When your radio controlled car fails to turn and instead continues going straight no matter the steering input, it’s extremely frustrating. A vehicle with no turning capabilities quickly becomes unusable. In this guide, we’ll explore the common reasons an RC car is not turning and how to properly diagnose the issue.
Table of Contents
Introduction
Modern RC cars rely on a radio signal from the transmitter to the onboard receiver to control steering and throttle functions. This allows full directional control at distance.
But glitches in the radio system, mechanical issues, or electrical faults can result in total loss of steering, leaving the car unable to turn and instead traveling only straight ahead.
Common causes include:
- Failed or obstructed servo
- Stripped steering servo gears
- Disconnected steering linkage
- Transmitter/receiver signal problem
- Loose wires or connectors
- Defective electronic speed control
- Locked front differential
We’ll dive deeper into each of these potential issues below. We’ll also provide tips on proper troubleshooting procedures to accurately diagnose the fault so correct steering control can be restored.
Key Takeaways on RC Cars Not Turning
- Inspect the steering servo for damage or obstructions preventing movement.
- Ensure steering linkages are securely connected from servo to wheels. Tighten or replace loose parts.
- Check for stripped gears or loose parts inside a defective steering servo. Replace if damaged internally.
- Rule out radio system glitches by checking batteries, connections, servos, and calibration.
- Examine the front differential and axles for debris causing binding or lockup.
- Methodically swap electronic components to isolate points of failure.
- Carefully inspect all steering components to find the fault preventing left/right movement.
Failed or Obstructed Servo
The steering servo translates signals from the receiver into mechanical movement to turn the wheels left and right. An obstruction or internal failure of the servo will result in no steering.
- Check that the steering servo is properly connected to the receiver and has adequate power. Try swapping servo ports.
- Inspect for any external damage to the servo case, output shaft, mounting, or horns.
- Try manually rotating the servo gears with the radio off using light force. Sticking or grinding could indicate a damaged geartrain.
- If the servo shows no signs of external damage, it may have suffered internal electronic failure. Replace a non-responsive servo.
Servos are a common failure point from crashes or moisture damage. When steering fails, the servo should be the first component checked thoroughly.
Stripped Servo Gears
If the steering servo is trying to move but only buzzes or vibrates without turning, stripped gears inside are likely the issue.
This is common if excessive force was applied while the servo was still powered on but unable to move freely due to an obstruction. It often occurs from severe crashes.
Symptoms include whining servos that twitch but fail to move the wheels in either direction. Replace the steering servo if stripped gears are suspected. Trying to repair servos internally rarely succeeds.
Disconnected Steering Linkage
Another possibility if the front wheels fail to respond at all is a disconnection in the mechanical linkage that transfers servo movement to the steering hardware.
- Ensure the steering servo horn/arm is securely fastened to the servo output shaft. Tighten down or replace stripped horns.
- Check that all steering linkages and rods are firmly attached at both ends with no slop or play.
- Examine ball joints and rod ends for any play or popping out – secure as needed. Replace worn parts.
- Look for any clevis pins, set screws, or connectors that may have backed out and disconnected.
Solid mechanical steering linkages free of slop are essential for responsive handling.
Radio Signal Issues
Problems with the radio signal getting from transmitter to receiver can also cause steering failures.
- Check the steering trim dial and settings for improper adjustments causing full left or right offset. Center trim.
- Try switching to a different model memory on the transmitter if available to rule out corrupted settings.
- Ensure proper binding between transmitter and receiver. Rebind if needed per instructions.
- Verify batteries have adequate charge in both transmitter and receiver packs. Replace/recharge weak batteries.
- Check all radio system wiring and connections for damage. Solid connections are critical.
- Range test the radio system for glitches at a distance – radio issues usually cause intermittent issues.
Loose Wires and Connectors
While complete disconnections will prevent steering, even slightly loose wires and connectors can cause random intermittent failures:
- Receiver harnesses should click and lock securely into ports when properly connected.
- Examine wiring for any frayed or cut wires that may be shorting.
