drive belts 01 - justanswer

InspectionInspect all used drive belts (including those that arebeing replaced). See Fig. 1.

NOTE: For an installed belt, gently twist it about90 degrees so you can see the sidewalls andbottom.

Replace a belt if any problem is found. Replace bothbelts of a set, at the same time. Matched belts mustbe from the same manufacturer.

1. Inspect for glazing (shiny sidewalls). See Ref. A.Glazing is caused by friction created when aloose belt slips in the pulleys. It can also becaused by oil or grease on the pulleys.

2. Inspect for separating layers. See Ref. B. Oil,grease, or belt dressings can cause the belt tofall apart in layers. If engine parts are leaking,repair the leaks. Do not use belt dressings onany belt.

3. Check for jagged or streaked sidewalls. See Ref.C. These are the result of a foreign object (suchas sand or small gravel) in the pulley, or a roughpulley wall surface.

4. Check for tensile breaks (breaks in the cordbody). See Ref. D. Cuts in a belt are usuallycaused by large foreign objects in the pulley, orby prying or forcing the belt during installation orremoval.

5. On poly-V belts, check for uneven ribs. See Ref.E. Foreign objects in the pulley will erode theundercord ribs, causing the belt to lose its grip-ping power.

6. Inspect for cracks. See Ref. F. Small, irregularcracks are usually signs of an old belt.

When inspecting serpentine drive belts (used onDodge gasoline engines), look for cracks that runalong the ribs. See Fig. 2. These are not normal.Replace any belt with cracks running along theribs. Small cracks that run across the ribbed sur-face are normal.

f150010a

A

B

C

D

E

F11/21/94

A. GlazingB. Separating Layers

C. Streaked SidewallsD. Tensile Break

E. Uneven RibsF. Cracks

Fig. 1

Drive Belts 01.00Pulley and Drive Belt Inspection

Business Class Trucks Service Manual, Supplement 7, January 1995 100/1

7. Check all pulley bearings for roughness. Replacethe bearings if they’re rough.

8. Inspect all pulleys for foreign objects, oil, orgrease in the grooves. Use a non-flammablecleaning solvent to remove oils. Use a wire brushto remove rust, and a file to remove burrs.

9. Inspect the pulleys for wear on the inner walls.Hold a small straightedge against the inside ofthe pulley walls (Fig. 3) , or use your little fingeror fingernail to find grooves in the inner walls. Ifthere are any grooves, replace the pulley.

10. Check the alignment of pulleys. See Fig. 4. Usea thin straightedge that is longer than the longestspan between the pulleys. Place the straightedgeinto the V-grooves of two pulleys at a time. Thestraightedge should be parallel to the outeredges of the pulleys; if not, the pulleys are mis-aligned.

Pulley misalignment must not be more than 1.6mm for each 305 mm (1/16-inch for each foot) ofdistance between the centers of the pulleys.

If the pulleys are misaligned, adjust them or theirbrackets if possible. Replace bent or broken pul-leys, pulley brackets, or shafts.

11. Check all drive component mounting parts forloose fasteners, cracks, or other damage.Tighten loose fasteners. Repair or replacecracked or damaged brackets.

11/08/94 f010876

A

B

A. Normal Cracks, Belt OkayB. Not Normal Cracks, Replace Belts

Fig. 2

f150011a06/23/94

1

2

1. Groove in Pulley Wall2. Small Straightedge

Fig. 3

f150012a06/23/94

A

A. Side View of Misaligned Pulleys

Fig. 4

Drive Belts01.00Pulley and Drive Belt Inspection

Business Class Trucks Service Manual, Supplement 7, January 1995100/2

Replacement (See Fig. 1)

1. Loosen the belt tensioner.

1.1 Loosen the bolt (Ref. A) in the center ofthe belt tensioning assembly.

1.2 Loosen the pinch-bolt (Ref. B) in the ten-sioning assembly clamp.

1.3 Back off the adjusting nut (Ref. C) untilthe tensioning assembly is drawn up offthe air compressor belts.

2. Remove the belts from the air compressor andfan pulleys.

3. Inspect the pulleys and belts (even if installingnew belts) as instructed under "Pul-ley and Drive Belt Inspection, 100."

