Hydro-Boost; Symptom Troubleshooting; Remove; Install - Taylor-Dunn C0-T50-80 Service And Parts Manual

C0-T50-80

HYDRO-BOOST

WARNING
Hydraulic fluid and components must be kept clean. Thoroughly clean exterior of any hydraulic component
before disconnecting hoses or fittings. Perform all maintenance and repairs in a clean environment. Do
not use cloth or paper towels to clean components due to possible contamination with lint or other fiber.
Failure to follow these guidelines will result in premature failure of hydraulic system components.
The Hydro-Boost is not serviceable. If the Hydro-Boost is not functioning correctly then it must be replaced.

Symptom Troubleshooting

Slow Brake Pedal A. Excessive seal friction in booster
Return B. Flared reaction end.
C. Broken Piston return spring.
D. Restriction in return from Booster to Pump Reservoir
E. Return line incorrectly connected
F. Broken spool return spring.
G. Heavy brake pedal.
Grabbing Brakes A. Broken spool return spring.
B. Faulty Spool action due to contamination
C. Low pump flow.
Booster Chatter, A. Slipping pump belt.
Pedal Vibration B. Low fluid level in Pump.
Accumulator leaks down. A. Two-function valve is faulty.
Reserve System Does B. Accumulator seal is faulty.
Not hold charge C. Pneumatic accumulator is faulty.
Excessive Brake Pedal A. Loose, glazed, or broken pump belt.
Effort B. No fluid in pump
C. Leaks in system hoses.
D. Leaks at tube fittings and connections
E. Leakage at pneumatic accumulator seal.
F. Leakage at piston seal.
G. Leakage at input seal.
H. Leakage at cover to housing seal
I. Leakage at spool plug seal.
J. Leakage at expansion plug.
Unit self-applies A. Restriction in Booster return line.
B. Return line incorrectly connected.
C. Dump valve faulty.

Remove

1: Remove the dash assembly.
2: Press the brake pedal numerous time to
discharge the accumulator.
3: Remove the master cylinder from the Hydro-
Boost. Refer to Master Cylinder section for
procedure. DO NO press the brake pedal after
the master cylinder has been removed.
4: Disconnect hydraulic lines from the booster. Keep
the ends of the hydraulic lines higher then the
pump reservoir so the fluid does not bleed out.
5: Cap the hydraulic lines so the debris cannot enter
the lines. See caution text at beginning of this
section.
6: Disconnect the input push rod.
7: Remove the mounting bolts and remove the
Hydro-Boost-Boost from the vehicle.
MC-T50E-02
Overhaul with New Seal Kit.*
Replace Booster
Replace Spring*
Clear or line replace line
Correct plumbing.
Replace spring*
Reposition pedal or add retracting spring.
Replace Spring.*
Flush steering while pumping brake pedal.
Tighten Belt.
Tighten Belt.
Fill reservoir-check for external leaks.
Replace valve and valve set.
Replace 0-Ring.
Replace accumulator*
Tighten or replace belt
Fill reservoir and check for leaks
Replace faulty parts
Tighten fittings or replace tube seats or 0-Rings.
Replace 0-Ring and retaining ring.*
Overhaul with new seal kit.*
Overhaul with new seal kit.*
Overhaul with new seal kit.*
Overhaul with spool plug seal kit.*
Replace Hydro-Boost
Clear or replace line.
Correct plumbing.
Replace dump valve.*

Install

Install the Hydro-Boost in reverse order of removal.
Tighten the master cylinder mounting bolts per torque
listed in the Hardware Torque table at the end of this
section.
Use the following procedure to bleed the Hydro-Boost:
a) Fill the pump reservoir.
b) Connect the battery.
c) Turn the key switch ON and place the shift lever
in forward. Wait 5-seconds then turn the key off.
d) Fill the pump reservoir.
e) Turn the key switch on and place the shift lever
in forward.
f) Turn the steering wheel all the way to the left and
right 2-times.
g) Turn the key switch off.
h) Press the brake pedal 5-times.
i) Repeat steps (d) through (h) then go to next step.
j) If hydraulic fluid foaming occurs, wait 1-hour and
start again at step (d)
Normal driving will purge any remaining air is the system.
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