Determining correct push rod length, 1 replacing both spring brakes on the axle – SAF-HOLLAND XL-AM20006BM Brake and Service Chamber User Manual

Page 14

XL-AM20006BM-en-US · 2014-04-22 · Amendments and Errors Reserved · © SAF-HOLLAND, Inc., SAF-HOLLAND, HOLLAND, SAF,

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Table 1

5.1 Replacing Both Spring Brakes on the Axle

1. To install new brakes on the axle, the correct push rod

length will be determined by the following:

Measure the “B“ dimension (Figure 21).

The brake mounting bracket MUST be parallel to the

slack adjuster centerline.

EXAMPLE:

“B“ = 5.5" (139.7 mm) Subtract set up stroke from “B“
Dimension. Use a set up stroke value from
.5“– 1.5“= 4“ (139.7 – 38.1 mm = 101.6 mm)

NOTE: The setup stroke is the approximate distance

the push rod will travel in a brake application. A
shorter set up stroke can be used for a quicker
brake response. If a shorter set up stroke is
desired, ensure brake linings are no dragging.
Recommendations are provided (Table 1).

2. Measure the clevis throat (Figure 20) and subtract it

from the previous figure.

EXAMPLE:

Clevis throat measure is 1.25" (31.8 mm), subtract
1.25" (31.8 mm) from 4" (101.6 mm) = 2.75 (69.9 mm)

This is the push rod length from the mounting surface
of the spring to the end of the push rod.

NOTE: When measuring and cutting the push rod to the

correct length, the spring brake MUST be fully
caged. If NOT caged, refer to Section 3.

3. Mark the correct length on the push rod. Use the jam

nut to facilitate marking of the correct length. Cut the
push rod using the best cutting device available.

4. Attach the clevis to the push rod. Make sure that no

more than two (2) threads (approximately .12" (3 mm))
extend into the clevis throat to insure no interference,
or no less than 1 thread is recessed into the clevis.
5PSRVFKBNOVUPODMFWJTUPGUMCT /tN

5. The spring brake is ready to be mounted on the bracket

as referenced in Section 1.

NOTE: The set up stroke is the approximate distance

the push rod will travel in a brake application.
A shorter set up stroke can be used for a quicker
brake response. If shorter setup stroke is desired,
ensure brake linings are NOT dragging.

CHAMBER TYPE

RATED STROKE

SET-UP STROKE

1.75" (44.5 mm)

1.00" (25.4 mm)

2.25" (57.2 mm)

1.38" (34.9 mm)

2.25" (57.2 mm)

1.38" (34.9 mm)

2.50" (63.5 mm)

1.50" (38.1 mm)

3.00" (76.2 mm)

1.75" (44.5 mm)

2.50" (63.5 mm)

1.68" (41.3 mm)

3.00" (76.2 mm)

1.88" (47.6 mm)

2.50" (63.5 mm)

1.75" (44.5 mm)

3.00" (76.2 mm)

2.00" (50.8 mm)

3.00" (76.2 mm)

2.18" (54.0 mm)

Figure 21

90°

CL OF SLACK ADJUSTER
PARALLEL TO MOUNTING
BRACKET

AXLE MOUNTING BRACKET

Determining Correct Push Rod Length