Upgrading The Brakes

[ Front Disc | Rear Disc | Rear Drum | Master Cylinder | Proportioning Valves | Break-In | Early L-Body Upgrade | SLH Packages ]

Description

This page describes the options available for upgrading the brake system.  It lists all stock brake systems and their applications as well as some other upgrades.  Putting together a well-balanced system is very important.
 

Front Disc Brakes

This section describes the types of front brake systems that are available for most platforms.  The two 54mm caliper versions were used on various vehicles for various years.  Most vehicles equipped with 260mm rotors (mostly turbocharged) received the Kelsey Hayes caliper, except for G and K-bodies which got the ATE.  To check for sure, just look at the number of pins on the calipers.
 

The ATE 54mm Brakes

This brake caliper is a single 54mm piston, floating design that rides on two pins with teflon-sleeved rubber bushings, which are connected to the vehicle-specific adapter.  The shoes are held in place by two anti-rattle retainers.  The outboard brake shoe is held in place with a separate hold down spring and the inboard shoe is held by the piston with a retainer spring on the shoe.  This caliper is generally not desirable for performance applications due to its heat dissipation characteristics and strange tendency to warp rotors when used hard.  There are three versions of the caliper for the three types of pads available, depending on what size rotor is used:

The Kelsey Hayes 54mm Brakes

This brake caliper is a single 54mm piston, floating design that rides on one pin with a rubber bushing, which is connected to the vehicle-specific adapter.  The shoes are held in place by two anti-rattle springs.  The outboard brake shoe has a clip on the bottom side and the inboard shoe has a clip on the top side.  The caliper itself also has an anti-rattle spring, which is clipped to the outer edge of the top of the caliper.  There are two versions of this caliper for the two types of pads available, depending on what size rotor is used:

The Kelsey Hayes 60mm Brakes

This brake caliper was used on all S-bodies (minivans).  It is a single 60mm piston, floating design that rides on one pin with a rubber bushing, which is connected to the vehicle-specific adapter.  The shoes are held in place by two anti-rattle springs.  The outboard brake shoe has a clip on the bottom side and the inboard shoe has a clip on the top side.  The caliper itself also has an anti-rattle spring, which is clipped to the outer edge of the top of the caliper.  These calipers were used with 260mm rotors.
 

Disc Brake Rotors

There are three brake rotors that were available with the above brake systems.  They are:

Rear Disc Brakes

This section describes the types of rear disc brake systems that are available for most platforms.
 

The 1987 - 1988 Chrysler 33mm Brakes

This brake caliper was used on several Shelby vehicles (Charger, GLHS, CSX, etc) as well as some 1988 and later G-bodies (Daytona Shelby, etc).  It is similar to the ATE brake caliper.  It is a single 33mm piston, floating design that rides on two pins with teflon-sleeved rubber bushings, which are connected to the vehicle-specific adapter.  The shoes are held in place by two anti-rattle retainers.  The outboard brake shoe is held in place with a separate hold down spring and the inboard shoe is held by the piston with a retainer spring on the shoe.  These calipers use a solid 275mm disc and a minimum lining thickness of about 7.0mm.
 

The 1989 - 1991 Chrysler 33mm Brakes

This brake caliper was used on the LeBaron and Daytona after 1988.  It featured the same setup as the previous 33mm brakes, except the emergency brake used an small, integral drum on the disc, instead of the inferior wedge/screw setup of the earlier design.
 

The 1988 Chrysler 36mm Brakes

This brake caliper was used on 1988 C-bodies (New yorker and Dynasty).  It is similar to the ATE brake caliper.  It is a single 36mm piston, floating design that rides on two pins with metal-sleeved rubber bushings, which are connected to the vehicle-specific adapter.  The shoes are held in place by one anti-rattle retainer that is mounted to the top of the caliper.  They also featured a redesigned emergency brake that used an integral drum instead of the older wedge/screw setup.  These calipers use a solid 275mm disc and a minimum lining thickness of about 7.0mm.
 