4. Loop the belts around the fan and air compres-sor pulleys.

5. Tighten the belts to the correct belt tension.

5.1 Tighten the adjusting nut (Ref. C) againstthe tensioning assembly clamp until theassembly is forced down against thebelts.

Check the belt tension while turning thenut, use your thumb to apply about 11 kg(25 lb) of force at the center of the long-est belt free-span until the belt deflectionequals one belt thickness per 305 mm (1ft) of pulley-center distance.

5.2 Install belt tension gauges at the center ofthe belts’ longest free-spans.

Turn the adjusting nut (Ref. C) againstthe tensioning assembly clamp to movethe assembly down and tension the belts.

Tighten the belts to 23 kg (50 lb).

IMPORTANT: Do not overtighten the belts;too much tension shortens belt and bearinglife.

5.3 Tighten the tensioning assembly clamppinch bolt (Ref. B) 80 N·m (59 lbf·ft).

5.4 Tighten the bolt through the tensioningassembly (Ref. A) 80 N·m (59 lbf·ft).

6. Check the belt tension again, and adjust ifneeded.

7. If installing new belts, operate the engine forabout 20 minutes, then check the belt tension. Allnew belts will lose tension after 20 minutes ofoperation. If necessary, adjust the belts to 23 kg(50 lb).

A

B C

06/16/93 f010343

Fig. 1

Drive Belts 01.00Air Compressor Belt Replacement, Mercedes-Benz

OM 366LA Engine

Business Class Trucks Service Manual, Supplement 0, June 1991 105/1

Replacement1. If the vehicle is equipped with air conditioning,

remove the refrigerant compressor belt. For in-structions, see Refrigerant Compres-sor Belt Replacement, Cummins B Series En-gine, 120 .

2. Insert a 3/8-inch breaker bar in the belt tensioner(see Fig. 1 ), and rotate the tensioner up and offthe belt (see Fig. 2 ).

3. Holding the belt tensioner up, remove the beltfrom the alternator pulley.

4. Slowly release the belt tensioner, and removethe breaker bar.

5. Lower the belt, and take it off the vibrationdamper.

6. Raise the belt, and take it off over the fan.

7. Inspect the pulleys and the belt (even if installinga new belt) as instructed under Pul-ley and Drive Belt Inspection, 100 .

8. Loop the belt around the fan and align it in therear channel of the fan pulley (see Fig. 2 ).

9. Loop the belt down and around the vibrationdamper pulley.

10. Insert a 3/8-inch breaker bar in the belt tensioner(see Fig. 2 ), and rotate the tensioner up whileinstalling the belt on the alternator pulley.

11. Slowly release the tensioner assembly onto thebelt. The tensioner automatically tightens the beltto the correct tension.

12. Remove the breaker bar from the tensioner.

13. The Cummins belt tensioner automatically ad-justs the fan and alternator belt to the correcttension. If the belt slips, repair or replace the ten-sioner. For instructions, see the Cummins ShopManual B Series Engines.

AUTOMATICBELTTENSIONER

ALTERNATOR

FANPULLEY

f01033401/06/93

Fig. 1

f010335

Rotate the belttensioner up andoff the belt.

10/29/93

Fig. 2

Drive Belts 01.00Fan and Alternator Belt Replacement, Cummins B

Series Engine



1. If the vehicle is equipped with air conditioning,remove the refrigerant compressor belt. For in-structions, refer to "Refrigerant Compres-sor Belt Replacement, Mercedes-Benz OM366LA Engine, 125."

2. If the vehicle is equipped with air brakes, removethe air compressor belt. For instructions, refer to"Air Compressor Belt Replacement, Mer-cedes-Benz OM 366LA Engine, 105."

3. Loosen the alternator mounting nut (Ref. C).

4. Back off the alternator adjusting rod nut (Ref. A).

5. Loosen the capscrew on the adjusting rod guide(Ref. B).

6. Rotate the alternator inward, and remove the beltfrom the alternator pulley.

7. Loop the belt down and off the vibration damperpulley.

8. Loop the belt up and off the fan pulley.

9. Inspect the pulleys and the belt (even if installinga new belt) as instructed under "Pul-ley and Drive Belt Inspection, 100."

