Brake System Troubleshooting Guide (AJA50639)

BRAKE SYSTEM TROUBLESHOOTING GUIDE

TECHNICAL SERVICE BULLETIN

SERVICE INFORMATION

Use this Job Aid for troubleshooting common brake system issues based on symptoms (steps are in proper troubleshooting order).

CONDITION
POSSIBLE SOURCES	Brake Pull	Sinking Pedal	Low/Spongy Pedal	Brakes Drag Rapid Wear	Excessive Brake Pedal Effort	Vibration During Braking	Rattling	Squeal	Groaning/Moaning	Grinding/Scraping	POSSIBLE SOURCES
Air in the Brake System		4	2								Air in the Brake System
Anti Squeal Shims			6				1	1	1	1	Anti Squeal Shims
Booster Unit				7	3				5		Booster Unit
Booster Vacuum Leak					4						Booster Vacuum Leak
Brake Lines	7		9	9							Brake Lines
Brake Pads/Shoes	2			8	1		3	3	2	3	Brake Pads/Shoes
Brake Pedal Switch				2							Brake Pedal/Switch
Brake Pistons	3		7	5							Brake Pistons
Brake Shield							2	2		2	Brake Shield
A/C Cycling		1									A/C Cycling
Fluid/Leak		2	1	3							Fluid Leak
Lug Nuts						4					Lug Nuts
Master Cylinder		3	4		5						Master Cylinder
Parking Brake				6			7				Parking Brake
Retaining Clips				4							Retaining Clips
Rotors/Drums	6		5		2	1		4	3	4	Rotors/Drums
Sliding Pins	1		3	1			4		4		Sliding Pins
Steering						2	5				Steering
Suspension	5					3	6				Suspension
Tires	4					5			6		Tires
VSA/ABS Unit			8								VSA/ABS Unit

BRAKE PULL

No.	Source	Check/Inspect for
1	Sliding Pins	Damaged, stuck, incorrect size/type
2	Brake Pads/Shoes	Metal to metal contact, contamination, mismatched pads
3	Caliper Pistons	Stuck pistons, damaged/leaking piston seals
4	Tires	Uneven wear, improper inflation, mismatched tire type/brand
5	Suspension	Loose/damaged components
6	Rotors/Drums	Contamination
7	Brake lines	Binding, kinks, pinched, weak, inner or outer bulging or damaged hose

SINKING PEDAL

After the vehicle comes to a complete stop, the brake pedal drops or sinks further than an identical vehicle.

No.	Source	Check/Inspect for
1	A/C Compressor Cycling	Brake booster vacuum from the engine is decreased when the A/C compressor cycles on during idle operation, leading to sudden brake pedal drop.
2	Fluid/Leak	Excessive fluid contamination/deterioration, check for brake system leaks in the lines, master cylinder, brake booster, VSA system, and any related hardware
3	Master Cylinder	Perform master cylinder inspection
4	Air in the Brake System	Bleed the system to ensure integrity

LOW OR SPONGY PEDAL

Brakes seem slow to respond or are soft/mushy when applied because of excessive pedal stroke.

No.	Source	Check/Inspect for
1	Fluid/Leak	Check for brake system leaks in the lines, master cylinder, brake booster, VSA system, and any related hardware, excessive fluid contamination/deterioration
2	Air in the Brake System	Bleed the system to ensure integrity
3	Sliding Pins	Binding
4	Master Cylinder	Perform master cylinder inspection
5	Rotors	Dished rotors with new pads installed.
6	Anti-Squeal Shims	Incorrectly installed, incorrect aftermarket component
7	Caliper Pistons	Damaged/leaking piston seals, excessive piston seal rollback, stuck piston
8	VSA/ABS Unit	Air in the modulator
9	Brake Lines	Weak, inner or outer bulging

BRAKE DRAG OR WEAR

Brake pads or shoes are in continuous contact with the disc brake rotors or brake drums leading to early, rapid, or uneven brake wear.

No.	Source	Check/Inspect for
1	Sliding Pins	Damaged, stuck, incorrect size/type
2	Brake Pedal/Switch	Insufficient pedal free play
3	Brake Fluid	Brake fluid contamination leading to swollen seals
4	Retaining Clips	Rust, contamination, inadequate lubrication or brake pad clearance
5	Caliper Pistons	Stuck caliper pistons/cylinders
6	Parking Brake	Insufficient drum shoe clearance, parking brake applied during driving, sticking or corroded cables
7	Booster Unit	Misadjusted push rod, check valve
8	Brake Pads/Shoes	Aftermarket material composition
9	Brake Lines	Binding, kinks, pinched, weak, inner or outer bulging or damaged hose

EXCESSIVE BRAKE EFFORT

The brake pedal must be pressed hard to stop the vehicle despite maintaining the normal pedal stroke/high or hard brake pedal.

