Spicer TPCS Troubleshooting Guide - Manual (Page 66)

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Service Procedures
Troubleshooting Wheel End Seals
Perform an air seal pressure check as follows (refer to
"Wheel End Seals" illustration).
1. Connect a hose from a pressure reservoir, 2" ID x 12"
long with 2' long 3/8" hose (or equivalent volume),
to the inlet tube.
2. Plug hub air port with a 3/8" pipe plug or 9/16-18
straight thread O-ring plug, as appropriate.
3. Open the valve from the air supply line and stabilize
the pressure in the reservoir to 100 PSI minimum.
Close air supply valve. Rotate the hub assembly while
monitoring the pressure gauge. The pressure reading should
not drop more than 15 PSI in 20 seconds.
Note: If the air leakage exceeds 15 PSI in 20 seconds, the hub
may need to be rotated several times to ensure a
complete pressure seal.
If air leakage rate remains outside of accepted limit, locate
source of leak:
• Loose Fittings.
• Spindle/Sleeve Outer O-ring.
• Air Seals.
Refer to the Service Manual for replacement procedure.