Intermittent noise on car, I cannot identify cause.

[mart]

I’ve had this car nearly 4 years. Toyota Corolla estate 2lt (Diesel turbo). I only use it about once or twice a week. I average about 3K miles per year, so it is not used much.

A few months back I started to hear a noise that sounded like metal to metal screeching. My initial thoughts were a calliper piston not retracting fully, and a pad worn down to metal rubbing on a disc. However, when braking, the noise completely disappears, until I take my foot off the break, then it’s back. At times, I have to drive about 7 miles from cold before the noise starts, but not always that far. The noise gets a bit louder when driving round a bend/roundabout etc.

Today was MOT time, and I drove about 4 mile to the testing garage. I felt confident that whatever was causing the noise would be discovered during the MOT, but it passed the test. The noise today was audible from first setting off.

I asked the MOT tester if he had discovered any issues and he said he had not. I’ve been advised to take the car straight down as soon as the noise appears and they will put it on the ramps-no appointment necessary. That is fair enough, but it’s puzzling me. Anyone experienced similar or got any ideas?

 

[Sarto]

Could it be a wheel bearing near the end of its life?

 

[PhillipM]

Wheel bearing.

 

[mart]

Would the increased noise on cornering indicate front, or hard to tell?

 

[Cobbler]

I had a similar problem with my Transit camper van, the brakes would squeal when driving & graunch under braking, sounded terrible, to the point that I removed the wheels twice on a foreign campsite, expecting to find damaged or disintegrating pads. This only occurred some time after fitting aftermarket pads. I changed them for genuine Ford pads as I got so concerned about the noise & it went away. The aftermarket pads were good quality ones, I can only think that they were very hard. It turned out that the genuine ones were no dearer than the pattern parts.

 

[mart]

At the moment I`m leaning towards the duff bearing idea (there is no noise at all when braking), but thank you for sharing your experience of the camper van. The pads are the same ones that were in the car 4 years ago. I`ve only done about 12K miles in that time.Anticipating the road, I invariably slow down naturally for junctions/roundabouts etc, and the brakes get minimal use in that respect.

 

[Richiew]

I would be surprised if it was the wheel bearing considering your car had an MOT today. If it is the case I would find another garage.

 

[Cobbler]

Might be worth taking the pads out & sanding the surface so you present a new surface to the disc. This would prove it if the note changed or went. My problem didn't start straight away on changing the pads, but some time later.

EDIT when I took the pads out on holiday I cleaned then as best I could & it stopped the noise for a short while.

 

[CompoSimmonite]

Find a big empty carpark and drive around in tight circles. Normally if noise starts / gets worse when wheels turned left or right that is an indication that CV joint problem.

 

[colnerov]

There could be a small stone or grit that has got lodged by the pads and rubbing against the disc, they make a 'orrible screeching noise.

 

[p0689109]

Could be a sticking piston in one of the calipers as the car is tending to spend a lot of time stationary. After braking the pistons just move back enough to give a running clearance and so perhaps one is just not moving enough. I would try removing the pads and resetting the pistons a couple of times. Not being familiar with the car has the calipers got a piston to each pad or are they the type that one piston is used and the reaction of that pulls the second pad into action? If the first just do 1 pad at a time and if the other I would check the sliding mechanism is nice and free.

 

[wookie]

I would be surprised if it was the wheel bearing considering your car had an MOT today. If it is the case I would find another garage.

I wouldn't be surprised, nor would I blame the garage, many years ago I had a Renault 21 with a n/s rear bearing that started rumbling once you got above 80 on the motorway, but there was absolutely no play in it at all when jacked up and it past a MOT just fine, I fit a new bearing and the sound disappeared. I even broke open the old bearing to check but it still looked perfect inside

 

[Crater Creator]

There could be a small stone or grit that has got lodged by the pads and rubbing against the disc, they make a 'orrible screeching noise.

^^^^^ this^^^^^

Wheel bearings are most noticeable on corners, on the wheel that is unloaded - so if it's worse on a left hand corner, it's the nearside bearing that's suspect.
I would start with taking the wheels off one by one and giving the whole suspension area a damn good powerwashing, see if any foreign objects get dislodged. Hey - it's free, nothing to lose!

 

[the snooper]

As you say it disappears when you brake I would expect there would be playing the bearing, the application of the brakes would be pulling the disc and bearing back into line , if it was a sticking brake it would have been picked up on the brake test

 

[the snooper]

If it's drum.on the rear I'd start there a shoe fixing may have gone and the shoes grinding on the drum until you brake and it's straightened up.by the hydraulics

 

[cumbriasteve]

My bet is a pad not clearing totally, when you break it obviously moves from that position and does it's job normally, take your foot off and it moves back but not quite enough and causes the screeching.

 

[Paul G]

Wild guess.

Free wheeling alternator pulley ?

 

[the snooper]

Wild guess.

Free wheeling alternator pulley ?

that stops making a noise when he brakes ?

 

[dobbslc]

They freewheeling on the overrun.
Try pulling up the handbrake gentle while moving, that might tell you if it's the front or rear.

 

[Crater Creator]

How does the alternator pulley freewheel on overrun? Unless there is somehow suddenly less electrical load required of the alternator it will still need to be driven?