| Master cylinders manufactured by ATE, Girling | | | | for fluid leaks, check that dash light is out |
| and Bendix utilize 2 or 3-chamber reservoirs, | | | | and reset pin in cylinder.PARKING BRAKE |
| a level sensor contact is built into each | | | | LININGS1. Remove wheel and tire and |
| chamber.A warning light is activated when | | | | disconnect hydraulic line, remove caliper and |
| brake fluid level is low or when pressure | | | | disc and turn the rear axle flange until the |
| differential between two brake circuits is | | | | threaded hole faces down, compress spring |
| caused by loss of fluid in either | | | | with spring and turn 90 degrees.2. Remove all |
| circuit.Floating type front disc brake | | | | retainers and hold-down springs, detach lower |
| calipers are used on the 190, 420 and 560 | | | | return spring opposite adjuster and pull |
| series; Not floating type calipers on other | | | | brake shoes apart enough to remove over rear |
| models with parking brakes are cable-actuated | | | | axle shaft flange, detach upper return spring |
| in rear brake rotor calipers.All models have | | | | and remove adjuster. |
| brake pad wear indicators and differential | | | | |
| pressure warning indicator.Wear sensors for | | | | Cleaning & Inspection Use brake vacuum |
| 420 and 560 series operates on inner pads | | | | cleaner to clear asbestos dust from assembly |
| only.The Anti-Lock Brake System is standard | | | | and check condition of linings and |
| on 420SEL, 300 and 560 series (optional on | | | | components.Disc brake rotor inside diameter |
| 190 series). | | | | is 160 m.m. parking brake lining width 25 |
| | | | m.m..Installation1. To install reverse |
| On diesel models, a vacuum pump is | | | | procedure, lubricate all adjuster components |
| incorporated to supply a vacuum to the power | | | | and sliding surfaces of backing plate with |
| brake unit.ADJUSTMENTS PEDAL HEIGHT & FREE | | | | silicone brake grease.2. Return adjuster to |
| PLAYPedal height measured from pedal pad to | | | | position and install on shoes with adjusting |
| pedal stop should be 150 m.m. | | | | wheel facing 45 degrees forward diagonal |
| | | | swing axle or 90 degrees forward diagonal |
| to adjust loosen lock nuts and turn stop | | | | swing axle with starting torque |
| light switch until correct pedal height is | | | | compensation.3. Attach hold down springs and |
| obtained tighten lock nuts; pedal free play | | | | retainers and return springs, install disc |
| should be 5-15 m.m..BRAKE LIGHT SWITCH | | | | and adjust parking brake.SINGLE DIAPHRAGM & |
| | | | PISTON TYPE VACUUM PUMPRemoval Diesel Only |
| The stoplight switch is located under dash, | | | | While holding lock nuts loosen vacuum lines |
| above brake pedal loosen lock nuts and adjust | | | | from pump, detach hex head mount screws from |
| switch so that contact button extends 6-8 | | | | crankcase and remove vacuum pump and |
| m.m. then tighten lock nuts.PARKING BRAKE | | | | gasket.Piston type vacuum pump screw |
| | | | connector is provided with oil retention |
| 1. Remove only one wheel lug bolt at each | | | | valve, when pump is stopped and vacuum is |
| rear wheel, raise vehicle.2. Rotate wheel | | | | available, valve prevents engine oil from |
| until lug bolt hole is positioned over | | | | entering power brake unit.Installation |
| parking brake adjuster, approximately 45 | | | | Install vacuum pump with new gasket to |
| degrees forward for diagonal swing axle and | | | | crankcase, the new gasket thickness is 2 m.m. |
| 90 degrees forward for diagonal swing axle | | | | Connect vacuum lines and test for proper |
| with starting torque compensation.ADJUSTING | | | | operation.DOUBLE DIAPHRAGM VACUUM PUMP |
| PARKING BRAKE MECHANISM | | | | (Diesel Only)1. Loosen upper radiator hose |
| | | | and drain some coolant and remove the fan |
| Parking brake must be adjusted if brake | | | | radiator shell and power steering pump |
| pedal can be depressed by more than 2 steps | | | | belt.2. Loosen vacuum lines from pump; remove |
| of 6 without any braking effect, do not alter | | | | hex head mount screws from crankcase remove |
| adjusting screw on parking brake intermediate | | | | vacuum pump with toothed intermediate sleeve |
