The Stovebolt Site Forums The Shop Area Driveline 1941 rear axle spring saddles

Another outstanding opportunity and challenge surfaced today. I measured the gap between the rear axle housing and the loose fitting rear spring saddles that screw together.

I have a 5/32" gap or space when the two halves are secured around the axle. Appears that this is excessive play in this assembly.

I understand that these need to rotate around the axle shaft but bouncing up and down does not seem to be what the initial tolerances were intended or allowed.

I made a 1/16" lead shim for the lower or bottom saddle and it took up a lot of slack - sort of like a soft bearing surface that formed to fit.

Shaving the cast saddles is another option but that seems like an excessive amount of time and a fair amount of material to remove on a flat belt sander.

Not convinced my temporary lead bearing is the best solution but it seems tht adding metal rather than taking away metal feels right.

To the jury: how would you tackle this outstanding opportunity to resolve this situation?

All the wear will be on the cap and top of the housing, as that is where the load is.
How does the housing look for wear?

Thanks - after stepping back and studying the situation I came to the same conclusion. The wear looks even but I am not sure what I would be looking for.

I had the same issue with my '37 1/2 ton rear axle. I ended up having a friend mill 0.050 inch off the top saddle surface that mates with the bottom saddle. It seems to have worked as things are snug. If my math is correct that would be 1.6/32 inch, approximately what you did with your lead shim. Your shim would take up the gap at the bottom where there is no load. As you know, there is a grease zerk and keeping the area greased would be important in keeping out dirt and water.
When I disassembled my axle the top of the housing was quite worn, as Dave predicted. I did not measure the wear but it was at least 1/32 inch.

I think what you have done will work and after tightening the u bolts you will be happy with the result.

Kent

I had a machine shop mill mine down as well. It works fine. As I recall I had material removed both top and bottom.

I have been thinking about my approach to tighten the axle housing to the saddles. Because the weight and wear and tear directly affect the upper half of the saddles - it is no wonder these wear down and cause a loose rear axle in spite of new springs and shackles.

The original saddles had a 5/32" gap that was excessive. Fortunately I had 2 other sets to compare the wear and the gap between the upper saddle and the axle housing. I found a set that reduced the gap to 1/16".

Although grinding the saddle halves to fit is a good option, my preference was to build up the inner area of the top saddle to replace what had been ground down from 75 years of use, dirt and rust action.

My first step was to fill the rust pits on the axle housing. I used a paste (LabMetal) that has aluminum powder in it. I let it cure overnight, a
filed, and sanded the axle housing smooth.

My solution was to use a two part slow curing epoxy paste called PC7. Similar to JB Weld, this mix is thicker and won't run or sag. I spread the mix on to the casting of the upper saddle. I then cut 1-3/16" x 4" long brass shim sheet strips and glued them using the PC7 as the binder on the inner saddle. I used two layers of this brass shim sheet by epoxying another layer of the this material next to the first set to make up for the gap. I placed a sheet of plastic wrap over the axle housing and pressed the two saddle halves together. The second layer of brass would sit next to the axle housing. The plastic wrap would allow for any PC7 to squeeze out and laminate the brass shim to the inner saddle but not allow it to bond to the axle housing. I screwed the two halves together and let sit to allow this brass sandwich to form to the out of round saddle and axle housing.

I removed the saddles and cleaned the squeeze out in the grease channels and reassembled onto the housing. Once hardened I will remove the plastic, grease the mating halves, and reassemble to the housing once again.

I have used this epoxy in other applications and after it cures (takes about 1.5 days depending on temperature but another week or more to fully harden) it's tough and hard as nails. Sandwiching the brass with the epoxy is a gamble - but this is a truck that will be out to pasture and will not be used as a work truck.

I will be curious to see how this works over time. I took pictures if anyone would like to see.

Would seem to me that the most precise way to correct the worn out issue would have a machine shop mill the cap surfaces and rebore the hole. Same method as line boring a engine block and main caps for the crankshaft