Brakes GENERAL 32-2: BRAKES 1. General This chapter describes that portion of the system which provides for stopping the aircraft while on the ground and taxiing/directional control of the aircraft. Includes items such as the hydraulic brake fluid system, brake calipers, discs, and pad assemblies. The brake system consists of an aluminum brake assembly on each main landing gear with single steel disc and two sintered (metal/ceramic) brake pads, master cylinder for each rudder pedal, hydraulic fluid reservoir, parking brake, and associated hydraulic tubing and hoses. The hydraulically operated brakes are individually activated by floor mounted toe pedals located at both pilot stations. The master cylinders are located forward of the each rudder pedal. The hydraulic fluid reservoir is located in the nose compartment on the upper RH side of FS 72.5. The reservoir is serviced with MIL-PRF-87257 hydraulic fluid. A parking brake mechanism holds induced hydraulic pressure on the disc brakes for parking. The parking brake system consists of a parking brake valve, control cable with handle, indication switch, and associated hydraulic tubing and hoses. The parking brake valve is mounted to the forward cabin skin, outboard of the pilot rudder pedals. The parking brake control cable handle is mounted to the LH console rib on the pilot-side under GTC#1. A position sensor, mounted adjacent to the parking brake valve actuation arm, sends position data to the MFD via the GEA 71 engine airframe unit. An alert indicates in the CAS window of the MFD when the parking brake is set. 1
TROUBLESHOOTING 2. Troubleshooting Trouble Probable Cause Remedy Brakes won t hold. Improper conditioning of brake pads and disc. Brake fluid or grease on disc and pads. Wrong brake fluid has caused blocking of pistons. Pads worn below minimum wear limits Perform Adjustment/Test - Conditioning Procedure for Brake Pads. (Refer to 32-2) Clean the disc and change the pads. (Refer to 32-2) Change all seals of the brake system. Use correct brake fluid. (Refer to 12-10) Change brake pads. (Refer to 32-2) Excessive toe pedal travel, spongy pedal. Air in brake system. Bleed brake system. (Refer to 32-2) Leak in the system. Perform Inspection\Check - Brake Pressure Test to locate leak. (Refer to 32-2) Loosen and re-torque leaking fitting using system fluid as lubricant. Replace leaking fitting washers. Replace leaking fitting. Replace brake line or component. Caliper assembly bolts are not tight. Torque bolts to proper value. Perform Adjustment/Test - Brake Pressure Test (Refer to 32-2) Defective seal in master cylinder or contamination in fluid. Replace master cylinder or inspect the brake reservoir for contamination. (Refer to 32-2) 2 03 Dec 2018
TROUBLESHOOTING Trouble Probable Cause Remedy Brake drag. Rapid disc and pads wear. Residual brake pressure due to excessive pressure in the reservoir. Wrong brake fluid has caused blocking of pistons. Pistons do not retract. Pads are blocked and do not release. Improper conditioning of pads and disc. Inspect for correct venting. Change all seals of the brake system. Use correct brake fluid. (Refer to 12-10) Check vent/return port in the master cylinder. Inspect and repair. Perform Adjustment/Test - Conditioning Procedure for Brake Pads. (Refer to 32-2) Excessive rusting, scoring or pitting or large pad deposits on brake disc that is evident with tactile inspection of brake disc. Repair or replace the disc and pads. (Refer to 32-2) (Refer to 32-2) Small pieces of pad frictional material damaged or missing at edges. Large portions of pad frictional material damaged or missing Typical condition of pads during use. Pads worn below minimum wear limits. Pads overheated (RTO, high-airspeed landings, or improper taxiing technique.) Inspect pad wear at each pre-flight, see AFM. Change brake pads. (Refer to 32-2) Change brake pads. (Refer to 32-2) 3 03 Dec 2018
