Wassup? I need some help or suggestions if anyone has had this problem, what it could be, etc.

I just replaced the rotors and pads on my 1998 A4. Before I did, the old rotors were pretty warped, and the pedal needed to be pushed down a bit further than normal. So, I replaced the rotors with drilled/slotted rotors and ceramic pads. I used my instruction book just to make sure I was doing everything right. Now, I was an IDIOT and put the retaining springs in incorrectly because I mis-interpreted the instructions, and they fell out. So for a couple days I was driving with no retention springs. The car stopped with no problem, even without the springs, but the pads weren't falling on the rotor correctly. When it would shift down into first gear, the brakes would hit what felt like warped rotors. The whole "thump thump" sound and then would stop. I knew it couldn't be warped rotors, they were brand new! So when I heard/felt the sound I would push the brake harder and the pedal would go through what felt like an air pocket or an un-lubed area.

Here's where my problem comes in. Even when I replaced the retention springs, drove it for a bit hoping the brakes would reset themselves, it still makes the sound/motion. I took it to America's Best, and they said there was air in the lines. They drained and replaced my fluid. Still makes that sound/motion. It can't be the rotors, as they're new. I took it back to AB, and they couldn't find out what's wrong. It shouldn't be the Master Cylinder, it's also brand new.

The only other things I can think of are the ABS (no warning lights, though), the servo (the disk behind the Master Cylinder), or the brake pedal itself.

Any thoughts? Feel free to email me at Magliwan@gmail.com. I'm going to take it to Just Brakes (possibly a bad idea, but you never know, they might tell me what I need to hear). Thanks in advance!

 

never take a german engineered car to a quick lube place. you get what you pay for.
they are just going to keep replacing stuff untill they fix it because they have no idea whats wrong. i doubt its ABS or the master cyl.

im guessing theres something not installed correctly. an air pocket would make it feel like your brakes were very spongy or you would have no pedal at all. i would take the brakes off completely again and reassemble them correctly this time. not a bad idea to replace the guide pins and boots while your in there. atleast make sure they are well lubed, not damaged/sticking, and everything is seated.

 

Thank you. I will take it apart (the front brakes, because that's where it feels like it is) and re-install.

As I was driving it today, it kinda feels like there's a bit of a pressure kick back that I have to push through. It sounds like it could be the servo. Because now it sounds more like a spring is kicking back RIGHT where the servo is.

I had a guy at Just Brakes look at it. I wanted to see what he thought. Of course, he said that it could be the ABS unit, which would be like 1000 bucks to replace. I said, there aren't any ABS lights on and it doesn't sound like it's coming from ABS. He then said that it's the drilled/slotted rotors that's causing the sound. It DEFINITELY couldn't be the servo. He also said that the rotors hadn't seated themselves yet. I mean, that could be the case, because I just did the work a couple weeks ago, and the car is driven 10 minutes to work and back.

Anywho, I don't trust the guy at JB, so I'm going to take everything apart and put it back in. Feel free to leave any other suggestions. Thank you again!

 

hi there, i dont think this is your problem but could be a factor. I had the same situation got drilled rotors after originals were on there way out. I also picked up ceramic pads to cut down on the dusting. But they never worked well together. I always had that thump thump feeling, and audible clapping noise when i was on the brakes and sometimes even off the brakes. And i followed everythign correctly so i knew nothing was wrong with the instal. I later found out that the ceramics dont work with cross drilled rotors.

When i changed back to stock pads and cross drilled rotors everything was fine. I dont know if the ceramics were duds or bad company, but problem was fixed right away.

 

Now THAT makes sense! Even the moron at JB said it's the rotors that are causing that problem/sound every time the pad hits the slot line. He also said it's because the rotors weren't settled. I think I'll try that with plain pads. I'll keep you posted. Otherwise, I don't know...

 

Hey Magliwan. You went to America's best on Old Milton? Those guys are hacks! If you need any professional help you can email me I do work on the side and know these cars well.

Also, let me guess, the Just brakes on highway 9?

 

No, it was actually JB on Cobb Pkwy in Kennesaw, and America's best on Wade Green in Crackworth.

It sounds like that's the chain problem, they get some dudes there and train them a little, but they're not certified. AB has done work on the car before, and it was satisfactory, but it was something that I diagnosed was wrong.

Anyway, I'm going to try what balkranjit suggested because it sounds like he had the exact same problem. I'm going to get some non-ceramic Duralast brakes from Autozone because those brakes have liftime warranties. I'll probably go ahead and do all four corners. If that doesn't work, I'm going to give it some time and let the rotors seat themselves. I'll let you guys know! I'm going to do them right now. Thanks again!

 

brake pads with a lifetime warrenty..... how is that possible?

get some mintex pads or hawk pads and call it a day. much better stopping power then duralast.

 

By lifetime, I mean that I can bring the old stuff in and get replacement for free or whatever. Anyway, I put the duralast on there and it's still making the sound. It feels a little like the brake is slipping on the new smooth rotor, and then catching.

Could it be the servo? I didn't even come close to that replacing the rotors. It's that or the calipers are failing. But it stops perfectly except for the slipping? thumping? Whatever it is.

I've been told by two people now that I should let the rotor's seat themselves. How long does that take? It's a 10 mile commute from work to home, with MAYBE 3-4 stops. That's pretty much where the car goes.

EDIT: The gentleman from whom I bought the rotors and pads said that it will take 2-3 hundred miles for the pads to seat into the zinc plating. So I guess it's a waiting/driving game.

 

Drive the **** out of them. I seat them in by braking hard under a little load, then a few 80-0 runs. Also, duralast are ****.