Wheel suddenly heavy, or smoke from the bonnet? Stop
If the wheel goes heavy while you're driving, hold it firmly, slow down and find somewhere safe to pull over, then switch off. It will still steer, but you'll need far more effort, especially at low speed, and that's no way to get through traffic. Smoke or a burning smell can mean fluid is dripping on hot parts: stop, switch off and get everyone clear of the car, on the side away from the traffic. If anyone is hurt or in danger, call 000.
Does your car even have power steering fluid?
Not every car does. There are three kinds of power steering, and it's worth knowing yours before you go hunting for a leak.
Hydraulic steering uses a pump driven by the engine, usually off a belt, to push fluid through hoses to the steering rack. This is the one that leaks.
Electric power steering uses a motor and a control unit instead, with no hydraulic system, so there's nothing to drip. If your car has this and something's on the driveway, it's a different fluid: start with oil, coolant or transmission fluid.
Electro-hydraulic steering sits in between: it has fluid, but the pump runs off an electric motor rather than a belt. Your owner's manual will show whether there's a reservoir to check.
Signs the fluid is getting away
- A clear, pink or amber puddle under the front of the car. AAA says healthy fluid has that tint, and it darkens with dirt over time.
- The wheel feels stiff at low speed, such as parking, then eases as you get moving.
- A whine or groan as you turn at low speed.
- Wet or stained hoses around the pump. NRMA says stains could indicate a leak.
- The reservoir keeps dropping. RACV says needing frequent top-ups is a sure sign the car should go to a mechanic.
What to do this week
Do the cardboard test
Park on level ground overnight with a clean sheet of cardboard under the front of the engine bay. In the morning, the colour and the spot tell you and the mechanic a lot. Slide it in from the side, without going under the car.
Check the level the maker's way
NRMA says to use the method in your owner's manual, because it varies by make and model. Some cars read cold, some warm.
If it's low, don't overfill
Use only the fluid the manual names, in small amounts. AAA warns that overfilling can build pressure that damages the seals. Treat a top-up as a way to reach the mechanic, not as the repair.
Keep your drive short
Avoid long trips and tight parking until it's looked at. Running a pump low on fluid can damage it, and that turns a hose job into a bigger one.
What will the mechanic check?
A wet engine bay hides the source, so they'll clean the area, top the system up, then run the engine and turn the wheel from lock to lock while watching for fresh fluid. They'll work along the path: reservoir, high-pressure hose, return hose, pump, then the rack.
NRMA says any soft, kinked, swollen or cracked hoses should be replaced by a reputable mechanic, and a hose is usually the smaller end of this job. A seal at the pump or a rack leaking into its rubber boots is bigger, because the steering has to be taken apart, bled of air and usually aligned afterwards.
Any good general mechanic can trace this. If it turns out to be the rack, ask whether they do that work themselves or send it out. A good written estimate names the leaking part, the fluid, and whether a wheel alignment is included.
Questions to ask the mechanic
- Where exactly is it leaking from, and can you show me?
- Is it the hose, the pump or the rack?
- Has running low damaged the pump?
- Does the estimate include the right fluid, bleeding the system and an alignment?
- How soon does it need doing if I can't get it done this week?
What you can do, and what's the mechanic's job
You can
- Find out from the owner's manual which steering your car has.
- Check the level the way the manual says, with the engine off unless it says otherwise.
- Do the cardboard test and take a photo of the mark.
- Note whether the steering feels heavier cold or warm.
Leave to the mechanic
- Tracing the leak under pressure.
- Replacing hoses, pumps, seals and steering racks.
- Bleeding air from the system.
- Checking the steering is safe before the car goes back on the road.
If it were our car
A few spots on the cardboard and steering that still feels normal: we'd send the job this week and check the level every couple of days until it's seen. A falling level with a whine or heavy steering: we'd drive it only as far as the mechanic, or ask for a mobile mechanic to come and look. We wouldn't rely on a stop-leak additive. It's a small leak until the day it isn't, so it's worth getting ahead of.