Brake pad warning light on then off

[obi_waynne]

My brake pad warning light keeps coming on, and then going off again.

It started when this wet weather hit but I'm not sure if I should bother taking a wheel off to check the pads or just go with my hunch that all is ok?

Anyone else get this? Surely a brake pad warning light should stay on once triggered?

 

[HDi fun]

Coincidentally mine is doing exactly the same thing. Pads are fine and I have bought the sensors just need to get them fitted.

 

[admin]

Don't make the mistake of just checking the outer pads, the inners can sometimes wear a lot more quickly. Get it checked out you need to take the wheel off.

 

[Loz]

I had a similar fault on an old car and I found the sensor wire had come loose and was shorting against the disc.

 

[pgarner]

the warning is only connected to one pad anyway so you would need to check all pads.

mines has done it a few times and i know it was new pads that were fitted when i changed the setup. could just bethe sensor wires corroded through.
if it has you could ether code out the sensor in vagcom or the easier option cut the sensor wire, strip the 2 wires back a bit, fit some heat shrink and tape over.
just remember this will mean that you need to use some common sense and keep an eye on your pads

 

[obi_waynne]

Took off the front wheel and inner pads were down to 2mm the outers still had 8mm left on them. Is it normal to wear this much on the insides?

I think I've caught it before I scored the disc though which is a good thing. It's a good job I didn't rely on the quick outerpad check I did through the alloy wheel.

 

[pgarner]

its the inside thats doing all the pushing but wouldnt have thought there would have been that much of a difference

 

[HDi fun]

Mine has sensors front and rear - the sensors themselves are sold separately from the pads

 

[obi_waynne]

The new ones are really spongy at the moment, there is a lip on the disc that I guess needs to be worn down.

I'll keep an eye on the pad wear this year, I suppose the pistons could be out of balance and putting more pressure on the inside.

Interestingly Audi didn't pick up on the worn inner pads, they must just check the outers when they do the check.

 

[pgarner]

shouldnt really be much of a lip on the disc waynne, anything more than 1mm then they should be replaced.

Audi probably just looked through the alloys

 

[obi_waynne]

I think it is about 1mm, it's not a lot. I don't fancy buying new discs for this they are drilled and vented as standard! I shudder to think what the cost will be.

 

[pgarner]

http://www.motorsportworld.co.uk/detprod.asp?productcode=D1045&PID=1198449

just shy of £100 for the pair for 312mm

or 130 for the 320mm

http://www.motorsportworld.co.uk/detprod.asp?productcode=D1574&PID=1198649

not sure what ones are on the A4 as theres 288, 312, 320 or the 345 but theyre for the S4

 

[HDi fun]

Does seem these days it's pads and discs once, second set of pads and then the whole lot again next time round.

 

[obi_waynne]

I'm really wishing i'd got the diesel now! (I guess the petrol is er, more fun?!)

 

[HDi fun]

I'm really wishing i'd got the diesel now! (I guess the petrol is er, more fun?!)

Why do you wish you had the derv model? Makes no difference to the braking setup at all.

 

[obi_waynne]

Smaller discs and pads. Saves about £50 per item. Fuel would cost a lot less and I wouldn't need to do the clutch for another 50K miles.

 

[pgarner]

clutches and dmfs generally wear quicker as more torque on them.
pads are more than likely the same - same pads on the s4 as the a4 just different clip to secure in the calliper due to the 59mm rather than 57mm one and the same pads are used in the 288 and 312mm setups as its the carrier thats different .
if yours is pre 08 then its looking like you have the 312mm discs so would have the same setup.

just be glad you didnt get the s4 as thats the discs and pads are what ive gotten, looking around £150 a disc couldnt believe it when i seen nearly £300 for the pair

 

[HDi fun]

Diesels can really batter DMFs with the monster torque figures. Very surprised Audi uses smaller discs as diesel cars are almost always heavier than petrol ones.

I assume that it's an effort to offer diesel buyers a bit more than just a fuel saving - in my estimation the fuel savings are matched by the increased whole life servicing costs of diesel engines.