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Chrysler, Dodge, and Plymouth Brake Upgrades

(For more information on fixing brakes, visit the brakes section of our repairs page).

The goal: To move heavy duty brakes onto a smaller vehicle for much better stopping power.

Wayne Toy wrote:

What I do, sometimes, is look at lots of cars in the junkyard beforehand to get a feel of what will fit,what won't and what I may be able to use in the future.  For instance, there are at least 3 versions of rear axles on a K-type car between 1984 and 1988, but they all interchange.  I know they interchange because I tried it.  That's info that is not well documented, but important to know if you need a rear axle and the exact model of car is not available.

The spindles are the same between the regular and heavy duty.  I swapped the 220 mm heavy duty brakes from a 1986 Daytona into a 1988 Shadow that had the regular duty brakes.  By the way, you need the hard brake lines that connect from the wheel cylinder to the rear axle assy bracket.  These lines are different between the 200 and 220 mm systems. The front brakes can be upgraded to 260 mm without changing the knuckle/hub - it will bolt onto the existing hub. The front caliper assys and the rear backing plates are the same between car lines, as are most mechanical components.  In fact, most of the mechanical components in the K derived vehicles interchange.

I switched the rear brakes from the 1986 Daytona to the Shadow because "they were there".  I was parting out the Daytona and the parts were available.  I left the front brakes on the Shadow alone because they came stock with 260 mm K-H brakes.  I like the Kelsey-Hayes brakes better than the ATE's, anyway because it is easier to remove and replace the rotor.  On the K-H, they slide on and off, while on the ATE's, you have to unbolt the mounting bracket.

Ed Trejis wrote:

1987 donor cars include:

  • The Town & Country wagon (K/C-45) came standard with the heavy duty brakes (front and back), was K based, and was a wagon - got different proportioning master cylinders
  • K-type-LeBaron have 260mm fronts but *not* 220mm back unless heavy duty optioned
  • All E, G, H, J bodies have 260mm front brakes
  • 220mm rear brakes are standard on E and K/C-45 only; available as heavy duty
  • K and G cars with optional heavy duty brakes

I have finally gotten around to installing bigger 260mm/220mm disc/drum in place of a K-car's 240mm/200mm. I have also logged a few thousand kilometres of traffic ranging from banzai downtown Toronto runs (*rims* too hot to touch) to West Virginia/Blue Ridge hills.

DISCLAIMER: The following are my experiences and observations. Many observations have the flavour of opinions or recommendations; however I am not now, nor have I ever been, a brake engineer; nor am I a consultant offering services or expert advice for money or considerations. If you do a botched brake setup and spin off a hill into a refinery that explodes catapaulting your car into the path of a speeding garbage scow which rams you and sends you to the bottom of the sea, and therefore try to sue my pants off for bad advice, I will hang my head in shame and consternation and guilt, all the while snickering under my breath.

NOTE: the following is tested on an '87 K-car wagon. You will notice that the '87 FSM lists a variety of brake proportioning setups, depending on car. The brake balance will no doubt work differently on a two-door Aries with A/C and cruise. You will have to figure the possibilities yourself.

FRONT BRAKES: these were done first, back in January. It's an EXTREMELY simple conversion. Go to junkyard, find K-H caliper adapter in good shape. The "horns" take the force of braking, and therefore get worn by the pad backing plates. You can of course go to Mopar and pay C$150 for each adaptor. You will also need K-H calipers, pads, pins, bushings; and of course 260mm rotors. You can bolt your old (ATE) brake hose right up.

NOTE: these are *passenger* car parts. Not the "SLH" package advocated by SDML. No one has yet explained to my satisfaction why a bigger piston/cylinder bore is so much better. (Well, I can think of a couple of reasons, but suspect they'd apply mainly to road racers.) The good thing is that *I did not have to change the master cylinder*.

Results: car stopped MUCH better. The front wheels did lock up first, especially noticable when there was gravel over pavement. Not really dangerous, but sometimes annoying. Didn't get to test it in any big snowfall (or did I?). The rear brakes were at this point in somewhat sad shape. I would speculate that you might get away with this on a 2 or 4 door car with fresh rear 200mm brakes; then again you may have to play with the proportioning.

