Usage:
508 Skidders
Description of Change: A new drag brake and hand control are used to reduce freespool chattering in winch. The winch lines groups have new components for the drum drag brake.
Adaptable To: The part number of the improved 3T4961 Winch Lines Group has not changed. A new 6Y0323 Tube Assembly (1), 016498 Elbow (2) and an additional 321268 Elbow (3) have been added to the group.
Illustration 1. Location of new components in winch lines group.
The new 8R7339 Winch Lines Group replaces the former 8V2275 Winch Lines Group.
The part number of the improved 3T4959 Gear And Clutch Group has not changed. A new 1K9060 Seal (4), 6Y0115 Body Assembly (5), 9W9530 Piston (6), 1H8171 Seal (7), 9W9532 Plug (8), 3D2824 Seal (9) and 9S8009 Plug (10) have been added to the group.
Illustration 2. Location of new components in gear and clutch group.
The new 8R6678 Control And Mounting Group replaces the former 6W1587 Control And Mounting Group and 3T6327 Valve Group.
Illustration 3. Side view of new components in control and mounting group.
Illustration 4. Top view of new components in control and mounting group.
The winch on certain 508 Skidders may experience freespool chattering. This is due to rotation of the drum while trying to engage the freespool coupler into the intermediate drive pinion. A drag brake modification and a new hand control can be installed to reduce the freespool chattering.
NOTE: The winches on some of the skidders were updated to the new design at the factory, but the hand controls were not. Use the skidder product identification number to determine if the hand controls needs to be updated. And use the winch serial number to determine if the winch needs to be updated.
The hand control on 508 Skidders (9NC1-304, 2HD1-84, 86-275, 305) needs to be updated.
The drag brake modification needs to be done on winch serial numbers 9DA1-517.
The charts identify the components necessary to do the two reworks.
Rework Procedures For The Winch
NOTE: Use 508 Skidder Service Manual and this procedure to complete the modifications.
1. Remove the winch from the skidder.
2. Remove the idler gears, freespool components, and drum from the winch.
3. Cover the brake and sump with suitable material to protect them from debris while working on the case.
4. Drill or cut two holes (A) in line 65.5 ± 1.0 mm (2.59 ± .04") diameter in the case. See Illustration 5.
Illustration 5. Location of body assembly and holes (A).
5. Install body assembly (5) in the case as shown in Illustration 5.
6. Drill a hole 11.50 mm (.245") diameter in the front wall of the winch case, as shown in Illustration 6. Use a 1/4"-18 NPSF tap to thread the hole.
Illustration 6. Location of tapped hole.
7. Clean all the debris from the winch.
8. Install elbow (2) in body assembly (5). Install elbow (3) in the back side of the front wall in the new tapped hole. See Illustration 1.
9. Install tube assembly (1) between the two elbows. Rotate body assembly (5) as necessary to locate tube assembly. See Illustration 1.
10. Weld body assembly (5) in place using a 6.0 mm (.23") fillet weld all around, on the outside of the case, both ends.
11. Install seal (4) in bore of body assembly (5). See Illustration 2.
12. Inspect coupler (48) and gear (49) teeth for damage. Replace if necessary. See Illustration 1.
13. Install the drum, freespool parts and idler gears.
14. Install plug (8), piston (6) with seal (7) and plug (10) with seal (9) in body assembly (5). See Illustration 2.
15. Install winch on skidder.
16. Fill winch and drum with oil.
Rework Procedures For The Hand Control
NOTE: Use 508 Skidder Service Manual and this procedure to complete the modifications.
1. Mark the hoses connected to the former 3T6327 Valve Group so they can be identified later. See Illustration 7.
Illustration 7. Location of hoses connected. New 6Y0746 Valve Group shown.
2. Disconnect the hose assemblies at the former valve group.
3. Remove the former 6W1587 Winch Control And Mounting Group and 3T6327 Valve Group.
4. Remove the former 9C7327 Clamp (outer), 9C7328 Clamp (middle) and 9C7329 Clamp (inner) from the two 6W9546 and 6W9550 Angle Assemblies. Keep the hardware that holds the clamps, it will be used later.
5. Remove the two former 6W9546 and 6W9550 Angle Assemblies from the frame. Keep the bolts and washers for later.
6. Remove the former oil supply line 6W9538 Hose Assembly, 6V9850 Elbow (at the valve end) and 6V8397 Seal (at the valve end) and two 4D7735 Clips. Install the new oil supply line [hose assembly (37)], two seals (43) and one clip (36), bolt (22), and washer (15). DO NOT TIGHTEN clip bolt at this time. See Illustrations 9 and 10.
NOTE: The new hose assembly has a different routing than the former hose assembly.
Illustration 8. Side view of new components in lines group.
Illustration 9. Front view of new components in lines group.
7. Install new adapter (47), connector (44) and seal (34) on the new tapped hole in the front wall of the winch. See Illustration 10.
8. Install the new drum drag brake hose assembly (33) and seal (43) to connector (44) (from Step 7) and route it up to the control valve as shown in Illustration 7. Install connector (44), seal (43) and seal (34) to the other end of the new drum drag brake hose assembly. Install clip (36) to the drum drag brake hose assembly as shown in Illustrations 8 and 9.
Illustration 10. Top view of new components in lines group.
9. Install angle assemblies (38) and (39) using the bolts and washers removed in Step 5. See Illustrations 9 and 10.
10. Position the hose assemblies between clamps [inner (40)], [middle (41)] and [outer (42)] and attach to the two angle assemblies using the hardware removed in Step 4. See Illustrations 9 and 10 for location of hose assemblies in clamps. DO NOT TIGHTEN clamp nuts completely at this time.
11. Remove 6V9873 Connector and 3J1907 Seal for the valve end of the disconnect hose assembly. Install connector (45) and seal (35) to the disconnect hose assembly.
12. Remove 6V8724 Elbow and 3J1907 Seal for the valve end of the input clutch hose assembly. Install elbow (46) and seal (35) at the valve end of the input clutch hose assembly.
13. Install the hose assemblies to the new 6Y0746 Valve Group as shown in Illustration 7.
14. Install the new hand control and valve group to the skidder. See Illustrations 3 and 4.
15. Tighten clamp bolts and clip bolts.
16. Start engine and check power train oil level. Add oil if necessary.
17. Bleed the air from the drum drag brake line by loosening plug (10). Move the hand control lever to the "Free Spool-Drag On" position until oil appears at the plug. Move the lever to the "Brake On" position and tighten the plug. See Illustrations 2 and 3.
18. Test the other winch functions.
19. Check the power train oil level again.