| lever; these screws are for balancing cable | | | | and gasket.Installation1. Clean sealing |
| lengths only.3. Using screwdriver inserted | | | | surfaces and install pump with new gasket to |
| through lug bolt whole hand turn adjuster | | | | crankcase and ensure intermediate sleeve and |
| until rear wheel cannot be turned, back off | | | | pump locating pins are properly seated in |
| the adjuster until wheel can be turned | | | | crankcase.2. Connect vacuum lines to pump, |
| without wheel dragging.TESTING THE BRAKE | | | | install belt radiator shell, fan and hose, |
| WARNING LIGHT | | | | check pump for proper operation.OVERHAUL |
| | | | FRONT DISC BRAKE CALIPERSDisassembly 420SEL, |
| 1. Dual warning light is mounted on dash, | | | | 300 & 560 SeriesRemove caliper from vehicle |
| turn ignition on and the light should glow | | | | and place piece of wood in front of piston, |
| when parking brake lever is pulled to one | | | | gradually apply compressed air into fluid |
| notch and go off when brake lever is fully | | | | inlet remove piston and remove dust boot from |
| released.2. To check circuit warning sensor, | | | | piston and piston seal from caliper |
| turn ignition on, release the parking brake | | | | bore.Cleaning & Inspection1. Wash parts in |
| and ensure light is off, | | | | alcohol or brake fluid and air dry, inspect |
| | | | caliper bore and piston for scoring scratches |
| Open bleeder screw on one wheel and depress | | | | or rust, standard front brake caliper bore |
| brake pedal and the light should light up.3. | | | | inside diameter is 60 m.m..2. Replace dust |
| Close bleeder screw, replenish the brake | | | | boot and piston seal when disassembling |
| fluid and bleed system, check that light goes | | | | caliper, remove small rust deposits in bore |
| out after testing and if not; differential | | | | with fine cloth.When installing new caliper |
| pressure pin in the master cylinder must be | | | | and check that calipers on same axle have |
| reset.REMOVAL & INSTALLATION OF DISC BRAKE | | | | pistons of same diameter, only identical |
| PADSRemoval 420SEL, 300 & 560 Series1. Raise | | | | calipers should be installed on front |
| vehicle and remove wheels, remove upper hex | | | | axle.Reassembly Coat piston and caliper bore |
| head caliper bolt.2. Pull clip of the brake | | | | with ATE brake cylinder paste, install piston |
| pad wear sensor out of plug by opening cap on | | | | seal into caliper bore and install piston and |
| plug, rotate caliper downward and remove pads | | | | dust boot.Disassembly 190, 300E, 300SDL & |
| from carrier.3. Standard front disc brake pad | | | | 420SEL this procedure also applies to all |
| assembly thickness including lining backing | | | | rear calipers.1. Remove caliper from vehicle |
| plate is 17.5 m.m. Standard rear pad assembly | | | | and remove disc pads from caliper and remove |
| thickness is 15.5 m.m..4. Front backing plate | | | | dust boot.2. Hold one piston in place using |
| thickness is 4.5 m.m. Rear backing plate | | | | piston Resetting Pliers, gradually apply |
| thickness is 5mm Minimum pad thickness is 2 | | | | compressed air to fluid inlet to remove |
| m.m..Mercedes Benz Single Piston Disc Brake | | | | opposite piston.3. Remove piston seal from |
| Caliper cleaning.1. Using brass cylinder | | | | groove of cylinder bore and remove remaining |
| brush clean disc pad guide surface in | | | | piston and seal in same manner. DO NOT |
| caliper, siphon fluid from master cylinder to | | | | separate caliper halves, replace only as an |
| prevent overflowing press piston to bottom of | | | | assembly, calipers installed on front axle |
| bore.2. Install disc pads and wear sensor | | | | must be from same manufacturer.Calipers on |
| wires, reverse removal procedure to complete | | | | rear axle may be different only if same brand |
| installation and check that dash light goes | | | | replacement part is unavailable.Cleaning & |
| out.Removal All Other Mercedes Benz Models1. | | | | Inspection1. Check cylinder bores of caliper |
| Raise vehicle and remove wheels, remove cover | | | | for wear or damage, small rust deposits may |
| plate from caliper and disconnect wear | | | | be removed from caliper bores with cloth.2. |
