Hello ! How do I remove this screw ?
View attachment 345877
Do not remove the flange yet.
As I said above, you need to test the play (jeu) between the pinion and the crown wheel. (pignon et couronne). So it would be better to drain the oil out of the differential holding part of the rear axle.
Slide the two half-shafts out far enough to free the differential off. (You'll need to take wheels, and brakes, brake back plates and discs off and separate the hubs to do this, also disconnect the ABS sensor where its wire is connected to the other part of the wire under the rear wings, do NOT try to remove the sensor. Allow the sensor and its wire to slide out as you pull the hub out, together with the half-shaft out. In fact, if you disconnect the wire from all of its clips you may not need to seperate the two halves of the plug connector.
Then undo the circle of bolts (number 14) that hold it to the axle casing.
You then take it out
with the flange in place. You need the flange to be in place so that you can lock it in a vice or something to be able to measure the play.
IF you find there is too much play, then you need to remove the flange etc to be able to adjust the position of the pinion, in mesh with the crownwheel.
Then lift it out of the axle and take it away to do this measurement.
Be aware a differential is quite heavy.
To remove the flange, put two bolts in two of the holes on the flange, from the back preferably, then run a nut down each one, tighten each one up, then put a longish bar of some sort between the two bolts so you can use that to lever against, to hold the flange still while you undo the bolt in the middle.
There are other more brutal ways of doing it!!
Before you get started on all this, check that you know what torque setting is required to tighten things to before you go undoing them. (I take it you do have a torque wrench (clé dynamométrique).
ARE YOU capable of doing all this? I think it takes a bit of experience, and of course the right tools. You will of course require a substantial jack and axle-stands (supports d'essieu). Do NOT work under the vehicle supported only by a jack.
For instance, separating the hub holder from the other part requires you to partially undo each of the 4 bolts then to whack the end of each bolt with a big hammer. After having found the holes where the other end of the bolts sit and squirted easing fluid into each one. You then keep on undoing each one gradually while continuing to whack each one in turn moving diagonally from bolt to bolt, until the hub frees off . Then you can lever it the rest of the way.
You should also clean up each bolt once the hub is separated and then put locking compound on the threads of each one when redoing them back up.
Remember you only have to mve them far enough to disengage the splined ends of the half-shaft from the differential. You do not need to take them right out. This is less risk to the seals in each end of the axle casing.