The weekend warrior’s guide to a 463 front wheel bearing replacement.

My 1994 463 G-wagen had some play on the front right wheel bearings and I decided they should be replaced.  There is a Mercedes-Benz procedure to adjust wheel bearing play but I thought that since my car had done 278,000km I thought she was due a set.  This was mainly done for my own piece of mind.

I am not a mechanic and have no formal training in this field.  As such please remember this when reading my personal account on how I managed to change my front wheel bearings.  I cannot be held responsible for anything that might go wrong when following this procedure.

Right!  Now that is out of the way let’s get down to nuts and bolts but first lets cover the tools required to do the job.  The first order of business is the tool to remove and fasten the slotted nut on a G-wagen.  There are essentially 3 types of tool and it is covered in great depth at the following website:

http://www.4x4abc.com/G-Class/slotnut.html

The first two tools are required for the 460 and 461 G-wagens.  The last tool is for the 463 G-wagen.  Make no mistake you need this tool to get the nuts on and off without damage.  The best is to get a decent size socket as a base and then get a machine shop to do the rest.  Here is a good template to use:

Otherwise if you have some spare cash to burn you can buy this from your friendly Mercedes-Benz spare parts division.  They are not cheap!

Another good tool to have in your arsenal is a tie rod separator and a bearing splitter, bearing puller and/or hydraulic press.

The rest you can get by with a decent ¾” and/or ½”socket set, decent torque wrench and basic tools.

This is the process I followed to dismantle:

1. Loosen wheel bolts on the front wheels (torque to 130Nm for alloys)
2. Jack up the front of the car and place on tressle jack stands
3. Check vehicle is secure to work on
4. Remove front wheels
5. Remove tie rod
6. Remove drag link
7. Remove front brake pads
8. Remove front brake calipers.  You will need a long socket wrench as the brake calipers are fastened to 190Nm-220Nm for the upper bolt and 250Nm-280Nm for the lower bolt.  Always use a torque wrench to fasten to the correct torque!
9. Clamp brake hoses so you don’t end up with brake fluid on the garage floor
10. Remove front brake discs
11. Remove ABS sensor from joint housing.
12. Tie up brake lines, brake wear sensor lines and ABS sensor line with a cable tie
13. Remove the wheel hub grease cap
14. Remove the outer slotted nut
15. Remove the slotted washer
16. Remove the inner slotted nut

You will be left with the following picture:

1. Pull off the wheel hub with outer wheel bearing.

1. Remove the bolts from the steel ring attached to the rear of the joint housing

1. Remove upper kingpin bolts

1. Remove lower steering knuckle bolts
2. Remove lower steering knuckle (watch out for the kingpin shims!!!)
3. Remove upper kingpin (watch out for the kingpin shims!!!)
4. Pull off joint housing

1. Gently remove the drive shaft and CV joint assembly (pull towards you)
2. The next order of business is to remove the old upper and lower kingpin bearings.  To do this each bearing has a tin cap that can easily be punctured in the centre by a large flat screwdriver.  Once you have made a big enough hole you can find an appropriately sized socket.  Choose one that has the outer dimater that best matches the outer diameter of bearing race (socket should be slightly smaller).  Attach the socket to a socket drive extension which is now poking through the freshly made hole in the tin cap.  Then hit the end of the socket drive extension with a hammer to pop the bearing race out.  Now you can do the top kingpin in the same way.

1. After you have removed and cleaned up all the grease you will be left with the axle seal and bushing that need to be removed and replaced

To remove the seal first I used a large (22) spanner and wedged it behing the seal and the axle housing.  I then hit the other end of the spanner with a hammer and out popped the seal.

The bushing is more difficult to remove and if yours is in good condition I recommend leaving it in.  For those keen to remove the bushing without a special tool I used the following method.  Locate the bushing split and use a lone hacksaw blade to cut along the split.  This will effectively widen the split.  Do not cut all the way through.

There is a ridge behind the bushing that slops it from being pressed in too far.  Avoid damaging this with the blade.  Once the split is widened cut another split about 5 – 10mm away from the original split.  Do not cut all the way through.  Remember the ridge!

The metal is quite soft and there will be a lot of metal shavings.  I suggest stuffing the axle tube with toilet paper to stop the metal getting too far down the tube.  It also helps with clean up.

