MJ Height Sensing Brake Proportioning Valve Adjustment Procedure

[HOrnbrod]

Height Sensing Brake Proportioning Valve Adjustment Procedure

In addition to the pressure differential valve, a mechanically activated height sensing proportioning valve is used on Comanche models. This valve, located above the rear axle, must be adjusted any time rear springs are replaced, or the valve is removed during service operations.

Any time the valve is adjusted, the lever bushing must be replaced. The adjustment must be made with the vehicle level and at curb weight. Special tools are needed for this job.
 

Fig. 1: Exploded view of the height sensing proportioning valve installed on the Comanche. The 1990-92 models DO NOT use a spring (5)
 

Fig. 2: Height sensing proportioning valve (1) and linkage (2)
 
Removal & Installation, See Figure 3

1.  Disconnect the valve lever and spring, if equipped.
2.  Disconnect and cap the brake lines.
3.  Unbolt and remove the valve.
4.  Installation is the reverse of removal. Torque the Valve bracket-to-frame bolts to 13 ft. lbs. (17 Nm) and tighten the valve-to-bracket bolts to 10 ft. lbs. (13 Nm).
5.  Perform the valve adjusting procedure outlined in this section.
 

Fig. 3: Proportioning valve connections
 
ADJUSTMENT

Except 1990-92 Comanche Models
1.  Remove the valve shaft nut and washer.
2.  Disconnect the valve lever and remove the spring.
3.  Remove and discard the bushing.
4.  Rotate the valve shaft and install adjusting gauge tool J-35853-2 or its equivalent.

The gauge must be properly seated on the D shape of the shaft and the valve lower mounting bolt. All linkage components, except the spring, must be connected before installing the new bushing.

5.  Place the bushing in the lever, and, using bushing aligning tool J-35853-1 or its equivalent, press the bushing and lever onto the shaft.
6.  Remove the lever and adjusting tool J-35853-2 or its equivalent and install the spring.
7.  Install the lever, washer and nut. Tighten the nut to 100 inch. lbs. (11 Nm).
8.  Connect the spring.

 

1990-92 Comanche Models

Valve adjustment requires Calibration Kit 6229 or its equivalent. Of course, this is not possible. To adjust, align shaft flat at the 6 o'clock position by eye.

1.  Raise the vehicle and support it safely with jackstands.
2.  Unload the vehicle and place on a level surface for accurate valve adjustment.
3.  Remove the nut attaching lever to the valve shaft.
4.  Pull the lever and retainer off the valve shaft and remove old the bushing. Discard the bushing.
5.  Clean the threads and splines on the valve shaft. If valve the link was disconnected from axle the bracket or lever, reconnect the link before continuing.
6.  Loosen the valve mounting bolts two full turns. Then turn valve shaft until the shaft flat is approximately between the 5 and 6 o'clock position.
7.  Install the valve adjusting gauge and it position on the mounting bolts and shaft. There should be no clearance between the gauge, shaft and bolts. The gauge should be seated on the shaft flat.
8.  Install the retainer on the lever, and the bushing on the retainer. Start the bushing and the lever on the valve shaft and press into place with the tools provided in kit 6229 or its equivalent.
9.  Remove the adjustment gauge and the bushing installer tool. Tighten the valve mounting bolts to 10 ft. lbs. (13 Nm) and tighten the lever nut to 100 inch lbs. (11 Nm).

[teamsmith]

If my lever is just dangling loose in the 6 o'clock position, does it mean I'm getting less brake than I should of my bed is full?

[HOrnbrod]

Most likely.

[Guest SAcquaviva]

I don't have the arm that goes from the valve to the diff, is thay bad?

[HOrnbrod]

I don't have the arm that goes from the valve to the diff, is thay bad?

 

Yes. Make one as described in this thread, or wire the lever up so it's roughly parallel with your axle tube.

 

http://comancheclub.com/topic/16955-adjustable-mj-load-sensing-valve/

[JoeLAW]

Is there a thread on how to delete this? Do you guys recommend it?

[Pete M]

Is there a thread on how to delete this? Do you guys recommend it?

 

questions are far more likely to get noticed if you put them in the tech forum. :thumbsup:

[JoeLAW]

 

 

 

questions are far more likely to get noticed if you put them in the tech forum. :thumbsup:

 

 

 

Noted! Still a noob at this thanks Pete!