Some info on the car before I begin explaining the problem. I've had all the bushings replaced with powerflex bushing including the diff with some black series bushings. Ive also installed some ohlins dfv coilovers less than 100 miles ago which perform great.

The problem:

Recently as I was driving around just putting miles on the car I took it to a long dead end where no one ever drives to perform an abs test to see if the abs was still engaging as it should. I was cruising at about 60 before braking hard, the rear locked up and ever since i have been getting "clunk" noise every time the rear passenger side wheel makes a complete revolution. The clunk is very consistent with each complete revolution of the wheel. Also I am getting the 4w abs light showing up in the cabin.

I tried looking around to see where the problem was thinking maybe it could be a seized brake caliper or something but everything seems to be fine. i even got the rotors turned incase there there was some short of problem with those. Brakes looks fine and so did the brake pistons.

Does anyone have any idea what is causing this problem? It would be a great help, I have searched everywhere but cant find anything.

Also my car is an automatic(currently) with a 3.9 diff if that helps at all.

PLEASE HELP

 

Sounds like an ABS sensor wire got pulled on while putting the coilovers on and ABS is no longer working (hence, the ABS malfunction light).

When you checked ABS function and locked the rear brakes it sounds like you "flat spotted" a tire badly so it goes clunk clunk when it rolls around to the flat spot.

 

Everything was fine after the coilover install. It drove around for a week perfectly fine no lights or anything.
Also while I was cleaning everything to possibly find the problem i checked out the sensors and they looked perfectly fine.
It doesn't really feel like a flat spot though, I feel as if something is wrong with maybe the diff or axle but have no idea if I'm right or a way to check?

 

Lift the rear end and manually rotate the tires and see if you feel/hear something. Also grab the tire from the top and bottom and give it a wiggle to check for play in the suspension. Do the same side to side.

 

^ x2, that's the best way to identify where the noise is coming from.

 

how old are your brake pads?
sometimes its the simplest thing..

 

Yeah I've already tried doing all of that and no noise or play at all :/ which is why it's confusing me even more. The noise is only there when the tires are on the ground and I'm driving around.

I mean yeah they are a few years old but they are in good condition and have tons of life left so I doubt that's the problem. Pad wear is even as well.

 

Theres a good chance that you have lost the spring that holds the brake pad in place. If the spring is gone, the pad can move and make a clunk when the wheel rotates. Pull the wheel off and see if you can move the pad.

 

Just checked and everything is in place where it should be :/. I don't think its the brakes.

 

You could change which side of the car your rear wheels are on and see if the clunk changes side to eliminate the wheel and tire (if you haven't tried this already).

Everything was fine after the coilover install. It drove around for a week perfectly fine no lights or anything.

I see now.

Have you checked the tone ring and the ABS sensor to make sure a pebble didn't lodge in the tone ring or something?

Small chance, but I do get pebbles stuck in my dust shields and pads all the time.

 

I actually did not try switching the wheels from one side to the other. I will try that, but I did check the tone ring and everything around it as well when I cleaned the abs sensors.

Although, say if I did flat spot the tire on one side really badly, that wouldn't explain the drag I'm getting would it? Because it seems alot harder to accelerate and decelerates way faster than before.

 

I would not think a flat spotted tire would affect accel/decel to such an extent.

Drive it gently and check if a brake rotor is hot. That will narrow down if it is brakes or drivetrain friction.

You might even be able to feel the heat off drivetrain components if its that, sounds like a lot of friction.

Have you checked the hydraulic side of the brakes? A pinched line could cause the brakes to be dragging on one side and when they get hot the rotor will warp/pulse.

 

Okay so I took it for a drive, checked the heat coming off the rotor and it seemed pretty consistent with the side im not getting noise from. Also switched wheels from one side to the other and nothing :/
No kinks in the brake line either.

Do you guys think it could possibly be my diff or axle?
PLEASE HELP

 

Have you checked all your bushes?

 

Yes, and they are all new as well.

 

You need to jack up the back end of your car, and remove the right rear wheel. Have someone turn the drivers side wheel, and look to see where the noise is coming from. I still think you have a loose brake pad.

 

In my experience the clunk only comes from a few things:

1) A bad Pillow Ball/Multiple pillows bad
2) PPF Power plant frame is Cracked and your Diff Case bushings are shot
3) Bushings are donzo and need to be replaced.

In your situation....if you've checked everthing else....inspect your PPF for cracks and your Diff bushings.


After reading your discription.. that sounds like either a bad wheel bearing or a bad axle....

 

I actually didn't look at the PPF, I will take a look at that today!
Also, luckily I bought from wheel bearing from j-auto awhile back, I guess I can swap those on if I can't find anything else. Do you know what exactly i should look for if it is in fact the axle?

P.S. Absolutely in love with your car, and your build thread is excellent!

 

Unfortunately, this was like one of the first things I tried

 

Did you retrieve the code for the ABS light? It may or may not be related to the noise but given that they both occurred after the same event it would seem logical to check that. Either they are related and fixing the ABS will likely correct or at least reveal the cause of your noise or they are not related and fixing the noise won't fix the ABS and you will have to pull the code to fix the ABS later anyway. In either case if you want the car pristine, and you obviously do, you will be pulling the code to fix the ABS so you might was well do it now since it might also shine light on your noise.

 

nYou know... like some others had said up above. If you jack the car up, and both rear wheels are off the ground, Go bear hug the wheel and move it up/down/left/right/diagonal. Give it some shakes.. make sure it's in neutral and turn it with your own force and stop it immediately. If you don't hear or feel any type of movement/clunk.. which may be a light tick or so... then i'm sure bearings/bushings/pillows are fine.

The PPF.... there may be parts that are harder to see. But get under the car with a solid flash light and look around. Also way to check your diff bearings...Jack the car up by the diff.. look and see how much it moves. if it starts moving a lot... don't continue.. if it is pretty rigid... it's prob not those bearings. But my guess is those are shot and you either cracked the PPF due to them being shot or they're so bad the diff is moving around under initial shock load.

p.s. Thanks for the kind words! I've been working on here all week. Got some updates coming up. Hope you find the source of your clunk and keep at it. You'll figure it out!