1. Brake & Wheel Systems
  2. Rear Disc Brake Options

89-94 Rear brakes offer the best options when upgrading rear brakes on 78-94 G, J, K, H, P, A, and even L body cars.


While 87 and 88 model year G bodies did come with rear disc brakes which were light weight they should be avoided due to the problematic parking brake system. Dodge Dynasty rear brakes should also be avoided for all years because their backing plates are not the same bolt pattern as the other cars(but we will get back to that).


'89-94 11" Vented rear disc brake specs:

11" Vented Rotors
36mm Calipers
Internal parking brake drum.
11" Backing Plates (marked 15)

Advantage/Disadvantages:
+ Biggest possible brakes
- Heaviest Rotor (14 lbs)
- Too powerful for most Lbodies.
- Somewhat rare and getting more rare.

Vented Rear Rotor Specs:



'89-94 (or Neon) 10" Non Vented rear disc brake specs:

10" Non Vented Rotors
34mm calipers (The same calipers as the 95-99 Neon).
Internal parking brake drum.
10" Backing plates (marked 14)

Advantage/Disadvantages:
+/- Smallest disc brakes.
+/- Weakest Brake setup.
+ 3lbs lighter rotor than the vented setup (11lbs)
+ Easy to find and share calipers with the 95-99 Neon.

Non Vented Rear rotor Specs:


Confirmed Weight of a non vented rear centric c-tek rotor.



Here are some other options that can upgrade the setup:

Neon Rotors are very similar to the non vented rotors but unfortunately have a taller hat.

Here is the difference between the solid rotors and neon solid rotors:

89-94 Non Vented Fwd Dodge.


SRT4 Neon (taller than 89-94 with the same thickness and 1lb lighter due to modern machining?):


Neon (thinner than the 89-94 making it 2lbs Lighter):


Confirmed Weight of an autozone Duralast 95-99 Neon Rotor (Over 2lbs lighter!).


One big advantage of this is that the 89-94 non vented rotors are no longer available for premium brakes such as centric premiums, powerslot, EBC, etc where the Neon rotors are readily available.

Neon backing plates can be used but the axle will have to be trimmed to clear the parking brake cable housing on the backing plate. The Neon also has an independent rear suspension and the axle is integrated into the rear suspension. The axle its self is different and has a smaller hole in the backing plate. In order to use the backing plate with a 85-94 hub the center hole must be enlarged. This makes using the 89-94 backing plates a much easier option especially if a rear dum hub is used (which will be described shortly).

Here is the catch with using 89-94 backing plates (and why I said Unfortunately earlier)...

The 2-2.5mm difference in rotor hat height will cause the Neon rotor to bottom out on the 89-94 non vented backing plate:

TD Rotor with Backing Plate:



Neon Rotor with Backing plate.


One solution is to use a 1/8" (3.1mm) spacer between the hub and rotor:




Neon rotor with spacer!


Caliper position with the Neon rotor and spacer:


Another option is to use a 85-94 rear drum hub with the 89-94 non vented backing plate and Neon rotor.

This isn't the best picture because it was taken for a different purpose (a modification that allowed a shorter Ford Festiva Dust cap) but you can see the difference in the hubs if you look closely.

Drum Hub on Left, Disc Hub on Right. (Notice that the rear disc hub is also shifted upward slightly in the picture. The measured difference in stub to hub face is 6mm)


The rear drum hub is offset about 6mm farther outward than the rear disc hub. It also does not have the extra step for the rotor which is thicker than a drum. My rotors fit very tightly and hub centric so I see no issue whatsoever with using the rear drum hub. The rear disc and rear drum axle stubs (spindles) are the same so there is no reason to change those.

The 6mm offset is well within the slider range of the caliper and it makes everything bolt on perfectly. I currently have this setup installed on my 87 GLHS.
In my experience the rear drum hub will work with most of the rear disc backing plates and rotors. Recently a member has reported that some vented setups with new thick pads will not work with the rear drum hubs due to the extra offset. It is possible that the offset was removed specifically for the vented rear setup. I have also used rear drum hubs with a vented setup and new pads so your mileage may vary.


36mm calipers that are bolt on compatible with the 89-94 non vented calipers came on lots of cars:
This is a case where something from a 91+ Dodge Dynasty is useful. The backing plates however are not bolt on so only the calipers are useful.

CHRYSLER 300M (1999 - 2004)
CHRYSLER CONCORDE (1998 - 2004)
CHRYSLER DYNASTY (1991 - 1993)
CHRYSLER IMPERIAL (1991 - 1993)
CHRYSLER LHS (1999 - 2001)
CHRYSLER NEW YORKER (1991 - 1993)
CHRYSLER SEBRING (2001 - 2006)
DODGE DYNASTY (1991 - 1993)
DODGE INTREPID (1998 - 2004)
DODGE STRATUS (2001 - 2006)



Custom Rear Brake Options!



10" Non Vented backing plates with..

10" Neon Rotors and 34mm Non Vented (or Neon) calipers.
+/- Smallest disc brakes.
+/- Weakest Rear Disc Brake setup (which can be good for an lbody).
+ 4-5lbs lighter than the vented setup.

10" Neon Rotors and 36mm Dynasty/Intrepid/Concorde Calipers
+ Strong brakes, light weight.
- Lighter and non vented rotors means more brake fade.

10" 89-94 Non vented Rotors and 36mm Dynasty/Intrepid/Concorde Calipers
+ Strong brakes, light weight.
+ More rotor to prevent brake fade compared to the Neon rotors.
- Less rotor and no vented means more brake fade compared to the full vented setup.


Changing the rotor size changes bias, changing pad material changes bias, etc etc so it isn't so straight forward....

Just use this: http://www.tceperformanceproducts.com/bias-calculator/

Typical Brake Options (assuming the same pad compound front and rear):
Examples in italics are not real or not viable options but for comparison only.

60mm caliper 11.69" fronts with 36mm caliper 10.64 rears is 75.2% (Intrepid)
60mm caliper 11.11" fronts with 36mm caliper 11.27 rears is 72.6% (11" fronts with vented rears)
58mm caliper 11.025" fronts with 36mm caliper 10.62 rears is 71.4% (SRT4)
54mm caliper 10.24" fronts with 34mm caliper 10.62" rears is 66.8% (10" all disc car)
54mm caliper 10.12" fronts with 34mm caliper 10.62" rears is 66.1% (Neon with rear discs)
-
60mm caliper 11.11" fronts with 34mm caliper 10.62" rears is 75.2% (not a factory option but it is what I am doing for my lbody)
60mm caliper 11.11" fronts with 36mm caliper 10.62" rears is 73.0% (not a factory option but it is my backup plan)
-
60mm caliper 10.24" fronts with 34mm caliper 10.62" rears is 71.3% (Lbody SLH package using caravan calipers and non vented rears)
60mm caliper 10.24" fronts with 36mm caliper 11.27" rears is 65.9% (proven bad lbody setup with 60mm calipers and 11" vented rears)

OEM brake pads have a coefficient of about .4 and a performance street pad like the Hawk HPS pads is more like .45.

Note: Using a stock pad in the rear and HPS pad in the front would change the ratios by about 2% in my setup using a really cheap rear pad (.35 coef) could change things by up to 5% so the pads actually change the bias more than the calipers and rotors making this exercise a bit mute.



Notes on things that don't work:

10" Non Vented rotors with 11" won't work because the pads would be outside of the rotor.
11" Vented Calipers with 10" brakes won't work because the calipers are too wide and the piston would pop out.
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