Meritor MM-2075 Maintenance Manual page 15

4. Remove the piston boots by prying the metal ring portion of
the boot out of the bore with a screwdriver. Use care to avoid
damage to the piston or bore. Discard the boots. Figure 4.9.
Figure 4.9
5. Removing the crossover tube allows the service of the pistons
to be performed one half at a time.
WARNING
When using compressed air to remove the pistons from the
caliper bore, do not place hands or fingers near the bore to catch
or protect the pistons. Serious personal injury can result.
6. Starting with the inboard caliper, utilize the outboard caliper
half bleed screw to seal the crossover tube port.
7. Place a section of plate stock across the pistons to be
removed. Use a C-clamp to hold the plate against the pistons
on one side of the caliper where the pistons are to be
removed. Figure 4.10.
Figure 4.10
CAUTION
When removing the pistons from the caliper bore, only direct
enough compressed air into the caliper brake fluid inlet to ease
the pistons out of the bore. Do not exceed 25 psi (172 kPa).
Damage to components will result.
(16579)
Printed in USA
4003796b
4003787b
Copyright Meritor, Inc., 2023
4 Removal and Disassembly
8. Apply compressed air through the caliper inlet port using a
rubber-nosed air fitting. Pressure should not exceed 25 psi
(172 kPa).
9. Gradually open the C-clamp to allow the pistons to move out
evenly until free.
10. Repeat the procedure for the outboard caliper half.
11. Seal one of the open hydraulic ports with a bleed screw.
12. Place a section of plate stock across the outboard pistons to
be removed.
13. Use a c-clamp to hold the plate against the pistons to be
removed.
14. Apply compressed air through the caliper inlet port using a
rubber-nosed air fitting. Pressure should not exceed 25 psi
(172 kPa)
15. Gradually open the c-clamp to allow the pistons to move out
evenly until free.
CAUTION
Install a new caliper if the caliper bores are excessively scored or
corroded. Do not hone the caliper bores, which can affect piston
fit and operation. Damage to components can result.
16. Remove the piston seals with a non-metallic device. Discard
the seals. Do not nick, scratch or scar the piston bores or seal
grooves. Do not hone the caliper bores.
If the caliper bores are excessively scored or corroded:
Install a new caliper.
CAUTION
The outside diameter of the piston is the caliper's primary
sealing surface and is manufactured to very close tolerances.
Replace a piston if the outside diameter is damaged. Do not
refinish or use abrasives, including an emery cloth, on the piston.
Damage to components can result.
17. Inspect the outside diameter of the pistons for scoring, nicks,
corrosion, wear and damage.
If any of these conditions exist: Replace the pistons. Do
not refinish or use abrasives.
CAUTION
Use a crocus cloth to remove minor stains and corrosion from
the caliper bore. Do not use abrasives, including an emery cloth.
If minor stains and corrosion cannot be removed, replace the
caliper bore to avoid damage to components.
MM-2075 / Revised 09-23
Page 11