3. Maintenance Practices A. Brake System Replenishing (Refer to 12-10) B. Brake Assembly (See Figure 32-2-1) (1) Inspection/Check - Brake Assembly (b) (c) (d) (e) Wipe off any debris from brake caliper assembly that may obstruct inspection. Check brake pad assemblies and discs for deterioration and maximum permissible wear. Ensure none of the following conditions exist. If damage is identified during inspection, brake cylinder and/or back plate must be replaced. 1 Signs of deep corrosion, 2 Anodizing color removed on more than 15% of external surface, 3 Heavy nicks, Anodizing removed on internal piston bore, 5 Scratched piston bore, and 6 Scratched or damaged seal groove. Anodizing coating must not be painted. Do not use sandpaper on any parts. Sandpaper will remove anodizing coating. Do not try to sand or polish internal piston bore, it will remove anodizing coating. See manufacturer s approved Instructions For Continued Airworthiness for more information regarding brake pad and brake disc wear limits. (Refer to 5-00) Verify brake pad assembly frictional material minimum thickness is not less than 0.00 inch (1 mm). Verify brake disc minimum thickness is not less than 0.33 inch (11 mm). 21 Dec 2016
(f) Check brake assemblies for evidence of overheating and/or deterioration. (g) Perform Inspection/Check - Wheel and Brake Clips. (Refer to 32-1) (2) Removal - Brake Assembly Verify parking brake is in off position and wheels are blocked. Raise airplane on jacks. (Refer to 7-10) (b) Remove main wheel and tire. (Refer to 32-1) (c) Disconnect hose from brake inlet fitting. Plug hose and cap inlet fitting to prevent fluid contamination. (d) Remove wheel/brake spacer. (e) Remove bolts, washers, and nuts securing brake assembly to trailing arm. (3) Disassembly - Brake Assembly Acquire necessary tools, equipment, and supplies. Description P/N or Spec. Supplier Purpose Plastic Dental Pick - Any Source Remove o-rings. Compressed Air Supply - Any Source Facilitate piston removal / cleaning. Acetone / ASTM D-329 - Any Source Surface clean wheel and brake metallic parts. Cotton Cloth (clean and lint free) - Any Source Clean parts. (b) (c) Remove screws securing back plate to brake cylinder. Separate cylinder, brake pads, brake disc, and back plate. WARNING If air pressure is used to remove pistons, pistons will be ejected at high velocities. 5
(d) (e) (f) (g) Care should be used in handling o-rings to prevent damage. Do not use metal tools to remove o-rings from pistons. Metal tools will scratch the seal groove and cause fluid leakage. NOTE If air pressure is used to remove pistons, replace caliper back plate and blow air pressure into brake cylinder inlet. Remove o-rings from pistons with plastic dental pick. Remove bleeder screw from brake cylinder. Remove cotter pins securing back stops to brake pads. Remove back stops. Clean brake assembly. WARNING Acetone is toxic and volatile. Use a well-ventilated room and avoid contact with skin and clothing. Do not inhale vapor. Do not use basic or acidic cleaning agents on wheel halves. Anodizing can be removed if exposed to basic agents. Do not damage ball bearing seal or expose to solvents. 1 Clean all metal parts using water with soap and wipe dry with a clean cloth. Use acetone only on seal grooves. Ensure that brush is compatible with acetone. 2 Clean seal grooves with a soft plastic brush and acetone. (Refer to 20-30) Do not use oily solvent or oily air pressure on internal threads because threadlocker will not properly lock screws if exposed to oil. Ensure no dust remains inside seal grooves. 3 Apply air pressure to dry internal threads and seal grooves. 6
() Assembly - Brake Assembly NOTE Thoroughly clean parts before assembling. Acquire necessary tools, equipment, and supplies. Description P/N or Spec. Supplier Purpose O-Ring Lubricant Dow Corning 55 Dow Chemical Co. Lubricate o-rings. Silicone Grease, Thick -58 to 392 F (-50 to 200 C) Compliant w/ FDA CFR 178.3570 Any Source Lubricate cylinder bores. Threadlocker, Medium Loctite 22 or 23 Any Source Lock threads. (b) Perform Inspection/Check - Brake Assembly. (Refer to 32-2) (c) (d) (e) (f) (g) (h) (i) Do not use silicone spray (liquid) in place of thick silicone grease where specified. Do not use tools to manually insert seals or pistons into cylinder bores. Never re-use a piston seal that has been removed from a cylinder bore groove. Lubricate new seals with thin coat of thick silicone grease. Lubricate cylinder bores with thin coat of thick silicone grease. Insert seals into cylinder bore grooves by hand only. Lubricate piston with thin coat of thick silicone grease. If piston does not slide into cylinder bores with pressure of only one or two fingers, it is sticking which can lead to brake damage and overheating. Do not attempt to sand or polish pistons. If pistons are sticking, they must be replaced. Insert pistons into cylinder bores by hand only. Verify pistons and o-rings are in proper alignment. Using silicone grease, lubricate contact area between back stops and back plate. 7
