Banging Brake

[AntneeUK]

Popped out in the snow today to pick up some dog food, and the road was all snow-free until I got to the pet-food place, whose car park was still under a bit of snow.

As I was leaving, i got to the first junction and pressed the brakes as I changed down to first. There was a banging noise, almost like when you don't push the clutch in far enough. Because I was changing gear at the time, my first thought was that it was the gearbox. Then it did it again the next time I applied the brakes.

I'm a bit nervous of the brakes as they've just been in pieces to be serviced and the fact that this happened has had me wondering whether it was a fault in the calliper, or was it more likely something that got in to the dimples or grooves on my discs?

I brake tested a few times for the rest of the journey home and it all seemed back to normal, but even so it had me worried. Any ideas?

 

[flame_88]

dont mean to patronize you but could it have been the abs kicking in?

 

[traumapat]

Sounds like abs. How did the pedal feel?

 

[AntneeUK]

Hey, no, patronise away. It could've been ABS, but there was no good reason for it, if you know what I mean. It was VERY light braking and there was no snow on the actual road that I was stopping on, only the one that I'd just come off of. I don't think I've ever triggered the ABS before in this car mind you, and the banging seemed much more pronounced than my previous encounters with ABS, but that's not to say that it wasn't that.

Is it possible that something had gotten in to the ABS sensors?

 

[cap r 225]

Mine did this today mate, wouldn't worry. Think mine was just the wheel locking and grabing for grip. I too was doing about 7-8mph.

 

[AntneeUK]

Yeah. I didn't think that ABS could even function at such a low speed to be honest, because the wheel speed sensor isn't that accurate at low speed

 

[cap r 225]

I don't think the ABS would need to kick in to be fair mate, the wheel scrabbling would make a similar noise.

 

[traumapat]

I ve had it kicking in at low speed. Tiny patch of oil will do it as would ice.
Unless it does it on a bone dry road i`d not worry.
It does make a racket though.... i always expect the tarmac to have rippled under the car!!

 

[AntneeUK]

It sounds almost like grinding a gear?

 

[Andy3004]

yep, it's the ABS...nowt to worry about!

 

[jonathan_phang]

I had this too on Thursday, when the snow got really bad here. I thought that there was a problem because I was expecting a light on the dash to show when it kicked in (like the traction control) but after reading the manual (If I interpreted it correctly), for the ABS, the light comes on when faulty, so must have been the ABS...

I felt a lot of reverb through the brake pedal, and yeah it was like I was grinding something... And I was crawling along too mate.

 

[AntneeUK]

Right, so Leon + snow + brakes + low speed = banging and grinding. Well at least that's put to bed. Put's my mind at rest too, thanks guys

 

[Shaunyboy]

If you sping a wheel by hand as fast as you can and press the pedal what hapens? you get a noise like banging where the pads have gripped, all it will be is wheel locking, doesnt have to be snow the roads are very greasy at this time of year, also i dont think abs works under about 15mph, there is somthing on the traction control which is active under 15mph to stop wheels locking, also traction control can make a banging when it cuts the power, my clio did it bang bang bang and it wud pick up speed again. Dont worry about it.

 

[AntneeUK]

Nope, not worrying any more, it was just the timing, with me having only got the car back on Wednesday from having the brakes serviced, and then this symptom that I've never experienced in this car before. It's all good though. Phew!

 

[AntneeUK]

ABS confirmed today. Had to pop to the inlaws and their road was an inch deep in ice. So, when there was nobody around I decided to test it at very low speed (probably around 5mph). I stood on the brake pedal and it did the same thing (basically a VERY pronounced pulsing through the pedal) and we slid for about 20yds! Back to engine braking and feathering the pedal after that

Thanks guys

 

[Shani]

Yeah. I didn't think that ABS could even function at such a low speed to be honest, because the wheel speed sensor isn't that accurate at low speed

As far as I know ABS will look for speed differentials of each wheel. So maybe just one wheel locked up hence the ABS kicked in.

 

[AntneeUK]

Yeah, you're right, but what I mean is that at low speeds, say below 5mph, the pulses from the sensor become inaccurate, so the ABS system ignores it, assuming that at 5mph you're in next-to-no-danger anyway. I was going so slow that I wouldn't have expected the ABS to have kicked in