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page 35

T-12-UT

Maintenance

Electric Brake System Troubleshooting

Most electric brake system malfunctions that cannot be corrected by either brake

adjustments or synchronization adjustments can generally be traced to electrical sys-
tem failure. Mechanical causes are ordinarily obvious, i.e. bent or broken parts, worn
out linings or magnets, seized lever arms or shoes, scored drums, loose parts, etc. A
voltmeter and ammeter are essential tools for proper troubleshooting of electric brakes.

Measuring Voltage

System voltage is measured at the magnets by connecting the voltmeter between

the two magnet lead wires at any brake. This may be accomplished by using a pin
probe inserted through the insulation of the wires leading from the trailer frame to the
brake assembly, or if necessary by cutting the wires. The engine of the tow vehicle
should be running when checking the voltage so that a low battery will not affect the
readings.

Voltage in the system should begin at zero volts and as the controller bar is slowly

actuated should increase gradually to about 12 volts. This gradual increase of voltage
is referred to as modulation. No modulation means that when the controller begins to
apply voltage to the brakes it applies an immediate high voltage (acting more like an
On-Off switch), which causes the brakes to apply instantaneous maximum power.

The threshold voltage of a controller is the voltage that is applied to the brakes

when the controller first energizes. The lower the threshold the smoother the brakes
will operate. Too high a threshold voltage (in excess of  2 volts as quite often found in
heavy duty controllers) an cause grabby, harsh brakes.

M

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INCREASING PEDAL PRESSURE

GR

AD

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 VO

LT

AG

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SE

ABR

UPT

 VO

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AG

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GOOD
MODULATION

POOR
MODULATION

IN

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EASI

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VO

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AG

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ZERO VOLTS

2 VOLT

(THRESHOLD)

12 VOLTS

Courtesy of Machine.Market 

Summary of Contents for T-12-UT

Page 1: ...ral Components 14 Sub Frame 14 Deck 14 2 2 Sub Assembly Components 14 Coupling 14 Jack 15 Cushion Cylinder 15 Deck Latch 15 Deck Hinge Assembly 15 2 3 Running Gear 16 Suspension 16 Hubs and Drums 16 B...

Page 2: ...ing Voltage 35 Measuring Amperage 37 Electric Brake System Troubleshooting Chart 38 2 9 Pre Storage Maintenance 40 2 10 Pre Season Maintenance 41 Section 3 Parts 42 3 1 Structural Components 42 Deck S...

Page 3: ...and skill can help compensate for these factors This knowledge will assist you to safely enjoy the maximum utility and productivity from your trailer First and foremost DO NOT operate the trailer unti...

Page 4: ...e full rated capacity of the trailer Extreme concentrated appli cations may require additional support for the load 1 4 Vehicle Load and Handling Limits Vehicle handling limits can be greatly affected...

Page 5: ...handling characteristics of the combination and allow the driver to utilize all the design responses of the vehicle to make evasive maneuvers in the safest manner Irregular terrain steep grades and c...

Page 6: ...er is with the vehicle and the road the less likely he will need to make abrupt emergency maneuvers which will take the vehicle to its limits Control and stability may be main tained if the driver kno...

Page 7: ...defect exists in a group of vehicles it may pursue a remedy campaign and recall those vehicles However NHTSAcannot become involved in individual problems between you your dealer or Gem State Mfg Inc T...

Page 8: ...R indicates an imminently hazardous situation which if not avoided will result in death or serious injury WARNING WARNING indicates a potentially hazardous situation which if not avoided could result...

Page 9: ...iler hitch to compensate for settling of tow vehicle springs when loaded Always visually inspect hitch for unusual appearances such as bent components cracks in welds or chipped paint where stress cra...

Page 10: ...t to both the trailer and the towing ve hicle Connect safety chains to tow vehicle using crossed pattern under tongue Allow slack for turning but avoid having chains drag on pavement Make certain that...

Page 11: ...r other unstable trailer characteristics which could result in an accident causing property damage bodily injury or death It is the operators responsibility to take whatever steps necessary to load th...

Page 12: ...ad ing it is very important that ramps are adjusted to proper spacing for equipment being transported When loading equipment onto deck drive slowly forward until appropriate tongue load is achieved Ra...

