MOT defect file
Power steering fluid leaking or below minimum
Last updated
Quick answer
Hydraulic fluid is escaping from the steering system, or the reservoir has dropped below its minimum mark. A weep is usually recorded rather than failed, but it is the warning that comes before the pump or rack gives up.
- Typical cost
- £90–£400
- DIY viability
- Possible with care
What you might notice
- A groan or whine from the front of the car when you turn, loudest on full lock and worst when the engine is cold
- A small reddish or amber puddle under the front of the car after it has been parked overnight
- Steering that goes heavy in one movement, or judders and grabs as air is drawn into the pump
- The reservoir sitting below its minimum mark when you check it, which on a sealed system means the fluid has gone somewhere it should not have
What causes it
- A perished or chafed high-pressure hose, which is the usual culprit and often leaks only under the load of full lock
- Corroded steel pipe runs along the underside of the car, particularly where a pipe passes through a clip and salt has collected
- Failed rack end seals, which is what a split gaiter and years of contamination eventually produce
- A leaking pump shaft seal, or a reservoir cracked at a mounting boss or by frost
Advisory or failure?
A power steering system that is leaking fluid, or a reservoir below its minimum level, is normally recorded as a minor defect — noted on the certificate without failing the car. It becomes a major defect where the leak is severe, where the fluid level is low enough that the assistance is impaired, or where a pipe or hose is so chafed, corroded or insecure that failure is imminent. Power steering that is not working at all is a major defect in its own right. Grading rises to dangerous where fluid is leaking onto a tyre, a brake disc or the exhaust, or where the condition could lead to loss of steering control. Note also that a defect elsewhere often shares the cause: fluid escaping past a rack end seal frequently sits inside a gaiter, and that gaiter will be assessed separately.
Can you fix it yourself?
Possible with care
Checking and topping up is straightforward, and worth doing properly: use the exact fluid specification in the handbook, since mixing types swells the seals and destroys the pump, and check the level cold with the wheels straight unless the book says otherwise. Finding the leak is the harder part — clean the area, then have somebody hold the wheel on full lock briefly while you watch, because most hose leaks only show under pressure. Replacing an accessible hose is a realistic driveway job, but the system has to be bled afterwards by turning lock to lock with the front wheels off the ground and the reservoir topped up as the air comes out. Do not hold full lock for more than a few seconds at a time, and never run the pump dry, which can wreck it in under a minute.
What it costs
Fluid is £10 to £20 a litre, so topping up costs almost nothing — but a system that needs topping up has a leak, and that is what you are actually buying a repair for. A high-pressure hose is £30 to £120 in parts with an hour to two hours of labour depending on access, plus bleeding, which puts most hose jobs at £120 to £280. A corroded pipe section made up and fitted is similar. The top of the band is a pump at £150 to £350 fitted, and a leaking rack goes beyond it entirely, since that job means removing the rack, bleeding the system and resetting the alignment.
What happens if you ignore it
A pump run low on fluid cavitates and destroys itself, so a £30 hose that was left alone commonly presents its bill as a pump or a rack. Fluid on the road is also a hazard to motorcyclists, and fluid landing on a hot exhaust or a brake disc is worse — the first is a fire risk and the second reduces braking at that wheel, which is why the severe version of this defect is graded dangerous. And when the assistance finally goes, it goes at once, which is a genuine surprise the first time it happens with a bend already turned in.
Common questions
- Is a power steering fluid leak an MOT failure?
- Usually not on its own. A leak, or a reservoir below its minimum level, is normally recorded as a minor defect and noted on the certificate. It becomes a major defect where the leak is severe, the level is low enough to impair assistance, or a pipe is so chafed, corroded or insecure that failure is imminent, and dangerous where fluid lands on a tyre, brake disc or exhaust.
- Why does my steering groan or whine when I turn the wheel?
- Low fluid is the usual cause: the pump draws air, which produces a groan or whine that is loudest on full lock and worst when the engine is cold. The steering may also go heavy in one movement, or judder as air passes through. Check the reservoir level cold with the wheels straight unless the handbook says otherwise.
- What colour is power steering fluid, and how do I find the leak?
- It is typically reddish or amber, and shows as a small puddle under the front of the car after it has stood overnight. Clean the area, then have somebody hold the wheel on full lock briefly while you watch, because most hose leaks only appear under pressure. Hold lock for a few seconds at a time and no longer.
- Can I just keep topping up the power steering fluid?
- Topping up costs almost nothing, but a system that needs it has a leak, and running low is what destroys pumps: a pump that cavitates can wreck itself in under a minute. Use the exact fluid specification in the handbook, since mixing types swells the seals. Fluid on the road is also a hazard to motorcyclists.
- How much does it cost to fix a power steering leak?
- Between £90 and £400. Fluid is £10 to £20 a litre. A high-pressure hose is £30 to £120 in parts with one to two hours of labour plus bleeding, so most hose jobs come to £120 to £280, and a made-up corroded pipe section is similar. A pump is £150 to £350 fitted, and a leaking rack goes beyond the band entirely.
The warning light behind this
This defect is what a tester writes down. What you see from the driver’s seat is a symbol, and it is worth checking which one, because manufacturers reuse the same shape for more than one system.
This is general guidance, not a diagnosis. The severity DVSA records depends on the specific fault found, so the same item can appear as an advisory on one test and a failure on another. Ask a qualified tester or mechanic to inspect the vehicle.
Has this been recorded on your car?
Check the full MOT history for any UK registration.