The Stovebolt Site Forums The Shop Area Driveline Sealed bearings

In my quest to install disc brakes on my 54 3/4 ton, I started investigating the whole ball bearing/taper roller bearing conversion. I know Classictruck.com and Chev's of the 40's has the tapered roller bearings, but alas they are EXPENSIVE! I'm not one to cut corners when it comes to safety, but I though I might be able to come up with a less expensive alternative. To make a long story short, what I found was that the new (not old stock) B45 and B46 bearings that are offered by Timken and others, seem to be sealed unit bearings. The replacement bearings are actually insert type ball bearings that you would typically find in shaft drive/industrial application.

Has anyone else ran into this?

Timken, NTN, Federal Mogul numbers: B45, B46

SKF numbers: YET-208-108CW, YET 207-107

Had a quick look in my bearing catalogue for the numbers you put up, leaving aside the seal issue, they appear to be ordinary "deep groove" style ball bearings. Unlike the stock bearings used on Stovebolt trucks, these aren't meant to have the preload between the inner and outer bearing adjusted with the front hub nut. A lot of older cars did have deep groove wheel bearings, but they always had a machined sleeve fitted between the two inside tracks of the inner and outer bearings to ensure that the (manufacter set) preload was always maintained once the hub nut was tightened against the outer bearing-so once fitted, these bearings can't be adjusted at all.

You could do this conversion and make it work, but I think that taper roller wheels bearings would be better, and more durable.

I see that your truck is a 3/4 ton, are you going to keep the original front hubs? it might be easier to adapt a modern 8 lug disc brake hub and get some sleeves machined up to go inside the new hub's taper roller bearings. Or to get your spindles turned down to match the new hub if the new bearings turn out to be smaller ID than your spindle.

Yeah, it was quite the head scratcher. The dimensions were the same for the old vs: new bearings. The specs look to be ok. on the bearings. The outers have a static rating of 3400lbs, and the inners 4200. That's 15200 lbs of load for the whole axle assembly. Of course, being an automobile, we have to think about things like axial load and shock load. Those bearings were design to be mount on a shaft that just goes round and round, not twist, turn, and bounce.

I'm with you, the more I look at it the more I'm for tapered roller bearings or even NOS ball bearings.

BTW, Yes I am planning on keeping the front hubs. I'm currently working on disc brake setup using a Chevy van rotor and caliper assembly. The rotors fit over the factory hub perfectly. My first attempt for the caliper brackets failed, so I'm on version 2 right now. Check out my pics at www.photobucket.com/whitedog76pics

a 3/4T truck that can handle over 7 tons on one axle? new math? seems like it's the "weakest link" that determines the final result

Bill

Red, I was referring to the bearings. There's no way I would ever put 7 tons on an axle, unless I had a Kenworth. The load ratings of the bearings are for a vertical load only, not axial. I'm not an engineer, so I'm going to stop right here before I sound like an @$$.

All I know is that there has to be a reason the auto manufactures went to the tapered roller design.

yes, but still a weakest link situation, if one point can take 3000 .... that's the limit, regardless of what the rest can take - think about it, block one side up on a 2x2 and the other side on a 4x4, will one will break first?

I think the change to tapered roller has more to do with the disc brake physical design arrangements due to the load being carried further out, not any inherent superiority - some very high end cars still use ball bearings, and all the newer bearings I've seen for our applications are now sealed and plastic caged, very high tech stuff

folks do seem to recommend changing to rollers with discs, but the B45/46 [slightly different dimensions] work fine and are the called for bearings for the trucks - not sure if there's a difference for a 3/4T AD, but the ones in my TF 1/2T have been working for years of daily use [drums brakes]

Bill

This is one of the reasons. Pairs of angle contact ball thrust style races (like the Stovebolt trucks use) and taper roller bearings have a set of load lines running through each race which make a virtual diamond shape looking from the front or back of the axle. Taper roller bearings make a narrower diamond load line pattern than ball thrusts, but as the load is taken across the whole of the taper roller the setup is far more rigid than with ball thrust bearings.

What this means in (hopefully) plain English is that you will get less "rock" on the hub and disc with taper roller bearings of the same size than with ball thrusts. So the potential for disc brake pad "knock back" is reduced with taper rollers. Any brake pad knock back means that you will have more brake pedal movement to bring the pads onto the disc faces when you brake.

Having said all that, well adjusted ball thrust bearings should work perfectly well with discs if the brake system is properly set up too.

BTW, Whitedog, I looked at your photos of your 3/4 ton disc conversion work-in-progress. Those huge calipers should give really impressive stopping power once you've finished the fit up.

Stuart: They are huge, when I saw them hanging out from under that smashed up van, I had to rescue them.LOL
They fit rather well, all things considered. I just need to take the time to get something made for my second version of a mounting bracket.

Even though a sealed bearing may fit the bore and spindle, it is not designed for wheel bearing use because there is no way to adjust the bearing preload and the wheel runout. I have been using Meritor wheel ends with sealed bearings for over 10 years. However, they require a special spindle, and If a bearing goes out, I have to replace the entire hub. I keep a spare new one on hand, but I have never had to use it. Some of the steering axles have logged over a million miles. Here is a link to Meritor's pre assembled wheel end.

http://www.meritorhvs.com/MeritorHVS_Documents/tp0251.pdf