If one of your front wheels has "play" - DO NOT repack the bearings!!
The bearings must be replaced !
Even used bearings should have no more play than 0.03 mm (0.00118"). Always replace on both wheels simultaneously, even if only one side shows wear. If you would repack and re-tighten the bearings instead of replacing them - they would fail within a very short period of time and cause other severe damage with it. This can be extremely costly. I highly recommend the workshop manual to do this job right.
Here is the list of bearing part numbers.
Especially with larger wider tires the Gelaendewagen bearings have a tendency to fail frequently. Seems to be the achilles heel of this vehicle. Running 35x12.50 R 15 tires on my Gs with a much wider wheel off-set and the increased load on the bearings I needed new bearings about every 20,000 miles. My extreme duty off-road use did not help either. I inquired in Stuttgart for optional heavy duty bearings (sometimes Mercedes-Benz has a heavy duty version of parts available) to remedy my frequent problems. But they didn't have any - but they sent me a complementary pack with 20 new bearings. Good for 5 replacements. That was an acceptable answer!
Whenever you or your mechanic checks or replaces front wheel bearings - make sure to inspect the rubber boot of the CV joint. If damage is apparent (cracks, holes etc) replace boot. Since the boot is off - clean out old grease & inspect balls then refill CV boot with new grease.
A workshop manual for axle services including the wheel bearings is available.
You will need the proper MB tool to loosen and tighten the slotted hub nuts (spindle nut). MB part number W 460 589 00 07 00. You may have to fabricate your own tool because some Mercedes dealers do not sell those tools to the general public. However, some independent dealers like Eurotruck-Importers are happy to sell or loan you the claw wrench.