What is this?

[Andyy]

Passenger side front caliper



Drivers side, with mystery part



I've had my brake warning light come on recently, oil level is fine.
What is it? Could this be the cause? Can i get the part alone or do i need a new caliper?

Thanks

[Batfinnk]

Looks like the bleed nipple to me. The calipers are identical so the passenger on is probably on the bottom of the caliper. That is just a blanking plug as they are symmetrical.

[MikeFish]

Yep, looks like a bleed nipple.

[Batfinnk]

Hahaha. He said nipple! Lol

[Andyy]

And could that be causing my warning lights? They're not perm, it seems to come on now and again (lets say 5-15 minute intervals) while driving and go between 5-60 seconds later.

Bat, checked the other side, it's at the top for both. At the bottom is some wire type thing (i must sound like such a dunce to any RS4 pro here)

[Batfinnk]

I think the most common thing to bring the wRning light on like that is normally a corroded or broken wire on the pad sensor.

[Andyy]

Just had new disks and pads fitted all round in jan by MRC, Is the pad sensor not a part of the pads ( i remember them having cables)

[Batfinnk]

Yes it is. More likely to be where it connects to the car side of the loom. It is a little connector attached to the hub assembly. Could be moisture in there. Worth popping off and squirting with some wd40 or something along those lines.

[Andyy]

Ahh ok, well i think i'm going to take it a specialist just as i'm not comfortable messing with it since it's a company car lol but at least i can try cut down the cost of diagnosis if i can give him a few places to look first

[Youngben]

that there is a bodge for 1! they have replaced the bleed nipple for a grub screw by the looks of it! both calipers should have 2 bleed nipples (one either side of the caliper) at the top! looks like that one may of got damaged or broken off and they have replaced it with a grub screw rather than get a new nipple or replace the caliper if they have had to re drill and tap the hole after the damage! as you say at the bottom of both calipers in the same place will be a pipe connecting both chambers/sides of the caliper for the fluid to travel across the caliper!

In regards to your question on brake lights on i would check your sensors! this can be done with a simple multi meter by disconnecting the plug and checking there is still a join all the way through the circuit!

[sonny]

Yep your missing a bleed nipple!

Some callipers have bleed nipples at the bottom, this is so that they can be used on both sides of the car. You cant bleed a car using the bottom bleed nipples as air will rise in the calliper resulting in the top pistons not being able to be forced out.

Not sure how you will be able to repair that.

[sonny]

The wires entering the pad wear sensor connection blocks can tend to brake loose causing a closes circuit. You should be able to see clearly

[joesnow]

Company car?? Got any jobs going??

[Andyy]

Cheers for the replies guys, all helpful stuff.

Yeah, company car get's better I'm 22 I have a cool boss

Ahh, hadn't noticed it was plugged with something else.


also it's not the brake pad warning light. It's the red warning light that's to say you have a fault in your braking system. Just encase anyone wasn't certain what i meant

[brn7y]

Don't fancy your company car tax bill!