Idler Bearing problem. Please Help! '98 XJ 4.0L w/AC

He guys,

I'm out on the road on my way to the Moab Fall Fling. For the last week or so I've noticed some vibration in the motor when getting over 4K rpm. I couldn't identify it though so I couldn't fix it. As it goes on the trip it got bad enough that I found the problem.

The bearing for the idler below the AC compressor that the fan is mounted to appears to be shot (not the tensioner pulley). The fan started hitting the radiator mount, which is how I identified my problem. I removed the fan and am running with the pulley but no fan attached. The vibration is gone but the bearing is still no good and this setup isn't going to work out on the trails.

When I look for the part online I cannot seem to find what I need. I assume these don't last forever and must somehow be available. Could someone fill me in on what I need and where I can get it between Western Nebraska and Moab? If needed I can have it Fed Ex'd to our hotel in Moab but it would be better if there were some place I could pick one up on the way.

I also don't have my FSM with me so I don't know if the bearing can be replaced or if the entire thing is replaced as an assembly.

Please help me get this fixed here out on the road!

Thanks,
B-loose

You have to press the bearing out and order it special from a bearing shop, all of which requires removing the accessory bracket and having the jeep be down until it all gets done. It's really easier to go buy another accessory bracket from the junkyard and replace the whole thing.

Also a good time to go all-electric if you've been waiting

ehall said:

You have to press the bearing out and order it special from a bearing shop, all of which requires removing the accessory bracket and having the jeep be down until it all gets done. It's really easier to go buy another accessory bracket from the junkyard and replace the whole thing.

Also a good time to go all-electric if you've been waiting

Click to expand...

I agree on the electric fan but I still need the idler for the belt. I hope I can find an assembly tomorrow.

B

Get the number off the bearing and take it to Napa. I've never had to replace the entire setup - the bearing pops out easily and Napa typically has the bearing in stock. That bearing fits a lot of applications.

DieselSJ said:

Get the number off the bearing and take it to Napa. I've never had to replace the entire setup - the bearing pops out easily and Napa typically has the bearing in stock. That bearing fits a lot of applications.

Click to expand...

if the bearing is in the Idler pulley, it presses out rather easily.

if the bearing is on the shaft for the fan and fan clutch, it can be a pain to get them apart.

Shorty said:

if the bearing is in the Idler pulley, it presses out rather easily.

if the bearing is on the shaft for the fan and fan clutch, it can be a pain to get them apart.

Click to expand...

Yeah he said idler but he talked about fan warbling so I assume he means the fan pulley

new idler pulley ready to install at advanced is like $16

This is the fan "idler" not the adjustment pulley. It is attached to a "dummy shaft" with an idler pulley. When you remove the fan/fan clutch assembly you can then remove the pulley and expose the shaft. It essentially looks like the shaft that sticks out of a water pump but it is only a shaft originating from the bracket that the AC compressor is mounted on.

I am going to continue on to Denver and then pull the entire bracket and see if I can indeed get the shaft and bearing out of the bracket and get a bearing from NAPA. If anyone knows what the bearing number that would be awesome.

Thanks for the help so far.

B-loose

I think your best bet on this is the junkyard. It's an oddball bearing, an elongated unit bearing similar to those in water pumps, and not very easy to get out without damage, owing to the shape of the bracket itself.

I found a salvage yard on the way that says they have one for $50 so I'm going to stop there. If they have it I'll get it. That way I'll just swap them and then I can see about repairing the old one to have for a spare. The guy didn't seem to sure of himself though.

WTF, is up with the setup though. This has to fail at least with the same regularity as a WP yet when checking the parts houses online there is nothing listed. You would think they would sell rebuilt units and require a core. Or do these things just fail that rarely?

B

ehall said:

Yeah he said idler but he talked about fan warbling so I assume he means the fan pulley

Click to expand...

that's why I clarified the response I quoted-- I agree with your first post and didn't want him stuck in B.F.E. waiting on the entire assembly once he mangled it attempting to remove the shaft/bearing on the side of the road

Late, I know. Re: Idler Bearing problem. Please Help! '98 XJ 4.0L w/AC

I havent verified this yet, but look like Pull-A-Part might sell this as a "medium bracket" which would go for about $15 including warranty and $1 admission.
In process of timing chain R&R on '89 XJ 4.0.

This is a pretty old post!

Seeing as it has been posted to again I thought I would add something. I did get the bracket from the junk yard in Denver. It got me back on the road and we made the rest of the trip there and back with no more problems. When I get home I worked on getting the old bearing out. Once I did I have the bearing number I needed to replace the bearing. The problem is, it is an actual water pump bearing and almost no one sells them. I even called Timken and they said they only sell them to the OEM's.

Then, I found one. Not the exact one mind you, but a water pump bearing. It was at a tractor supply company, MSC I think. The part number was different but I gave it a shot. It turned out that the front shaft was longer so all I did was cut it off the the length I needed.

The difficult part was getting the old bearing out. From the factory the press the bearing in from behind to a shoulder cast in the bracket. The only part left in the bracket was the bearing race so there was no way to press it out as the should ID is the same as the race ID. What I did was grind the face of the bracket flush with the bearing and then press the bearing race out the front. Then I pressed in the new bearing flush with the front of the bracket. Now I had a bracket with a brand new bearing, not another used one.

As it turned out, the bracket I got in Denver had the bearing fail this winter. This time though it failed spectacularly and sent the fan through the radiator. This was the reason actually that I set about rebuilding the ones I had. I didn't want another used one and they are around $200 at the dealer.

HTH,
B

Do you have a picture of your modified bracket? Did defacing (hah) the bracket make the fan bearing any weaker?

Defacing the bracket shouldn't affect strength much if at all. It likely machined this way to aid consistency during manufacturing. The shoulder doesn't bare any load and is likely only there as a "stop".

I had the rebuilt on there a few months without any indication there would be a problem. I will take a picture of it in the next day or so.

B

Did you ever get a pic? I think mine's going out.

No. I sort of forgot about it. I'll try to get one in the next day or two though. If you bearing is getting noisy but still intact there is a good chance you can replace the bearing without modifying the bracket as I needed to. With mine the bearing was so toasted that the only thing left in the bracket was the outer race. Without modifying the bracket in my case there was no way to press the race out because the casting has a shoulder at the front that the press the bearing to from the rear.

The hardest part of this is finding a suitable replacement WP bearing. The one I found, and the only one I've ever seen for sale separately, is not the same but can easily be made to work by trimming the front of the shaft.

Again, I'll try to snap some pictures and post them up.

B-loose

Thanks. What are the specs on the bearing? So I can try to find it before pulling the thing apart.

http://www.agrisupply.com/water-pump-bearing-shaft-double-ended/p/26733/

Here is the bearing I used. The front is too long but I just cut it to the same length as the old one. Every other dimention is correct.

B

One question;

How do you remove the nose mount where the
fan clutch bolts? It looks to be a press fit...?