Fluid leaking underneath the vehicle
A patch or a drip on the driveway where the car has been standing.
Direct causeA seal, hose or joint no longer containing fluid in a system that is either pressurised or gravity-fed from a reservoir.
Physical realityPosition and colour together identify the system faster than anything else. Power steering runs at very high pressure — over 100 bar at full lock — so a seal that merely seeps when parked can spray while driving, which is why the puddle underestimates the fault.
Safety riskDepends entirely on which fluid. Brake fluid means do not drive the vehicle. Power-steering fluid is medium: you lose assistance gradually and the pump is damaged by running dry. Water dripping behind a front wheel in summer is aircon condensation and is normal.
Required fixIdentify the fluid, clean the area, then re-inspect after a short drive. An old stain spread across a sump guard points nowhere; a fresh drip on clean metal points at its source.
What usually causes it
- Steering rack end seals — often shows as fluid tracking out of the rubber bellows rather than dripping cleanly.
- Power-steering pump shaft seal — a leak at the front of the pump, usually with fluid flung around the belt area.
- High-pressure hose — fails at the crimped end or where it has chafed against something.
- Reservoir or return line — a cracked reservoir or a perished clamp leaks at low pressure, so it drips when parked and not while driving.
Diagnostic verification criteria
How a workshop separates these causes rather than replacing parts in sequence.
- Primary indicator: Colour and position read together. Power-steering fluid is red or amber where ATF is specified and green or clear where a synthetic hydraulic fluid is — the reservoir cap states which. Engine oil is brown to black and sits further back. Coolant is green, pink or orange and smells sweet. Brake fluid is pale yellow, near a wheel or the master cylinder, and is the one that stops the job.
- Tolerance limit: A damp film on a housing is a seep and can be monitored. A drip that forms a coin-sized puddle overnight is a leak and the reservoir level must be checked before every drive until it is repaired.
- Secondary failure risk: Topping up a power-steering reservoir without finding the leak hides the loss rate. Running the pump low aerates the fluid and erodes the pump internally, so a cheap seal job becomes a pump replacement.
RM Steering and Suspension traces steering and suspension leaks in Brackenfell, Cape Town. We identify the fluid and its source before quoting.
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