The cotter pins must be bent close to the back plate and can be shortened down to 1/ inch on each side. If cotter pins protrude from back plate, they may contact and damage the wheel. (j) Insert new cotter pins to secure back stops. (k) Install new brake pads. (Refer to 32-2) (l) Apply medium threadlocker to new screws used to secure back plate to cylinder. (Refer to 20-0) (m) Install screws securing brake pads in place. Torque screws 220 in-lb (25 Nm). (Refer to 20-60) (n) Re-torque all screws 220 in-lb (25 Nm). (Refer to 20-60) (o) Ensure brake pads slide without effort. (p) Position brake disc between brake pads. (5) Installation - Brake Assembly Position brake assembly to trailing arm and secure with bolts, washers, and nuts. Torque 210 to 220 in-lb (23.73-2.86 Nm). (Refer to 1-20) (b) Install wheel/brake spacer. (c) Connect hose to brake inlet fitting. (d) Perform Adjustment/Test - Bleeding the Brake System. (Refer to 32-2) (e) Install main wheel and tire. (Refer to 32-1) (f) Remove jacks and lower airplane. (Refer to 7-10) 8
C. Brake Pads See manufacturer s approved Instructions For Continued Airworthiness for more information regarding brake pad and brake disc wear limits. (Refer to 5-00) (See Figure 32-2-1) (1) Inspection/Check - Brake Pads (b) Check brake pads for deterioration and maximum permissible wear. Replace brake pads when minimum thickness of frictional material is less than 0.00 inch (1 mm). NOTE Small missing pieces along edges and internal material are typical for pad wear. Check for large portions of frictional material missing. (2) Removal - Brake Pads Verify parking brake is in off position and wheels are blocked. Acquire necessary tools, equipment, and supplies. Description P/N or Spec. Supplier Purpose Cotton Cloth (clean and lint free) - Any Source Clean parts. (b) Raise airplane on jacks. (Refer to 7-10) (c) Remove main wheel/tire (Refer to 32-1) (d) While back plate is separated from cylinder, do not apply brake pressure. NOTE Do not remove caliper back plate from axle. Do not disconnect hydraulic fitting. Do not remove brake disc. Retain brake disc in place. Remove screws securing back plate to brake cylinder. 9
(e) Remove and discard brake pads. (Refer to 32-2) (f) Perform Inspection/Check - Brake Assembly. (Refer to 32-2) (g) Do not use solvent to clean pistons and surrounding area. Solvent will penetrate to and damage piston seals. Use only a dry cloth. Clean around pistons with a dry cloth to remove dirt and dust. (3) Installation - Brake Pads NOTE Thoroughly clean parts before assembling. Acquire necessary tools, equipment, and supplies. Description P/N or Spec. Supplier Purpose Threadlocker, Medium Loctite 22 or 23 Any Source Lock threads. Safety Wire, Stainless Steel 0.00 inch (1 mm) diameter wire Grade 302 Any Source Secure brake disc to wheel. (b) (c) If pushing back pistons by hand is difficult, pistons and seals are sticking or may be blocked. Brake maintenance is required with change of seals and eventual change of other parts. Verify fluid reservoir volume and remove fluid if necessary to prevent fluid from overflowing. Push pistons back by hand. Never intermingle old and new brake pads. All four brake pads (two left and two right) must be replaced at the same time. Brake pad insulator and grid are part of new brake pads and should not be re-used. (d) Install new brake pads. (Refer to 32-2) (e) Apply medium threadlocker to screws used to secure back plate to cylinder. (Refer to 20-0) 10