| indicator wires.2. Drive out retaining pins | | | | CAUTION: DO NOT clean chrome-plated surfaces |
| toward inside of vehicle, on Bendix brakes | | | | of pistons with polishing or emery cloth |
| retaining pins have locking pins, then remove | | | | damage to surface may result.Remove deposits |
| the locking pins and retaining pins then the | | | | with soft brass wire brush or rough cleaning |
| cross spring retainers.3. Remove disc pads | | | | cloth, replace piston if chrome surface is |
| from caliper, if not reusable note condition | | | | damaged.2. Heavy rust deposits or badly |
| and location of pads for re installation.4. | | | | scored bore will require replacement of the |
| Standard front disc brake pad assembly | | | | caliper rust deposits in front of piston seal |
| thickness including lining backing plate is | | | | groove may be removed with fine emery |
| 17.5 m.m. Standard rear pad assembly | | | | cloth.3. Standard front brake caliper bore |
| thickness is 15 m.m..5. Front backing plate | | | | inside diameter is 60 m.m. Standard rear |
| thickness is 4.5 m.m. rear backing plate | | | | caliper bore I.D. Teves is 38 m.m. and rear |
| thickness is 5 m.m. minimum pad thickness is | | | | caliper bore I.D Bendix Girling is 42 |
| 2 m.m..1. Using cylinder brush clean disc pad | | | | m.m..Reassembly1. Coat piston and caliper |
| guide surface in caliper, siphon fluid from | | | | bore with ATE brake cylinder paste, install |
| master cylinder reservoir to prevent | | | | piston seal into the caliper bore and then |
| overflowing, press pistons to bottom.2. | | | | install piston.2. With caliper installed on |
| Mercedes Benz Disc Brake Pads.3. Install | | | | the diagonal swing axle elevation on the |
| cover plate retaining pin locking keys and | | | | piston faces upward.On diagonal swing axle |
| wear sensor wires, check that dash light goes | | | | with starting torque compensation, elevation |
| out, and the reset pin at master | | | | on piston must be at bottom and project at |
| cylinder.DISC BRAKE CALIPER REMOVAL1. Raise | | | | least 10 m.m. above shield, use DOT 4 or |
| and support vehicle remove the wheel, open | | | | higher rated brake fluid during the |
| bleeder screw on caliper assembly and pump | | | | overhaul.2. Check position of piston in |
| out fluid, disconnect and plug brake lines at | | | | caliper with Piston Gauge for front or for |
| caliper assembly.2. Remove caliper bolts, | | | | rear.3. Adjust with Piston Rotating Pliers |
| remove caliper assembly from | | | | and install dust boot, install heat shield |
| vehicle.Installation To install reverse | | | | into piston with recess in shield fitting |
| removal procedure, tighten all nuts and bolts | | | | into elevation of the piston.REAR DISC BRAKE |
| and then bleed hydraulic system and check | | | | CALIPEROverhaul procedure is the same as |
| that the dash light goes out, reset pin in | | | | front caliper of 300E, 300SDL and 420SEL |
| master cylinder if necessary.DISC BRAKE ROTOR | | | | models.MASTER CYLINDER CAUTION:BENDIX master |
| REMOVAL (Front)1. Remove caliper assembly and | | | | cylinder painted Blue cannot be overhauled |
| hub grease cap, remove contact spring for | | | | and replace as an assembly only.Disassembly |
| radio shielding, loosen clamping nut socket | | | | Tandem & Stepped Tandem1.On tandem master |
| screw on wheel spindle.2. Remove clamping nut | | | | cylinder remove the reservoir and push piston |
| and washer, remove wheel hub and rotor | | | | in |
| assembly, remove bolts securing hub to rotor, | | | | |
| remove rotor.Cleaning & Inspection1. Clean | | | | remove stop screw; remove the push rod |
| disc and check for cracks, scoring or | | | | piston assembly and O ring.2.Remove the lock |
| excessive wear, replace as necessary.2. | | | | ring from housing and remove the floating |
| Before installing stock replacement disc, use | | | | circuit piston, and stop washer with two |
| solvent to remove nitrocellulose corrosion | | | | vacuum seals and intermediate ring.3.Tap |
| preventive paint from rotor | | | | lightly on housing with plastic mallet to |
| surface.Installation To install reverse | | | | remove the floating circuit piston |
