NAPA Brakes Technical Tips

NAPA Brakes Technical Tips bulletins are intended to help installers avoid common installation and service errors. The technical service literature presented here is derived from our own experience and the product knowledge we’ve gained from component analysis and research. Following these tips will ensure the best possible performance and service life of your replacement units.
In each technical bulletin, you will find the following information:
  • Application and vehicle(s) involved.
  • Problem and condition.
  • Solution and repair procedure.


ABS Systems and Master Cylinders

Before you replace any brake components, the cause of the original unit failure must be determined and corrected. Installing a replacement unit without correcting the problem will lead to early failure. Always refer to your vehicle service manual for specific installation procedures and specifications.

Brake Bleeding Vehicles with Antilock Brakes

or all vehicles with an Antilock Brake System (ABS) where the brake pedal feels spongy after parts have been replaced of the brake system has been opened. When the brake system is opened for any repair, air is introduced into the system. ABS brake systems may require special tools or equipment to help remove all the air.

Preventing ABS Problems after a Caliper or Pad Change

For all vehicles with an Antilock Brake System (ABS) and ABS failure or malfunction soon after the caliper or pads have been replaced. After the caliper is removed, if the caliper piston is forced back into the bore without opening the bleeder, contaminated fluid will be forced back into the ABS hydraulic unit and/or master cylinder causing valves/pistons to stick.

Intermittent ABS Operation Caused by a Cracked Sensor Ring

For all vehicles with an Antilock Brake System (ABS) and sensor rings located on the outer drive axle joint with intermittent ABS failure or trouble codes. Rust can develop between the axle and the ABS speed sensor ring. The rust acts like a wedge and causes the ring to crack, creating a false or erratic signal which results in intermittent ABS operation.

RABS or RWAL Low or Sinking Pedal

For all Dodge, Ford, and GM Trucks with R.A.B.S. and R.W.A.L. Anti-Lock Braking Systems and vehicles with a low or sinking brake pedal. Contamination may be causing the dump valve portion of the Anti-Lock Braking System to remain open, allowing the brake fluid to bypass into the accumulator and create a low or sinking brake pedal.


Wheel Speed Sensors

Hall-effect sensors provide information to the PCM such as crank speed, cam position, driveshaft speed, and vehicle speed. Hall devices require a power supply and have three wires. Active Wheel Speed Sensors are relatively new devices that also require a power supply to function, but they only have two wires. This is extremely important, because if you don’t know that the vehicle uses active sensors, then your diagnostics can mislead you into replacing a sensor that is perfectly functional.


Brake Hose May Cause Low Pedal

For all vehicles with power brakes. This document will help you diagnose a sinking, low, or spongy brake pedal by isolating the master cylinder, and test the brake hoses to figure out where the circuit containing the defective component is located.

Subaru Cold Weather Braking Effort Problem

For all 1998 and 1999 Legacy Sedan, Wagon, Outback, and Forester Subaru vehicles with power brakes that require high effort (hard brake pedal) in extremely cold weather. Braking ability gets better as air temperature rises. These Subaru vehicles have an in-line check valve, and in cold weather the moisture freezes and blocks the vacuum booster, which makes braking harder.


Top Ten Caliper Replacement Tips

For all vehicles equipped with brake calipers. These tips and tricks address the root causes of common caliper problems that technicians face during caliper replacement, and the precautions and corrections that ensure a successful caliper installation. Refer to your vehicle’s service manual for specific diagnostic instructions

Brake Caliper Assembly: Lubrication

Not all lubricants are created equally, and some can cause rubber components in the brake caliper to swell and resist movement. Other compounds do not provide much protection of metal-to-metal contact points. Since brake systems experience a wide heat range, it’s important to select a product that will do the job under such conditions.

Slider-Style Brake Caliper Problems

For all vehicles with floating/sliding brake calipers that have a worn pad, uneven pad wear, or abnormal caliper operation. The caliper is not free to move because of bent or binding mounting pins, worn slides, bent or damaged mounting brackets, swollen or hardened guide seals, or lack of lubrication.

Sticking Caliper Piston Cause and Solution

For all vehicles equipped with caliper pistons that are not returning properly or are stuck in the bore due to residual hydraulic pressure, which is keeping the piston applied. After installing and bleeding the replacement caliper, if the piston does not return properly or sticks, open the bleeder valve and recheck. If the piston releases, the caliper is working correctly.