10. Loop the belt around the fan and align it in thefront channel of the large, two-channel fan pulley.

11. Loop the belt down and around the vibrationdamper pulley. Align the belt in the front channelof the two large pulley channels.

12. To install the belt on the alternator, rotate the al-ternator inward along its adjusting rod.

13. Loop the belt onto the alternator pulley, and alignit in the front channel of the two alternator pulleychannels.

14. Tighten the belt by turning the adjusting rod nut(Ref. A) against the adjusting rod guide until thealternator rotates outward against the belt.

Check the tension while turning the nut, use yourthumb to apply about 11 kg (25 lb) of force at thecenter of the longest belt free-span until the beltdeflection equals one belt thickness per 305 mm(1 ft) of pulley-center distance.

15. Install a belt tension gauge at the center of thebelt’s longest free-span.

16. Turn the alternator adjusting rod nut (Ref. A)against the adjusting rod guide to move the alter-nator outward and tension the belt.

17. Tighten the belt to 75 kg (160 lb).

IMPORTANT: Do not overtighten the belt; toomuch tension shortens belt and bearing life.

18. Tighten the capscrew securing the adjusting rodguide (Ref. B) 80 N·m (59 lbf·ft).

19. Tighten the alternator mounting nut (Ref. C) 80N·m (59 lbf·ft).


21. If installing a new belt, operate the engine forabout 20 minutes, then check the belt tension. Allnew belts will lose tension after 20 minutes ofoperation.

If necessary, adjust the belt to 75 kg (160 lb).

Drive Belts 01.00Fan and Alternator Belt Replacement, Mercedes-Benz

OM 366LA Engine


f010336

A

B

C

ALTERNATOR

Rotate thealternatorinward toremove thebelt.

06/17/93

Fig. 1

Drive Belts01.00Fan and Alternator Belt Replacement, Mercedes-BenzOM 366LA Engine

Business Class Trucks Service Manual, Supplement 0, June 1991115/2


1. Loosen the refrigerant compressor mounting nuts(Ref. A).

2. Loosen the adjusting rod locknut (Ref. C), thenback off the adjusting rod nut (Ref. B) until thebelt can be removed.

3. Remove the belt. Don’t pry or roll it off the pul-leys.

4. Inspect the pulleys and the used belt (even ifinstalling a new belt) as instructed under "Pul-ley and Drive Belt Inspection, 100."

5. Loop the belt around the fan and the compres-sor, and align it in the front channels of the pul-leys.

6. Tighten the belt by turning the adjusting rod nut(Ref. B) against the compressor mount until thecompressor moves up.

Check the belt tension while turning the nut, useyour thumb to apply about 11 kg (25 lb) of forceat the center of the longest belt free-span untilbelt deflection equals one belt thickness per 305mm (1 ft) of pulley-center distance.


8. Tighten the compressor belt, by turning the ad-justing rod nut (Ref. B) against the compressormount to rotate the compressor up and awayfrom the fan pulley. Tighten the belt to 45 kg(100 lb).

IMPORTANT: Do not overtighten the belts; toomuch tension shortens belt and bearing life.

9. Tighten the adjusting rod jam nut (Ref. C)against the compressor mount 80 N·m (59 lbf·ft).

10. Tighten the compressor mounting nuts (Ref. A)80 N·m (59 lbf·ft).


12. If installing a new compressor belt, operate theengine for about 20 minutes, then check the belttension. All new belts will lose tension after 20minutes of operation.


f010342

Lower thecompressorto loosenthe belt.

A

BC

01/09/96

Fig. 1

Drive Belts 01.00Refrigerant Compressor Belt Replacement, Cummins

B Series Engine


Replacement (see Fig. 1)

1. Remove the refrigerant compressor belt.

1.1 Loosen the compressor mounting nuts(Ref. A), and back off the adjusting rodnut (Ref. D).

1.2 Loosen the nut on the adjusting rod guidebolt (Ref. B).

1.3 Lower the compressor by sliding theguide down along the adjusting rod. Re-move the belt from the compressor andvibration damper pulleys.

