Buti Ngwenya vehicle rebuild& services

06/09/2026

🔧 Why Do You Feel Knocks in the Suspension When Driving Over Bumps?

When you drive over a pothole, speed bump, or rough road, the suspension system has to absorb the impact and control the movement of the wheel. A major component responsible for controlling this movement is the suspension bushing.

Suspension bushings are usually made from rubber or polyurethane and are installed between components such as the control arm and subframe. They allow controlled movement while reducing vibration, road shock, and noise from reaching the vehicle body.

When a bushing is in good condition, its rubber remains flexible and holds the suspension component firmly in position. As the wheel moves over a bump, the bushing flexes and absorbs part of the impact. This helps maintain stable wheel movement and provides a smoother, quieter ride.

However, as the bushing ages, it can become cracked, hardened, torn, or separated from its metal sleeve. Once this happens, excessive movement or play can develop between the suspension components.

When the vehicle hits a bump, the control arm may move farther than it should. That sudden movement can produce a knocking or clunking sound. You may also notice increased vibration, unstable or wandering steering, uneven tyre wear, or a loose feeling from the front end.

Worn bushings are not the only possible cause. Similar symptoms can come from worn ball joints, tie-rod ends, shock absorbers, suspension mounts, loose bolts, or damaged control arms.

If you hear repeated knocking over bumps, don't simply ignore it. A mechanic should inspect the suspension for excessive play, cracks, leaks, and loose components. After replacing suspension parts, a wheel alignment may also be necessary.

👉 Remember: A small suspension bushing can have a big effect on ride comfort, handling, tyre wear, and overall driving safety.

Dr.mechanics

05/09/2026

🚧 ROAD CHAINAGE & CROSS-SECTION SURVEY 🛣️📐

Understanding offsets, levels, and cross-sectional data is essential for accurate road design and earthwork calculations. This illustration explains how survey points are recorded at different chainages along the centerline to determine the existing ground profile and required construction levels.

🔹 GNSS Receiver: Used to capture accurate coordinates and elevation data in the field.
🔹 Bench Mark (TBM): A fixed reference point with a known Reduced Level (RL).
🔹 Chainage Reference: Identifies the position along the road alignment, such as 0+000, 0+050, and 0+100.
🔹 Centerline (CL): The main reference line from which left and right offsets are measured.
🔹 Offsets: Horizontal distances measured perpendicular to the centerline. Negative values represent the left side, while positive values represent the right side.
🔹 Survey Points: Break points collected at important changes in ground slope, such as natural ground, top of slope, toe of slope, and ditch bottom.
🔹 Design Formation Level: The proposed finished road level used for construction design.
🔹 Cut (Excavation): Occurs when the existing ground level is above the design formation and soil must be removed.
🔹 Fill (Embankment): Occurs when the design formation is above the existing ground and material must be added.

📊 Cross-sectional survey data is crucial for road alignment, earthwork quantity calculation, progress monitoring, grading, and quality control. Accurate chainage, offsets, and elevations ensure that the road is constructed according to the approved design.

Mechanics Manual

02/09/2026

31/08/2026

Best feeling EVER ! 😅💯💯

31/08/2026

⚡ How Car Fuses Work: The Ultimate Breakdown! 🚗💡
​Ever wondered what protects your car’s electrical system from blowing up? It all comes down to these tiny hero components: Fuses! 🛡️🔧
​Here’s a quick guide to what each fuse handles based on its amperage rating:
​🔹 10A (Red) ➔ Headlights 🚘💡
Keeps your path illuminated safely during night drives.
​🔹 15A (Blue) ➔ Windows / Power Seats / Sunroof 🪟🪑
Powers your daily comfort and window controls.
​🔹 20A (Yellow) ➔ Power Outlets 🔌📱
Charges your phone and accessories on the go.
​🔹 25A (Clear/Gray) ➔ Climate Control (A/C) ❄️🌡️
Runs your air conditioning and heating system to keep the cabin comfortable.
​🔹 30A (Green) ➔ Cooling Fan 🌪️🔥
Prevents your engine from overheating during long trips or heavy traffic.
​🔹 40A (Red/Large) ➔ Main Alternator & Battery Protection 🔋⚡
Safeguards the high-current line connecting your battery and alternator.
​🔹 100A (Blue/Heavy Duty) ➔ Main Battery Charging System 🚗⚡
Acts as the main shield for your vehicle’s entire electrical backbone.
​💡 Quick Tech Tip: Fuses protect circuits by melting when the electric current exceeds their rating. This cuts off power immediately to prevent severe electrical damage or fires! ⚙️🛠️

31/08/2026

⚡ 10 Symptoms of a Bad Crankshaft Position Sensor

The crankshaft position sensor (CKP sensor) is a critical engine-management component. It monitors the crankshaft’s position and rotational speed and sends this information to the ECU. The ECU uses the signal to coordinate fuel injection and ignition timing. When the sensor or its circuit begins to fail, the engine can develop intermittent or severe running problems.

1. 🚗 Engine Won’t Start

Without a reliable crankshaft signal, the ECU may not know when to trigger ignition or fuel injection correctly.

2. 🔑 Hard Starting

A weak or intermittent signal can make the engine crank longer than normal before starting.

3. 🛑 Sudden Engine Stalling

A failing sensor may lose its signal when hot or during vibration, causing the engine to shut off unexpectedly.

4. 🔄 Intermittent No-Start

The vehicle may start normally one moment and refuse to start later, making this fault particularly difficult to diagnose.

5. 🔥 Engine Misfire

Incorrect crankshaft-position information can disturb ignition and injection timing, resulting in misfires.

6. 📉 Rough or Unstable Idle

An inconsistent RPM signal can interfere with engine control and produce an unstable idle.

7. 🐌 Poor Acceleration

Incorrect timing information may cause hesitation, reduced throttle response, or loss of power.

8. ⛽ Increased Fuel Consumption

If the ECU receives inaccurate engine-speed or position information, fuel control may become less efficient.

9. 💡 Check Engine Light

The ECU may detect an abnormal crankshaft signal and store a related diagnostic trouble code.

10. 📊 Tachometer Drops or Acts Abnormally

On some vehicles, losing the crankshaft signal can cause the tachometer to suddenly drop or show no RPM.

🧑‍🔧 DIAGNOSTIC TIP

Don't replace the sensor based only on a fault code. A bad connector, wiring circuit, reluctor/tone wheel, sensor gap, or power supply can create similar symptoms.

A proper diagnosis should include checking the sensor signal with appropriate scan-tool data or an oscilloscope, inspecting wiring and connectors, and verifying that the crankshaft signal is present during cranking.

Remember: A crankshaft sensor code doesn't always mean the sensor itself is bad. Diagnose the entire circuit before replacing the part.

Dr.mechanics