Technical Bulletin. T28, T250, T412 & T618 - Power Pack Sheave/Hub Assembly, Alignment and Belt Tensioning Procedure

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Technical Bulletin T28, T250, T412 & T618 - Power Pack Sheave/Hub Assembly, Alignment and Belt Tensioning Procedure TB034 Products Affected: All TracStar 28 and TracStar 250 Machines All TracStar 412

1 Technical Bulletin T28, T250, T412 & T618 - Power Pack Sheave/Hub Assembly, Alignment and Belt Tensioning Procedure TB034 Products Affected: All TracStar 28 and TracStar 250 Machines All TracStar 412 and TracStar 618 machines with Yanmar Engines This bulletin contains instructions for the following procedures: 1. Sheave/Hub assembly and alignment with power pack removed from the chassis 2. Sheave/Hub alignment with power pack installed on the chassis 3. Proper tensioning of the serpentine belt Failure to follow these procedures may cause damage to the shafts and bearings of the generator, engine and pump. Section 1 Sheave/Hub assembly and alignment with power pack removed from the chassis 1. Install the sheaves. With the power pack lying on its side (generator up), install the keys into the keyways of the generator shaft, the engine shaft and pump block shaft. If the keys are not tight in the keyways, stake the keys so they will not come out. Install the correct sheave/hub assemblies to the appropriate shafts according to the assembly drawings. a. Install the proper sheave/hub assembly to the shaft of the generator. Locate and tighten the sheave flush to the chamfer of the generator shaft. (Figure 1) Flush with chamfer of shaft Figure 1: Generator Sheave Close-up b. Using the generator shaft sheave/hub assembly as the reference, install the sheave/hub assemblies to the pump block shaft, (see Figure 2), and the engine shaft, (see Figure 3). Use a straight edge to confirm the pump block and engine sheaves are square and level with the sheave/hub assembly installed on the generator shaft. TB034.doc Page 1 of 7 6/2/10 REV. B

All sheaves should be level and square to the sheave on the generator shaft after tightening within ±1/16.

2 c. Tighten all sheave/hub assemblies to 108 in-lbs. d. Check the level of each sheave/hub assembly after tightening. Tightening the mounting bolts will move each sheave/hub assembly closer to the end of the shaft where it is mounted. All sheaves should be level and square to the sheave on the generator shaft after tightening within ±1/16. Use straight edge to set pump block sheave square and level with generator Figure 2 Figure 3 2. Install the belt tensioner and the serpentine belt. Pass the threaded end of the belt tensioner assembly through the base of the frame and secure with (1) 1/2-13NC SPHERICAL NUT. Do not tighten the nut yet. Install the belt tensioner assembly by inserting (1) 3/8-16NC X 1 LG hex head cap screw with (1) 3/8 REG split lock washer through the bottom of the frame and into the belt tensioner shaft passed through the belt tensioner assembly. Secure the belt tensioner mounting hex head cap screw with Loctite 242 or equivalent. Install the serpentine belt and tighten the spherical nut to between 6 and 10 ft-lbs torque. Do not exceed 10 ft-lbs. 3. See Section 3 for Proper tensioning of the serpentine belt Use straight edge to set engine sheave square and level with generator sheave TB034.doc Page 2 of 7 6/2/10 REV. B

Section 2 Sheave/Hub alignment with power pack installed on the chassis. 1. Loosen the belt tensioner. Loosen the tensioner bolt until the belt is loose. 2. Remove the belt guard.

3 Section 2 Sheave/Hub alignment with power pack installed on the chassis. 1. Loosen the belt tensioner. Loosen the tensioner bolt until the belt is loose. 2. Remove the belt guard. Remove the belt guard from the base of the power pack to allow access to the belt and sheaves. Use a notched straight edge to check sheave alignment. A notched straight edge, (see figure 4), must be used to check the alignment between the motor sheave and the generator sheave or the motor sheave and the pump block sheave. 6-3/4 in. 2 in. 1 in. 20 in. 3/8 in. Figure 4: Notched Straight Edge The notched straight edge must be at least 20 inches long with a notch cut from 6-3/4 to 8-3/4 from one end. The notch must be at least 3/8 deep. The straight edge will be used to check the alignment of the sheaves while the tensioner is installed. Figure 5 shows the proper use of the notched straight edge. Note: The power pack shown in Figure 5 is not installed on the chassis for clarity. The notch of the straight edge passes over the tensioner assembly The straight edge assures the sheaves are aligned properly Figure 5: Using the Notched Straight Edge TB034.doc Page 3 of 7 6/2/10 REV. B

The straight edge is more difficult to see when the power pack is installed. Figure 6 and Figure 7 demonstrate the alignment can still be measured.

Figure 7: View From Below the Chassis with the Belt Guard Removed All sheaves should be leveled and square to the sheave on the generator shaft within ±1/16.