2. If removed, install and adjust the fan and alterna-tor belt. For instructions, refer to Fan and Alter-nator Belt Replacement, Mercedes-Benz OM366LA Engine, 115.

3. Inspect the pulleys and the belt (even if installinga new belt) as instructed under Pul-ley and Drive Belt Inspection, 100.

4. Loop the belt around the small vibration damperpulley.

5. Loop the belt around the compressor pulley, andalign it in the rear channel of the two pulleychannels.

6. Tighten the belt by turning the adjusting rod nut(Ref. D) against the adjusting rod guide until thecompressor rises against the belt.

Check the belt tension while turning the nut, useyour thumb to apply about 11 kg (25 lb) of forceat the center of the longest belt free-span untilbelt deflection equals one belt thickness per 305mm (1 ft) of pulley-center distance.


8. Turn the adjusting rod nut (Ref. D) against theadjusting rod guide to rotate the compressor up-ward and tension the belt.

9. For a regular V-belt, tighten the belt to 45 kg(100 lb). For a Powerband® V-belt ( see Fig. 2 ),tighten the belt to 64 kg (140 lb).

IMPORTANT: Do not overtighten the belt; toomuch tension shortens belt and bearing life.

10. Tighten the nut on the adjusting rod guide (Ref.B) 45 N·m (33 lbf·ft).

11. Tighten the refrigerant compressor mounting nuts(Ref. A) 45 N·m (33 lbf·ft).

12. Tighten the adjusting rod jam nut (Ref. C) 190N·m (140 lbf·ft).


14. If installing a new belt, operate the engine forabout 20 minutes, then check the belt tension. Allnew belts will lose tension after 20 minutes ofoperation.


f010344b12/12/94

A

B

CD

Fig. 1 f010032A B

10/10/94

A. Regular V-BeltB. Powerband® V-Belt

Fig. 2, Drive Belts, Cross Sections Shown

Drive Belts 01.00Refrigerant Compressor Belt Replacement,

Mercedes-Benz OM 366LA Engine



1. Loosen the four mounting capscrews that attachthe fan hub to the engine.

2. Loosen the adjusting rod to relieve tension fromthe belts.

3. Remove the belts by slipping them off the pulleysand working them over one fan blade at a time.On some vehicles, it may be necessary to re-move the fan blade. For instructions, refer to theengine cooling section of this manual. Don’t rollor pry the belts off the pulleys; the distance be-tween the pulley centers must be short enoughto allow belt removal without using force.

4. Inspect the pulleys and belts (even if installingnew belts) as instructed in "Pul-ley and Drive Belt Inspection."

5. Work the belts over the fan blades, one blade ata time. Install the belts on the pulleys withoutprying or rolling them into place.

6. While keeping the belts seated in the pulleygrooves, turn the adjusting rod to increase belttension. Use your thumb to apply about 25 lb (11kg) of force at the center of the longest belt free-span to check the tension while turning the ad-justing rod.

7. When belt deflection is about 1/2 to 3/4 inch (13to 19 mm), install a belt tension gauge at thecenter of the belt’s longest free-span.

8. Turn the adjusting rod to increase or decreasebelt tension. Final tension must be 60 to 80 lb(27 to 36 kg).


9. Tighten the fan hub mounting capscrews 75 to83 lbf·ft (100 to 112 N·m).

10. Check the belt tension and adjust it if needed.

11. Operate the engine for about 30 minutes (or 15miles), then check the belt tension. Check againafter 8 hours (or 250 miles). Adjust belt tensionas needed.

f010577

1

2

05/20/93

1. Adjusting Rod2. Mounting Capscrews

Fig. 1, Fan Belt Adjustment

Drive Belts 01.00Fan Belt Replacement, Detroit Diesel Series 50

Engine

Business Class Trucks Service Manual, Supplement 3, May 1993 130/1

Replacement (Refer to Fig. 1)

1. Back off the adjusting rod nut.

2. Loosen the adjusting rod guide mounting bolt.

3. Loosen the adjusting rod mounting bolt.

4. Loosen the alternator mounting bolt.

5. Turn the adjusting rod jam nut to rotate the alter-nator up and toward the engine. Turn the nut un-til the alternator is close enough to the engine toallow belt removal. Remove the belts by slippingthem off the pulleys and working them over onefan blade at a time. Don’t roll or pry the belts offthe pulleys; the distance between the pulley cen-ters must be short enough to allow belt removalwithout using force.

