACD®, Rockford™, Twin Disc® and WPT Power® mechanical over center power takeoffs. It builds on tech support information contained in eight earlier tech tips we have published on Twin Disc and Rockford power takeoffs. For additional help and tips, please take a look at:
- Tech Tip #41, SAE Bell Housing Sizes
- Tech Tip #48, Maintaining Your Rockford or Twin Disc Power Takeoff Clutch
- Tech Tip #67, Installing a Rockford and Twin Disc Power Takeoff: How to Remove a Troublesome Pilot Bearing
- Tech Tip #73, How to Make Your Twin Disc or Rockford Power Takeoff Last Longer
- Tech Tip #111, Power takeoff Clutches for Wood Chippers , and
- Tech Tip #114, Available SAE Housing Sizes, Available SAE Clutch Sizes, Torque Capacities and Key Dimensions
Sometimes customers running Deutz®, John Deere® or Perkins® diesels come to us and complain about the short life of their power takeoffs. They tell us that despite their best efforts their clutch packs or PTOs fail too soon. We make suggestions about not over greasing the PTO assembly, scheduling regular clutch adjustments, using good facings/friction discs, using only quality pilot bearings, etc., but their PTO clutch units still fail too early.
One of these failures we had a chance to investigate more closely, you could see that the PTO input shaft was over twisted ruing not just the pilot bearing and PTO, but also the flywheel. If you have ever priced out a new Deutz flywheel for a BF6L912 series Deutz diesel you can imagine how the customer felt when he saw the egg shaped hole in his Deutz flywheel that used to house his pilot bearing. He was not a happy camper.
Clearly excessive side load on the output end of the power take off shaft was caused this failure. In other words, sideways force on the output end of the PTO shaft was pulling it to one side and this side load was causing the other end of the PTO shaft to dance around in the pilot bearing while also causing problems with the PTO.
In response to this, we came up with a solution. Foley Engines now offers both standard aftermarket Twin Disc and Rockford style power takeoffs with a one-piece housing. These units will work well unless you have excessive side loads. We now also have aftermarket Twin Disc and Rockford style PTOs with a two-piece housing. The two-piece housing PTO has a couple of advantages over the one piece housing design. First, the two-piece housing allows you to unbolt and remove the rear of the PTO housing to work on it while the front of the housing can remain bolted to the engine bell housing. More importantly, the bolts that hold the rear section of the PTO housing onto the front section form a circular pattern. This allows someone with a side load problem to bolt a support plate directly to the back of the PTO using those bolts and bolt holes for the support plate. Using a support plate will prevent the side loads from causing the shaft to deflect or pivot. While your PTO will love you if you use a rear support plate, your Deutz or Perkins flywheel supplier won’t be so happy.
Manufacturers names, symbols and numbers are for reference purposes only and do not imply manufacturing origin.
