Tech Tip #48: Maintaining Your NACD, Rockford, Twin Disc or WPT Power Power Takeoff Clutch

Keeping your Rockford, Twin Disc®, NACD or WPT Power over-center clutch in good operating condition is easy if you know these guidelines. This Foley Tech Tip will show you how to check your clutch for adjustment, how to adjust it, and how to keep it lubricated.

When to Adjust Your Twin Disc, Rockford, NACD or WPT Power PTO

The key to maintaining your clutch is knowing when to adjust it and with many things this depends on how how much and what kind of use it gets. You should monitor the force necessary to engage your clutch and if that force drops by 10-15% from the recommended engagement force ranges, your clutch facings are wearing and your PTO needs adjustment. Sometimes that is hard to tell day to day so a good rule of thumb is to measure the engagement force weekly during active use.

Note that when you replace your PTO or the clutch pack within it, you should recheck the engagement force after a day or so of use as there is often some settling after the first adjustment that will cause the clutch discs to loosen and the second adjustment should set you into normalized adjustment intervals.

How to Monitor Engagement Force

Engagement force measures the force to engage the clutch in your PTO:  Too light and friction discs will not be held firmly causing wear in the disc or often excessive heat that can damage the clutch pack itself.  Too heavy and you are putting to much pressure on PTO components potentially damaging them and most noticeably it will be difficult to engage or disengage.  There are two common locations to measure this force:  1) where the engagement handle meets the operating shaft there is often a socket fitting to allow you to use a torque wrench; or 2) You can measure the amount of pull from the handle at a specified height (force measurements for the two methods will be different). The chart below tells you when it is time to adjust your Twin Disc or Rockford PTO.

How to Adjust Your Clutch

Here are the steps to take: Disengage the clutch, remove the inspection plate, and rotate the clutch to gain access to the adjusting ring. Depending on the manufacturer and clutch the adjusting ring will be held in place by a “lock” of varying styles (i.e. pin you pull up, spring that is lifted up or screw lock that holds adjusting ring outer notches in place). When unlocked you will be able to rotate the adjusting ring to increase or decrease the engagement force. Rotate the adjusting ring counterclockwise to lighten force; clockwise to increase the engagement force for the clutch. Then adjust to obtain the proper handle engagement force for your PTO. When done, reposition the locking mechanism to lock in the adjustment you just made.

Lubricating Your Clutch

Use lithium base #2 grease prior to installation of your PTO. Grease the release bearings (if not sealed), the main bearings (rotate the shaft by hand until the grease comes out), and the cross shaft. Once a PTO is installed, follow this schedule below.

Lubrication Schedule

Finally, don’t over-grease your PTO. It may sound counter-intuitive, but we see a number of clutch failures every year due to over greasing. 

Please call us with any questions about your over-center or spring-loaded PTO. Foley Engines stocks new and remanufactured units, clutch packs, friction discs, and other maintenance parts. If in doubt about your NACD, Twin Disc, Rockford or WPT Power PTO, call us. We take tech support seriously and want to share our knowledge with those who need it!!

Manufacturer’s names, symbols, and numbers are for reference purposes only and do not imply manufacturing origin.