Caliper Letter Codes: SE1887 or SE1887B

For Ford Escort, EXP, ZX2 1991-2001 front brake calipers, loaded or unloaded, which are causing the brake rotors to grind against the brake caliper bracket. The counter person must make sure the customer gets the correct caliper for the application. Please reference the catalog for specific applications.

Brake Fade, Excessive Pedal Travel: E250, E350, F250, F350

For Ford 1991-89 E250, E350, F250, F350 vehicles with excessive brake pedal travel or brake pedal fade, which may occur during application, especially when heavily loaded or on steep downhill grades. This may be caused by the original brake caliper piston material. According to Ford TSB 91-20-8, switching to phenolic piston equipped calipers may correct problem.

Why Can’t I Get a Good Brake Pedal? (Early GM 4-Wheel Disc Vehicles)

This procedure applies to early GM 4-wheel disc brake vehicles. Refer to the vehicle’s service manual for specific adjustment procedures. This procedure MUST be performed as part of the rear caliper replacement operation. Failure to adjust the parking brake lever can result in no parking brake and possible premature brake wear or damage.

GM “W” Body Calipers Seized

This procedure applies to early GM “W” body vehicles with corrosion causing the slider pin to stick and seize in the brake caliper. The use of different metals in the original design results in corrosion in the caliper slider pin bore, causing the slider pin to seize.


Diagonal Split Bleeding Sequence

For all front wheel drive (FWD) vehicles with diagonal split brake systems where the brake system won’t bleed, uneven pad wear, low brake pedal, or warning lights that won’t go off due to an improper brake bleeding sequence. These diagonal split systems require a special bleeding sequence.

Rich-Running Fuel Injected Engine Causes Booster Failure

For all vehicles with gasoline fuel-injected engines and vacuum boosters with a booster failure due to a ruptured diaphragm. Improper fuel management causes excess gas or gasoline fumes to enter the booster, thus destroying the diaphragm. Ensure proper operation of the fuel management system.

Solving Brake Lockup on Honda/Acura Boosters

Applicable to Acura and Honda power brake boosters and master cylinders when brake lockup occurs after changing the power brake booster or master cylinder. The adjustment between the booster pedal rod and master cylinder must be checked when replacing either unit. Refer to your vehicle service manual for the specific procedure and special tools required (07JAG-SD40100).

Hydro-Boost Flush Procedure

Applicable to all vehicles with power steering pump powered hydroboost brake systems with pedal kickback, grabbing brakes, increased pedal effort, hissing noise while applying brakes, or increased steering effort. Can be caused by contamination of hydroboost system due to deteriorating hoses, contaminated fluid, or steering unit failure.

Hydro-Boost Tips

Applicable to all vehicles with power steering pump powered hydroboost brake systems that are experiencing improper operation or a noisy system. Hydro-boost brake systems are self-bleeding if there is no other problem in the system. Use this initial bleeding procedure when replacing or servicing any component in a hydro-boost system. Always refer to the vehicle service manual for specific installation and testing procedures.

Hydro-Vac Booster Requires Diaphragm Oil

Applicable to various Ford, Chevy, Dodge, GMC, International, Mack medium-duty trucks, and heavy equipment vehicles using Hydro-Vac Boosters (51-8028, 8056, 8060, 8091). These units have a leather diaphragm and while in service, the oil dries out, causing the diaphragm to harden and eventually fail. The diaphragm leather requires oiling.

A Filter In-Line, Saves Time

Applicable to all gasoline vehicles with vacuum power brake boosters that experience premature brake booster failure because of improper operation. A failing brake booster can be caused by gasoline, gas fumes, or moisture entering the booster and damaging internal rubber components.

Weak or No Booster Assist Due to Vac Hose Problems

Applicable to all vehicles equipped with vacuum brake boosters experiencing weak or no power brakes assist caused by insufficient vacuum volume to operate booster at maximum efficiency. While a defective booster will cause a hard pedal, a spongy or low pedal requires a hydraulic system check. Repair as necessary.

Wrong Pedal Rod or Brake Light Switch Adjustment Problem

Applicable to all vehicles equipped with firewall-mounted brake boosters where the brake lights stay on, as if the replacement unit pedal rod was too. This can be caused by a misadjusted brake pedal rod, misadjusted brake light switch, or the wrong unit. First, verify the application and the unit ordered. Next, verify that you have received the right unit. Finally, inspect the switch and pedal rod and adjust if possible.