(f) Install screws securing brake pads in place. Torque screws 220 in-lb (25 Nm). (Refer to 20-60) (g) Re-torque all screws 220 in-lb (25 Nm). (Refer to 20-60) (h) Ensure brake pads slide without effort. NOTE When new brake discs are installed, all brake pads must be replaced with new ones. (i) Position brake disc between brake pads. (j) Position wheel/tire onto axle while placing brake disc into wheel slots. (k) Install main wheel/tire. (Refer to 32-1) (l) Install safety wire securing brake disc to wheel. (Refer to 20-50) (m) Apply brake pressure 5 to 10 times and check brake fluid level in the reservoir. When brakes are released, wheel should turn freely. (n) Verify brake efficiency and residual drag on the wheel. (o) Remove jacks and lower airplane. (Refer to 7-10) (p) Service reservoir. (Refer to 12-10) (q) Perform Adjustment/Test - Conditioning Procedure for Brake Pads. (Refer to 32-2) () Adjustment/Test - Conditioning Procedure for Brake Pads This conditioning procedure will wear off high spots and prepare brake pads and disc friction surfaces. A visual inspection of the brake disc will indicate the brake pads condition: a smooth surface with light and regular grooves indicates that brake pads and disc are properly conditioned. If rough surfaces on brake disc exist and/or reduced brake performance is noted, the brake pads and disc may be conditioned again following the instructions below. When new brake pads have been installed, it is important to condition them properly to obtain the service life designed into them. Rated brake torque value is reached only after a full conditioning of brake pads and disc. Brake torque value can be only 50% of rated brake torque before the conditioning. It means that even with full brake effort the aircraft will not stop as usual. Pilot must take into consideration this parameter to avoid loose of aircraft control during the conditioning procedure. 11
Improper conditioning may affect braking performance and increase wear of brake pads and disc. Avoid high brake pressure until after conditioning. NOTE Rough surfaces (deep grooves and isolated bumps) on brake disc indicates that an excessive brake effort has been applied during conditioning. If rough surfaces exist, sand surface irregularities and repeat Adjustment/Test - Conditioning Procedure for Brake Pads. (Refer to 32-2) (b) (c) (d) (e) (f) Perform two (2) consecutive stops from 30-35 knots down to 5 knots. Apply light brake effort during these two stops; do not try to apply full brake effort. Allow brakes to cool down for 5 to 10 minutes. Perform two (2) consecutive stops from 30-35 knots down to 5 knots. Apply light brake effort during these two stops; do not try to apply full brake effort. Allow brakes to cool down completely to ambient temperature (~30min). Perform brake conditioning with cool down. 1 Perform two (2) consecutive stops from 30-35 knots down to 5 knots. Apply light brake effort during these two stops; do not try to apply full brake effort. 2 Allow the brakes to cool down for 5 to 10 minutes. 3 Perform two (2) consecutive stops from 30-35 knots down to 5 knots. Apply light brake effort during these two stops; do not try to apply full brake effort Allow brakes to cool down for 5 to 10 minutes. 5 Apply brakes and check for restraint at high static throttle (MTO thrust). If brakes hold, conditioning is complete. If brakes cannot hold aircraft during static run-up, allow brakes to cool down completely, then repeat brake conditioning with cool down. 12
D. Brake Discs See manufacturer s approved Instructions For Continued Airworthiness for more information regarding brake pad and brake disc wear limits. (Refer to 5-00) (See Figure 32-2-1) (1) Inspection/Check - Brake Discs (b) Verify brake disc minimum thickness is not less than 0.33 inch (11 mm). NOTE Pad deposits on discs indicate operation at high temperatures, which may result from improper taxiing technique, high airspeed landings, or a combination of both. Light pad deposits appear as dark, circular discolorations on disc surface and will typically be cleared during normal operation. Heavy pad deposits are evident during tactile inspection and may appear as bumps or even small surface cracks in disc. Heavy pad deposits will not be cleared during normal operations and disc and pads should be replaced. Verify brake disc surface is smooth with light and regular grooves. Deep grooves, isolated bumps, and large pad deposits on the disc evident with tactile inspection indicates the disc and pads should be replaced. (2) Removal - Brake Discs Verify parking brake is in off position and wheels are blocked. Remove brake pads. (Refer to 32-2) (b) Remove bolts and washers securing back plate, brake pads, and brake disc to axle. Remove brake disc from airplane. 13