REAR BRAKES: more complicated, because Chrysler made about four different varieties of things just to annoy you. From the junkyard, you have to get rear backing plates and parking brake lever. I wound up with '89 Dynasty parts. I'm glad I did so, because the Dynasty drum setup is very nice. In particular, the automatic adjuster system is very precise (and will stay that way I think), and the brake shoes look heavy-duty. You will need shoes and other brake hardware (springs, adjuster assembly, cylinder) specific to the year and model of car. (E-body and Dynasty brake cylinders DO NOT interchange! Different shape where they fit into the backing plate! Don't ask how I know.) Drums and bearings are pretty generic, though. (Mopar drums come with the hubs and bearing races installed....bonus!) You will also have to fabricate the brake lines that run along the control arms from the pivots to the backing plates, unless your present lines are good enough to bend a bit so they meet up with the slightly different cylinder location.

You might as well change the bearings and seals, and even spindles if yours are trashed. Looking in a junkyard, though, all EEKs seem to have problems with bearings spinning on the spindle.

The parking brake was an interesting excercise. The long and short of it is, I *believe* that you should be able to re-use your existing parking brake cables because all the lengths are pretty much the same. (It seems that Chrysler made K-car regular parking brake cables, heavy-duty-brake parking brake cables, and wagon parking brake cables. Or at least dealers claim this.)

Results: better brake balance. At the limit, the rears lock up first, but it's a very, very high limit. I have had no reason to approach it, except just toying around in a Solo II. A near-panic stop when you're approaching a traffic light at 20 km/h over the limit, at the very limit of "should I stop, or go through", is stable with no hint of rear or front lock-up. In fact, the car now has the best brakes of any car I can recall driving. If rear lockup proves to be a problem in snow, I will try a slightly less agressive proportioning valve.

I suspect that the front and rear brakes would be in better balance had I used HD Reliant or E-body rear brakes, instead of the rather heftier Dynasty models.

I drove across the ridges of the Allegheny (Shenandoah?) mountains, which means up and down using switchbacks. I did *not* downshift heading down, ever. Just let the car run free to the next switchback (posted 15 MPH or 25 MPH), step on the brakes, watch the speedo needle dive from 80 km/h or more down to 40 km/h or less, and repeat until down in the valley. Never any hint of fade or overheating. No bad smells.

Steven (Rampage) wrote:

Cautions:

This information is being presented to inform and enlighten you as to the possibilities with your K car. I am not recomending that YOU do this with YOUR car. This is what I have done to mine. If you do this to YOUR car you are doing so at your own risk.

What follows is a description of the brake upgrade I did to my 1983 Reliant Sedan. The same information with small variances applies to any Extended K car through 1986. That covers LeBaron, 400, 600, Caravelle, Aries and New Yorker. Before you rush to the store and buy things DO YOUR RESEARCH!

Overview

There has been much written on brake upgrades for Front Wheel Drive Chrysler vehicles. Most of the tips and tricks involve upgrading the Chrysler L body series (Dodge Omni, Charger / Plymouth Horizon, Turismo). Recently, I needed to do a brake job on a 1983 Plymouth Reliant I had purchased for $100.00. The brakes were a mess so I decided that instead of replacing the stock brakes I would upgrade them.

I made this decision for several reasons. The first was replacing all the brake hardware, especially at the front, would be almost the same cost as the upgraded hardware. Second, I could not justify spending about the same money to repair the brakes and not improve on the stopping power. Third, was the curiosity to prove how interchangeable our cars really are.

Before I plunged in I began to plan and research. This is the only way to fly whenever you have a car project to do. After evaluating my options I decided that I would leave the stock brakes on the rear since most of the braking force (85-95%) is concentrated at the front. As I wasnít racing the vehicle I opted for a modified version of the SLH package which I have used with success on my L body cars.

Plan: To upgrade the front braking system of the Reliant to the fabled SLH spec with minor modifications.

To verify my hypothesis that the costs would be the same, I did a little research. Before I could proceed however, I had to know exactly what braking system I came on my Reliant. I discovered that in 1983 Reliants (and any K car for that matter) came with two types of brakes; Standard Duty and Heavy Duty. I also had a four bolt wheel hub (found on most K cars through early 1985) and 13" wheels.