6. Inspect the pulleys and used belts (even if in-stalling new belts) as instructed in "Pul-ley and Drive Belt Inspection."

7. Work the belts over the fan blades, one blade ata time. Install the belts on the pulleys withoutprying or rolling them into place.


9. While keeping the belts seated in the pulleygrooves, turn the adjusting rod nut to rotate thealternator away from the engine and increasebelt tension. Turn the adjusting rod nut until finalbelt tension is 60 to 80 lb (27 to 36 kg).


10. Tighten the adjusting rod jam nut 176 N·m (130lbf·ft).

11. Tighten the alternator mounting bolt and the ad-justing rod mounting bolt 123 N·m (91 lbf·ft).

12. Tighten the adjusting rod guide mounting bolt 46N·m (34 lbf·ft).


f01065101/22/96

1

2

3

4

5

1. Adjusting Rod Jam Nut2. Adjusting Rod Nut3. Adjusting Rod Mounting Bolt4. Alternator Mounting Bolt5. Adjusting Rod Guide Mounting Bolt

Fig. 1, Alternator Belt Adjustment

Drive Belts 01.00Alternator Belt Replacement, Detroit Diesel Series 50

Engine



1. Loosen the compressor mounting bolt and thecompressor adjustment bolt that attach the com-pressor bracket to the engine.

2. Rotate the compressor downward, toward theengine to allow belt removal without using force.

3. Remove the belt without prying or rolling it off thepulleys.

4. Inspect the pulleys and belts (even if installingnew belts) as instructed in "Pul-ley and Drive Belt Inspection."

5. Loop the belt around the pulleys.


7. While keeping the belt seated in the pulleygrooves, rotate the compressor up and awayfrom the engine until the belt is tensioned 41 to45 kg (90 to 100 lb).


8. Tighten the compressor mounting and adjust-ment capscrews 46 N·m (34 lbf·ft).


f01065011/27/95

1

2

1. Compressor Mounting Bolt2. Compressor Adjustment Bolt

Fig. 1, Refrigerant Compressor Belt Adjustment

Drive Belts 01.00Refrigerant Compressor Belt Replacement, Detroit

Diesel Series 50 Engine


Replacement1. Place a 5/8-inch wrench over the pulley bolt on

the automatic belt tensioner, and turn the wrenchcounterclockwise to relax the belt tensioner.See Fig. 1.

2. Remove the engine accessory drive belt.

3. Inspect the pulleys and the drive belt (even ifinstalling a new belt) as instructed in Sub-ject 100 .

CAUTIONWhen installing a serpentine drive belt, route thebelt correctly. If the belt is not routed correctly,the water pump pulley may rotate in the wrongdirection, allowing the engine to overheat.

NOTE: If the pulley must be removed from theautomatic belt tensioner: The pulley bolt has lefthand threads.

4. Position the drive belt over all the pulleys exceptthe drive belt tensioner. For the correct belt rout-ing, see Fig. 2 and Fig. 3 .

5. Place a 5/8-inch wrench over the pulley bolt onthe automatic belt tensioner, and turn the wrenchcounterclockwise to relax the belt tensioner. Fin-ish installing the belt. See Fig. 1.

6. Correct drive belt tension is required for optimumperformance of belt-driven engine accessories. Ifthe specified belt tension is not maintained,check and repair the following:

Make sure the correct belt is installed.

Make sure the belt is routed correctly.

Check for worn bearings on all the engine acces-sory pulleys.

Check for a loose engine accessory pulley.

Check for misalignment between accessory pul-leys.

