Replacing jeep fan bearing (Steve-O's greaseable mod)

[Fringeless]

While installing my ebay 200 amp alternator, I found out that my fan bearing was shot. I found a youtube vid of a guy who details the replacement. https://www.youtube.com/watch?v=6SQnw1lqYjs
I ordered the bearing mentioned in the the vid for 14 bucks. When I received it, I noticed that it had a hole in it. I figured what the hell, I could install a zerk fitting right over the hole.

How convenient, the parts manufacturer decided to bore out a cornholio. Perfect for regreasing my fan bearing.

So, I took my calipers and measured from the front of the race to the hole, then I added .100" to that measurement (difference of where bearing stops and front casting). I then scribed this measurement and tapped out a hole for a zerk fitting. Note. Do this on the top left side only (between the 10 and 12 oclock gussets), the right side will not provide enough clearance for getting a drill or tap perpendicular to the hub, unless you have a long-ass drill bit and long-ass tap. (note I used a small 12-point socket instead of tap driver- clearance issues)

Finished product, ready for some good moly grease. Whats up?

Steve-O iratefla

 

[Fringeless]

Dang it! I posted this in the wrong place.

 

[Fringeless]

anyone know how to move this to mod tech?

 

[tonytech]

Thanks for posting! I am really learning a lot from this forum.

 

[Bryan C.]

anyone know how to move this to mod tech?

Moved it for ya.

 

[cal]

That bearing is by design a water pump bearing.

Isn't that the water bleed hole so you see a weep on your motor when the seal starts to fail, and not a path for grease to reach the bearing?

 

[Fringeless]

Moved it for ya.

Thanks buddy.

 

[Fringeless]

That bearing is by design a water pump bearing.

Isn't that the water bleed hole so you see a weep on your motor when the seal starts to fail, and not a path for grease to reach the bearing?

Yes, you are correct. However, even though this particular bearing is a water pump bearing, it is not installed in a waterpump (it is the mechanical fan idler bearing- the water pump is separate on the 4.0 xj). Since the hole is placed for coolant egress, why not use it for grease ingress? When I pulled my old bearing, it was dry as a bone (note it did not have the same hole). I think that by adding a grease fitting, I can keep it alive for along time. makes sense to me.
Steve-O

 

[cal]

But is that grease actually going to get to the bearing?

I'd want to cut one open and look at the path of that bleed hole.

 

[souske]

How do you grease it without taking it back off?

 

[Fringeless]

But is that grease actually going to get to the bearing?

I'd want to cut one open and look at the path of that bleed hole.

Yes it gets to the bearing. It pushed grease out of the front and back.

 

[Fringeless]

How do you grease it without taking it back off?

You dont take it off. The fitting is right behind the fan pulley. or underneath the ac compressor pulley.

 

[mhead]

Pleased to post that I purchased the bearing recommended here from Quadratec their part number 917104 83. I replaced the fan bearing on my 1992 XJ 4.0 with A/C. Quadratec bearing fit fine.

I removed the fan boss by using a fairly big puller. Boss is pressed onto bearing with about as much force as a power steering pump pulley. A lot. But it came off. I measured the distance from boss to shaft end before pulling since the replacement bearing shaft is slightly shorter and I wanted to get the boss back in the same position.

Pressed out bearing by pressing shaft down into the mounting bracket with the bracket backed by a socket stack. No real problem. Press worked well.

I was reluctant to press in new bearing by simply pressing on the shaft since this method would have to transfer press force from shaft through bearing to outer race, the race being in contact with the mounting bracket. Instead I found a socket with nearly the same OD as the race. I cut the rear bearing shaft down since it was too long for socket and since it serves no purpose that I could see. Pressed bearing into mounting bracket with no problems.

I then used press against bearing rear shaft to press fan boss on the front side shaft being careful to measure boss position relative to bearing shaft end and allowing for the fact that the new shaft is slightly shorter than the old.

New bearing seems to have a slight amount of play. Will see what develops here.

 

[mhead]

One more thing... If you press the fan boss onto the bearing too far, as I did, the fan blades will hit the harmonic balancer. Before putting the serpentine belt on or the fan shroud, test mount the fan and check clearance between the blades and balancer. I have most of 1/4" now. It is probably a good idea to check this clearance before removing the old part just as a way to know if the new position is correct.

New bearing seemed to have a little play but it runs quiet now. We'll see how many miles...