The 1989 - 1991 Chrysler 36mm Brakes

This brake caliper was used on 1989 and later LeBaron GTCs and Daytona Shelbys.  It is similar to the 1988 36mm brake caliper except that it used 275mm vented rotors..
 

Rear Drum Brakes

This section describes the types of rear drum brake systems that are available for most platforms.  The typical upgrade is for L-bodies to go to the 220mm system.  All you need is the back plate and brake and drum assemblies.  Just remember that the newer 220mm drum brakes will have five wheel studs, instead of four like some of the earlier L-bodies.
 

The Chrysler 200mm Drum Brakes

These drum brake were used on most platforms.  They are a two shoe, internal expanding type and feature a 14.3mm cylinder with an automatic adjustment system that is activated each time the brakes are applied.
 

The Chrysler 220mm Drum Brakes

These drum brake were used on the heavier vehicles and on the Daytona chassis.  They are a two shoe, internal expanding type and feature a 14.3mm or 15.9mm cylinder with an automatic adjustment system that is activated each time the brakes are applied.
 

Master Cylinders

This section describes the types of master cylinders that are available for most platforms.
 

The Chrysler 21mm Master Cylinder

This master cylinder was used on all Chrysler FWD vehicles with rear drum brakes.  It featured an anodized aluminum body with a glass-reinforced nylon reservoir.  It had a 21.0mm bore and a 32.9mm stroke and a pedal ratio of 3.8 for L-bodies and 3.3 for all other vehicles.  The primary and secondary outlets have a balanced pressure output that is distributed by a differential valve below it.  The primary (front) outlet operates the left front and right rear brakes, while the secondary (back) outlet operates the right front and left rear brakes.
 

The Chrysler 24mm Master Cylinder

This master cylinder was used on all 1989 and later Chrysler FWD vehicles with rear disc brakes (Daytona Shelby, LeBaron GTC).  It featured an anodized aluminm body with a glass-reinforced nylon reservoir.  It had a 24.0mm bore and a 32.9mm stroke and a pedal ratio of 3.3.  The primary and secondary outlets have a balanced pressure output that is distributed by a differential valve below it.  The primary (front) outlet operates the left front and right rear brakes, while the secondary (back) outlet operates the right front and left rear brakes.
 

The Chrysler 28.5mm Master Cylinder

This master cylinder was used on all 1984 - 1992 Dodge D150 trucks.  The primary and secondary outlets have a balanced pressure output that is distributed by a differential valve below it.  The primary (front) outlet operates the left front and right rear brakes, while the secondary (back) outlet operates the right front and left rear brakes.  This cylinder uses a different size flare connections than the stock unit.  You will need adapters for your brake lines, available from Edelman, (p/n 258340 and 258350) or remove the fittings from the same truck and put them on your lines (you will need a flaring tool).
 

Differential and Proportioning Valves

Brake systems distribute the pressure from the master cylinder through a differential valve.  These function by splitting the two master cylinder outputs between the left-front and right-rear brakes and vise versa.  This way if one set fails, the other set can still stop the vehicle because the brakes are split diagonally from each other.  In most cases, pressure to the rear brakes has to be reduced.  This is accomplished through a proportioning differential valve.  There are several different proportioning valves available, depending on the brake system combination your vehicle has.  They function by reducing the amount of brake fluid pressure to the rear brakes after a certain input pressure point, called the split point.  The ratio by which the rear brake pressure is reduced after the split point is called the proportioning slope.  The lower the slope value, the more the pressure to the rear brakes is reduced.  So, if you find that your rear brakes tend to lock up prematurely, then you need a valve with a lower slope and/or lower split point.  A perfectly balanced brake system does not need a proportioning valve.  Instead these use a basic differential valve that have no proportioning feature, and therefore have no split point and have a slope of 1.  Stock proportioning valves are identified by the color of the indent tag.  Below is a chart of available valve configurations.
 
