Front end pop and ABS engagement?

[wlepse]

So this isn't my daily so I don't really have a good feeling for when this started but I thought I felt something a few weeks back. It seems to feel like it is coming from the right front corner and I only noticed it at slow speed and often when turning. Since we have had several issues with power steering i was suspect this might be something to do with the belt or the power steering pump itself. I also was wondering if this could be a bad clutch on the AC or something but I don't think that is the case anymore since it has happened a few times in succession and I don't think it would cycle that frequently. But doing some searching I am seeing a lot of references to springs popping and in one Mact suggested it was bad spring mounts. The truck does have ~120k on it and I am running the original struts so perhaps I am due to replace these. But does anyone have any other suggestions of things to check? I should also mention that just this week it started a new thing, mainly while going slow (~20mph or less) and turning left and braking you get the sensation like the ABS is licking in on the right front wheel. Again this could be due to worn struts but typically I have seen ABS only kick in if you hit a pothole and the strut can't control wheel hop. In this case I don't seem to get a noticeable hop or feel like the front end is bouncy, rolling or feels out of the norm.

 

Any thoughts? At this point I am leaning towards new struts and mounts but wondering if I should be doing something else while I am in there.

 

[WWWPerfA_ZN0W]

Since ABS is engaging, check the wheel speed sensor and tone ring on both front axles. You now have reason to.

[evh]

I'll take "Tone Ring" for $200 Alex.

 

I have had two tone rings go bad. The ring cracks and when flexed you can get exactly what you are describing. Turning the wheel and braking puts just enough stress on the cracked ring to make it kick on the anti-locks. Then it comes back together when the stress is gone and behaves normal.

 

Again, we are all guessing, but that is mine.

[wlepse]

I can see that causing ABS engagement but you think it could also be causing the popping sensation too? Now that I am paying more attention I have felt the popping while stationary and starting to turn the wheel. That sounds more like suspension to me since nothing is rotating yet.

 

As for tone ring replacement, are you guys just replacing the ring or the whole drive shaft? I am reluctant to replace the whole thing since I believe it goes through a seal in the PTU and I think you need a special tool.

[evh]

Not sure what the POP would be. Unfortunately you can't buy the tone ring separately. I think you have to buy the whole "hub/bearings, etc". It is all one unit. Do some searching here as someone tried to glue theirs. It is a pricey repair ($450-$550ish)

 

It sounds like you can recreate it by braking and turning. I'm guessing if you had the right scan tool(s) you could drive and see if the anti-lock kicks on. That would confirm the tone ring or the anti-lock system.

Edited August 17, 2018 by evh

[enigma-2]

The popping sound is probably the right strut mount bearing has seised. As you turn the spring goes through a twisting motion. The upper strut mount contains a bearing the allows the spring to rotate. When the strut bearing freezes up the spring begins to twist and with no bearing to relieve the torque built up, the end of the spring snaps back to its resting position. This creates the popping sound.

 

In addition, you also feel the snap in your steering leading you to believe that something else is at play.

 

When replacing the struts and mounts, I would recommed only Motorcraft. Don't go cheap and use Chinese parts unless your planning on dumping the car immediately afterwards.

 

May consider replacing the rear shocks at the same time.

Edited August 18, 2018 by enigma-2

[wlepse]

I did the rears last year since one was leaking...probably too much mulch one time. So I will plan to swap the fronts out since what you are saying makes sense.

 

But definitely have a tone ring issue too. Today I really accelerated hard and ABS, traction control etc came on. Two minutes later it was off. Looks like some places are selling just the ring but it might be more prudent to swap the shaft since the CV joints are probably close to going.

[evh]

All the lights coming on and then going off are classic tone ring symptoms. On one of mine (I don't remember if it was a front one or back one), all the lights came on only after I went over 78ish. When I slowed down, they all went off. The thinking was centrifugal force was separating a crack in it. When I slowed down it would close back up.

[wlepse]

Anyone have any tips on figuring out which wheel is the issue? I was hoping the lights would stay on and I could pull a code indicating which sensor is getting a bad signal but so far this is still an intermittent issue. Just wondering if anyone has any tips to figure out which one is bad short of pulling them.

[wlepse]

So I used FORScan Lite to pull the codes and much to my surprise the code was C0031:2F-68 for left front wheel sensor. I was convinced it was the passenger side, but I am having issues finding good info on this code. I was expecting this would be the same codes posted in a sticky to this sub forum to indicate a bad tone ring. But it isn't quite the same. I did see one reference for a different Ford model that said this was a wiring issue where there are small breaks. But nothing on this forum...has anyone else seen this?