102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ1 Page

SECTION 12C DRIVE AXLE SUSPENSION

CONTENTS OF THIS SECTION

SUBJECT PAGE General Description...... 12CĆ1 Components...... 12CĆ1 Maintenance...... 12CĆ1 Torque Specifications...... 12CĆ8 Specifications...... 12CĆ9 Service Tools ...... 12C-10

GENERAL DESCRIPTION needs for the rear suspension system, therefore, only procedures for disassembly and removal of serviceable The D series rear axle suspension system is typical components will be discussed. with basic or optional drive axle configurations. There are All serviceable suspension components are some minor differences in the attachment of the radius mechanically fastened to the coach chassis and axle rods between the specific models, but otherwise, the assembly. A periodic inspection of these fasteners the installations are similar. The 102DL3's radius rods attach condition of torque seals and lock straps on 102D3 to the front of the chassis, whereas the 102D3's radius coaches, with special attention to their specific torque, rods attach at the rear. should be undertaken.

COMPONENTS WARNING The typical rear suspension systems (Figure 1 & 2) are composed of the following: Left and right suspension supports assemblies, structure on 102D3 models having Avoid accessing suspension components from provisions for attaching the shock absorbers with outside coach wheel well areas. Unintentional studĆdesign upper mounts and structure on 102DL3 Actuation of the height control valves with fully models having provisions for attaching shock absorbers inflated air springs could result in serious injury. with eyering upper mounts. One set each of upper Always block the coach body adequately during (diagonally mounted) and lower (longitudinally mounted) any inspections and/or repairs in these areas. radius rods stabilize the rear axle assembly. Four heavy duty shock absorbers, along with four rollingĆlobe type air RADIUS RODS springs, (of one piece design), support the rear The lower radius rods maintain the axle longitudinally. suspension. Two left and right height control valves The two upper radius rods are offset, forming a wishĆ regulate pressure in the rear axle air springs. bone, and maintain the axle both longitudinally and laterally. The upper radius rods also act to limit vehicle roll MAINTENANCE while turning and are subject to higher loads. The following instructions apply to radius rods used on This section will address the specific maintenance the rear drive axle suspension. Radius rod ends are requirements of the rear suspension system and its mounted via mounting tabs on the rubberized saddle components. There are no specific periodic maintenance pins that act as rod bushings. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ2 Page

RH SUPPORT AIR SPRING ASSEMBLY MOUNTING PLATE

SHOCK

UPPER DRIVE AXLE RADIUS RODS

AIR SPRING

BUMPER

L&R SUPPORT ASSEMBLY TIE RODS LH SUPPORT ASSEMBLY

8085

Figure 1. Rear Suspension 102DL3

Inspection NOTE:ă If worn bushings are not replaced, excessive wear to other suspension components and tires will NOTE: Do not rely on visual inspection for determining result. the serviceability of radius rod and their bushings.

MCI recommends checking radius rod bushings at Radius Rod Removal 50,000 mile (80,450 km) intervals to determine if the ă1.ăElevate and block the coach body. Elevate and bushings require replacing due to wear. The Magnaflux block the rear axle at the correct ride height as outlined in process is recommended for detecting cracks in the Section 3G of this manual. radius rods. ă2.ăRemove the drive axle wheels. Due to the mounting configuration of the radius rods to the rear suspension supports and rear bogie assembly, ă3.ăUnfasten and remove the upper radius rods from special attention should be placed on the inspection of the axle's top mounting bracket shown in Figures 1 and 2. these rods and their saddle pin bushings. ă4.ăUnfasten and remove the remaining radius rods. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ3 Page

