Front wheel bearings

[sermis]

I tried to adjust the front brakes. When you turn the wheel it will spin and then one of the shoes will grab. Drove it and drum was getting very hot. I pulled the hub to check the brake shoes. Shoes look ok but the bearings are not the same. Are both front bearing the same? One of the bearings is a F A G K3994 and the other is Bower 392. Obvious they are not the same width bearing. I have not noticed any problems so far but really don’t want any thing to go bad. I repacked the rears and they were all the same.

 

[Crazyguyla]

Sermis,

Are those PLS/ Hemmt worklights you have on your bench?

 

[sermis]

Well they are sometype hand held light with a magnet on the back, not sure what they are from. I also have some that are metal.

 

[JRBAMATEX]

Those look like the right bearings. If they are the ones you took out I feel pretty confident that they are the right ones. At any rate they look just like the ones I replaced that I really didn't need to.

On the break shoes adjustments what I did was put everything back together but I adjusted my shoes althe way to the inside of the wheel as far of the drum as I could. Then when I was sliding the drum back on I adjusted the shoes out toward the drum so I could be sure which direction the adjustments needed to go. Then once I got the drum and hub and everything back on I just eased the break adjustment out in small eaqual amounts until I could just bearly sense a little drag between the shoes and the drum. It worked great and the truck stops straight without hands on the wheel. I have checked for unusual heat and everything is cool.....

Hope this helps some.

 

[sermis]

Well I was thinking that the rear bearings were the same size. Maybe they are different. I was doing a hub flip to run singles at the time and kept everything together, inside / outside.

 

[FreightTrain]

The inners axle bearings are 3994 and the outters are 392 front and rear.The races are the same though.

 

[red devils dude]

buy new bearings

 

[houdel]

The inner and outer bearings should be identical in size except for the inner bore diameter. The inner bearing has a larger bore diameter to fit over the step in the spindle. The OD and width are the same inner and outer, and the cups are the same for both. If your wheel bearings are not the same width and OD, one of them is wrong. As stated above, the inner bearing is a bca 3994, the outer bearing is a bca 392. They are the same for front and rear.

 

[sermis]

The numbers are the same but the width of the bearings are different. Look at the PIC above. Right ones or not. I was wondering if the Bower 392 might not be right.

 

[jasonjc]

They look right. I can remember witch is witch but one is wider than the other. on all 6

 

[Floridianson]

Sermis Do you know how to do the major brake adjustment? That is where you loosen the large nuts on the bottom of the backing plate and take up the play on the bottom of the shoe first.Then you do the top of the shoe by turning top bolts.
If this adjustment is out it could cause the drum to get hot as all the shoe is not in contact with the drum when braking.

 

[Floridianson]

If you turn the bearings over the one with the large face is the outside. This is where the spindle nut runs up on.

 

[sermis]

I adjusted the bottom of the shoes and not the top. I think that is where the problem was. When I pulled the drum, one of the top adjusters was backed all the way off.

 

[houdel]

OK, I admit it, I was wrong in my earlier post in this thread about wheel bearing sizes. The inner and outer wheel bearings are the same outside diameter, but the inner bearing is thicker than the outer bearing and has a larger bore diameter to fit over the step in the spindle.

Interestingly, both the inner and outer bearing use the same raceway (or "cup", as is properly called in the bearing trade. Technically a tapered roller bearing is properly known as a "cone". It is the combination of a cup and a cone which make up a "bearing assembly", as neither part can function without the other). By the way, the same part numbers are used for both the front and rear axle bearing applications.

Thus when doing a hub flip, you just have to reinstall the inner and outer cones in their original locations and flip the hub, as the cups (raceways) are the same for both the inner and outer cones (bearings).

I happened to have a NOS Federal-Mogul BCA 392 outer cone (bearing) in my pile of spare parts. Just to satisfy myself I went to my local (very small) "Parts Plus" auto parts store to order a new inner cone (bearing) and cup (raceway). Much to my amazement, he had the BCA 3994 inner cone in stock, and the BCA 3920 cup was delivered from his warehouse the very next day. I was surprised to learn that the BCA 392 outer cone is not stocked by his warehouse and much be special ordered, as this is a fairly common part on medium duty Chevrolet and GMC trucks.

Anyhow, to dispel all doubts the following picture displays both cones and the cup along with their respective packaging with the correct part numbers. If you get into doing some axle work you may want to check with your local parts store to find out what is in stock, what is readily available and what has to be special ordered before tearing your truck apart! FYI, the numbering system seems to be pretty well standardized, so a Federal-Mogul, Timken, Bower or NAPA BCA 392 (or whatever part number) are most likely going to be the same part.

For what it is worth, the Timken BCA 3994 cone cost me $26.65, the Timken BCA 3920 cup cost me $11.28, and I don't recall what I paid for the BCA 392 cone.

 

[rmgill]

I distinctly recall from my truck when I flipped the hubs less than a month ago, that the bearings themselves were the same width with the inner race being the key difference. One would slide further in, the other would not. the Bearings themselves seemed the same outside diameters.

 

[devilman96]

Its possible to have a warped drum, high spot, low spot, etc but change the races first as that is where the drum is spun from durring cutting.

With the bearings I use the theory better safe than sorry so I would toss the bearings and get new... Don't be lazy... Always replace both the cup and cone when changing them.

 

[houdel]

Ryan - I thought I had recalled reading somewhere that the inner and outer cones were identical in diameter and width, the only difference being the bore size. That is what I stated in my original post and ended up getting blown out of the water. The 3290 cup fits both the 392 cone and the 3994 cone perfectly. Maybe at on time there was (or maybe still is) an outer cone identical to the inner cone except for the bore size. We need to get Gerhard involved in this discussion, if anyone would know it would be he.

 

[sermis]

I had to pull one of the rear hubs due to brake issues. The bearings are the same as the front ones I posted. One is narrower than the other. I guess I just did not remember or did not really pay attention. I did keep bearing and race together when I did the hub flip.

 

[rmgill]

Nope, I know that my bearings were wider. Both sets. Same width. They were NOT sized differently width wise. Yes, the inner race was not the same because the spindle is different widths. Could there be two specs for bearings? One has a narrower bearing and the other spec has mostly identical (save for inner race size) bearings?

 

[derby]

I just got done pulling the race's out of my 5 ton hub.they are the same patr# but the bearings are not the same.I don't know if the deuce is set up the same though.I know the bearings in the 5 ton are bigger.I was refering to the set up.also I was quoted $87.00 and $104 for just bearings from Napa.$54.00 and $66.00 from Sam Winer+ race and shipping.Anybody know of anyplace cheaper.(sorry Sermis don't mean to steal your thread)