- Look for loose solder joints or corroded bullet connectors that could be intermittently cutting power.
- Check small ribbon cables inside the receiver box for loose insertion or damaged ports.
Wiggling wires while powered on may reveal brief losses of steering control. Refasten all loose connections.
Defective ESC
While less likely, a malfunctioning electronic speed control (ESC) could potentially cause steering issues, since ESCs feed power to servos:
- Ensure the ESC connections to the receiver and battery are solid.
- Test steering functionality with a different ESC or disconnect the ESC to isolate its effects.
- Also examine the ESC wiring going into the motor for short circuits diverting power.
- Try powering the servo directly from a standalone battery pack as a further test.
If servos and radio components check out, examine the ESC wiring and power delivery as a potential factor.
Locked Front Differential
If the front wheels turn freely with no power applied but still fail to steer the vehicle, the differential may have locked up:
- Limited slip differentials can lock if gears jam. Disassemble to clean out debris.
- Check for overfilled differentials or thick, old grease preventing proper motion.
- Examine cases for damage cracks causing binding. Replace damaged housings.
- Ensure proper shimming if replacing diff components. Incorrect shims can preload gears and lock movement.
Clogged or damaged differentials prevent steering servo input from turning the vehicle.
Diagnosing the Specific Issue
If your radio controlled model still fails to turn correctly after the above checks, further diagnosis is required:
- Isolate components, such as disconnecting the servo and testing it independently.
- Try an alternative servo proven to be functional.
- Ensure the receiver and transmitter are bound properly on the same model memory.
- Swap in a new receiver and servo to confirm radio system operation.
- Check gear mesh between servo output and steering linkage.
- Remove tires and wheels to check axle function.
Carefully isolating variables through substitution testing or removal will enable identifying the specific fault in the steering system.
Preventing Steering Failure
- Check and secure all steering linkages before each drive. Tighten down or replace worn parts.
- Perform radio system range checks before each use.
- Set failsafe to center steering if signal is lost.
- Fasten servo horns securely with full metal linkage hardware. Plastic strips easily.
- Maintain gear mesh with no excessive play or friction.
- Upgrade steering servo and components to metal gear digital high-torque units.
Proper inspection, maintenance, and electronics selection reduces the chances of losing steering control.
Frequently Asked Questions
Why does my RC car cut out when turning?
If an RC car cuts power intermittently only when turning, the first suspect is a loose steering servo power connection or wiring issue. Turning puts extra load on the servo, exposing bad connections.
How do I know if my steering servo is bad?
If the servo is unresponsive but other electronics seem to function, it likely indicates a failed servo. Verify proper power connections, then try a proven working servo. If the new servo restores steering control, the original servo is confirmed to be defective.
Can overcharging an RC battery cause steering problems?
In some cases, an overcharged and damaged battery can provide power inconsistently, which may affect steering performance. But most steering issues are isolated to components and wiring in the steering assembly.
Why does my RC car turn one way but not the other?
If the vehicle can only turn in one direction, binding tie rods, a knocked linkage, or gear obstruction could be preventing full range of motion. The differentials could also be seized. Inspect mechanicals fully.
How do I fix sloppy steering on my RC?
Sloppy steering is often due to loose servo horns, worn ball links/rod ends, and loose fasteners in the steering assembly. Secure and tighten all hardware. Replace any extremely worn components causing play.
Conclusion
An RC car that fails to turn is extremely aggravating, but methodically inspecting the steering assembly and electronics will help isolate the cause. Issues like stripped servo gears, disconnected linkage, radio glitches, or locked diffs prevent proper steering.
Carefully examine the servo wiring, linkages, differentials, radio system, and electronic connections to properly diagnose the fault. Then repair or replace any damaged components restoring full steering control.
If your RC car suddenly loses the ability to turn, don’t assume the worst. In most cases the fix is simple, whether a loose connector, bad servo, or stripped gear. With a thorough process of elimination, you’ll be zipping around the driveway again in no time!