M38A1 Throw Out Bearing

[madmike]

I purchased a new bearing from John at Midwest Military and it came in two pieces, the bearing part wrapped in protective paper. I am reassembling the engine and drive train and when I wanted to place the bearing in the housing, I noticed the bearing would not go together. Thinking it is an interference fit, I used the old bearing, face to face, and lightly tapped the collar to see if it would slip in place and look like the old bearing. It does not want to do that and I tried to call John, who is away at a convention. Until next Monday.

So...my question is, should the bearing go together as one piece? If so, how much force would be anticipated to make this happen? I don't want to ruin the part. I tried to separate the old bearing and it did not want to come apart so I suspect the bearing does need to be joined, which would also make it the same depth as the old one. The last one of these I did was on a flat head Ford back in the early 60's. That's all I remember about it.

If anyone has experienced this I would appreciate your feedback.

Mariposa Mike

[Oldsalt]

The bearing should slide onto the carrier without too much force, but you have to be sure that you have it perfectly aligned as it slides on, or it will bind and you will not be able to get it on. Also, you want to use something that only puts pressure on the center race of the bearing when tapping it on. You don't want to put any pressure on the outer part of the bearing or the balls inside. Use something like a socket or piece of pipe that only contacts the inside ring of the bearing.

[RimfireJim]

. . . it came in two pieces, the bearing part wrapped in protective paper.

Can you be a bit more descriptive? A throwout bearing is a ball bearing (as compared to the tapered roller bearings used in many other places on the Jeep, for instance). A typical ball bearing consists of an inner race, an outer race, multiple balls, and a cage or separator that keeps the balls equally distributed around the assembly. If by "two pieces", do you mean the outer race is separate from the rest of the assembly? If so, very strange.

Ball bearings are assembled into a single unit by shoving all the balls to one side (before the cage is installed), which creates enough space between the races to get the last ball in. Then the balls are spaced around equally and the cage installed, keeping the races from going off in two different directions. I believe the cages are usually two halves that are spot welded together, but it's been a while since I looked at one closely.

-Jim

[madmike]

Jim & Old Salt...the bearing is all one piece. But it came separated from the collar that attaches to the clutch arm. There is a ridge on the inside of the bearing which appears to make this an interference fit. I spoke to a friend of mine that has experience with civie Jeeps and he said I may have to press the bearing into the collar. He has seen them come from the parts store both ways. My attempt to put them together was to use the old bearing face against the new and hit the old collar with a hammer..but lightly. This makes it difficult to keep it in alignment and it wants to cock to one side.

I am thinking now I may have to find a press or I might place it in a vise if I can get a good angle. But I wanted to check on this site first for ideas from those who have gone down this road before. And why wouldn't there be advice in the package with this bearing. Maybe it's assumed a pro is doing this work. So if you or Old Salt have any ideas to keep me from destroying this gem, please let me know.

[Oldsalt]

A vice should be able to put plenty of force on the bearing to get it to slide on, but like I said before, you want to use something to keep the force only on the center race. The last time I did one, I was able to press the bearing on with my hands. It doesn't really need to fit that tight to stay together, because once it is installed it can't come apart. It's trapped between the clutch and the linkage fork. It is possible that the bearing was poorly made and has a ridge on it that shouldn't be there. Every bearing I've ever seen was completely smooth inside. I know that you got it from Midwest Military and normally they sell quality parts, but even quality makers can produce duds. If the ridge is really significant I'd call Midwest and see about getting another one sent to you.

[madmike]

Thanks Old salt. I have to wait until Monday to talk to John which is okay since the trans needs more cleaning before installation. I will update this post after I talk to him and maybe have this part together.

Mariposa Mike

[C15TA]

Mike, put the collar in the freezer for a while and try again. You could also break the old bearing apart and use the inside race as Oldsalt described.
Barry

[DJ]

"put the collar in the freezer"

and the bearing in the sun

[madmike]

I had success today. The bearing is together with the collar and it looks factory. Or at least like the one I took out. I opted to do the heat and freeze method, which did not allow me to put the pieces together without some force. I first tried the previous methods then went to the vise. After placing aluminum protective jaws in the vise, it went together quite easily. Probably because the pieces were still cold and hot. I only had to rotate the piece once in the vise. If you do not own a press, I recommend the hot and cold method. There was definitely less resistance.

So life is good until the next crisis as this beauty comes together. The engine is complete and painted now, the trans will be installed tomorrow or Tues. and the transfer case still needs the clean and paint routine. After that we have engine placement in the newly painted frame. Things are lookin' up. Thanks gents for the hints and help.

Mariposa Mike