Hydraulic Brake Coupler; Troubleshooting; Surge Brake Troubleshooting - JLG t350 Service And Maintenance Manual

SECTION 3 - CHASSIS & TURNTABLE
3.7

HYDRAULIC BRAKE COUPLER

Troubleshooting

IF ANY OF THE FOLLOWING CONDITIONS DEVELOP, TRAILER
MUST NOT BE USED UNTIL PROPER CORRECTIVE ACTION IS
TAKEN.
Symptom
Squeaking, Clatter, or Chucking
Release handle does not close easily
Brake Overheating, Side Pull, Brakes do
not Operate, Poor Brake Performance
Towing Vehicle Shaking Back and Forth
3-10
Table 3-4. Surge Brake Troubleshooting
Cause
Lack of Hitch Ball Lubrication
Binding Linkage & Pivots on Brake Actuator
Loose Hitch Ball
Loose Hitch
Actuator loose on trailer frame
Hitch ball worn or too small
Overheated Brakes
Broken Brake Drum(s)
Low Brake fluid level
Worn out shock absorber
Partial application of breakaway cable
Brakes improperly adjusted
Broken brake return spring
Seized actuator master cylinder
Worn out brake shoes
Leaky wheel cylinders
Oversized ball
Ball not fully inserted into socket
Foreign material in actuator socket
Only one brake is applying
Leaking wheel cylinder
Seized wheel cylinder piston
Foreign Material in Brake Unit
Low hydraulic fluid level
Bent shoulder bolt
Bent push rod in the shock absorber
Damaged socket assembly
Broken/Pinched brake lines
Brake actuator frame damaged
Worn brake shoe(s)
Worn vehicle suspension
Hitch not secure
Under-sized hitch ball
– JLG Lift –
Solution
Lubricate with conventional automotive grease or commer-
cial lubricant made for hitch balls
Oil linkage & pivots on brake actuator
Inspect hitch and tighten
Inspect hitch and tighten
Inspect brake actuator and tighten
Replace
Replace wheel bearing
Replace brake drum(s) & check brake shoes
Fill & bleed brakes
Replace
Fully release breakaway cable
Check brakes
Replace return spring
Replace/rebuild actuator master cylinder
Replace brake shoes and check brake drums
Replace/rebuild wheel cylinders and replace brake shoes.
Clean drums and other hardware.
Check ball size
Check for proper ball size. Check to see if tongue jack is fully
retracted. Hold release handle open when inserting ball.
Clean and lubricate
Check brake adjustment
Check and replace wheel cylinder and bleed brakes
Check and rebuild/replace wheel cylinder and bleed system.
Clean thoroughly
Fill and bleed brakes
Replace
Replace shock absorber
Replace actuator
Replace
Replace actuator
Replace brake shoe(s)
Replace shock absorber
Tighten all bolts and nuts
Replace with proper size
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