SHOCK RH SUPPORT ASSEMBLY AIR SPRING

AIR SPRING MOUNTING PLATE UPPER DRIVE AXLE RADIUS RODS

BUMPER L&R SUPPORT ASSEMBLY TIE RODS

LH SUPPORT ASSEMBLY

9290

Figure 2. Rear Suspension 102D3

Bushing Removal ă1.ăPlace radius rod eye with saddle pin bushing on Radius rod bushing removal and installation tools are top of spacer pipe in press (Figure 3). shown on the SERVICE TOOLS" page at the end of this ă2.ăPlace the round bar on top of radius rod saddle subĆsection. pin's mounting tab. Rear axle radius rod bushings require the use of a ă3.ăApply pressure with the press until the bushing special sleeve installation tool 20Ć389. The replacement drops out of the eye and into the pipe. The round bar will saddle pin bushings have metal outer sleeves. drop out also. Additionally, a 2Ćinch diameter round bar, (for removing ă4.ăRemove the radius rod, bushing and round rod pins), and a 7Ćinch long piece of 3Ćinch nominal size from press. (schedule 80) pipe will be needed as a press spacer. ă5.ăClean the remainder of the bonded rubber residue NOTE:ăAll tools are to be used in conjunction with a from inside diameter of the rod eye. hydraulic press in the removal and installation procedures that follow. Bushing Installation ă1.ăCoat exterior of new saddle pin bushing with NeverĆSeize compound or equivalent antiĆseize CAUTION compound.

Support or block components in accordance NOTE:ăAntiĆseize compounds are applied only to the with good hydraulic press operating procedures. bushing's outer metal sleeve. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ4 Page

ă4.ăRemove tool, radius rod and pipe from press. BUSHING REMOVAL TOOL Radius Rod Installation

ă1.ăSet coach at the correct ride height (Figure 7). ă2.ăApply a thin coating of antiĆseize on all mounting surfaces of the radius rod saddle pins and reinstall. RADIUS ROD W/BUSHING NOTE: AntiĆseize is applied only to saddle pin bushing's tabĆtoĆchassis mating points and fasteners.

PIPE STAND PRESS ă3.ăInstall fasteners with hex nuts out and torque to 220 ftĆlbs (300 N.m). 8068 SHOCK ABSORBERS Figure 3. Bushing Removal The main function of the shock absorber is to regulate ă2.ăPlace radius rod, bushing and appropriate sleeve the vehicle axle travel by dampening the rebound motion. installation tool in press, centered on top of spacer pipe Fluid contained within the shock absorber is forced through a restricted opening by a piston when the (Figure 4). suspension air springs are flexed. The shock absorbers are heavyĆduty doubleĆacting BUSHING INSTALLATION type. They are of welded construction and cannot be TOOL repaired. Defective shock absorbers must be replaced PRESS with new units. Some early models 102DL3 shock absorbers have stud type mountings at both shock ends. All other models RADIUS ROD are fitted with shocks that have a stud type mount at the bottom and an eyeĆring type mount at the top for RADIUS ROD BUSHING horizontal attachment to bogie assembly. Follow the applicable procedures for removing shock absorbers. PIPE STAND Shock Inspection 8069 A visual inspection of the shock absorbers should be Figure 4. Bushing Installation included with the suspension inspection. A road test may also determine if the shock absorbers need service NOTE:ăCorrect Orientation of the saddle pin tabs in (Figure 5). relationship to their mounting must be made before Points to inspect include: pressing pin into rod eye. ă1.ăshock absorber body for physical damage of evidence of oil leakage ă3.ăApply pressure to top of tool until bushing is seated inside the radius rod eye. ă2.ăshock absorber rod for bending, nicks and scratches, or evidence of oil leakage (a light film of oil on NOTE:ăCutĆouts are provided in the sleeve installation the rod is normal) tool for determining correct seating. ă3.ărubber bushings for deterioration. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ5 Page

Figure 6. Misting vs Leaking

Heat Test Shock absorbers function at temperatures ranging from ambient to 350'F. A shock's role is to dampen the oscillation of the coach's springs. It does this by transforming the energy produced by the spring to heat Figure 5. Visual Shock Check and dissipating it. As a result the shock should be slightly warm to hot to the touch after normal use. 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: Leaking and Misting ă1.ăDrive the vehicle at moderate speeds for at least Misting shocks are often misĆdiagnosed as failures. 15 minutes. Misting is the process whereby very small amounts of ă2.ăWithin a few minutes of driving the vehicle, touch shock fluid evaporate at high operating temperatures each shock absorber carefully on its body below the dust through the upper seal of the shock. When the mist" cover or tube, after first touching a nearby part of the reaches the cooler outside air, it condenses and forms a chassis to establish a reference ambient temperature of film on the outside of the shock body. When mixed with the metal. road debris and dust, a grime will often coat the entire ă3.ăAll shock absorbers should be warmer than the body of the shock. Misting is a perfectly normal and chassis. Suspect a failure in any shock absorber that is necessary function of the shock. The fluid which noticeably cooler than it's mate on the other end of the evaporates through the seal area helps to lubricate axle. Different temperatures from axle to axle do not prolong the life of the seal.( Figure 6) indicate failures, but cooler temperatures on any one axle Many technicians find it difficult to differentiate does warrant removal and examination of the cooler between a misting shock and true leaker which needs to shock absorber. be replaced. A leaker will show clear signs of fluid leaking ă4.ăTo inspect for an internal failure, remove and in streams from the upper seal. these streams can most shake the suspected shock. Listen for the sound of metal easily be seen when the shock is fully extended, and one parts rattling inside. Rattling of metal parts can indicate inspects as far up the main body of the shock as possible. that the shock has an internal failure. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ6 Page

