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Rear Disc ABS Options

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Were rear disc brakes on the 2001.5 and 2002 trucks only available with all-wheel anti-lock brakes? Or were there rear disc trucks made with rear wheel anti-lock (RWAL) only? I'm wondering how folks handle the drum to disc axle swap in regards to ABS as it seems like most of the rear disc trucks I've seen have all-wheel anti-lock. Is it prudent to run rear discs with rear wheel anti-lock only? This situation might exist if putting a rear disc axle in something like a 1999 truck with RWAL rear drums.

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  On 6/9/2023 at 11:59 AM, wish4hemi said:

Were rear disc brakes on the 2001.5 and 2002 trucks only available with all-wheel anti-lock brakes? Or were there rear disc trucks made with rear wheel anti-lock (RWAL) only?

 

Here is what I recall.

 

All trucks from 1994 through 2002 have disc brakes on the front axles.

 

1994 - 2001   -  front disc brakes and rear drum brakes, rear axle anti-lock brakes only (not independent rear wheel anti-lock)

2001.5 - 2002 - front disc brakes and rear disc brakes, four wheel independent anti-lock brakes

 

  On 6/9/2023 at 11:59 AM, wish4hemi said:

Is it prudent to run rear discs with rear wheel anti-lock only? This situation might exist if putting a rear disc axle in something like a 1999 truck with RWAL rear drums.

 

I think the answer is yes.  I believe the RWAL system uses a single sensor at the ring gear location - not a sensor at each rear wheel.  It would seem that the ABS controller would not know whether or not the rear brakes are drum or disc.

 

- John

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I wonder if the RWAL module under hood is "calibrated" for drums in the way it modulates fluid to the rear when necessary. I might also wonder if the height sensing proportioning valve typical on drum-equipped 2500 8,800 GVW trucks would need to be removed with rear discs.

 

It looks like the master cylinders between drum and disc trucks are different as well according to the parts books. Raybestos lists MC390426 for the 1999 (rear drum, 1.250" bore) and MC390732 for the 2002 (rear disc, 1.313" bore). 

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Welcome To Mopar1973Man.Com LLC

We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features.  Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.