| removal, tighten all bolts and fittings | | | | assembly.On Teves reservoir only remove cap |
| evenly, bleed hydraulic system if necessary, | | | | end covers and strainer and splash guard, O |
| lubricate and adjust wheel bearings, see | | | | rings and contact the inserts.On Bendix |
| appropriate article in suspension | | | | models, remove strainer from cover, DO NOT |
| section.Removal rear brakes1. Remove rear | | | | remove the contact inserts.Always use DOT 4 |
| wheel and tire and disconnect and plug brake | | | | or higher brake fluid during overhaul. |
| lines, remove caliper assembly.2. Using rear | | | | |
| axle shaft Assembly Tool 116 589 24 61 00, | | | | .Cleaning & Inspection1.Clean all parts with |
| pull rotor out from axle shaft flange.1. To | | | | alcohol or brake fluid and flush residue out |
| install reverse procedure, coat the axle | | | | of housing, check bore in housing and the |
| splines with high temperature lubricant | | | | piston for score marks and rust.2. Small rust |
| grease wheel bearings and install seal if | | | | spots in housing may be removed with emery |
| necessary.2. Tighten all bolts and fittings | | | | cloth scored or badly rusted parts cannot be |
| evenly and bleed hydraulic system.REAR AXLE | | | | repaired and require replacement of complete |
| SEAL Removal1. Remove rear wheel and tire and | | | | master cylinder.3.On tandem models with |
| release locking plates, remove mount bolts | | | | standard master cylinder inside diameter is |
| and caliper, wire caliper out of the way.2. | | | | 23.81 m.m. maximum bore wear limit is 23.92 |
| On vehicles with starting torque | | | | m.m..4.On the stepped tandem models, standard |
| compensation, disconnect brake hose holder | | | | master cylinder I.D. for push rod circuit is |
| and hang caliper assembly with wire.3. Loosen | | | | 23.81m.m. and I.D. for floating circuit is |
| and remove 8 m.m. bolt or 12 m.m. bolt with | | | | 19.05 m.m..5. Maximum master cylinder bore |
| spacing sleeve and clamping disc at center of | | | | I.D. is 23.92 m.m. for push rod circuit and |
| rear brake rotor.4. Using rear axle shaft | | | | 19.16 m.m. for floating circuit.Reassembly1. |
| Assembly Tool, remove rotor from rear axle | | | | To assemble reverse disassembly procedure, |
| shaft flange and pry rear axle seal from | | | | coat the bore of master cylinder with brake |
| rotor at inner wheel bearing and discard.If | | | | fluid.2. Install new floating circuit piston |
| the brake rotor is difficult to free from the | | | | assembly and push in piston assembly and |
| axle flange strike the outer circumference | | | | install lock ring.3. Install the new push rod |
| lightly with a plastic hammer and ensure | | | | piston assembly and screw in stopper screw |
| parking brake is released.Installation1. Coat | | | | using new copper washer for Gray iron master |
| inside of new axle seal lip and wheel | | | | cylinder or new aluminum washer for light |
| bearings with grease, install bearings and | | | | alloy master cylinder.Replace O ring to |
| seal into rear brake disc.2. Coat axle | | | | ensure proper vacuum seal at power brake unit |
| splines with heat resistant lubricant and | | | | and bleed hydraulic system, check that the |
| install disc, to complete installation | | | | dash light is out.Differential pressure |
| reverse removal procedure.Mercedes Benz | | | | warning indicator reset pin located at the |
| master cylinder removal1. Drain master | | | | front end of master cylinder MUST be reset |
| cylinder fluid and disconnect and plug brake | | | | once and indicator light in dash panel has |
| lines, disconnect electrical wires.2. Remove | | | | been triggered.POWER BRAKE UNITManufacturer |
| the bolts securing master cylinder to power | | | | does not recommend disassembly of this unit, |
| brake unit and remove master | | | | if problem is found in power brake unit |
| cylinder.Installation1. Reverse procedure; | | | | complete assembly must be replaced, DO NOT |
| always replace rubber "O" ring seal between | | | | disassemble power brake unit, determine |
| master cylinder and power unit.2. Bleed | | | | whether source of problem is in power brake |
| hydraulic system and check complete system | | | | unit or the check valve. |