4 The straight edge is more difficult to see when the power pack is installed. Figure 6 and Figure 7 demonstrate the alignment can still be measured. Avoiding the tensioner Measuring sheave alignment Figure 6: Using the Notched Straight Edge on an Installed Power Pack Measuring sheave alignment Avoiding the tensioner Figure 7: View From Below the Chassis with the Belt Guard Removed All sheaves should be leveled and square to the sheave on the generator shaft within ±1/16. Loosen, move and tighten the sheaves until they are aligned properly. Tighten all sheave/hub assemblies to 108 in-lbs torque. 3. See Section 3, Proper tensioning of the serpentine belt TB034.doc Page 4 of 7 6/2/10 REV. B

Section 3 Proper Tensioning of the Serpentine Belt - Without Tension Spring: (Early model TracStar 28/TracStar 250 machines & All TracStar 412/TracStar 618 machines with Yanmar diesel engines) 1.

5 Section 3 Proper Tensioning of the Serpentine Belt - Without Tension Spring: (Early model TracStar 28/TracStar 250 machines & All TracStar 412/TracStar 618 machines with Yanmar diesel engines) 1. After the power pack is installed to the chassis, confirm belt tensioner adjustment nut is tightened to 6-10 ft-lbs. 2. Start engine 3. If belt slipping or noise is detected, tighten the tension adjustment nut until slipping and/or noise is eliminated, but do not exceed 15 ft-lbs. 4. If belt slipping or noise continues at 15 ft-lbs, clean the belt to make sure no grease or oil is present on the contact surfaces between the belt and sheaves. Tighten cleaned belt until slipping or noise is eliminated, but do not exceed 15 ft-lbs. 5. If cleaned belt continues to slip or make noise, confirm sheave alignment is within ±1/ Install jam nut to lock spherical nut in place. 7. Tensioning procedure is complete Proper Tensioning of the Serpentine Belt - With Tension Spring: (Later model TracStar 28 and TracStar 250 machines) Figure 8: TracStar 28/TracStar 250 with Tensioning Spring TB034.doc Page 5 of 7 6/2/10 REV. B

1. Using a calibrated torque wrench and a 1 1/8 crows foot, tighten belt tension adjustment nut to 6-8 ft-lbs. (There is not enough room for a 1 1/8 socket to fit over adjustment nut.

6 1. Using a calibrated torque wrench and a 1 1/8 crows foot, tighten belt tension adjustment nut to 6-8 ft-lbs. (There is not enough room for a 1 1/8 socket to fit over adjustment nut. Therefore you must use a crows foot to tighten adjustment nut. However, the torque value on your torque wrench must be adjusted to accommodate for the additional lever length added to the torque wrench by using the crows foot.) To ensure proper torque values, orient crows foot axially with torque wrench, calculate desired torque wrench setting using the below equation, and tighten. T1 = Torque indicated by torque wrench when tightening adjustment nut to 6-8 ft-lbs (This will be the value you set the click-type torque wrench to or the value you read on dial and digital torque wrenches) T2 = Actual Torque applied to tension adjustment nut (will be 6-8 ft-lbs not to exceed 8 ft-lbs) L1 = Length of torque wrench with out crows foot or extension. (Measure from center of handle to center of drive nub) L2 = Length of crows foot. (Measure from center of drive nub to center of tension adjustment nut) T1 = T2 x (L1 / (L1+L2)) Example: L1 = 20 L2 = 2 T2 = 6-8 ft-lbs T1 = 6 ft-lbs x (20 / (20 +2 )) = 5.45 ft-lbs T1 = 8 ft-lbs x (20 / (20 +2 )) = 7.27 ft-lbs So, if you have a 20 torque wrench and a 2 extended crows foot then you want to set your torque wrench to ft-lbs to achieve 6-8 ft-lbs of torque on the tension adjustment nut 2. Start engine 3. If belt slipping or noise is detected, tighten the tension adjustment nut until slipping and/or noise is eliminated, but do not exceed 8 ft-lbs on adjustment nut. 4. If belt slipping or noise continues at 8 ft-lbs, clean the belt to make sure no grease or oil is present on the contact surfaces between the belt and sheaves. Tighten cleaned belt until slipping or noise is eliminated, but do not exceed 8 ft-lbs on adjustment nut. 5. If cleaned belt continues to slip or make noise, confirm sheave alignment is within ±1/16. TB034.doc Page 6 of 7 6/2/10 REV. B

7 6. Tighten locking bolt or locking nut on tension adjustment nut if applicable. 7. Tensioning procedure is complete. TB034.doc Page 7 of 7 6/2/10 REV. B

8 ENGINEERING STANDARD REVISION HISTORY LISTING NUMBER: TB034 DESCRIPTION: T28, T250, T412 & T618 POWER PACK SHEAVE/HUB ASSEMBLY, ALIGNMENT AND BELT TENSIONING PROCEDURE APPR. REV DATE BY DESCRIPTION OF REVISION SWB B 6/2/10 PSE EXPANDED ITEM 1 OF PROPER TENSIONING OF SERPENTINE BELT WITH TENSION SPRING TO INCLUDE TORQUE CONVERSION EQUATION TO ENSURE PROPER TIGHTENING OF SERPENTINE BELT.

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