Is it the tarp, the arm, or the motor?
A tarp system that stopped working looks the same from the cab no matter which part failed. Buying the wrong part costs you the money and the day, and you are still parked. Work down this list — it takes about five minutes with the truck shut off.
Before you touch anything
Shut the truck off and drop the bed all the way. A tarp arm under spring tension can swing hard enough to break a wrist, and every check below is safe to do with the system at rest and unsafe to do with it live. If you have to run the motor to test it, stand clear of the arm's arc.
The fast split: does the fabric move?
Almost every case sorts into one of two buckets on the first question, so ask it before anything else:
If the system moves the tarp across the bed and the problem is what the fabric looks like when it gets there — holes, fading, torn edges, material escaping — it is a tarp problem.
If the tarp does not get there at all, moves slowly, stops halfway, goes crooked, or will not come back, the fabric is a passenger. Something in the drive is the problem, and a new tarp changes nothing.
The ten symptoms
Find the one that matches. The tag on each tells you whether we can sell you the fix — and on four of these, we can't.
The tarp stops halfway across the bed.
It's the system, not the tarp- What it usually means
- Usually the motor losing torque under load, or a spring that has lost tension. If it stops at the same spot every time, suspect something mechanical in the way instead — a bent bow, a bad roller bearing, or the tarp binding on a load that's heaped past the rails.
- How to check
- Run it with an empty bed. If it crosses fine empty and stops loaded, it's power — motor or spring. If it stops at the same point either way, it's an obstruction.
The motor groans, runs slow, or gets hot.
It's the system, not the tarp- What it usually means
- The motor is on its way out, or it is fighting a bind somewhere else in the system and telling you about it. Electrical is worth ruling out first because it's free: a corroded ground or a tired battery makes a healthy motor sound exactly like a dying one.
- How to check
- Clean the ground strap and check voltage at the motor while it runs. If it's getting full voltage and still groaning, it's the motor.
The arm won't swing back, or flops loose.
It's the system, not the tarp- What it usually means
- A broken or fatigued return spring, or worn pivot bushings. Springs are a wear item on an arm system and they fail gradually, so the arm gets lazier for weeks before it quits.
- How to check
- With the system at rest, look at both springs side by side. A stretched or snapped one is usually obvious next to its twin.
The tarp rolls crooked or bunches on one side.
It's the system, not the tarp- What it usually means
- The roller or the arms are out of square, so one side is pulling ahead of the other. A tarp cut square cannot fix a frame that isn't.
- How to check
- Measure from the roller to the front lip on both sides. If the two numbers differ, that's your answer — and a new tarp will roll crooked too.
Material blows out the back at highway speed.
Check one more thing- What it usually means
- Either the tarp is too short for the bed and never covered the tail properly, or it's long enough but the rear isn't being secured. This is the most common single complaint and it splits about evenly between the two.
- How to check
- Pull the tarp over on an empty bed and look at the tail. If fabric hangs past the tailgate with room to tie, you have a securing problem, not a tarp problem. If it stops short of the tailgate, you need a longer tarp — and Texas law requires the cover be secured front and back either way.
It tears at the same corner every time.
Check one more thing- What it usually means
- Something is cutting it, and the tarp is the victim rather than the cause. A sharp edge on the bed rail, a bolt head backed out, a bad arm angle dragging fabric across metal. This is the one people get wrong most expensively — they buy three tarps in a year and never look at what's eating them.
- How to check
- Run your hand — carefully, with a glove — along the rail where the tear lines up. You will usually find the culprit in about ten seconds. Fix that first, then buy the tarp.
The fabric is faded and stiff, and cracks when you fold it.
It's the tarp- What it usually means
- UV has finished it. This is how most tarps die in Central Texas, and it happens before the stitching or the hardware gives out. A brittle tarp does not fail gradually — it holds until the first windy day and then goes all at once.
- How to check
- Fold a corner back on itself hard. If it creases white, crunches, or cracks, replace it now rather than on the shoulder of I-35.
Grommets are pulling out along one edge.
It's the tarp- What it usually means
- Wind whip at highway speed, working the same edge thousands of times. Once a grommet line starts letting go, the ones next to it carry more load and follow quickly.
- How to check
- Count them. One pulled grommet on an otherwise sound tarp is a repair. Three or more along the same edge means the hem is fatigued and the tarp is finished.
There are holes in the middle of the fabric.
It's the tarp- What it usually means
- The load is punching through — rebar, jagged demolition debris, sharp limestone. Holes in the field of the tarp rather than at the edges usually means the material is not rated for what you are hauling, not that you got a bad tarp.
- How to check
- Look at what you hauled last week, then look at whether you're running standard mesh under scrap. If so, replacing like with like just buys you the same hole in three months.
Bow system: the cable is frayed or the bows are bent.
It's the system, not the tarp- What it usually means
- Bows take hits from loaders and from overheight loads, and a bent bow puts the cable on a path it wasn't designed for, which is what frays it. The tarp riding on top of a bent bow wears in a stripe.
- How to check
- Sight down the row of bows from the back of the truck. They should form an even arc. If one is low or twisted, fix the bow before you spend money on fabric.
The expensive mistake
Four of the ten symptoms above are not tarp problems, and three more can go either way. If you are replacing tarps more than about once a year on the same truck, the odds are good that the tarp is not what is broken — something on that truck is destroying it, and it will destroy the next one on the same schedule.
The other pattern worth naming: drivers who replace a motor and then, weeks later, the tarp. If the fabric is already old and you have the system apart, doing both at once costs one shutdown instead of two. Operators who have been burned twice tend to do this without being told.
We sell tarps, so read this with that in mind — which is exactly why we marked the symptoms that are not a tarp problem. Selling you fabric that won't fix your truck costs us the customer.
Related
Turns out it is the tarp?
Tell us your truck and we'll point you at the exact size — in stock in Austin, or a real build time if it isn't.