tentoesover

Hello, a little over a year ago I was having some ABS issues that I thought was the module, so I sent it in to Module Masters for refurbishment. I installed it without issue, but I have been having intermittent ABS failures since (wasn't bad during the dry summer, but when the humidity went up, the alarms came back). I cleaned all 4 ABS sensors, to no avail, so I hooked up a borrowed Vag-Com and found that the right rear was the troublesome sensor. I replaced that sensor with a good German unit, but I am still getting the failure on the right rear. While driving, the last box on the Vag-com scope screen for ABS shows no speed increase, while the others seem to be acting normally. Does anyone have any ideas on what I should do next? Before it fails (after I start the car) the brake pedal pushes back, pulsing a bit.

tentoesover

Does anyone have any experience with the tone ring going bad? I pulled the rotor off and half of the tone ring was a little rusty, while half was scraped shiny from contact with the sensor. The axle nut was less than hand tight. SO, I cleaned the tone ring, reinstalled everything and tightened the axle nut a little better, but no luck, the ABS alarm still comes in. I just popped down to the auto parts store and bought a new rotor and brake pads and bearings. We'll see how that goes tomorrow.

BTW, the Vag-com could see the sensor working while I had the wheel in the air and I spun the wheel, but a quick spin around the block and it read less than half what the other sensors were reading, and then finally read nothing.

I need a beer.

tentoesover

So, it looks like I'm on my own here, I'm going to keep writing my experience down because someone will eventually have the same problem and hopefully they can gain from my experience.

I went to pick up the rotor at the parts store today and there was no ABS tone ring on the rotor. I returned the rotor, but bought the bearings and the brake pads. I'm going to see if I can find just a tone ring locally tomorrow. The chain parts store had no idea how to get one. Hopefully the Euro parts place can get it.

4Driver4

The tone ring is part of the CV joint. If you are getting zero reading with VAG-COM and you know the sensor is good, the ring is missing.

tentoesover

I'd guess that tidbit is for a Quattro. I'm FWD. It's a separate part, attached to the rotor on mine. $40 for the ring at the local Euro parts house, and it does NOT come on the rotor.

For those looking to buy this part, the part# for my '98 A4 FWD (and a few other years) is W0133-1733869 There's suppliers if you google it.

4Driver4

Sorry about that. Did you specify?

I always assume Quattro. And your comment "The axle nut was less than hand tight" also lead me to Quattro.

tentoesover

I appreciate you lending your expertise...I suppose I didn't specify that mine is FWD. When I took it apart, I could see that the tone ring was connected to the rotor, but I didn't realize it was a separate, press-fit part, it seemed to be attached. It does not help that many suppliers show a generic picture of a rotor, or that the first mention of the part I heard the guy called it a tone ring, and most companies call it an ABS Ring...what a hassle.

I'm surprised I'm the first on here to document this. It sure would have been easier to learn from someone else's mistakes.

I was lucky to have found a VAG-COM and an older laptop on Craigslist for cheap a few days ago. Hopefully it will help smooth things out.

4Driver4

Smart purchase. Great tool!

tentoesover

It's really come in handy. If anyone in the Santa Rosa CA area needs it, contact me and you can come over.

OK, so I got the ring replaced and changed out the bearings and so far, so good. I put 10 miles on it and it seems to be ok. The new tone ring is a robust, high quality cast piece, while the orig was a cheap, stamped steel piece. I knocked it into place with a plastic mallet.

SO, grand total.
Should have only spent $40 or so on the tone ring, but had the Module rebuilt at $100 and a new sensor at $100. So, $240, still cheaper than having the shop fix it, I'm sure. I went through a LOT of rubber gloves, but that's incidental.

I also bought a tired old laptop with a licensed VAGCOM for $100, plus brake pads and bearings at about $40. Oh, and instead of beating the crap out of my calipers with the wrong tools every time I change the pads, I bought a caliper piston retract tool for $40 (at Harbor Freight). I think I did OK, I have a lot of new experience and a few new tools. I hope this helps someone out there.

Time to work some overtime so I can have the center LCD display repaired. I'll have to send that one out, my soldering skills suck.

ECS Tuning-Audi

Glad to hear you got it figured out. I was going to mention the ring might be corroded or worn but looks like you got the advice you needed prior!

Cheers!

Jason