Page 13: ...loose or missing suspension fasteners Check brake adjustment see page 25 Quarterly Lube Dico surge actuator rollers see Surge Actuator Maintenance on page 27 Annually Pack wheel bearings see page 18...

Page 14: ...ompound or wood For wood decks it may be necessary to apply a new coat of wood preservative after decking has aged and become dry The best time to apply preservative is during warm weather for better...

Page 15: ...Fully collapse the cylinder and then remove the filler plug and drain out the old fluid Add 10W hydraulic fluid until the cylinder is full and all the air has been expelled Deck Latch If the latch bec...

Page 16: ...ngation of bolt holes and loosening of fasteners Whenever loose or replaced the fasteners in your suspension system should be torqued as detailed below 1 U bolt 45 to 60 lbs ft 2 Shoulder Type shackle...

Page 17: ...t free cloth and inspect each roller completely Also clean and inspect the cups races inside the hub Any pitting spalling bluing heat damage or corrosion is cause for replacement NOTE Bearings must al...

Page 18: ...rication If your axles are equipped with the E Z Lube feature the bearing can be lubricated without removing the hubs from the axle The feature consists of axle spindles that have been specially drill...

Page 19: ...stall it before pressing in the new seal Apply a Permatex sealant to the outside of the new seal metal seal shells only 3 Tap the seal into place using a clean wood block Hub Reinstallation and Bearin...

Page 20: ...he relationship of the center line of the tire to the hub face of the axle Care should be taken to match a replacement wheel with the same offset wheel as originally equipped Failure to match offset c...

Page 21: ...nd in good condition for applying installation torque Tighten the lug nuts in the following pattern in three steps first to 20 25 lbs ft next to 50 60 lbs ft and then to the final torque of 80 to 95 l...

Page 22: ...acturers Association or the tire manufacturer Inflation Pressure Correct inflation pressure for the ST235 80R16 tire is 65 psi and is the most impor tant factor in tire life Inflation pressure should...

Page 23: ...per tire catalog Side Wear Loss of camber or over loading Adhere to load limits Have axle aligned Toe Wear Incorrect toe in Have axle aligned Cupping Loose bearing or out of balance Adjust bearing ba...

Page 24: ...to verify that the electrical system is functioning properly If it is then replace the lamp if not then troubleshoot the electrical system Junction Block The junction block requires no regular mainte...

Page 25: ...y if you are going to be working under the trailer Brake Adjustment Brakes should be adjusted 1 after the first 200 miles of operation when the brake shoes and drums have seated 2 at 3000 mile interva...

Page 26: ...to 1 16 thickness or less contaminated with grease or brake fluid or abnormally scored or gouged Hardware Check all hardware Check shoe return spring hold down springs and adjuster springs for stretch...

Page 27: ...auses the trailer brakes to be applied Surge Actuator Maintenance Before towing check that the brake fluid reservoir is full If not refill to 3 8 inch below the top of the reservoir with DOT 3 brake f...

Page 28: ...s for age checking cracking of the outer rubber sheath damage blisters or other signs of impending failure and replace as neces sary Hydraulic Brakes The hydraulic brakes on your trailer use a single...

Page 29: ...r left rear if tandem axle You should always begin the bleeding operation on the wheel cylinder that is farthest from the master cylinder Have the loose end of the hose submerged in a glass container...

Page 30: ...INDER PISTONS REPLACE EXCESSIVE DRUM WEAR BLEED SYSTEM TRAPPED AIR IN LINES CORRECT OVERLOADED TRAILER TROUBLESHOOT SYSTEM MALFUNCTIONING ACTUATION SYSTEM ADJUST BRAKES OVERLOADED TRAILER REPLACE SHOE...

Page 31: ...s in the brakes The high capacity electromagnets are energized and are attracted to the rotating armature surface of the drums which moves the actuating levers in the direction that the drums are turn...

Page 32: ...a modulation function that varies the current to the electric brakes with the pressure on the brake pedal or amount of deceleration of the tow vehicle It is important that your brake controller provid...

Page 33: ...not all trailer brakes are capable of wheel lockup If the controller is applying the trailer brakes before the tow vehicle brakes then the controller level adjustment should be adjusted so that the t...

