Gudenrath

I have a 96 Cherokee sport that just started making a grinding/rubbing noise in the front end when I go over 20mph. It's a pulsing noise until I hit 55 then it sounds constant. I jacked up the front end and the wheels are solid so I don't think it's a wheel bearing. I took off the rotar guards since they were corroded so I know it's not those. The diff fluid is good so I know it's not the gears. I lifted it 3" with coil spacers but that was about a month ago so I don't think that has anything to do with it. I'm totally stumped. I just replaced the water pump too but I made sure all the pulleys were tight so there's not anything lose in the engine bay. All the u joints are tight too so it's not that. I have no idea what it could be and it's driving me crazy.

94XJYKuz

Diagnoses is tough with the info given so far. Did you have the calipers off and check brake pads when removing the rotor guards? Have you been off road lately, maybe a rock stuck somewhere around anything that rotates? Are you certain it is from the front, XJ's are just a big sound chamber, easy to get a noise direction mixed up. Just some random thoughts on a Sunday morning. Good luck.

Gudenrath

The rotor guards were so corroded I didn't have to take anything apart, I just ripped them off. When I jacked up the front I spun the wheels and didn't hear or see anything rubbing but like I said it only happens when I'm going faster than 15mph. I thought about jacking the entire jeep up and stepping on the gas while a buddy looks under it but that doesn't seem very safe.

Gudenrath

And if the brake pads were hitting the rotors wouldn't it be a constant sound unless the rotors were warped?

GeneXJ

My vote is for wheel hubs. But if not, could it be the fan clutch or the AC compressor? You said you checked that the pulleys were tight. Was the AC pulley spinning freely?

If its only when you are moving, I would check the wheel hubs to make sure they are still good. You can take off the rotors and spin them to make sure there is no play or grinding. My jeep was making a wobbling sound at highway speed (although there was no grinding). I replaced the hubs and it seemed to go away. Easy to check - although they are a bit of a pain to get off.

If its dependent on the speed of the engine and not just the vehicle, it could be a bad bearing in a pulley.

My fan clutch went a while back and I heard intermittent grinding sound at low speed an idling (kinda like a bad water pump but mellower) . After I replaced that, I was still getting the grinding sound - it was not the fan clutch.

After a while I found out what it was when my serpentine belt snapped because it was actually the AC compressor. The ball bearings on the pulley were ground in half before it finally locked up.

I have had a lot of issues with front rotors locking up, but that never caused a sound. When they rub, it usually a squeaking sound and you cannot hear it at high speed.

Gudenrath

Yea it's coming more from underneath than in the engine bay but it's kind of hard to tell so it very well may be the bearings. I'll take the tires and rotors off tonight and check. I thought bad bearings made more of a whirring sound though. I'll check and see if any pulleys have any play in them too. My ac hasn't worked since I've purchased the jeep so maybe it's time to replace that pills anyways. Will I be able to spin the bearings without taking them off?

GeneXJ

Yeah, you should be able to spin them if you can spin the wheel - and you do not have to remove a lot of stuff to test them (At least initially). I think just lifting up your wheel and shaking it from side to side, checking for play would give you a good idea.. The hub is fully visible once you take off the brake rotor. Your wheel studs attach to the hub, which spins on bearings, and then the stationary part of the hub is bolted to the steering knuckle with 3 bolts.

It is a real pain to remove - not complicated, just a lot of high torque bolts, so if there is no obvious play, I wouldn't jump into it.
I think my old gave off a little grinding sound when I spun it, so I replaced it, but if you can hear your grinding sound while driving, it would probably be something way more blatantly obvious.

This guy right here explains things far better than me though. He actually just shakes the wheel to see if the hub is worn out. Although you probably want to do a bit more investigation than that.


Also, just throwing this one out there - a few months ago my rear wheels got loose after doing some trails, and started making a clunking/grinding sound that I was sure was coming from the front. Silly thing, but doesn't hurt to check.

Gudenrath

I appreciate the feedback. I hope it's just a wheel bearing and not something more serious or complicated. I'll check the back ones too while I'm at it just to be sure that's not where it's coming from. The noise is cyclic which made me think there's no way it's a wheel bearing but who knows since nothing looks like it's rubbing against anything.

Gudenrath

TOok the tires off and checked the wheel bearings. They aren't making any noise when I spin them so that's not it. The next thing I think I'll do is jack the whole jeep up on four jack stands and step on the gas while someone is underneath to pinpoint where the sound is coming from exactly.

GeneXJ

That sounds like it could be the beginning of a horror movie haha. Did you check the rear lugs btw? Because if its not the front wheels/hubs, and you don't know exactly where its coming from, could be the rear.

Jeepin'_Aint_EZ

Just simply spinning the hub is not a good indicator if the bearing is bad. Here is the proper way to check play in a wheel bearing. Leaving the wheel on is better being as it provides leverage.




One hand normally at 11-1 o'clock position and the other at 5-7 o'clock position. Can't hurt to try a few different spots. Push with the top hand while pulling with the other. Put your purse down and be a man about it too. You can also put a bar under the tire and lift. This is how I check ball joints but it will also indicate wheel bearing play.

Also, does the noise get louder or quieter when you turn left or right? For example, when you steer left, the noise may get louder but when you steer right it gets quieter.

Gudenrath

Yea I shook the crap out of both wheels before I took the tires off and they didn't budge at all. And turning doesn't really affect the sound at all while driving. I'll check the back tires tonight. i think lifting the entire jeep off the ground is my best bet though unless I want to take it to a shop to have them figure out where the sound is coming from which is the last thing I want to do. I should be able to just put the back on jack stands and step on the gas till i hit 20mph since that's when the noise starts. And if I don't hear anything then I know it's something in the front wheels

Gudenrath

So I jacked up the back and put it in drive and went up to 60mph and didn't hear anything. But both back wheels have a noticeable amount of play in them. Does that mean both wheel bearings in the back are bad?? They don't wobble back and forth, the whole wheel moves in and out from the axle slightly on both sides.

Jeepin'_Aint_EZ

They're supposed to have some play in-and-out. Normal. Not your culprit lol

Have you checked your front pinion for play? Just because the fluid level is good doesn't mean there isn't anything worn out in there.

Gudenrath

Yea there's about a half inch of play in the front pinion