102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12BĆ1 Page

SECTION 12B

FRONT AXLE SUSPENSION

CONTENTS OF THIS SECTION SUBJECT PAGE General Description...... 12BĆ1 Components...... 12BĆ1 Maintenance...... 12BĆ1 Torque Specifications...... 12BĆ8 Specifications...... 12BĆ9 Service Tools...... 12BĆ9

GENERAL DESCRIPTION assembly. Periodic inspections of these fasteners, with special attention to their specific torque, should be The D series front axle suspension system is typical undertaken. with any basic or optional steering axle configurations. Furthermore, the basic suspension system can be alternately equipped for heavy duty service operations. WARNING

COMPONENTS Avoid accessing suspension components from outside coach wheel well areas. Unintentional The typical front suspension system (Figure 1 & 2) is Actuation of the height control valves with fully composed of the following: Left and right suspension inflated air springs could result in serious injury. support, with the latter having provisions for attachment Always block the coach body adequately during of the transverse radius rod. One set of each upper and any inspections and/or repairs in these areas. lower radius rods and one transverse rod, along with the antiĆsway bar, stabilize the front axle assembly. The basic front suspension mounts two (prior to June 1999 RADIUS RODS production) or four (effective with June 1999 production) The radius rods maintain the correct axle location. The heavyĆduty double acting shock absorbers. Two upper and lower radius rods maintain the axle rollingĆlobe type air springs support the front chassis, longitudinally. The single transverse radius rod maintains with one height control valve governing air spring the axle both longitudinally and laterally and limits vehicle pressure. roll. The following instructions apply to radius rods used at the front axle. Radius rods are mounted at both ends MAINTENANCE through rod eye bushing. These bushings are made of rubber and have a steel inner and outer sleeve. New This section will address the specific maintenance bushings should be used when rods are replaced. requirements of the front suspension system and its components. No specific periodic maintenance needs Inspection are required for the front suspension system, therefore, MCI recommends checking radius rod bushings at only procedures for disassembly and removal of 50,000 mile (80,450 km) intervals to determine if the serviceable components will be discussed. bushings require replacing due to wear. The Magnaflux All serviceable suspension components are process is recommended for detecting cracks in radius mechanically fastened to the coach chassis and axle rods. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12BĆ2 Page

SHOCK ABSORBER

AIR SPRING

AXLE

SWAY BAR

UPPER RADIUS ROD

LOWER RADIUS ROD 9267 Figure 1. Two Shock Front Suspension (Prior to August 1999 Production) 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12BĆ3 Page

Air Spring

Additional Shocks (Set of 2)

Upper Radius Rod

Shocks (Set of 2)

Tie Rod Arm

Sway Bar Lower Radius Rod

Figure 2. Four Shock Front Suspension (Effective with August 1999 Production)

NOTE: Do not rely on visual inspection for determining ă4.ăRemove radius rod from mounting pins or the serviceability of radius rods or their bushings. brackets. Bushing Removal To check the bushings for wear, place the coach over a Radius rod bushing removal and installation tools are pit, grab each rod in both hands and check for free play. If shown on the Service Tools" page of this subĆsection. a movement of 1/32 inch or more can be detected, the bushings need to be replaced. All bushings for the transverse, upper and lower radius rods use removal tool number 20Ć321 and installation tool number 20Ć322. Additionally, a 3 inch long piece of 4 inch NOTE:ăIf worn bushings are not replaced, excessive nominal size (schedule 80) pipe will be needed as a press wear to other suspension components and tires will spacer. result. NOTE:ăAbove mentioned tools are to be used in conjunction with a hydraulic press in the removal and Radius Rod Removal installation procedures that follow. Follow the procedure's steps in order. ă1.ăElevate and block the coach body as outlined in Section 3G of this manual. Elevate and block the front CAUTION axle at the correct ride height (refer to Figure 4). ă2.ăFlatten locking plate tabs and unfasten nuts. Support or block components as needed in Remove capscrew and nut holding the retaining accordance with good hydraulic press bushings in place (lower rear rods). operating procedures. ă3.ăRemove radius rod end plates from anchor pins. ă1.ăPlace radius rod eye and bushing on top of pipe Remove the four (4) retaining half bushings (lower rear spacer in press (Figure 3). rods). ă2.ăPlace the removal tool on top of radius rod eye. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12BĆ4 Page

ă3.ăApply pressure with the press until the bushing drops out of the eye and into the pipe. The tool will drop BUSHING INSTALLATION out also. TOOL ă4.ăRemove the radius rod, bushing and pipe from the PRESS press.