Page 34: ...re de signed to provide the proper input force and friction characteristics Your magnets should be inspected and replaced if worn unevenly or abnormally As indicated below a straight edge should be us...

Page 35: ...hicle should be running when checking the voltage so that a low battery will not affect the readings Voltage in the system should begin at zero volts and as the controller bar is slowly actuated shoul...

Page 36: ...aintenance From Trailer Harness From Trailer Harness To measure VOLTAGE measure across both brake magnet wires To measure AMPERAGE measure between one open brake magnet wire VOLTMETER AMMETER Courtesy...

Page 37: ...brake amperage draw can be measured by inserting the ammeter in the line at the magnet you want to check Disconnect one of the magnet lead wires and attach the ammeter between the two ends Make sure t...

Page 38: ...tion are traceable to improperly adjusted or non functioning controllers See your controller manufacturers data for proper ad justment and testing procedures If the voltage and amperage is not satisfa...

Page 39: ...CORRECT CORRECT BROKEN BRAKE COMPONENTS OVERLOADED TRAILER ADJUST CLEAN OR REPLACE INCORRECT BRAKE COMPONENTS UNDERADJUSTMENT CORRECT MACHINE OR REPLACE GREASE OR OIL ON LININGS OR MAGNET IMPROPER SY...

Page 40: ...ll be off the tires The best way to jack the trailer for this is to place the jack under the trailer frame rail using a wood block to protect the finish Raise the jack until the suspension assembly on...

Page 41: ...ke magnets with an ohmmeter The magnets should check at 3 2 ohms If shorted or excessively worn replace the magnets 6 Lubricate all brake moving parts BRAKE LINING CONTAMINATION Do not get grease or o...

Page 42: ...4 ASSY 2 2 FenderAssembly SA 03285 3 1 Right Hand Tail Light Bracket SA 12779 4 1 Left Hand Tail Light Bracket SA 14218 5 8 D ring B 40 6 1 Upper Side Plate Assembly SA 12525 7 2 Lower Latch Side Pla...

Page 43: ...page 43 T 12 UT Parts P A R T S 3 1 5 2 4 7 6 Courtesy of Machine Market...

Page 44: ...ber 1 1 2 x 10 x 16 1 1 2x10 16 4 Deck Lumber 1 1 2 x 12 x 16 1 1 2x12 16 2 86 Torx Deck Screws 1 4 20 x 2 1 2 32519 Rubber Deck Ref Quantity Description Part No 1 11 Rubber Compound Decking 9102 16 2...

Page 45: ...2 1 Screw and Nut Assembly 712216 3 1 Crank Assembly Kit 800075 4 1 Screw Nut and Bearing Replacement Kit 500220 Note Kit names are bold type while component names are regular type kit com ponents if...

Page 46: ...2 UT Couplers Ref Quantity Description Part No 1 1 2 5 16 Lever Lock Coupler 07678 97 2 4 5 8 11 UNC x 1 5 8 Hex Head Bolt Grade 5 04051 3 4 5 8 11 UNC Stover Lock Nut 03730 Parts 3 2 1 Courtesy of Ma...

Page 47: ...ntity Description Part No 1 1 Pintle Eye 09557 97 2 2 5 8 11 UNC x 4 1 2 Hex Head Bolt Grade 5 02434 3 2 5 8 11 UNC Nylon Insert Lock Nut 02587 Note Pintle Eye and associated hardware is an available...

Page 48: ...g Bolt 17207 2 1 Utility Latch Hook C 12534 3 2 Glide Latch Bearing GFI 1214 06 4 1 Latch Pin C 04150 5 2 E Clip 10385 00118 Lower Latch Assembly 1 1 Utility LatchAssembly SA 12536 2 1 Utilty Latch Ha...

Page 49: ...page 49 T 12 UT 5 1 2 2 3 5 Upper LatchAssembly Lower LatchAssembly 3 4 1 4 Courtesy of Machine Market...

Page 50: ...page 50 T 12 UT Parts 1 Cushion Cylinder Ref Quantity Description Part No 1 1 Cushion Cylinder 30X08 Courtesy of Machine Market...