11/21/94 f010038

1

2

3

45

A

A. Turn counterclockwise to remove the belt.1. Idler Pulley2. Tensioner Pulley Bolt3. Tensioner Mounting Bolt4. Tensioner5. Tensioner Pulley

Fig. 1, Relieving Belt Tension

10/17/95 f011022

12

34

5

6

78

1. Air Injection Pump2. Automatic Tensioner3. Alternator4. Idler5. Water Pump6. Crank Pulley7. Refrigerant Compressor8. Power Steering Fluid Pump

Fig. 2, Drive Belt Routing with a RefrigerantCompressor

Drive Belts 01.00Accessory Drive Belt Replacement, Dodge

Magnum Engines

Business Class Trucks Service Manual, Supplement 32, September 2005 145/1

10/17/95

12

34

5

6

7

f011023

1. Air Injection Pump2. Automatic Tensioner3. Alternator4. Idler Pulley5. Water Pump6. Crank Pulley7. Power Steering Fluid Pump

Fig. 3, Drive Belt Routing without a RefrigerantCompressor

Drive Belts01.00Accessory Drive Belt Replacement, DodgeMagnum Engines

Business Class Trucks Service Manual, Supplement 32, September 2005145/2

Replacement1. Insert a 1/2-inch rachet drive into the square hole

in the belt tensioner, and turn the tensionerclockwise. See Fig. 1.

2. Remove the engine accessory drive belt.

3. Inspect the pulleys and the drive belt (even ifinstalling a new belt) as instructed in Sub-ject 100 .

CAUTIONWhen installing a serpentine drive belt, route thebelt correctly. If the belt is not routed correctly,the water pump pulley may rotate in the wrongdirection, allowing the engine to overheat.

4. Position the drive belt over all the pulleys exceptthe drive belt tensioner. For the correct belt rout-ing, see Fig. 1 .

5. Insert a 1/2-inch rachet drive into the square holein the belt tensioner, and turn the tensionerclockwise. See Fig. 1.

6. Position the tensioner against the belt, and re-move the rachet drive from the tensioner.

f01083103/06/95

A

A. Turn the belt tensioner clockwise, off the belt.

Fig. 1, Accessory Drive Belt, Caterpillar CFE SeriesEngine

Drive Belts 01.00Accessory Drive Belt Replacement, Caterpillar

CFE Series Engine

Business Class Trucks Service Manual, Supplement 32, September 2005 150/1

Replacement (See Fig.1or Fig.2)

1. Remove the belt.

1.1 Back off the adjusting nut. Loosen themounting nuts and the adjusting link boltjust enough to allow movement of thecompressor.

1.2 Push the loosened compressor towardthe drive pulley until the distance betweenthem is short enough to allow belt re-moval without using force.

1.3 Remove the belt, without prying or rollingit off of the pulleys.

2. Install the belt.

2.1 Inspect the pulleys and used refrigerantcompressor belt (even if a new belt is be-ing installed) as instructed in Sub-ject 100 .

11/20/95

A

A−A

A

f011031

2

3

4

5

1

5

3

2

1

1. Refrigerant Compressor2. Compressor Mounting Nut

3. Jam Nut4. Adjusting Nut

5. Adjusting Link Bolt

Fig. 1, Rotary-Type Compressor Installation


M11 Engine

Business Class Trucks Service Manual, Supplement 31, October 2004 155/1

2.2 Make sure the distance between the pul-leys is short enough to allow belt installa-tion without using force.

2.3 Install the belt on the pulleys without pry-ing or rolling it into place.

2.4 Back off the jam nut to the end of the ad-justing rod.

2.5 While keeping the belt seated in the pul-ley grooves, turn the adjusting nut againstthe adjusting link to increase belt tension.Use your thumb to apply about 11 kg (25lbs) of force at the center of the belt free-span to check the tension while turningthe nut. When belt deflection equals one

belt thickness per 305 mm (1 foot) ofpulley-center distance, stop.

3. Adjust the belt.

3.1 If not already done, back off the adjustinglink jam nut to the end of the adjustingrod, and loosen the mounting nuts andadjusting link bolt just enough to allowmovement of the compressor.

