SKwan

I was going uphill in my A4 Avant Quattro 2.8 V6 with Tiptronic with the cruise control on. Traffic ahead slowed a bit so I tap the brakes to disable the cruise control but the brake pedal didn't move. I pressed it again and the pedal still didn't give. The car didn't slow down nor did the brake pedal travel far enough to disengage the cruise control. Luckily, I still had time to manually turn off the cruise control and slow down. The brakes were fine after that. The road wasn't wet or anything. The car was in fourth gear at around 3000 RPM.

Any opinions?

Bob Petruska

Maybe the wet braking issue isn't due to water on the rotor (lack of shields). I too have experienced the hard pedal with no movement on misty days which I attributed to the wet braking issue. Now maybe the ABS braking system is affected somehow by moisture under certain conditions......just very interesting!

kanahoot

after washing my car about 2 hours ago I pulled my car out of my drive way and when I pressed on the brake it just didn't work, AT ALL! I threw it in neut and pulled the brake slow, lucky I was't going over 3mph but the brake just felt like the rotors were slipping right through the brake pads???

SKwan

I've experienced that more than once. The difference was that the pedal didn't move. It was as if something was wedged under the brake pedal but there wasn't. Luckily, it wasn't a panic situation.

ed4

and it scared the hell out of me. Turning off the cruise control restored full travel of my brake pedal. I normally don't like using the cruise control feature in any car but I use it on occasion, just so I can stretch and bend my tired legs.<p>Ed from Troy

98 2.8-30Vqt
01 1.8Tqmsc retrofit HID's

ed4

it was seemed as if the power brake hydraulics shut off momentarily. Kinda like sitting in my car w/o the key in the ignition and experiencing the strong resistance of the brake pedal from pumping the brakes 4 or 5 times.<p>Ed from Troy

98 2.8-30Vqt
01 1.8Tqmsc retrofit HID's

James R.

The brakes and cruise control are both vacuum operated on the non drive by wire cars. All the cars rely on a hydraulic vacuum brake booster...but the non DBW cars also rely on vacuum to do the cruise control. There are some valves which are only engaged when the cruise control is on...if there was a leak in that part of the system it could starve the brake booster cyl making the pedal stiffer than normal.

If you wanna see the sophisticated cruise control pop the hood and take a look at the throttle body you'll notice a rod which connects to a bag. This bag is deflated by vacuum which changes the throttle angle...making the car accelerate or deccelerate depending on which way it goes. Anyhow if there was a leak forward of all the cruise solenoid valves this might cause the cruise to work marginally...and could potentially starve the brake booster. Anyhow it's just a theory...have it check with the VAG they can make a false air measurement...it has to do with the delta between engine load and metered air flow...if the engine has to little load at idle it could indicated that there is a leak in the intake tract. They have an engine leak detector spray which they can spray on various parts and observe changes in the CO levels in the exhaust...and in more extreme cases the engine speed will actually change.

Anyhow good luck...get it checked out ASAP...or stay away from the cruise till you're sure.

Regards,

James R.

2001 A4 1.8TQMSX-ESP On order, arrives Sept/Oct if I'm lucky.

For sale 24,500 all mods listed plus all orig parts including turbo included in this price.

99 1.8TMS (Neuspeed K04, 5 Bar FPR, Beru Ultra X Plugs, K&N Filter, Remus Exhaust, S4 Wheel Well Liner Mod, Bilstein Sport Shocks, Neuspeed Sport Springs, Neuspeed Front Anti Sway, Brembo Rotors, Mintex Red Box, Ronal R-7's 17", 225/45/R17 Bridgestone S02 PP, Smartire (neat gimmick), Greddy Turbo Timer, European Projectors, Clear Sides and Full Tint...)<p>

skabaru

...have a tendency to accumulate on the rotors and render then useless for a second or so before the pad can actually scrap the residue off...

I usually ride the brake for a bit after I pull out after a cleaning to make sure it all gets cleared off...<p>2001 A4 1.8T QMSX Avant (on order, damn sport seats)

SKwan

Thanks, I'll have it checked out.

SKwan

That's exactly how it felt.