Page 51: ...page 51 T 12 UT Parts P A R T S 3 3 Running Gear Suspension 7K Ref Quantity Description Part No 1 2 7000 Rubber Torsion Axle 7700353 1 Courtesy of Machine Market...

Page 52: ...ScrewAssembly SB42159 8 1 Spring Adjusting Screw SB24765 9 1 Shoe Lever SB18502 95 10 1 Travel Link SB17917 95 11 1 Locknut 05962 12 2 5 16 Star Washer 05424 13 1 Pin Front Shoe 05824 14 2 Retaining R...

Page 53: ...page 53 T 12 UT Parts 15 24 17 25 7 8 21 1 18 22 5 4 6 9 11 10 2 12 14 20 19 16 13 11 12 3 23 Courtesy of Machine Market...

Page 54: ...ng 040 045 00 7 2 Shoe Hold Down Pin 049 011 00 8 2 Shoe Hold Down Spring 048 077 00 9 1 AdjusterAssembly 043 004 00 10 1 Adjusting Screw Spring 046 018 00 1 Magnet Kit K71 105 00 11 1 Magnet black wi...

Page 55: ...page 55 T 12 UT Parts P A R T S 9 10 8 6 12 11 13 17 1 7 14 15 3 2 5 16 4 Courtesy of Machine Market...

Page 56: ...02 3 1 Inner Bearing Cup 031 030 01 4 8 1 2 Wheel Stud 007 262 00 5 1 Brake Drum 8 stud on 6 5 circle 008 219 04 6 1 Outer Bearing Cup 031 017 01 7 1 Outer Bearing Cone 031 017 02 8 1 Spindle Washer 0...

Page 57: ...tity Description Part No 1 1 Tire ST235 80R16 2 1 Wheel 17 153 14 SP 3 8 Wheel Nut 1 2 20 60 006 080 00 Note Tires are not available through Gem State Manufacturing contact your local equipment tire r...

Page 58: ...il Light sealed 60202R 5 2 Oval Mounting Grommet 60700 6 1 License Plate Lamp 26331 7 1 Main Harness 50923 8 2 Marker Clearance Harness 50321 0216 9 1 Tail Light Harness 51305 10 1 Pigtail 94853 Note...

Page 59: ...page 59 T 12 UT Parts P A R T S 5 4 10 9 7 2 3 2 1 8 6 Courtesy of Machine Market...

Page 60: ...s White Ground Yellow Left Turn Stop Brown Tail and Marker Green Right Turn Stop Red or Blue ECU Power Electric Brakes Brown Tail and Marker Red or Blue Electric Brakes Black Accessories Yellow Left T...

Page 61: ...Note Kit names are bold type while component names are regular type kit com ponents if itemized are indexed under the kit name Kit component quantities are per kit other parts and kit quantities are...

Page 62: ...Brake Line 3 16 X 20 1 2 5 Bend LH 0716 001 2 10 1 Brake Line 3 16 X 20 3 Bend RH 0716 001 3 11 1 Brake Line 3 16 X 20 3 Bend LH 0716 001 4 12 5 Tube Clamp COV 0411Z1 Finish Surge Line Kit 0716 007 3...

Page 63: ...page 63 T 12 UT Parts P A R T S 12 6 7 4 5 10 1 14 11 8 9 3 13 15 2 Courtesy of Machine Market...

Page 64: ...olt Grade 5 05961 13 2 5 16 External Tooth Lock Washer 05424 14 4 1 4 20 UNC x 2 Hex Head Bolt Grade 5 00618 15 4 1 4 Lock Washer 00057 16 1 Emergency Lever 05951 17 1 Push RodAssembly 03534 18 1 Comp...

Page 65: ...page 65 T 12 UT P A R T S 9 7 5 3 1 20 25 24 17 15 14 21 23 13 12 16 10 8 2 6 11 18 4 22 Courtesy of Machine Market...

Page 66: ...page 66 T 12 UT Tool Box Ref Quantity Description Part No 1 1 Tool Box GEM001 W Parts Courtesy of Machine Market...

Page 67: ...tative in your immediate area If you do not have or can not find a representative in your area then contact the factory Warranty Administrator for assistance 1 800 447 0213 4 Give a detailed descripti...

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