L-110 Rear Drum Repair and Slip-Fit Modification

I thought I’d post this since it might be helpful to someone. It seems there are regular questions about how to replace the brake drums on the corporate 1/2 ton axles. These are the ones with drums swaged to the hubs. The design is antiquated, and also has a few quirks that make them harder to service than you’d hope.

I tried to have the drums swaged, which didn’t go well due to an error I’ll describe later. Ultimately I decided to convert the hubs to accept new drums with a slip-fit.

My truck is a 1952 L-110 long bed that was originally a farm truck in southern Idaho. It eventually made its way down to Logan, Utah where it served as high school transportation until 1993. From what I was told it was parked because of brake problems. I think I discovered what the problem was…

This is what I started with. Not a pretty sight. The drum is supposed to be swaged on. It isn’t. Instead, it is floating on the lugs alone, with no center index. As a result (and probably from reusing the drum when it was “repaired”) the holes are wallowed out and the drum does not turn true. The lugs are old replacements of unknown origin.

Here is the new drum – Raybestos 2316R. It appears to be made of cast iron and is machined very well. The lug holes are 0.600”. The additional holes in between are a shade over 3/8”, probably about 0.385” but I don’t recall.

Back to the hubs. Unfortunately, they seem to have suffered damage from a BFH during the original repair. The drum surface is not true. high spots are shaded red. The lip is pretty banged up as well. Just FYI, I drove the studs out using a hammer, by supporting the hub underneath with sockets.

In order to true the hub I needed to get it on a lathe - without putting the oil seal surface in the chuck. And in order to do that, I needed a center. My brother (who did all the machine work here) made this nice mandrel from 2” diameter aluminum bar. The taper is a perfect fit, minus some corrosion inside the hub.

Some shots of the hub being turned. You can see just how off-center the whole thing is. It seems there may have been some core shift when these were cast. We tried to clean it up a bit but decided not to go all the way. It doesn’t really matter anyhow, as long as the mating surfaces are good.

I don’t have any shots of the drums being swaged, or of the lugs. However, the lugs I used were Napa part NOE 6411128, which is the same as Dorman 610-095. Note that there is no left-hand thread version available, so if you use these on the left side you’re going to get new nuts as well.

The swaging didn’t go well. The machinist (not my brother in this case) wanted the holes in the drums reamed to 0.615” so the knurling on the studs would bite into the drum. Bad idea. The drum is iron and iron doesn’t compress well. But it does chip. I think the studs pressed in off-center as they chipped and this resulted in the drum being off by about 1/16”. Not so good.

In retrospect I think that if the holes had been enlarged to 0.625”, just 0.002” larger than the outer knurl, then this would have worked out fine and I would have been done.

Anyhow, back to the drawing board. I cut the brand new studs off, pressed out the drum, ground and removed the studs from the hub… and then beat the living crap out of the drum. This was wrong. I know it was wrong. I could have re-used it with the second set of holes. But I have to admit that after so much time and effort lost, I had to relieve some stress.

After thinking about it for a while –and getting a new drum – I decided not to swage the drums. Instead, I would modify the hubs with a center index to locate the drum, and only use the studs for the braking force – like pretty much every other drum you’ve seen.

Cutting the flange down wasn’t an option. First of all, the hub is only about 3/8” thick to start, plus it’s very soft, mild steel. I needed to retain the strength. Plus the drum had to stay in the same location. So, I needed to add some material.

I decided to do this by turning a shoulder on the hub, then fitting a ring over it, then turning the ring to match the center of the drum. A quick search on eBay and $10 later I had the perfect material – some large industrial washers. They are:

Brand: FABORY
Part Number: U38402.175.0001
Thickness: 0.180"
Inside Dia.: 1-7/8"
Outside Dia.: 4"

My brother didn’t take any pictures of the machining. But this was the process:

- Turn the shoulder on the hub
- Turn the washer inner diameter to the shoulder daimaeter, minus a few thousandths
- Heat the washer and drop it on the hub. Once it cools it’ll be set (though I used some high temp Loctite as well)
- Turn the washer (now on the hub) to slip into the drum center.

Now, in order to modify the drum’s lug holes to 0.625” we needed a way to get the holes centered. We made a little aluminum tool with one 0.600” end and a 3/8” shaft. With the drum bolted to the bed of a mill, the tool allows you to center the cutting head perfectly. Swap to a 5/8” mill, then cut, x5. Sorry, no pics of this either.

Easy as that, if you have the tools.

I reinstalled the old studs, the ones that had been used when the original repair was made. I don’t know what they are, but seem to match pretty close to a Crown A474 or Dorman 610-032. The exception is that apparently some of the older parts (like mine) were 0.623” diameter, where the new ones are 0.630”. If I’d had more of the Dorman 610-095 would have used them again.

The end result was better than expected. Everything fits nice and snug but comes apart easily. It turns very true. And best of all, no more pulling the hubs to service the brakes!

I should mention a couple of other points. First, the star adjuster needs to be shortened by about 1/8” on a lathe. The reason is that the new drum with new shoes can’t be adjusted back far enough to slide the drum on. Shortening the star adjuster lets it all fit. I didn't know this until everything was going back together. Another week of waiting. Bah.

Also, since this fix requires that any additional new drums need to be modified to 0.625” lug holes. A minor inconvenience. I looked at wheel stud options with 0.600” shoulders but the ones I tested were too loose in the hub. I could have made it work (new set of holes in the hub) but the effort seemed more than necessary. This almost worked, but not quite. Would have been nice as then the drums would not need modification. I don't recall the part number.

One thing you might be wondering is why I'd go to all this trouble just to be stuck with the same old IHC axle that so many people replace. The answer is simple: I'm stubborn.

Also, besides parts cost, I paid for labor in hamburgers.

Also, I don't have a garage, shop, or even covered parking. Or a truck (besides this one, obviously). So replacing my axle with a 9 or 8.8 didn't make a lot of sense considering the logistics.

Also, this is my fifth year with the truck and I just need the darn thing to go. (And it does go now. I drove it around the neighborhood on Thanksgiving weekend).

Also, the low gear ratio doesn't bother me as I have an overdrive tucked away for later.

These are some very specific arguments that might not make sense in your situation.

Great story AZD! I applaud your perseverance (and stubbornness lol). My machine shop guy made the same mandrel to turn my drums on my Kb when I was doing the brakes. Luckily I didn't have the damage you had encountered and my drums were thick enough to turn down. That trick allows them to be turned without having to separate them. Nice. This is just one more example of the trials and tribulations of owning an IH, just can't order new parts out of the resto catalog. Good job. Sidenote: You mention Logan Ut and it brings back memories of a great Italian dinner my wife and I had at a little pizza shop downtown there. We were on our honeymoon and touring the U.S. The next day I got a speeding ticket on our way to Zion. It was August of '77.

Thanks, MACGIVER!. Yeah, it was a real pain, but once I was in that deep I wasn't going to lose.

Logan is a nice little town, though less little each day. I spent some time up there for school and still pass through occasionally. Coincidentally, I've spent a lot of time out in your area between Mt. Pocono and Scranton. Don't even need the GPS much anymore. Very pretty out there.