(3) Installation - Brake Discs Both brake discs (LH & RH) must be replaced at the same time. When the brake discs are replaced, all () brake pads must be replaced with new ones. Position brake disc, brake pads, and back plate to axle and secure with washers and bolts. (b) Install brake pads. (Refer to 32-2) E. Brake Hose (See Figure 32-2-1) (1) Removal - Brake Hose Verify parking brake is in off position and wheels are blocked. Disconnect brake hose from bulkhead fitting at Main Landing Gear rib, WS 51. Cap fitting and plug hose to retain fluid and prevent contamination. (b) Disconnect hose from brake inlet fitting. Cap fitting and plug hose to prevent contamination. (c) Remove nut, washer, saddle clamp, and bolt securing brake hose to trailing arm. (d) Remove nut, washers, saddle clamp, and bolt securing brake hose to trunnion. Remove brake hose from airplane. (2) Installation - Brake Hose (b) (c) Position brake hose to trunnion and secure with bolt, saddle clamp, washers, and nut. Position brake hose to trailing arm and secure with bolt, saddle clamp, washer, and nut. Uncap fitting and connect brake hose to brake inlet fitting. 1
(d) Uncap fitting and connect brake hose to bulkhead fitting at Main Landing Gear rib, WS 51. (e) Perform Adjustment/Test - Bleeding the Brake System. (Refer to 32-2) 15
Figure 32-2-1: Brake Assembly A 2 1 2 3 TRUNNION (REF) 18 10 5 17 16 15 1 12 13 12 11 DETAIL 10 A 5 9 2 3 8 7 6 5 LEGEND 1. Stand-Off 2. Clamp 3. Bolt. Nut 5. Washer 6. Brake Hose 7. Fitting 8. Cylinder 9. Screw, Bleeder 10. O-Ring 11. Piston 12. Brake Pad 13. Brake Disc 1. Cotter Pin 15. Back Stop 16. Back Plate 17. Screw 18. Spacer SF50_MM32_0156 16
F. Brake Master Cylinder (See Figure 32-2-2) (1) Removal - Brake Master Cylinder (b) (c) Remove bolts and washers securing brake line hoses from master cylinders. Plug hoses and cap master cylinder fittings. Remove bolts, washers, nuts, and cotter pins securing master cylinders from rudder pedal idler linkage. Remove bolts, washers, spacers, and nuts securing master cylinders to fuselage attach brackets. (2) Installation - Brake Master Cylinder (b) (c) Place master cylinders on floorboard mounting points, install bolts and secure with washers, spacers, nuts, and cotter pins. NOTE For pilot-side master cylinders: Inlet is connected to co-pilot master cylinders. Outlet is connected to parking brake valve. For co-pilot side master cylinders: Inlet is connected to brake reservoir. Outlet is connected to pilot-side master cylinders. Install LH and RH brake hoses per marked labels. Install bolts and new washers securing brake hoses to master cylinders. Torque bolts 11-155 in-lb. (15.9-17.5 Nm). (Refer to 20-60) Connect piston rod to upper connection at rudder pedals and install bolts, washers, and nuts. (d) Perform Adjustment/Test - Bleeding the Brake System. (Refer to 32-2) 17 03 Dec 2018
G. Parking Brake Valve (See Figure 32-2-2) (1) Removal - Parking Brake Valve Remove LH valence trim. (Refer to 25-10) (b) Remove LH crew seat. (Refer to 25-10) (c) Disconnect brake lines and hoses. 1 Disconnect brake lines from parking brake valve. Cap or plug ports and lines. 2 Remove bolts and washers securing master cylinder hoses from parking brake valve. Cap or plug ports and hoses. (d) Remove cotter pin, washers, and clevis pin securing control cable to parking brake valve actuation arm. (e) Remove bolts, washers, and nuts securing parking brake valve to forward cabin skin. Remove parking brake valve from airplane. (2) Installation - Parking Brake Valve (b) (c) (d) (e) (f) Position parking brake valve to outboard console rib with actuation arm adjacent to firewall and brake line fittings oriented towards fuselage floor. Secure with bolts, washers, and nuts. Remove caps from ports, lines, and hoses. Connect LH brake line to LH outlet on parking brake valve. Connect RH brake line to RH outlet on parking brake valve. Do not cross LH and RH brake hoses. Connect master cylinder brake hoses. 1 Install bolts and new washers securing LH master cylinders brake hose to LH inlet on parking brake valve. Torque bolts 18 in-lb (16.7 Nm). (Refer to 20-60) 2 Install bolts and new washers securing RH master cylinders brake hose to RH inlet on parking brake valve. Torque bolts 18 in-lb (16.7 Nm). (Refer to 20-60) Install clevis pin, washers, and cotter pin securing control cable to parking brake valve actuation arm. 18 03 Dec 2018