No.	Source	Check/Inspect for
1	Brake Pads/Shoes	Glazing, contamination, aftermarket material composition
2	Brake Rotors/Drums	Contamination, glazing, heat spots, corrosion
3	Booster Unit	Misadjusted push rod, frozen check valve
4	Booster Vacuum Leak	Perform booster unit inspection test
5	Master Cylinder	Perform master cylinder inspection

VIBRATION DURING BRAKING

A judder or pulsation is felt through the brake pedal, steering wheel, seat, floor, or elsewhere in the vehicle when the brakes are applied.

No.	Source	Check/Inspect for
1	Rotors/Drums	Excessive lateral runout or parallelism, corrosion, heat spots, contamination
2	Steering	Loose/damaged components
3	Suspension	Loose/damaged components
4	Lug Nuts	Over torqued causing excessive rotor lateral runout
5	Tires	Dynamic or static imbalance

RATTLING NOISE

A noise similar to a baby rattle originating from the brake area when driving over bumpy surfaces either off or on the brake.

No.	Source	Check/Inspect for
1	Anti-Squeal Shims	Incorrectly installed, incorrect aftermarket, loose
2	Brake Shield	Check for foreign material caught between the shield and rotor, bent/loose/misaligned shield
3	Brake Pads/Shoes	Excessive clearance
4	Sliding Pins	Loose, incorrect size/type
5	Steering	Loose/damaged components
6	Suspension	Loose/damaged components
7	Parking Brake	Sticking, cut or frayed cables, excessive drum shoe clearance against backing plate

SQUEALING NOISE

A noise similar to skidding tires or a loose fan belt when the brakes are applied.

No.	Source	Check/Inspect for
1	Anti-Squeal Shims	Inadequate lubrication, loose, missing, damaged, incorrectly installed, incorrect aftermarket
2	Brake Shield	Metal to metal contact, check for foreign material caught between shield and rotor, bent/loose/misaligned shield
3	Brake Pads/Shoes	Metal to metal contact, aftermarket material composition
4	Rotors/Drums	Metal to metal contact, glazing, scoring, heat spots, corrosion, aftermarket material composition

GROANING OR MOANING NOISE

A noise similar to blowing across the top of an empty bottle (moaning) or a twisting wooden beam on a ship (groaning) when the brakes are applied.

No.	Source	Check/Inspect for
1	Anti-Squeal Shims	Incorrectly installed, incorrect aftermarket
2	Brake Pads/Shoes	Metal to metal contact, inadequate clearance, aftermarket material composition
3	Rotors/Drums	Glazing, scoring, heat spots, corrosion, aftermarket material composition
4	Sliding Pins	Binding
5	Booster Unit	Misadjusted pushrod
6	Tires	Uneven wear, driver may be sensitive to tire compound on different road surfaces

GRINDING OR SCRAPING NOISE

A noise similar to the sharpening of a tool on a grinding wheel when the brakes are applied.

No.	Source	Check/Inspect for
1	Anti-Squeal Shims	Incorrectly installed, incorrect aftermarket, loose
2	Brake Shield	Check for foreign material between shield and rotor, bent/loose/misaligned shield
3	Brake Pads/Shoes	Metal to metal contact, inadequate clearance, aftermarket material composition
4	Rotors/Drums	Aftermarket material composition, corrosion

LIQUIDS AND LUBRICANTS USED ON THE BRAKE SYSTEM

Lubricant	Part Number	Use
Brake Cleaner	P/N 08700-9201	Cleans brake drums, liners, cylinders, springs, and disc pads; degreases brake fluids, grease and oil
Heavy Duty Brake Fluid DOT 3	PN 08798-9008	The only brake fluid specifically formulated for use in Honda vehicles and AKEBONO caliper piston seals.
Honda Silicone Grease	P/N 08C30-B0234M (supersedes 08C30-B0224M/Honda caliper grease)	Use on caliper piston seals and boots, sliding pins and boots
Spray Cleaner and Polish	P/N 08700-9203	Cleaner for degreasing parts and removing brake dust from alloy wheels
Hondabrite All Surface Cleaner	P/N 08732-0020B	Cleaner for degreasing parts and removing brake dust from alloy wheels
Molykote 44MA	Call Dow Corning: (800) 248-2481	Use on the backing plate and brake shoe contact points  and on the ends of the shoes, shoe adjuster bolt and connecting rod
Molykote M77	P/N 08798-9010 call Dow Corning at (800) 248-2481	Use between brake pads and pad shims, brake pad ends and between caliper bracket and pad retainers
Shin-Etsu Silicone Grease	P/N 08798-9013	Use on master cylinder inner bore lip and rods
T68	P/N 08734-0016	Use on master cylinder inner bore lip and rods