Weird Brake Problem!! HELP

[downhillracer]

I have a 2003 a4 1.8t quattro and am having a weird brake problem. If i apply the brakes hard the car does not even have enough power to cause abs to kick in then if i do another hard brake apply it gets a bit better and then another and it gets better and finally it will start to have good braking after 4-5 really hard stops. I am afraid to drive my car because of this problem! What do you guys think??

[old guy]

It sounds like your brake booster is not working properly. It could be something as simple as a vacuum leak. Check your suction pump at the back of the motor. It has been known to fail and will cause a problem with your brakes as described. Once it goes completely you will know it for sure since the car will not idle and will run rough. It could also be a problem with the booster itself. I remember reading a post recently where AZ member nihil had the brake booster on his '02 replaced under an AOA recall. Might want to check into that.

good luck!

EDIT: I am making the assumption that your pedal is staying firm but you just aren't getting full braking force. If you are having to pump the pedal to get decent brakes then it sounds like your master cylinder is worn out.

[dirtybrd]

But using the brakes more with a booster issue will cause the pedal to get harder along with braking. To me sounds like a master cylinder going bad.

[downhillracer]

yes the first few brake applies the pedal is soft and on the first hard apply usually goes to the floor but it gets firm and stops really well after a few hard stops.. its really weird

[downhillracer]

and once its starts stoping hard the pedal sucks down and abs works like it should...also if it was a master cylinder problem wouldn't i get a brake warning light because the pressure differential switch in the master cyl....unless there is no pressure differential between the 2 sections...idk...do you guys think it could be crappy pads that don't work well unless they are hot...thoughts???

[old guy]

It sounds to me like a worn master cylinder. Have you ever had the brake fluid flushed? I would try that first. It probably won't make any difference but it's a lot cheaper than replacing the master cylinder.

[Audi Skate Snow]

sounds like the master cylinder, or as simple as having some air in your lines. Try bleeding the brakes or even doing a flush, then go from there.

[Teratorn]

Sounds like air in the lines. With each pump on the pedal, you're compressing the air in the lines. I would start with bleeding the brakes. Then the master cylinder from there.

[A4TL]

remember every 2years 24K -- brake fluid flush

seems excessive but man its your life if the brake system isn't 100%

[dirtybrd]

If there is air in the lines you'll have a leak somewhere, unless you just opened the system.

[Audi Skate Snow]

If there is air in the lines you'll have a leak somewhere, unless you just opened the system.

true... which makes me think the master cyl... primary seal, secondary piston.... 9 out of 10 times on master cyl's that is what usualy goes.

[downhillracer]

the only reason I don't think its the master cyl is if the secondary cup seal was leaking you would have an external leak and if the primary cup seal was leaking you would have and internal leak causing the differential pressure switch inside the master to set the brake and or abs light. so i will do a flush and see what happens.. thanks guys

[Audi Skate Snow]

the only reason I don't think its the master cyl is if the secondary cup seal was leaking you would have an external leak and if the primary cup seal was leaking you would have and internal leak causing the differential pressure switch inside the master to set the brake and or abs light. so i will do a flush and see what happens.. thanks guys

true, probably just air in lines.. but kinda odd it just started happening.

[downhillracer]

true, probably just air in lines.. but kinda odd it just started happening.

Well i just bought the car lol the old owner probably never noticed it because he drove like a granny, he always took it to the dealer to get serviced when needed so i assume the fluid got changed but we shall see what happens after i bleed it.

[BurnAll4S4]

i have the same problem and replaced the master, no luck :(

any update on this?

[downhillracer]

BUMP! no one has had this problem besides me and burnall4s4