front brakes not working well

[rocky.ca]

Hey guys, I just picked up a 2000 A4 1.8t about a week ago. I have noticed that the braking SUCKS, almost like the front isnt really doing anything and the back is doing most of the work. I proved this theory the other day by giving it a hard rip and seeing the rear rotors glow while the front ones were fine. the pads, from what i can see through the spokes of the wheel look alright, does anybody where to start to diagnose this?

[itsjeo]

question.. not to sound rude or anything.. but how did you see the brakes glow while driving the car?

[NK2007]

Hey guys, I just picked up a 2000 A4 1.8t about a week ago. I have noticed that the braking SUCKS, almost like the front isnt really doing anything and the back is doing most of the work. I proved this theory the other day by giving it a hard rip and seeing the rear rotors glow while the front ones were fine. the pads, from what i can see through the spokes of the wheel look alright, does anybody where to start to diagnose this?

Welcome!

To start, inspect for leaks then bleed the brakes. You very well may have air in the lines if the reservoir level dropped too low, drawing air into the front lines.

Give this a try, and let us know if it works.

Neill

[rocky.ca]

because i was driving to a resteraunt and when i got there and parked the car (it was late at night) the rear brakes were glowing and there were intermittant flames comming off of the pads... wierdest thing i have ever seen. i will try bleeding them asap, there are no leaks though. any other ideas?

[big_greasy_taco]

and there were intermittant flames comming off of the pads... wierdest thing i have ever seen.

Uhh, flaming breaks... intermittant at that?

[rocky.ca]

yep.. like ive said, wierdest thing i have ever seen. just intermittent poofs of flame... nothing big and the rear brakes work perfectly still. just those god damn fronts

[NK2007]

Hmm... I've never seen white hot brakes, but if they were, make sure not to set the e-brake while they are that hot, or the rotors may warp

[MattzWarsteiner]

Look at the hydraulic block by the ABS module under the hood. A previous mech may have mis-routed the lines so the fronts are connected to the rear ports. During normal braking, the proportioning valve in the block sends the majority of pressure up front.

If you have a firm pedal, that would likely rule out air in the lines. This problem could be caused by a blockage,or a bad ABS block. Any lights on the dash or trouble codes you can share?

It would be odd, but both front calipers could be seized too. Glowing rotors or fiery pads are not cool. Check this out before something not so happy occurs Rocky!

[rocky.ca]

I will give all of those a look. tomorrow is my working on the car day. no lights on the dash

[rocky.ca]

btw does anyone have a brake schematic or a picture of where the lines should go into the hydraulic block?

[MattzWarsteiner]

btw does anyone have a brake schematic or a picture of where the lines should go into the hydraulic block?

I can offer this.........

A4s with typical ABS:
Looking from the engine outward:
TOP OF UNIT
MC1 MC2
RR LR
LF RF
PUMP MOTOR HERE

A4s equipped with traction control ABS modules appear to
have the MC lines on the sides of the block near the top
and front calipers also on top, rears at the lowest
point of the block.

It seems unlikely for the master cylinder to be at fault since the car uses two separate diagonally opposed hydraulic circuits. LR/RF and RR/LF each share a MC circuit.

[onemoremile]

because i was driving to a resteraunt and when i got there and parked the car (it was late at night) the rear brakes were glowing and there were intermittant flames comming off of the pads... wierdest thing i have ever seen. i will try bleeding them asap, there are no leaks though. any other ideas?

You've got a rear caliper problem. My bet is that the parking brake line is pinched or stuck somewhere.

[rocky.ca]

i dont think so because if i drive normally they are fine. i was just having a spirited stint...

[im sofa king]

You may just have shitty front pads. Those lifetime pads that people throw on are hard as a rock and don't brake too well at all

[Nebone]

Do this test.

When your car has been sitting over night so everything is cold, start it and drive it about 100 yeards slowly and then slowly stop. If your rear brakes are HOT already, then you have seized calipers or a sticking rear pad. They normally should be just a tad warm from that one slow braking. Carefully touch the rear rotor to check this.