How to Choose the Right Brake Fluid

Applicable to all vehicles. It’s important to choosing the right fluid for your braking system (DOT 3, 4, or 5). You should use the fluid specified by the original vehicle manufacturer. DOT 3 & 4 brake fluid is a mineral-based fluid. DOT 5 is silicone-based. Refer to the vehicle service manual to determine which brake fluid your vehicle requires.

Can I Mix Brake Fluid?

Applicable to all vehicles. When servicing a brake system, you must always replace the brake fluid using OE specified brake fluid. Mixing fluids or using petroleum based fluids will ruin seals and gaskets and cause brake failure. Refer to the vehicle service manual to determine which brake fluid your vehicle requires.

Brake Lockup Nissan Quest and Mercury Villager (P3188 & M3188)

For Nissan Quest/Mercury Villager minivans with ABS (up to the 2002 model year) using the master cylinder part number P3188 and M3188 and the left front/right rear brake is locking up due to contaminated brake fluid that may have blocked the ABS modulator valves (dampener valve), or an ABS component failure that is preventing the brake pressure from being released.

Angle Mounted Master Cylinder Bleeding Procedure

Applicable to all vehicles with angle-mounted master cylinders that are unable to obtain a firm brake pedal when bleeding the master cylinder on the vehicle. This is caused by air trapped in the upper end of the master cylinder past the secondary port. Always flush the entire brake system with approved fluid when any brake component is replaced.

Failed Booster Seal Causes Master Cylinder Leaks

Applicable to all vehicles equipped with power brake booster assemblies that are facing chronic master cylinder failure due to fluid leaking past the secondary seal in the master cylinder bore. This is caused by a defective master cylinder pushrod seal in the power brake booster. Always flush the entire brake system with approved fluid when any brake component is replaced.

Low Pedal on Late Model Ford Pickup Trucks

Applicable to 1995 Ford F250 and F350 trucks with brake master cylinder part number 10-4007 or 10-2690 experiencing a low or long pedal throw action. According to Ford technical service bulletin TSB 96-25-19, the master cylinder should be changed to a unit with a larger bore size. Upgrade to brake master cylinder part numbers 10-2827 or 10-2828 as necessary.

Step Bore Bench Bleeding Procedure

It is difficult to bleed all of the air out of this style of brake master cylinder after it is installed on the vehicle. However, it is very easy to bench bleed the unit before it is installed. Follow NAPA’s new and improved brake master cylinder bench bleeding procedure to properly bleed your brake system.


Brake Pad Break-In/Bedding-In/Burnishing

Break-in, bedding-in, and burnishing brake pads all mean the same thing. These terms refer to the process of conditioning new disc brake pads and brake rotors. The following steps are recommended to achieve optimum performance and life out of your new brake pads.

Brake Pad Wear Chart Diagnosis Caliper Problems

For all vehicles equipped with disc brakes experiencing uneven brake pad wear. Depending on the brake pad wear pattern, the caliper slide pins, caliper bushings, mounting hardware, brake lines, brake hoses, brake rotors, or brake booster may need to be replaced. Refer to the diagrams to identify the problem with your brake system and how to repair it.


4401810BRNG Removal & Installation Instructions

For all Ford vehicles equipped with 4401810BRNG drum brakes. The following steps and diagrams illustrate the recommended procedures for brake drum removal and installation.

Brake Drum Run Out Validation Flow Chart

Applicable to all vehicles equipped with brake shoes and drum brakes. The most accurate way to measure run-out is using a brake lathe and a dial test indicator. Refer to the flow chart to know the recommended procedure for brake drum removal and installation, and how to measure brake drum run-out.

Ford Focus Drum Brakes Rear Wheel Bearing Failure

Applicable to Ford Focus vehicles from 2000 to 2008 equipped with brake drums and brake shoes that are experiencing repetitive rear wheel bearing failures. If the hub is damaged or has an out of round spindle, premature bearing failure is imminent. Refer to the recommended procedure for hub replacement and torque specification.

Brake Rotor Rusting of Braking Surface

Applicable to all vehicles equipped with brake shoes and drum brakes with rust flaking or rust pitting on the braking surface. Refer to the technical service bulletin to understand the different categories of rust, along with its causes and effects.
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