3.2 Install a belt tension gauge at the centerof the belt free-span.

3.3 Turn the adjusting nut to adjust the ten-sion to a reading of 59 kg (130 lbs) for anew belt, or 36 to 45 kg (80 to 100 lbs)

11/20/95 f011033

4

3

11

34

5

2

2

1. Refrigerant Compressor2. Compressor Mounting Nut

3. Adjusting Nut4. Jam Nut

5. Adjusting Link Bolt

Fig. 2, Piston-Type Compressor Installation

Drive Belts01.00Refrigerant Compressor Belt Replacement, CumminsM11 Engine

Business Class Trucks Service Manual, Supplement 31, October 2004155/2

for a used belt. A used belt is any beltthat has been in operation more than tenminutes.

IMPORTANT: Do not overtighten the belt;too much tension shortens belt life and bear-ing life.

3.4 Tighten the adjusting link jam nut 210N·m (155 lbf·ft).

3.5 Tighten the compressor mounting nuts 41N·m (30 lbf·ft), and the adjusting link bolt88 N·m (65 lbf·ft).

3.6 Check the belt tension, and adjust it ifneeded.

3.7 If a new refrigerant compressor belt wasinstalled, operate the engine for about 20minutes, then check the belt tension. Allnew belts will lose tension after 20 min-utes of operation.

3.8 If the refrigerant compressor belt tensionis not between 36 to 45 kg (80 and 100lbs), adjust the tension to 45 kg (100 lbs).


M11 Engine

Business Class Trucks Service Manual, Supplement 31, October 2004 155/3


1. Remove the belt.

1.1 Loosen the locknut that secures the idlerpulley to the fan bracket.

1.2 Turn the idler pulley adjustment capscrewuntil there is minimal distance betweenthe pulley centers.

1.3 Remove the fan belt by slipping it off ofthe pulleys and working it over one fanblade at a time. Don’t roll or pry the beltoff of the pulleys; the distance betweenthe pulley centers must be short enoughto allow belt removal without using force.


2.1 Inspect the pulleys and used fan belt(even if a new belt is being installed) asinstructed in Subject 100 .


2.3 Work the belt over the fan blades, oneblade at a time. Install the belt on the pul-leys without prying or rolling it into place.Be sure the ribs on the belt are seated inthe grooves on each pulley.

2.4 While keeping the belt seated in the pul-ley grooves, turn the idler pulley adjust-ment capscrew to increase the belt ten-sion. Use your thumb to apply about 11kg (25 lbs) of force at the center of thebelt free-span to check the tension whileturning the capscrew. When belt deflec-tion equals one belt thickness per 305mm (1 foot) of pulley-center distance,stop.

3. Adjust the belt.

3.1 If not already done, loosen the locknutthat secures the idler pulley to the fanbracket.

3.2 Install a belt tension gauge at the centerof the belt’s longest free-span.

3.3 Turn the idler pulley adjustment capscrewto increase or decrease belt tension, butdo not adjust the tension to the full valuewith the idler pulley adjustment capscrew;belt tension can increase when the idlerpulley locknut is tightened. Final tensionmust be 36 to 45 kg (80 and 100 lbs).


3.4 Tighten the idler pulley locknut 163 to 190N·m (120 to 140 lbf·ft).

3.5 Loosen the idler pulley adjustment cap-screw one-half turn, to prevent breakage.


3.7 If a new fan belt was installed, operatethe engine for about 20 minutes, thencheck the belt tension. All new belts willlose tension after 20 minutes of opera-tion.

3.8 If the fan belt tension is not between 36to 45 kg (80 and 100 lbs), adjust the ten-sion.

12

3 3

3

4 5

11/20/95 f150560

1. Adjusting Screw2. Adjusting Screw Jam Nut3. Alternator Mounting Fastener4. Idler Pulley Adjustment Capscrew5. Idler Pulley

Fig. 1, Fan and Alternator Belt Installation

Drive Belts 01.00Fan Belt Replacement, Cummins M11 Engine



1. Remove the belt.

1.1 Loosen the three mounting fasteners justenough to allow movement of the alterna-tor.

1.2 Loosen the adjusting screw jam nut.

1.3 Turn the adjusting screw counterclock-wise, backing off the alternator toward thedrive pulley far enough to allow belt re-moval without using force.