(g) Perform Inspection/Check - Parking Brake Control Cable. (Refer to 32-2) (h) Bleed brake system. (Refer to 32-2) (i) Install LH valence trim. (Refer to 25-10) (j) Install LH crew seat. (Refer to 25-10) H. Parking Brake Control Cable (See Figure 32-2-2) (1) Removal - Parking Brake Control Cable Remove LH crew seat. (Refer to 25-10) (b) Remove LH valence trim. (Refer to 25-10) (c) Remove cotter pin, washers, and clevis pin securing control cable to parking brake actuation arm. (d) Remove bolt, washer, and clamp securing control cable to forward cabin skin, console rib, and handle mounting bracket. (e) Remove nut and washer securing control cable handle to bolster panel mounting bracket. (f) Remove control cable carefully, ensuring cable does not interfere with any flight controls, brake hoses, or wiring. NOTE Note routing of control cable prior to removal to facilitate re-installation. Pull control cable through installation hole in bolster panel mounting bracket. Remove control cable from airplane. (2) Installation - Parking Brake Control Cable Acquire necessary tools, equipment, and supplies. Description P/N or Spec. Supplier Purpose Threadlocker Loctite 222 Any Source Lock threads. 19 03 Dec 2018
(b) Route control cable through installation hole in bolster panel mounting bracket and secure with washer and nut. Verify control cable does not interfere with or rub against any flight controls, brake hoses, or wiring. (c) Route control cable through oval clearance hole, across pressure bulkhead, under outboard console rib, and over to parking brake valve. 1 From outboard console rib, route control cable above protruding electrical bulkhead fittings and down to parking brake valve. (d) Install clevis pin and washers through parking brake valve actuation arm. (e) Secure control cable to parking brake valve actuation arm by wrapping control cable 1.5 turns around clevis pin. (f) Install cotter pin securing control cable to parking brake valve actuation arm. (g) Install cable stop. 1 Place parking brake valve actuation arm in OFF position. 2 Apply threadlocker to threads of cable stop installation screw. (Refer to 20-0) 3 Position cable stop with 1.8 inch (.6 cm) of cable wire visible between end of cable sheath and top of cable stop. Install screw securing cable stop to control cable wire. (h) Install bolt, washer, and clamp securing control cable to firewall. Do not tighten bolt. (i) With parking brake control handle in OFF position, push cable sheath down so that parking brake valve is in OFF position. Tighten bolt securing control cable and clamp to firewall. (j) Install standoffs and clamps securing control cable to firewall. (k) Install LH valence trim. (Refer to 25-10) (l) Install LH crew seat. (Refer to 25-10) (3) Adjustment/Test - Parking Brake Control Cable (b) (c) (d) Remove bolts, washers, and clamps securing control cable to forward cabin skin, console rib, and handle mounting bracket. Loosen set-screw securing cable stop to cable. Push cable handle completely in (OFF position). Set parking brake valve arm with stop against mounting bracket. 20 03 Dec 2018
(e) (f) (g) Install clamps, washers, and bolts securing control cable to forward cabin skin, console rib, and handle mounting bracket. Pull cable handle completely out until valve arm reaches parking brake sensor (SET Position). Adjust cable stop to contact end of cable sheath and secure set-screw. (h) Perform Inspection/Test - Parking Brake Control Cable. (Refer to 32-2) () Inspection/Check - Parking Brake Control Cable Remove LH crew seat. (Refer to 25-10) (b) Remove LH valence trim. (Refer to 25-10) (c) Push parking brake handle completely in (OFF position). (d) Verify parking brake arm stop contacts valve mounting bracket. If not, perform Adjustment/Test - Parking Brake Control Cable. (Refer to 32-2) (e) Verify the Parking Brake Set CAS is not present on the PFD and/or Parking brake OFF is indicated on the Landing Gear synoptic page of the EIS. (f) Pull parking brake handle completely to stop (Set position). (g) Verify parking brake arm reaches sensor and cable stop reaches the end of the cable sheath. If not, perform Adjustment/Test - Parking Brake Control Cable. (Refer to 32-2) (h) Verify The Parking Brake Set CAS is present on the PFD and/or Parking brake SET is indicated on the Landing Gear synoptic page of the EIS. (i) Install LH valence trim. (Refer to 25-10) (j) Install LH crew seat. (Refer to 25-10) 21
