Heard strange grinding noise under braking . Upon inspection found the front drive shaft is rubbing against the exhaust pipe(see picture). Recently had the following work completed: new muffler, front pinion shaft seal, tie rods, track bar, four wheel alignment. Any suggestions regarding the root cause? TIA.
Front Drive Shaft Rubbing Hole Through Exhaust
- Thread starter md993a
- Start date
You found a problem, now to solve. You will need to cycle the suspension to see why it’s hitting. Something changed with the new track bar most likely.
Suspension zigged when it should have zagged.
Suspension zigged when it should have zagged.
If the axle isn’t centered, it can cause the issue. If the axle is pushed to the passenger side, the u joint can rub the exhaust. I would start with verifying the axle is center
I saw a post about hanging a washer from a thread off the center of the fender down to the tire. Did that on both sides and the string lines up on same spot on both sides so I am now suspecting an exhaust installation issue. Could it also be bad shocks or springs since it only rubs under heavy braking? The Jeep drives and handles very well. Tracks straight, no unusual tire wear.
LONGJP2
TJ Expert
He just had exhaust work done, no telling if they moved that part. Edit: You're right, that's the downtube so it's unlikely they moved it.
It only rubs when I hit the brakes hard. But, at normal position it appears to me that the drive shaft and down pipe are still too close to each other. Still scratching my head as to root cause. Shocks/springs?
Again, it's possible the track bar length is now incorrect/too long which could shift the axle over enough toward the passenger side so the driveshaft could rub on the exhaust.
Is the passenger-side front tire protruding out of the fender well further than the driver's side tire is? If so that's a clear sign the track bar has been adjusted too long.
I took a washer and tied it to thread , hung it from the middle of the fender to the top of the tire. It matched on both tires(assuming the fenders are perfectly matched).
1) Loosen the bolts at the top of the down pipe where they meet the exhaust manifold.
2) Push the exhaust away from the driveshaft.
3) Tighten the bolts at the manifold again while pushing the exhaust away from the driveshaft.
2) Push the exhaust away from the driveshaft.
3) Tighten the bolts at the manifold again while pushing the exhaust away from the driveshaft.
Here is a picture while the Jeep is parked. As you can see they are extremely close to each other. Doesn’t look normal.
Loosen the bolts at the flanges at the manifold. Jack up the exhaust on the right side near the starter until the head pipe that goes around the front of the oil pan is level or slightly high on the right side, tighten the flanges back down. Then check the rear hanger to make sure they have not come apart or not reinstalled correctly after the muffler work.
Thanks mrblaine. I have already checked the hangers to make sure they are secured properly and they are. I’m just wondering how much I will be able to move the down pipe to prevent this issue. When I tried to move the pipes by hand there was no movement or play in the exhaust system. I’m leaning towards taking it back to the shop that did the front end work. I had that done well after the exhaust work. Certainly a perplexing issue.
LONGJP2
TJ Expert
I understand there's room for adjustment when the bolts are loose. I've moved mine. Just doesn't seem as likely for a muffler change.
I'm sure it was close before, and didn't take much to make it start rubbing.
When first reading this thread I was going to say that the exhaust pipe isn't the worst of your potential problem. You are kinda lucky that the welded area is doing so much damage to the exhaust because that worn ring right beside it is definitely getting weaker.
How do I come up with such a strange claim? Many years ago a friend's brother had a mustang with the emergency brake cable rubbing the driveshaft. I can't say how long it rubbed but he found out it had rubbed just minutes after the driveshaft became two pieces.
LONGJP2
TJ Expert
A few years ago I replaced my exhaust system with the ridiculously expensive CARB approved system that I bought from the Jeep dealer. With the pre-cats pulled in as close to the pan as possible, the front driveshaft knuckle still hit the pipes (both of them). I have my axle displaced half an inch to the left now and the pipes have some dents in them. I believe that the replacement system just has different dimensions than the original OEM system.
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