I did my cost breakdown to determine the best scenario for the upgrade. One thing I realized was that upgrading the stock brakes would also require a change of wheel sizes from 13" to a minimum of 14". As I am planning to do some additional upgrades to improve front end handling this is not a problem.

Early Front Wheel Drive Chrysler Braking Systems:

The Chrysler braking system in Front Wheel Drive cars is designed with safety in mind. It is a dual reservoir, cross line system. The left front brake is connected to the right rear brake, and the right front brake is connected to the left rear brake. In early K and L models, the brake lines are connected from the dual reservoir master cylinder through a distribution block that acts to route the fluid through these cross lines. Beginning with 1984 models (although early models may still have the block) lines are routed from the master cylinder into a proportioning valve which meters to the brakes to prevent brake lockups.

Many people have advocated changing the brake block for a proportioning valve when performing this upgrade. You should consider this option if you are going to use your K in high speed applications (i.e. trying for the best quarter mile et at the county dragstrip next Friday night). Since I plan on using my Reliant for daily driving, this swap may be unnecessary.

Consider this while making your decision; the MiniVans used a brake block through 1990 when the systems started being configured with ABS. The only proportioning valve the MiniVans had was a spring actuated rear valve that allowed more fluid to the rear depending upon the load carried.

The Idea Behind The Upgrade:

The idea behind the upgrade is quite simple; to achieve more bang for the buck. Stopping power is achieved by increasing the brake pad surface area over the rotor. The calipers supplied with early K and G Bodies (Daytona/Laser) and the Shelby Charger were a 2 pin ATE brand caliper. These calipers were OK for stopping power but their pads were rather small and thus did not have too much surface area across the caliper face.

A manufacturing change allowed for the use of Kelsey Hayes calipers. This caliper has a single guide pin and has pads which cover a larger swept area over the rotor face.

In the case of the standard duty vs heavy duty brakes on the early Reliants the pads on the standard duty were smaller per surface area of the rotor. Thus, the desire for the upgrade. Simply upgrading calipers and pads for an early Reliant doesnít cut it because the brake rotor itself is a small diameter. The early Reliant brake rotor is about 9.5 inches in diameter. The Dodge Daytona rotor for the same year is about 10.5 inches in diameter. Imagine what an improvement this would be on an L body that had 8 inch non vented rotors!

So here it is in a nutshell:

  • Increase the pad surface area over the rotor.
  • Increase the rotor size
  • Increase the fluid volume moved into the caliper resevoir.

To perform these three upgrades the following must be changed:

  • Get larger brake pads and change calipers to support them
  • Get larger rotors
  • Get a larger master cylinder that is sized to fit the new calipers.

Reliant Brake Upgrade Cost Comparison Chart:

All cost breakdowns were constructed using prices from AutoZone. Your prices may differ. The point of these tables was to show that the price comparisons were in the ball park for better stopping power.

What follows is the cost comparisons of doing a stock rebuild of the entire braking system vs the SLH upgrade using parts I have found that work best.

Reliant Standard Duty

Reliant Heavy Duty

Part No

Part Description

Cost

Part No

Part Description

Cost

77379 Brakeware Lft Hose $7.99 77379 Brakeware Lft Hose $7.99
5322 Aimco Right Rotor $15.99 5323 Aimco Right Rotor $21.99
C246 Fenco Lft Caliper $11.99 C260 Fenco Lft Caliper $12.99
MKD170 Brake Pads $16.99 MKD220 Brake Pads $16.99
Total Cost $93.93 Total Cost $123.92

Below is the SLH upgrade that I have done on several L bodies and most recently on my Reliant.

Part # Description Cost Source Vehicle
77379 Brakeware Lft Hose $8 Reliant
77380 Brakeware Right Hose $11 Reliant
5327 Aimco Rotors (2) $12 x 2 = $24 Daytona (4 lug)
C542, C543 Femcpo calipers (2) $13 x 2 = $26 Minivan (single pin)
  Brake pads $17 Minivan (KH calipers)
M1983 Master cylinder, 24mm $20 Minivan
  Total cost $106  

In addition to the above parts list you will also need the following from Junkyard or other sources:

  • Left and Right caliper backing plates for single pin Kelsey Hayes MiniVan calipers.
  • A set of four 14 inch wheels (15 inch recommended).

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