Figure 32-2-2: Cabin Brake System (1 of 2) RUDDER PEDAL IDLER LINKAGE (REF) 9 10 3 6 8 7 3 8 1 3 6 7 2 2 2 A FUSELAGE FLOOR (REF) 6 3 5 DETAIL A LEGEND 1. Brake Master Cylinder 2. Spacer 3. Bolt. Washer 5. Bracket 6. Nut 7. Cotter Pin 8. Brake Line Assembly 9. Elbow Fitting 10. Union B SF50_MM32_0157 22
Figure 32-2-2: Cabin Brake System (2 of 2) 12 13 7 3 1 19 12 1 13 18 1 15 5 6 1 2 17 16 1 12 13 8 3 3 8 3 3 6 12 11 2 12 DETAIL 6 B LEGEND 2. Spacer 3. Bolt. Washer 5. Bracket 6. Nut 7. Cotter Pin 8. Brake Line Assembly 11. Parking Brake Cable Assembly 12. Clamp 13. Stand Off 1. Screw 15. Parking Brake Sensor 16. Parking Brake Valve 17. Clevis Pin 18. Actuation Arm 19. Cable Stop SF50_MM32_0306A 23
I. Bleeding the Brake System (See Figure 32-2-3) If a brake line has been disconnected or the brake pedal has a spongy feel, there is a strong likelihood that air has entered the brake system. To ensure proper braking, all trapped air must be removed from the brake system. If brake fluid contaminates the disc, it must be completely cleaned with solvent. Do not apply solvent directly to the brake caliper. Solvent will damage seals. If brake fluid contaminates the brake pads, they must be replaced. The pads are porous and cannot be adequately cleaned with solvent. (1) Adjustment/Test - Bleeding the Brake System Acquire necessary tools, equipment, and supplies. Description P/N or Spec. Supplier Purpose Wheel Chocks WCK1001 Cirrus Design Block wheels. Hydraulic Fluid MIL-PRF-87257 Any Source Replenish brake system. Pressurized Brake Bleeder 7300 (or equivalent) Ammco Tools Pressurize brake system. Tubing - Any Source Drain brake fluid. Syringe - Any Source Add/remove brake fluid. Hose Clamps - Any Source Secure tubing to fittings. Container, one gallon Container, one quart - Any Source Contain overflow. - Any Source Contain overflow. (b) (c) (d) Place wheel chocks into position. Disengage parking brake. Verify pressure on both gauges read zero before opening tank. Fluid may spray out if there is residual pressure in the system. 2 03 Dec 2018
(e) Verify there is sufficient hydraulic fluid in tank. Refill if less than one gallon of fluid is left with either new or recycled fluid. Filter fluid and follow procedure on tank. (f) Verify valve on feed tubing is closed and pressure regulator is turned to zero (fully counter-clockwise). Connect an air source to the hydraulic tank. (g) Slowly pressurize tank by adjusting regulator until pressure reaches 10 PSI. (h) Place opposite end of feed tube in to empty gallon container. (i) Open valve on feed tube and allow system to flow until all air has been purged, and then close valve. (j) Remove and retain plastic plug from top of brake reservoir. (k) Temporarily install 1/8" NPT fitting and feed tubing to reservoir. (l) Connect overflow tubing to flared end of bleeder valves on both brake calipers. Place opposite tubing ends in empty gallon container. (m) Loosen both bleeder valves one turn. (n) Verify parking brake is off. (o) Slowly increase tank pressure by adjusting regulator until both gauges reach 25 to 30 psi. (p) Open feed valve from hydraulic tank to tubing attached to reservoir. (q) Verify there are no leaks in system. Address any leaks in system before continuing brake bleeding procedure. (r) (s) (t) (u) NOTE It is acceptable if fluid at the calipers is not yet clear of bubbles. Ensure end of RH overflow tubing is completely submerged in fluid. For approximately 1 to 2 minutes, allow fluid to flow until feed tube is clear of bubbles and there is fluid flowing out of overflow tubing attached to both calipers. Move tubing as necessary to push air through system. Caliper may be damaged if bleeder is over tightened. Close bleeder valve on left side. Leave bleeder valve on right side open one turn. Fully depress, then slowly release RH pedal on co-pilot side 3 times. Fully depress, then slowly release RH pedal on pilot side 3 times. 25 03 Dec 2018
