Brake warning light

[SimonM]

Today I was driving some local tracks which involved a bit of mud and some ruts but nothing too drastic, and I heard a metallic scraping noise coming from what sounded like the right front tyre. I pulled over and checked but could see nothing out of the ordinary, then after a while I stopped again and the brake warning light came on whilst I was idleing, and went off again about 10 secs later. The brake fluid level is sitting in between max and min, so it is possible there is a slow leak but I can't say that it has dropped substantially.

The noise sounded like it may be the brakes stuck on. I pumped the brake pedal whilst I was moving and pulled the hand brake on and off( when I was stopped :)), and the noise soon disappeared.

Over the last couple of weeks I have noticed a light knocking/clicking noise as I apply the brakes but not sure if this is related. Interestingly enough this noise is gone also now.

The old boy has clocked over 300k now so it no surprise that there a few issues starting to occur. Just wondering what people's suggestions are with this one.

[Vin Rouge]

A scraping noise from the front brakes sometimes indicates that a stone is wedged between the disc and the metal guard. If it is this, the standard first step to removal it is to drive backwards and stamp on the brakes.

[SimonM]

It is certainly possible that it was something like a stone but it was the brake warning light that really concerned me. Is it possible that a stone or similar could cause the warning light to come on? I hope it is that simple.

[Sleepy]

Mine used to come on when descending (very) steep hills. Were you on the flat when it came on?

[SimonM]

Mine used to come on when descending (very) steep hills. Were you on the flat when it
came on?

Paul I noticed the noise first as were going up a hill and when I stopped on the flat I noticed the light had come on.

[Sleepy]

Paul I noticed the noise first as were going up a hill and when I stopped on the flat I noticed the light had come on.
I would top up the brake fluid, (exchange it if it is a bit old), make sure there is no stones or crud under your disc pads and then monitor. Also check for any obvious leaks.

The first time I heard my brakes squeal due foreign debris it sounded bloody awful:o but actually not something to worry about once cleaned/cleared

Stones under disc pads is quite a common problem (annoyance?) when offroading.

If you're not sure, a mechanic can check all this for not a great expense.

[Fraz]

is it possible that the stone/debris forced the pads apart, thus lowering your fluid amount and possibly your ecu detected this and threw the light on for you?

[SimonM]

is it possible that the stone/debris forced the pads apart, thus lowering your fluid amount and possibly your ecu detected this and threw the light on for you?

Sounds reasonable. I haven't had any problems since. It will be interesting to see what happens when I hit the tracks this weekend.

[SimonM]

Mine used to come on when descending (very) steep hills. Were you on the flat when it came on?

Hey Sleepy - I went out driving yesterday afternoon and going down a steep track the light came on ;). Went off as soon as I hit the flat again.

[JDNSW]

Hey Sleepy - I went out driving yesterday afternoon and going down a steep track the light came on ;). Went off as soon as I hit the flat again.

I have an idea that the warning light warns of two distinct problems. One is low fluid, but the second is an excessive difference in fluid movement between front and back circuits. This will be due to either a fluid leak in one of the circuits, or excessive movement of one piston, usually due to something pushing the piston back too far prior to the application of the brakes. This will be either a stone or mud wedged under the pad or free play on the wheel bearings. (Or, very unlikely, a loose calliper) Of course, another, quite possible cause, is a wiring fault!

John

[Sleepy]

I would never discount JDNSW's theory. ;)

As I mentioned this used to happen in my 2001 110 on steep downhills (although not on my 2005 90:confused:). The vehicle brakes system appeared all ok (it was only a couple of years old) and the fluid level was ok. I put it down to the angle of the fluid moving forward in the reservoir.

[SimonM]

I have an idea that the warning light warns of two distinct problems. One is low fluid, but the second is an excessive difference in fluid movement between front and back circuits. This will be due to either a fluid leak in one of the circuits, or excessive movement of one piston, usually due to something pushing the piston back too far prior to the application of the brakes. This will be either a stone or mud wedged under the pad or free play on the wheel bearings. (Or, very unlikely, a loose calliper) Of course, another, quite possible cause, is a wiring fault!

John

John - I wonder whether the clicking noise I have had was a piston sticking, is that possible?