RADIUS ROD

RADIUS ROD BUSHING

PIPE STAND BUSHING REMOVAL TOOL 8069 Figure 4. Installing Radius Rod Bushing

RADIUS ROD W/BUSHING

PIPE STAND PRESS 1 11" 2 RIDE 8068 HEIGHT Figure 3. Removing Radius Rod Bushing

2

Bushing Installation 3

ă1.ăCoat exterior sleeve of new bushing with 5 NeverĆSeize or equivalent antiĆseize compound. 4 NOTE: AntiĆseize compounds are applied only to the bushing's inner and outer metal sleeves. 1. AIR SPRING 4. LOWER RADIUS ROD 2. SHOCK ABSORBER 5. AXLE 3. UPPER RADIUS ROD 8070 ă2.ăPlace pipe, radius rod, bushing and appropriate Figure 5. Front Ride Height

installation tool in press (Figure 4). ă3.ăApply pressure to top of tool until bushing is CAUTION centered inside the radius rod eye. ă4.ăRemove tool, radius rod and pipe from press. When reinstalling radius rods, make sure that the rod is centered on the bushing before tightening retaining nuts. The radius rod should Radius Rod Installation be held in a centered position with a pry bar against the coach body or axle while the stud NOTE: Improper ride height will preĆload rubber nuts are tightened. bushings and shorten service life. ă3.ăPlace radius rod on mounting pins, or in bracket (lower rear rods). ă4.ăInstall end plate onto anchor pins, or retaining ă1.ăSet coach at the correct ride height (Figure 5). bushing (lower rear rods). ă2.ăApply a thin coating of antiĆseize to interior sleeve ă5.ăReplace the studs (if removed), washers, of newly installed bushing. lockstraps and nuts. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12BĆ5 Page

ă6.ăTorque mounting nuts to 150Ć165 ftĆlbs Many technicians find it difficult to differentiate (203.4Ć223.7 N.m). between a misting shock and true leaker which needs to ă7.ăRebend lockstrap tabs. be replaced. A leaker will show clear signs of fluid leaking in streams from the upper seal. these streams can most SHOCK ABSORBERS easily be seen when the shock is fully extended, and one The main function of the shock absorber is to regulate inspects as far up the main body of the shock as possible. the vehicle axle travel by dampening the rebound motion. Fluid contained within the shock absorber is forced through a restricted valve opening by a piston when the suspension air springs are flexed. The shock absorbers are heavyĆduty doubleĆacting type. They are of welded construction and cannot be repaired. Defective shock absorbers must be replaced with new units. Shock Inspection A visual inspection of the shock absorbers should be included with the suspension inspection. A road test may also determine if the shock absorbers need service (Figure 6). Points to inspect include: ă1.ăshock absorber body for physical damage of evidence of oil leakage ă2.ăshock absorber rod for bending, nicks and scratches, or evidence of oil leakage (a light film of oil on the rod is normal) ă3.ărubber bushings for deterioration. Leaking and Misting Misting shocks are often misĆdiagnosed as failures. Misting is the process whereby very small amounts of shock fluid evaporate at high operating temperatures through the upper seal of the shock. When the mist" reaches the cooler outside air, it condenses and forms a film on the outside of the shock body. When mixed with road debris and dust, a grime will often coat the entire body of the shock. Misting is a perfectly normal and necessary function of the shock. The fluid which Figure 6. Visual Shock Check evaporates through the seal area helps to lubricate prolong the life of the seal.( Figure 7) 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12BĆ6 Page

parts rattling inside. Rattling of metal parts can indicate that the shock has an internal failure. Shock Removal ă1.ă Unfasten and remove hex nut, retaining washers and rubber bushings from both ends of the shock. ă2.ăCollapse shock and withdraw from the upper mount, then lift stud end out of mounting hole in the suspension support. Shock Installation CAUTION

New rubber mounting bushings should be used when shock absorbers are replaced. Improper bushing preĆload may result from reuse of old bushings. ă1.ăWire shock in collapsed position for installation. ă2.ăApply antiĆseize compound (P/N 21Ć7512Ć7) to the threads of the lower shock mount. NOTE: Place inner/upper retaining washers over Figure 7. Misting vs Leaking bushings before installing shocks.ă

ă3.ăInstall upper stud end into its mount, and position lower stud end over mounting hole and cut retaining wire. Heat Test ă4.ăInstall outer/lower retaining washer and hex nut Shock absorbers function at temperatures ranging and torque to attain proper bushing preĆload (Figure 8). from ambient to 350'F. A shock's role is to dampen the oscillation of the coach's springs. It does this by AIR SPRINGS transforming the energy produced by the spring to heat The front axle suspension's air springs should be and dissipating it. As a result the shock should be slightly inspected at regular intervals for any wear marks or warm to hot to the touch after normal use. cracks. If ride deterioration is experienced and there is suspicion that a shock has failed internally, which is visually undetectable, perform the following "SHOCK HEAT TEST" within a few minutes of operating the equipment: ă1.ăDrive the vehicle at moderate speeds for at least 15 minutes. ă2.ăWithin a few minutes of driving the vehicle, touch each shock absorber carefully on its body below the dust CUPPED WASHER cover or tube, after first touching a nearby part of the RUBBER BUSHING chassis to establish a reference ambient temperature of the metal. SHOCK MOUNTING ă3.ăAll shock absorbers should be warmer than the 1.72" (44.2mm) BUSHING chassis. Suspect a failure in any shock absorber that is WASHER noticeably cooler than it's mate on the other end of the NYLOC NUT axle. Different temperatures from axle to axle do not indicate failures, but cooler temperatures on any one axle 9329 does warrant removal and examination of the cooler Figure 8. Shock Installation shock absorber. ă4.ăTo inspect for an internal failure, remove and Air Spring Removal shake the suspected shock. Listen for the sound of metal ă1.ăTurn battery switch to OFF. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12BĆ7 Page

