I replaced my driver's rear hub today and rotors and pads on all four wheels. Also replaced the passenger front caliper last week.

 

I test drove the car all last week with just the front passenger caliper and rotor replaced. I noticed ABS like movements in the brake while at a stop a few times but the light did not come on.

 

I also test drove this morning after replacing the other front caliper and pads. No lights came on and the brakes felt normal.

 

I then test drove after replacing the driver's rear hub, pads, and rotor. Also replaced the other sides rotor and pads. This is when the light started coming on. The AbS activates while coming to a stop but the brakes work fine after that.

 

It feels like the passenger front is the one triggering the ABS, but the light didn't come on until I replaced the rear hub.

 

I cleaned all of the sensors and swapped relays because my ABS turned on in the middle of the night a couple of months ago for no reason at all. I had no other problems with my brakes at the time except probably the right front caliper was shot and the left rear wheel bearing was going.

 

The sensors did have a lot of metal fragments before I cleaned things up.

 

Any advice?

Is the abs sensor on that hub reconnected properly? Is the tone wheel still in good shape on that half shaft? If so, it may be the clearance between the sensor and the tone wheel teeth. It is fairly tight clearence. I noticed on mine there are metal fragments too; I just left it the way it was.

 

There was a note by Subaru about the abs relay sticking on some units. Hence the pump running for no reason in the middle of the night that you experienced.

The sensors and wheels look OK. Plus, it doesn't happen right away. I can stop a few times before it happens. My last test drive it didn't happen at all. I'll check back in sometime tomorrow after I go for a drive in the A.M.. Thanks.

if the ABS light came on, read the codes. subaru's ENDWRENCH site has all the procedures and codes listed. i went through this a couple weeks ago in my legacy and the endwrench site proved very helpful. showed exactly which pin to ground (just above your gas pedal, there's a connector). ground one pin, very easy. and the ABS light blinks your code. then read the code - it will tell you what is wrong. let me know what you come up with, curious. is yours activating just as you're coming to a stop - like at 3 - 5 mph?

Haven't dealt with this but make sure the tone ring isn't cracked on the hub where the bearing was replaced. Since you had a bad relay, I understand the car is an older model with tone rings mounted to the hubs.

The end of the sensor must look loike a cylinder in shape. If there is any rounding at the edges it needs to be replaced.

The ABS is fairly straight forward to troubleshoot per the endwrench peice.

 

nipper

Still having the ABS problem. Last time I had this problem it turned out to be a broken tone wheel. The only other thing I can think of would be air in the line since I did replace the passenger front rotor and I had a neighbor help me bleed the brakes and she didn't have any idea what she was doing. Can air cause this problem? It basically comes on after I brake for the first time, which is disengaging the ABS as far as I know. The brakes do work but I want things to be safe...

Silly question:

 

Did you use a brake cleaner on the new rotors?

 

Unless you did you could be having pad slippage from the anti-rust coating on the rotors. Although it should wear off within a short period of time depending on how far and how much use they get.

Which pin do i need to test?

you haven't mentioned yet if the ABS light is on. if it is, you can read the code and be done with this. all you need is a piece of wire from your negative battery terminal. ground that in the appropriate pin and follow the directions (very simple). you should download or look at the subaru ENDWRENCH ABS information. everything you need to know is there, it's silly for us to look up bits and pieces and post it here. those articles are completely and even detail differences across models/years which we can't do from memory. there are multiple threads posting all of this, spend a little time and get the right information and it'll take you a couple minutes.

here's my post about ABS and the information i found to do the job. i had never touched ABS stuff before and these links i found through searching walked me right through it. i used the search function to find it.

 

http://www.ultimatesubaru.org/forum/showthread.php?t=76811

 

good luck and hopefully it has some codes for you!