(v) (w) (x) (y) (z) (aa) Purge air from RH caliper. 1 Fully depress and hold RH pedal on co-pilot side. Close RH bleeder valve, then slowly release RH pedal on co-pilot side. 2 Open RH bleeder valve. 3 Fully depress and hold RH pedal on pilot side. Close RH bleeder valve, then slowly release RH pedal on pilot side. Open RH bleeder valve. Repeat RH caliper air purge at least 5 times. Verify fluid flowing out of tubing attached to RH caliper is clear of bubbles before continuing procedure. Caliper may be damaged if bleeder is over tightened. Ensure end of LH overflow tubing is completely submerged in fluid. Close bleeder valve on RH side and open bleeder valve on LH side one turn. Fully depress, and then slowly release LH pedal on co-pilot side 3 times. Fully depress, and then slowly release LH pedal on pilot side 3 times. Purge air from LH caliper. 1 Fully depress and hold LH pedal on co-pilot side. Close LH bleeder valve, then slowly release LH pedal on co-pilot side. 2 Open LH bleeder valve. 3 Fully depress and hold LH pedal on pilot side. Close LH bleeder valve, then slowly release LH pedal on pilot side. Open LH bleeder valve. (ab) Repeat LH caliper air purge at least 5 times. Verify fluid flowing out of tubing attached to LH caliper is clear of bubbles before continuing. NOTE The system is purged of air when there are no air bubbles in overflow tubing. Calipers may be damaged if over tightened. (ac) Close both bleeder valves. (ad) Close hydraulic tank feed valve and depressurize tank by removing air source. Verify pressure on both gauges reads zero. (ae) Remove overflow tubing from bleeder valves. (af) Torque bleeder valves 18.0 ±7.0 in-lb (16.7 ±0.8 Nm). (Refer to 20-60) (ag) Clean any residual fluid from bleeder valves, including inside opening. (Refer to 20-30) 26 03 Dec 2018
(ah) Remove 1/8" NPT fitting and feed tubing from brake reservoir. Cap off feed tubing after removal to prevent spillage. (ai) Perform Servicing - Brake Fluid Replenishing. (Refer to 12-10) (aj) Re-install plastic cap onto brake reservoir. (ak) Store overflow fluid in properly labeled gallon containers until tank needs to be refilled. NOTE While depressing rudder pedals, all pedals should feel similar. (al) Depress each rudder pedal with your feet and confirm there is solid pressure and pedals do not sink under steady pressure. (am) Engage parking brake. Verify brakes are holding by pushing on each end of wing and confirming airplane does not move. (an) If parking brake does not hold, but pedals have solid pressure, check rigging adjustment of parking brake valve. If rigging is determined to be correct, valve may be defective. (ao) If any of these checks fails, repeat brake bleeding procedure until satisfactory results are obtained. 27 03 Dec 2018
Figure 32-2-3: Bleeding the Brake System LEGEND 1. Pressurized Brake Bleeder 2. Tubing 3. Bleeder Valve. Brake Fluid Reservoir 5. Fitting 6. Overflow Container 7. Hose Clamp 8. Air Pressure Regulator 9. Brake Fluid Type Placard 6 2 9 3 2 7 2 5 1 2 8 SF50_MM32_0158 28
J. Brake System Pressure Test This pressure test will identify the location of any leaks. (1) Adjustment/Test - Brake System Pressure Test Acquire necessary tools, equipment, and supplies. Description P/N or Spec. Supplier Purpose Wheel Chocks WCK1001 Cirrus Design Block wheels. Hydraulic Fluid MIL-PRF-87257 Any Source Replenish brake system. Hydraulic Hand Pump Isopropyl Alcohol - Any Source Pressurize brake system. TT-I-735 Grade A or B Any Source Solvent clean. (b) (c) (d) (e) (f) (g) Place wheel chocks into position. Disengage parking brake. Verify pressure on gauge reads zero before opening tank. Cap and valve should be hand tightened only. Ensure relief valve is completely closed and filler cap is secure. Verify there is sufficient hydraulic fluid in tank. Refill if less than one gallon of fluid is left with either new or recycled fluid. Filter fluid and follow procedure on tank. Do not attach hydraulic hand pump to brake fluid reservoir inlet. Support attachment of pump to prevent damage to brake line. Disconnect brake fluid reservoir and attach hydraulic hand pump. NOTE Hold pressure for 1 minute and inspect all fittings for leaks between every increase. 29 03 Dec 2018
(h) Increase pressure by 100 psig increments until maximum pressure of 900+0/-30 psig is reached. 1 At 900+0/-30 psig, system pressure should not drop during 1 minute hold and no brake fluid should leak. (i) If any leaks were discovered during pressure test, release system pressure and close valve. 1 Note location of leak. 2 Service as required to repair leaks. 3 Solvent clean any fluid that leaked on aircraft. (Refer to 20-30) (j) Perform Adjustment/Test - Bleeding the Brake System if any fittings were loosened or re-torqued, or if brake system was opened anywhere other than the brake fluid reservoir. (Refer to 32-2) 30 03 Dec 2018