Model 4700 Maintenance Manual
Section 7. Component Procedures
Drive and Brake
Drive Unit/Motor Assemblies
Refer to Figure 7-18 for bracketed numbers referenced in this procedure.
• internal tooth disk [5]
Place the drive unit in a holding device or on the wheel bolts to perform the following steps.
• internal tooth disk [5]
1. Use an impact wrench to loosen the countersunk bolts in the cover [1].
• external tooth disk [4] • external tooth disk [4] NOTE : Align the “high spots” on the internal tooth disks for maximum “spring” action. 6. Insert the disk set into the ring gear [7].
Do not damage mating surfaces during disassembly. 2. Carefully pry the cover [1] off the drive unit. NOTE: When the housing cover is removed, the spur gear [2] remains connected to the internal disk carrier [3] as a single unit. 3. Remove the disk set (four external tooth [4] and three internal tooth disks [5]) and thrust washer [6] from the ring gear [7]. 4. Lightly rub the new internal tooth disks with a flat sanding block to visually establish “high spots”. These “high spots” must be in alignment when installed to ensure correct braking. See Figure 7-19. Figure 7-19.
7. Put the internal disk carrier [3] into the correct fitting position. Slide the disks into their correct position by slightly turning or moving the internal disk carrier. 8. Carefully remove the internal disk carrier from the fitting position. Make sure that the position of the disk is not changed. NOTE : If the wearable brass brake activation pad [8] is replaced, make sure it is positioned correctly. See Figure 7-20. Figure 7-20.
Brake Activation Pad
High Spots On Brake Disk
This hole must be positioned toward the bottom of the drive unit
High Spot
5. Assemble the new disk set in the following order: • thrust washer [6] • external tooth disk [4] • internal tooth disk [5] • external tooth disk [4]
Publication 1160093, Issued: 20 May 2013
Assembly 1. Thoroughly clean all the parts and remove all residual thread-locking compound. 2. Check brake disks for wear and damage. Replace if necessary. NOTE : Replace brakes in sets only. 3. Smooth the sealing surface with an oilstone or a double-smooth file.
7-25