ă2.ăBlock front axle at the correct ride height. NOTE: Effective with unit #45959 a new sway bar is ă3.ăRemove the front axle wheels. used. The sway bar incorporates new link assemblies, cushions and stop collar type cushion clamps (Figure ă4.ăRelease air from the front suspension air springs 6). via the leveling valve. ă5.ăDisconnect the air spring's lower retainer from Removal suspension support mounting plate. ă1.ăTurn battery disconnect switch to OFF". ă6.ăDisconnect and remove air supply line, fitting and ă2.ăBlock front axle at the correct ride height, and hex nut (stud side) from top retainer. remove front wheels. ă7.ăCollapse air spring bellows and remove. ă3.ăUnfasten and remove the flanged hex nuts securing the sway bar links to support and bar. Tap the Air Spring Installation ends of link from their mounting holes. ă1.ăInstall air spring assembly in reverse order of the ă4.ăUnfasten and remove the cushion DĆclamps from removal procedure. bogie leg crossmember and remove sway bar. Installation ANTIĆSWAY BAR ă1.ăReinstall sway bar in reverse order of Removal" The antiĆsway bar connects the suspension support procedure. Torque the flanged nuts to 165Ć170 ftĆlbs assembly to the coach bogie legs. MCI recommends (224Ć230 Nm), back off and retorque to 95Ć100 ftĆlbs periodic inspection of the sway bar bushings and links at (129Ć136 Nm) and the DĆclamp nuts to 80Ć90 ftĆlbs 50,000 mile (80,450 km) intervals. (108Ć122 Nm).

DĆClamp Nut Flanged Nuts (8 Locations) (4 Locations)

C0669

Figure 9. Sway Bar Assembly 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12BĆ8 Page

3

7

6

8

2 5

1

4 9267 Figure 10. Torque Chart (Two Shock Version Shown / Prior to August 1999)

TORQUE SPECIFICATIONS ă1.ăSuspension Supports To Axle Mounting Hex Nuts (Rod Retainer)...... 175Ć200 ftĆlbs (237Ć271 N·m) ă2.ăRadius Rod Retainer Hex Nuts (Lower Rear)...... 350Ć390 ftĆlbs (474Ć528 N·m) ă3.ăAir Spring Mounting Hex Nuts...... max. 25 ftĆlbs (34 N·m) ă4.ăRadius Rod Mounting Stud Hex Nuts (Upper & Lower) ...... 150Ć165 ftĆlbs (203Ć223 N·m) ă5.ăStabilizer Link Hex Nuts...... 95Ć100 ftĆlbs (128Ć135 N·m) ă6.ăStabilizer Bar Retainer Clamp Hex Nuts...... 80Ć90 ftĆlbs (108Ć122 N·m) ă7.ăStabilizer Bar Support To Axle Mounting Hex Nuts...... 160Ć190 ftĆlbs (216Ć257 N·m) ă8.ăRadius Rod Mounting Pin Studs...... 60Ć65 ftĆlbs (81Ć88 N·m) 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12BĆ9 Page

SPECIFICATIONS SUSPENSION AIR SPRING Manufacturer ...... Goodyear Part Number ...... 12LĆ1Ć140 Type ...... Rolling Lobe Size ...... 12.8 inches (325 mm) SHOCK ABSORBER Manufacturer ...... Gabriel Part Number ...... 12LĆ5Ć96 RADIUS RODS Manufacturer ...... Clevite Part Number ...... (Upper & Lower) 12LĆ5Ć61 Part Number ...... (Transverse) 12L-5-62 SWAY BAR ASSEMBLY Make ...... Hellwig Part Number ...... 12LĆ5Ć83

SERVICE TOOLS

MANY OF THE TOOLS LISTED IN THIS SECTION ARE SPECIALLY DESIGNED TO MEET THE NEEDS OF VARIOUS SERVICE OPERATIONS. THEY ARE AVAILABLE FOR PURCHASE THROUGH MOTOR COACH INDUSTRIES, SERVICE PARTS DIVISION AND UNIVERSAL COACH PARTS OR, WHERE PRACTICAL, MAY BE MANUFACTURED BY THE OPERATOR. IN THESE CASES, DRAWINGS ARE AVAILABLE UPON REQUEST.

3.560 in dia.

2.45 in 4.00 in dia.

3.53 in

20Ć321 20Ć322 Removal Tool for Radius Rod Bushing 12J-1-133 Installation Tool for Radius Rod Bushing 12J-1-133 9288