tatra805
Silver Member
I thought this might be usefull for other people also so made it a separate thread.
As part of my trailer build i want to run landrover rims on the military axle i used as base frame for the trailer.
This posed 2 problems related to the hubs.
- The original rims are 4 hole while the LR rims are 5 hole
- The difference between positioning diamtere of the holes is 100mm vs 160mm, and on top of this the diameter of the flange is only 165.
Not wanting to drill the new holes at the edge of the original flange, which would also mean drilling in the wall of the brake drum and cause other issues with the brakes which i want to keep.
So this is how we did it:
The original hub assembly consists of a brake drum and a bearing housing with a flange. Both are hold together by pressed in wheel studs.
We disassembled the hub by knocking out the studs.
Then we cut 2 rectangle plates made out of 10m thick plate. With the grinder made them octagonal to spare some lathe time.
These plates were then transformed to discs on the lathe. (thanks once again to Zoro for his time and effort, despite the cold willing to spend the time on it) We did not make the new stud holes at this point, see later.
Although the first idea was to use the old studs to reposition the brake drum i decided to shift the holes and weld them. Also the outer rim was welded (spot, then area and after completion i will weld them complete around. The brakes will only be used as a parking brake so i see no reason why i would have to replace the brake drums in the coming 200 years.
Once this was done the new discs were positioned, tack welded and then fix welded to the hubs.
As the holes for the new rims will be near the edge of the old flange I only tack welded the outside edge to avoid to much drilling in the welds. (complete welding to be done after the hole drilling)
Now this is done, the whole hub assembly goes back on the lathe to make the 5 rim holes centered on the hub and to round the discs to the center of the disc.
I would really advise this method and not making the holes in the plates when making the discs as you then have to 100 % exact center the discs on the hubs before welding them. Although this is possible and not such a hassle when machining the discs you then have to keep your tolerances during the whole process, while now tolerances are only set at the end phase.
Regarding the welding, i used my MIG to make the tack welds and weld the 8 holes of the brake disc. For the disc on flange welding (10mm filling needed) i first MIG welded the disc with minimal wire-feed and maximum current setting possible to really melt the hub and disc materials while giving a little extra material. ( the gap was too deep and not wide enough to enter with an electrode) I then welded the disc using a 7018 2.5mm base rod and then for visual appearances went over that weld with the MIG to have an equal fill of the weld so it can be nicely grind flat with the disc.
I am sure that a pro will doubt this technique but i simply dont trust MIG for welding in heavy materials. Heat transfer is not as big and penetration control is easier but to my experiences never as deep with MIG.
With 2 hubs to make it was quite easy to control the cooling down and avoid warping by switching between the 2. This is quite important as you want all discs to be parallel to the original flange to avoid wheel wobble.
Now we only have to drill the holes and the new rims can be fit.
As part of my trailer build i want to run landrover rims on the military axle i used as base frame for the trailer.
This posed 2 problems related to the hubs.
- The original rims are 4 hole while the LR rims are 5 hole
- The difference between positioning diamtere of the holes is 100mm vs 160mm, and on top of this the diameter of the flange is only 165.
Not wanting to drill the new holes at the edge of the original flange, which would also mean drilling in the wall of the brake drum and cause other issues with the brakes which i want to keep.
So this is how we did it:
The original hub assembly consists of a brake drum and a bearing housing with a flange. Both are hold together by pressed in wheel studs.
We disassembled the hub by knocking out the studs.
Then we cut 2 rectangle plates made out of 10m thick plate. With the grinder made them octagonal to spare some lathe time.
These plates were then transformed to discs on the lathe. (thanks once again to Zoro for his time and effort, despite the cold willing to spend the time on it) We did not make the new stud holes at this point, see later.
Although the first idea was to use the old studs to reposition the brake drum i decided to shift the holes and weld them. Also the outer rim was welded (spot, then area and after completion i will weld them complete around. The brakes will only be used as a parking brake so i see no reason why i would have to replace the brake drums in the coming 200 years.
Once this was done the new discs were positioned, tack welded and then fix welded to the hubs.
As the holes for the new rims will be near the edge of the old flange I only tack welded the outside edge to avoid to much drilling in the welds. (complete welding to be done after the hole drilling)
Now this is done, the whole hub assembly goes back on the lathe to make the 5 rim holes centered on the hub and to round the discs to the center of the disc.
I would really advise this method and not making the holes in the plates when making the discs as you then have to 100 % exact center the discs on the hubs before welding them. Although this is possible and not such a hassle when machining the discs you then have to keep your tolerances during the whole process, while now tolerances are only set at the end phase.
Regarding the welding, i used my MIG to make the tack welds and weld the 8 holes of the brake disc. For the disc on flange welding (10mm filling needed) i first MIG welded the disc with minimal wire-feed and maximum current setting possible to really melt the hub and disc materials while giving a little extra material. ( the gap was too deep and not wide enough to enter with an electrode) I then welded the disc using a 7018 2.5mm base rod and then for visual appearances went over that weld with the MIG to have an equal fill of the weld so it can be nicely grind flat with the disc.
I am sure that a pro will doubt this technique but i simply dont trust MIG for welding in heavy materials. Heat transfer is not as big and penetration control is easier but to my experiences never as deep with MIG.
With 2 hubs to make it was quite easy to control the cooling down and avoid warping by switching between the 2. This is quite important as you want all discs to be parallel to the original flange to avoid wheel wobble.
Now we only have to drill the holes and the new rims can be fit.
