Nivaventure, Reconditioning the rear axle

Reconditioning the rear axle

Here is how we completely recondition a rear axle (brakes + bearings + rear diff).
After putting the axle on stands, take off the drum. To do this, unscrew the 2 10mm bolts.
To remove it, replace the two bolts in the two tapped holes provided for this purpose. If it's really rusty, it's best to apply penetrating oil liberally to the half-shaft (around the chrome cap) and the 5 wheel retaining bolts and then try again the next day.
Now, try not to pass out when you see what is revealed! Here is what can happen when you frequently go in mud and water and never think to remove the drums to clean them... Everything is clogged up, rusty...
To take the brakes apart, start with the 2 shoe steady springs and cups (push inwards and turn a quarter of a turn).
Take off the large shoe return springs.
Here we have it. There's just the half shaft to take out.
Undo the 4 brake backplate bolts. Is it hard? If all else fails, you can angle-grind them, they are 'standard' bolts so esily replaced (in any case, I recommend systematic replacement of all removed bolts by new ones). Also think about unscrewing the brake pipe now.
Extracting the half-shaft. This is often hard... there is a special tool availabe (a slide hammer). It's not worth doing your head in trying to make one - it's enough to replace the wheel the wrong way round, put just 2 road nuts on (diametrically opposite) and don't tighten them up (leave at least 1 cm play). Then, by punching the tyre in various places the axleshaft will free itself (it's the play in the wheel studs that does the job of the slide hammer).
Take out the oil seal. A large screwdriver should do it, making sure you don't scratch the interior of the axle and ruin its sealing.
Now, cleaning; - start with de-rusting, de-greasing, washing, cleaning off, etc... the bearing lockplate.
Once clean, with a new paper seal.
Do the same with the brake backplate.
Clean the wheel cylinder. Don't hesitate about replacing the seals and bleeding it. If it's too far gone change the whole thing.
Re-fit it on the support.
If they are in a satisfactory state, clean the brake shoes.
Re-fit them (mind your fingers when refitting the large springs!!!). There, it looks better!
On the axle, clean the interior with a metal brush (a brass brush! Careful not to scratch it...)
Remove dust and grease with petrol.
Wipe it, it should shine all over.
Liberally grease it (there's never too much) and put a new oil seal in.
With the brakes done, on to the half-shafts. After having removed the old bearing (the locking collar can be cut off with an angle grinder), you should clean and grease well ready for the new bearing. It goes on almost effortlessly, just tap the central ring with a bronze drift.
Here is the new bearing locking collar (race). Warning, NEVER refit an old locking collar!!! The problem is that it is elastic and heat-mounted, and its bore must be perfect.
To fit the new race, the trick is to heat it in oil. Personally, I leave it to boil for 10 minutes. The film of oil lubricates the fitting and creates a thermal filter which maintains the temperature of the race for several seconds.
Using pliers, put the race on the half-shaft AS FAST AS POSSIBLE (put all the tools next to each other and practice with 'dry runs').
The race is in position and just needs to be forced down.
Using a tube of the appropriate diameter and a sledgehammer, hit the race home. All this must be done within 10 seconds! Do the same with the other half-shaft.
The rear diff. Take it out, and check the various parts : to note, the play in the bearings, the state of the teeth and the pinions. In my opinion, the only thing that can be 'DIY'd is the sideways play in the crownwheel. It's allowable to gently tighten the two rings to pinch the side gears a bit more on an old axle. On the other hand, don't go any further taking the diff or pinions apart as the adjustments are hard... In my case, there was so much play everywhere that I chose to change the diff for a secondhand one in good condition (with no play). Later I will see about renovating the old one.
Clean and de-grease the axle body. Clean all the deposits from the inside of the axle and clean the seal placement area.
Once the diff is in condition and well cleaned, fit a new seal.
Fit the diff. I recommend putting universal blue sealant on the screws to ensure a good seal on the threads.
The diff replaced, you can re-fit the half-shafts. You can put some grease on the grooves to make refitting easier, but most importantly don't force it when the half-shaft is not engaged! To get it home, you can hit the half-shaft with a rubber mallet.
Fit 4 new bolts, taking care to grease them (remember the taking-apart!) and close the spring pins.
Tighten everything fully, there should be NO play at all. On the photo, you can see the grease squeezing out, that's perfect! This means that the parts will take longer to rust together.
Finally, refit the drum taking care to liberally grease the bottoms of the bolts and the wheel disk.
Do the same on the other side, the oil level in the axle, bleed the brakes and adjust the handbrake. The job is done!
Thanks to Fabrice for this fine report and many thanks to hoverfrog for this translation.