a good press is required I think. I am not sure you could do without one but you guys over there are much smarter about these things.

Just remove the nut and then press the bearing housing off. I was told you really never should remove the splined hub from the axle and I know that one needs a HUGE press as my 12ton would not separate the hub from the axle shaft. Silly me, I thought that was the way to get to the bearings, but once I cleaned off the grease I found that nut and then pressed the bearing housing off. I also took advantage of it being removed to machine it for a proper seal instead of felt.

But in order to keep you next week apt. for the MOT, just tightening that nut up "may" do the job, but I would not drive long distances without really looking into the bearings, they are relativaly cheap.

Re: 1934 SLM rear axle hub

by mothy » Fri Jul 12, 2013 7:30 am

by mothy » Fri Jul 26, 2013 8:31 pm

Progress of sorts. The diff is out and bits inspected.

The offside halfshaft has a very sloppy fit into the diff. There is enough movement to be felt at the wheel.

So I am not sure what is worn and what is supposed to be like what it is.

The tube that the halfshaft slides into has enough clearance to start entering a 0.025" feeler gauge.
The inner spline which I presume is on the sun wheel can be moved using a screwdriver about 1/8"

Later on I discovered that the other halfshaft has a greater diameter at the point where it sits in the the of the diff, by around 0.022". Clearly this does not slop around as much. So maybe its a halfshaft issue.

Then to complete the afternoon I have found 2 chipped teeth an on the crown wheel. I am cleaning off two spare diffs which have decades of crud on them, to see if either are serviceable.

---------------------

Away from the forum, here is my progress.

1. One spare diff had an intact crown wheel, but chipped pinion.

2. The other diff had a serviceable crown wheel and pinion. The half shaft tubes and sun gears did not appear to have any wear. However was very dirty, mucky, crusty and so on.

3. Washed it off and was not too sure about the diff carrier bearings, as they were taper roller and not angular contact, so changed them over from the original diff carrier from the car.

Above is the angular contact bearing LS12AC

Above is the taper bearing which came out of the car, and apparently is wrong.

Here is another gocha the annular adjusting rings are of different thickenesses and the wrong one will give insufficient support or adjustment. I must have accidently got those mixed up when transferring bearings from one diff to the other.

Above, 2 tyre levers make easy work of removing the bearings.

4. New bearings are £46 each, so carefully washed the existing ones out and oiled them and they feel good.

5. The bearings would not seat in bearing mounts, they were of greater diameter.

Below, taper bearing taken from the car and trial fitted in replacement case. That is 17 thou of feeler gauges slid in.

Here is angular contact bearing trial fitted in the case from the car. All the feeler gauges are slid in here. It is fortunate that this was the scenario I first tried and saw the bearing caps would not seat. If it had been as shown as above I may never have noticed that the bearing was loose in its seat.

6. Decide to use diff casing that the replacement crown wheel and pinion came from, because the bearings fit in that casing. Below is the correct bearing in the correct case.

7. New half shaft arrived today and is nice snug fit in diff carrier.

8. Went to local agricultural engineers to have work half shaft pressed out of hub. It let go with an almighty bang!

Finally it is back together and running OK. There is some axle whine but it is quite understated and probably would not be hear at all if the car was a saloon. Maybe it will quieten down once the rust has been work off the crown wheel and pinion. The original problem of the OSR wheel moving when shaken is now cured. Whether the fix is a different diff carrier or the replacement halfshaft which is 20 thou thicker where it enters the diff carrier remains to be seen.

Here is what the sun and planet wheel arrangement looks like. it is the same design as the Austim Seven and possibly the get-you-home method of pushing the broken half shaft through the diff so that it engages with the other sun wheel and locks the diff up will work. The half shaft I took out has not got a long enough spline to push further through, but the new one has, so that trick may work with new half shafts.

Here is the sun gear, the side on the right would have been in the diff carrier. I did not measure any wear from one side of the wheel to the other. Not having any calipers I could not measure the receiving hole, however the wheel moves side to side about 40 thou when located in the hole. The other sun wheel only moves around 10 thou.

What is unclear is whether the half shaft is supported by the sun wheel, or the entry hole which clearly has a helical oilway.

Lapping in the tapers, putting the road wheel on the spline gave a bit more pressure and ease of turning.

Clocking the backlash.

There we go! It's not too bad a job and if the second hand crown wheel and pinion fails I will purchase one of Dave Hardwick's high ratio 4.8:1 sets.

August 4, 2013