Tag Color
Function
Material
Split Point
Slope
(none)
Differential
Brass
-
1
Grey
Differential-Proportioning
Brass
500psi
0.27
Tan
Differential-Proportioning
Brass
600psi
0.43
White
Differential-Proportioning
Brass
750psi
0.43
Black
Differential-Proportioning
Brass
800psi
0.59

This table shows some of the vehicles that these valves were used in.  Some bodies had different valves depending on their brake configurations (disc/drum, disc/disc, ABS, etc) and specfic body styles (2-door, 4-door, etc).
 
Tag Color
Bodies
(none)
E
Grey
L, J, P
Tan
K, P
White
G, H
Black
G, K

Proper Brake Break-In

The bonding material used on modern brake pads requires a heat and pressure cycle to cure it.  By following this "brake-in" procedure from Ed Peters, you will complete this curing process and also break-in the pad and rotor surfaces.
  1. With the new pads installed, be sure to torque the lug nuts in a star pattern with equal amounts of torque.
  2. Start the engine and pump the brakes until you feel them being applied (the pedal does not sink too far).
  3. Check your brake fluid levels.
  4. Accelerate the vehicle at a moderate rate to 60mph
  5. "Apply the brakes just enough so that if a cup of coffee was sitting on the passenger seat, it would fall to the floor" (ala Ed Peters) until you reach 30mph.
  6. Then accelerate gently at about 1/2 throttle back to 60mph.  This is the cool-off period for the rotors.
  7. Repeat steps 5 - 6 at least 20 - 25 times.
  8. Once completed, drive at a moderate speed for a few minutes, minimizing the use of the brakes, so that the rotors can cool.
  9. Once you park the vehicle, the brakes will stick and may even be smoking.  This is normal.
  10. For the first ten minutes while parked, roll the vehicle back and forth about 2-3 feet every 10 seconds.  This is to keep from warping the rotors with the hot pads.
  11. Now allow the vehicle to sit for at least 12 hours so that the curing process can complete.

The Early L-Body Brake Upgrade

This package brings the sub-standard brake system of the 1983 - 1986 L-bodies up to par with the later, stock systems.  For 1984 - 1986 vehicles, you will need If you have a 1983 1/2 Shelby Charger, you will also need the proportioning valve and some of the brake lines from a later model L-body.  It is best to get new pads and rotors for the front and new shoes and have the drums resurfaced for the rear.  Also regrease the pins on the calipers and replace any other components that may be in bad shape.
 

The SLH Brake Packages

The SLH (stops like hell) package is a set of balanced brake upgrades that can be used on most platforms.  It was originally documented by Mark Panos and has been reprinted by Dempsey Bowling on his SLH Brake Packages page.
 

The SLH 1 Package

This package upgrades the front calipers to the Kelsey Hayes 60mm units to improve stopping power even more.  You need to have 220mm rear drum brakes to use this upgrade.  You will need: You need the larger master cylinder to balance the additional fluid movement requirements of the 60mm calipers.  You also may need to change your proportioning valve if you find that the rear brakes are not balanced properly.  What valve is needed depends on the weight distribution of the vehicle.
 

The SLH 2 Package

This package upgrades the rear brakes to the 33mm solid rear disc brake system.  You will need these parts from a 1989 or later Datona or LeBaron: You need the larger master cylinder to balance the additional fluid movement requirements of the 33mm calipers.  You also may need to change your proportioning valve if you find that the rear brakes are not balanced properly.  What valve is needed depends on the weight distribution of the vehicle.
 

The SLH 3 Package

This package is an additional upgrade for the rear brakes.  If you can find them, it uses the 36mm vented disc brakes from the 1989 - 1991 Daytona Shelby and some LeBaron GTCs.  You will need from the donor vehicle: You will need the 60mm front brakes from SLH 1 and the 28.5mm master cylinder from SLH 2.
 
 
 
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This page is maintained by Russell W. Knize and was last updated 06/03/99. Comments? Questions? Email minimopar@myrealbox.com.

Copyright © 1996-2003 Russ W. Knize