Shock Removal (Stud Mount) ă2.ăCollapse shock and withdraw from the upper ă1.ă Unfasten and remove hex nut, retaining washers mount, then lift stud end out of mounting hole in the and rubber bushings from both ends of the shock. suspension support.

1 6 1 1 2

11" RIDE HEIGHT 2 (27.9 cm) 1.AIR SPRING 2 2.SHOCK ABSORBERS 3.SUSPENSION SUPPORT 3 3 5 4.LOWER RADIUS ROD 5 5.UPPER RADIUS ROD 4 4 6.AXLE BUMPER 7.AXLE 7 7 8.JACKING POINT

8 8 8071 Figure 7. Rear Suspension (102DL3)

Shock Removal (EyeĆring Mount) ă4.ăInstall outer/lower retaining washer and hex nut ă1.ăUnfasten and remove hex nut, retaining washers and torque to attain proper bushing preĆload (Figure 8). and slide shock and conical bushings off shock mounting stud. AIR SPRINGS The rear axle suspension's air springs should be ă2.ăFollow Step 1 of the previous procedure for inspected at regular intervals for any wear marks or removal of bottom shock mount, then collapse shock and cracks. remove from suspension support. Shock Installation (Stud Mount) CAUTION

New rubber mounting bushings should be used when shock absorbers are replaced. Improper bushing preĆload may result from reuse of old bushingsă ă1.ăWire shock in collapsed position for installation. ă2.ăApply antiĆseize compound (P/N 21Ć7512Ć7) to the threads of the lower shock mount. 1.74" (44.2mm) NOTE: Place inner/upper retaining washers over bushings before installing shocks.ă

ă3.ăInstall upper stud or eyeĆring end into its mount, and position lower stud end over mounting hole and cut 9329 retaining wire. Figure 8. Shock Installation 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ7 Page

Air Spring Removal ă5.ăDisconnect the air spring's lower retainer from suspension support mounting plate. ă1.ăTurn battery switch to Off". ă6.ăDisconnect and remove air supply line, fitting and ă2.ăBlock rear axle at the correct ride height as hex nut (stud side) from top retainer. outlined Section 3G of this manual. ă7.ăCollapse air spring bellows and remove. ă3.ăRemove the rear axle wheels. Air Spring Installation ă4.ăRelease air from the rear drive suspension's air ă1.ăInstall air spring assembly in reverse order of the springs via the leveling valve. removal procedure. 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ8 Page

TORQUE SPECIFICATIONS 2 1. 220 ft. lbs 2. 25 ft. lbs. max. 3. 25 ft. lbs. max. 4. 220 ft. lbs. 5. 100 ft. lbs. 2 4 5 5 1 1 1 1 2 1 1 1 1 3 4 1 1 5 5 1 8086 2 3 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ9 Page

SPECIFICATIONS SUSPENSION AIR SPRING Manufacturer ...... Goodyear, Firestone Part Number ...... 12LĆ1Ć140 Type ...... Rolling Lobe Size ...... 12.8 inches (325 mm) SHOCK ABSORBER Manufacturer ...... Delco, Gabriel Part Number...... 12LĆ5Ć88 (Stud & EyeĆring)

RADIUS RODS Manufacturer ...... Clevite Part Number...... 12LĆ4Ć135 (Upper 102DL3) Part Number ...... 12L-4-134 (Lower 102DL3) Part Number ...... 12L-5-79 (Upper 102D3) Part Number ...... 12L-5-78 (Lower 102D3) 102D SERIES MAINTENANCE MANUAL 12-SUSPENSION August 2000 Date 12CĆ10 Page

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.

2.6

1.545

.395

1.45

5 A

.13 .21 FLAT 2.730 DIA. OVERALL 2.730 0

A

AA P/N 20Ć389 9571

Install and Removal Tool for 12LĆ4Ć216