Description for the
Gravely 800/8000 Series 4 Wheel Tractor
2 Pc. Clutch Cam Roller
These clutch cam rollers are used in the 800 and some early 8000 Series Tractor's forward or reverse clutch.
These rollers are the equivalent replacement of the original "Gravely" produced roller assembly as first designed for this clutch application.
The 1 pc. roller design followed this 2 pc. original roller design, thus, this 2 pc. roller can interchange with the 1 pc. roller. Perhaps this design change came about due to a change in the manufacturing process (and therefore the design) of the pressure plate that possibly allowed the separate axle pin to shift off center giving the roller unequal support.
As with a large number of products offered by Cogan Valley Machine Co, this part is made of the best stuff, grade 4140 steel. These rollers have been hardened throughout to 55+ RC. The roller axle pin are standard hardened dowel pins as they were for their first design.
We have been told that Gravely has made some of these rollers from something called Sintered Metal, a form of powdered steel, pressed under high pressure, then case hardened creating a soft center. This material is rather inexpensive to produce but has a short wear life. If the rollers fail, they generally cause damage to the pressure plate soon after, thus adding to the cost of repair. Replace your inferior rollers with our A+ quality rollers before your clutch service cost becomes a major repair job!!
This after market manufacturer and some dealers we spoke with, are of the opinion that this 2 pc. roller design is superior because the roller does not wear the clutch plate as quickly since the axle pin does not turn in the roller pin seat as the 1 pc. roller will. Therefore, though not currently available from Gravely, the 2 pc roller would be preferred due to the prolonged pressure plate life.
Due to the two different pressure plates out in the marketplace, we find it necessary to supply two lengths of dowel pins with these rollers to address the created potential problem of the roller axle pin side shift. With this addition, the preferred 2 pc design once again may be used with the currently produced pressure plate.
We offer a 3 roller set for near Gravely's list price for just one roller as currently produced.
Thank you for looking to Cogan Valley Machine for your quality Gravely after-market parts.