1.4 Remove the belt, without prying or rollingit off of the pulleys.


2.1 Inspect the pulleys and used alternatorbelt (even if a new belt is being installed)as instructed in Subject 100 .


2.3 Install the belt on the pulleys without pry-ing or rolling it into place. Be sure the ribson the belt are seated in the grooves oneach pulley.

2.4 While keeping the belt seated in the pul-ley grooves, turn the adjusting screwclockwise to increase the belt tension.Use your thumb to apply about 11 kg (25lbs) of force at the center of the belt free-span to check the tension while turningthe adjusting screw. When belt deflectionequals one belt thickness per 305 mm (1foot) of pulley-center distance, stop.

3. Adjust the belt.

3.1 If not already done, loosen the adjustingscrew locknut, and loosen the threemounting fasteners, just enough to allowmovement of the alternator.

3.2 Install a belt tension gauge at the centerof the belt free-span.

3.3 Turn the adjusting screw to adjust thetension to a reading of 36 to 45 kg (80and 100 lbs).


3.4 Tighten the adjusting screw locknut 129N·m (95 lbf·ft).

3.5 Tighten the alternator mounting fastener81 N·m (60 lbf·ft), the adjusting block nut47 N·m (35 lbf·ft), and the adjusting armbolt 75 N·m (55 lbf·ft).


3.7 If a new alternator belt was installed, op-erate the engine for about 20 minutes,then check the belt tension. All new beltswill lose tension after 20 minutes of op-eration.

3.8 If the alternator belt tension is not 36 to45 kg (80 and 100 lbs), adjust the ten-sion.

12

3 3

3

4 5

11/20/95 f150560

1. Adjusting Screw2. Adjusting Screw Jam Nut3. Alternator Mounting Fastener4. Idler Pulley Adjustment Capscrew5. Idler Pulley

Fig. 1, Alternator and Fan Belt Installation

Drive Belts 01.00Alternator Belt Replacement, Cummins M11 Engine


This subject contains the following tables:

• Fastener Torques, Cummins B Series Engine

• Fastener Torques, Mercedes-Benz OM 366LAEngine

• Drive Belt Tensions, Cummins B Series Engine

• Drive Belt Tensions, Mercedes-Benz OM366LA Engine

Description Grade Size Torque N·m (lbf·ft)

Refrigerant Compressor Mounting Nuts 5 1/2–13 80 (59)

Refrigerant Compressor Adjusting Rod Jam Nut 5 1/2–13 80 (59)

Table 1, Fastener Torques, Cummins B Series Engine

Description Grade Size Torque N·m(lbf·ft)

Alternator Adjusting Rod Guide Capscrew 8 1/2–13 80 (59)

Alternator Mounting Nuts 8 1/2–13 80 (59)

Air Compressor Tensioning Assembly Clamp Pinch Bolt 8.8 M12 x 1.5 80 (59)

Air Compressor Tensioning Assembly Bolt 8.8 M12 80 (59)

Refrigerant Compressor Adjusting Rod Guide Bolt Nut 8 3/8–16 45 (33)

Refrigerant Compressor Mounting Nuts 8 3/8–16 45 (33)

Refrigerant Compressor Adjusting Rod Jam Nut 5 5/8–18 190 (140)

Table 2, Fastener Torques, Mercedes-Benz OM 366LA Engine

Description Tension kg (lb)

Refrigerant Compressor Belt 45 (100)

Table 3, Drive Belt Tensions, Cummins B SeriesEngine

Description Tension kg (lb)

Refrigerant Compressor Belt 45 (100)

Air Compressor Belts 23 (50)

Fan/Alternator Belt 75 (160)

Table 4, Drive Belt Tensions, Mercedes-Benz OM366LA Engine

Drive Belts 01.00Specifications


drive belts 01 - justanswer

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