Once you have cut deep enough you need to get a punch or small flat screw driver and bend you newly cut  tab by hitting the screw driver or punch with a hammer.  This will effectivley bend the tab up and you can then grab on to the tab with a pair of water pump pliers or vice grip and pull the bushing out.

This part takes some patience so once you start you will have to commit to getting it out.  Gentle taps with the hammer will get the tab to bend eventually.

Your job of dismantling the axle is done.  Now you need to remove the old bearing and seals from the joint housing.

Here is a picture for parts reference. (Spot the typo).

Removal of the old bearings and seals without the special tools requires some lateral thinking and patience.  The first thing to do is remove the outer and inner seals.  This is easily done by wedging a large flat screwdriver behind the seal and tapping out with a hammer.  Remember to move the screwdriver around in a seal and tapping with a hammer as you go along.

The inner roller bearing cage can now come out of the joint housing.  All the is left is to remove the inner and outer bearing races.  If you have cleaned up your joint housing and removed all the old grease you will see the old bearing races protruding slightly from the inside of the joint housing lip.  I used a large (40mmx40mm) aluminium drift and wedged the corners on the protrudig bearing races and hitting them with a large hammer.  Tap in one spot and them move around the bearing about 90deg on and then hit there.  Working your way around the bearing race.  A few blows and and out she pops!  Do this for both the inner and outer bearings and your joint housing has earned a nice parafin bath.

Removing the outer bearing from the wheel hub requires the use of a bearing splitter, puller and/or a hydraulic press.  First you need to cut the bearing cage and remove all the roller bearings.  This will expose the bearing ridge.  Attach the bearing splitter to the ridge of the bearing case.

Now you can use a hydraulic press or bearing puller to exctract the bearing.

Points will be awarded for the correctly identified brake disk used to support the pressing operation.

Saftey first!  Use safety glasses when doing this!  The bearing metal is quite brittle and some shards of metal might break off.  Eye patches are only cool at pirate parties!

Excellent!  Everything is now ready for assembly.  Do not throw away your old bearings just yet however.  They can be used to press fit the new bearings.

Here are the tools I used for pressing in the new bearings.

A word on bearings:

When I priced the bearings for this job the outer wheel bearing from my friendly Mercedes Benz dealer was 10x more expensive that the inner bearing dispite have an outer diameter of only 10mm more (90mm vs 80mm).  I originally decided to get this from a local bearing supplier and requested from them 32011X/Q but when they arrived I realised that this was not the correct bearing.  The inner chamfer that presses onto the wheel hub is quite specific and you need to specify the whole part number i.e. 32011X/QVB206.  It seems this part is only available from SKF.

Notice the chamfer on the bearing.  This is important or you will not be able to press the bearing onto the wheel hub far enough ending up with everything being mis-aligned.  The outer diameter of the bearing is 90mm.  I could get this bearing from the local SKF supplier at half the cost of the Mercedes part.

The inner bearing has an outer diameter of 80mm.  This bearing was really cheap (3x cheaper than the SKF local agent) from Mercedes so I bought this and all the other parts (seals, bushings etc.) for this job at Mercedes.

My bearing naming convention:

The outer and inner wheel bearings come in two parts.  The outer tapered bearing race and the inner roller bearing cage and bearing race arrangement.

Grease:

For this job I bought two types of grease:

1. Castrol BNS (A high temperature wheel bearing grease, for use on the wheel bearings) x1 500g tub for both sides

2. Castrol LM (A general purpose wheel bearing grease for packing into the joint housing) x2 500g tubs per side (procedure calls for 800g per side)

No I don’t work for Castrol nor am I endorsing their product.  It was at my local parts store and has a good reputation.

Parts:

I used this site to get my bill of materials to do both sides.

http://www.4x4abc.com/G-Class/bearings463list.html

Assembly:

1. Outer wheel bearing

I used the old bearing to press on the new outer bearing onto the wheel hub.  Since the inner diameter of the bearings are the same the old bearing will need to be pressed off the wheel hub shaft once the new one is firmly in place.  Use the same technique described above for removal.

Once the new bearing was on the wheel hub I replaced the outer dust seal (A463 34 01 59) and packed with wheel bearing grease.

The old bearing can be used to fit the other half of the outer wheel bearing into the joint housing.  I used a grinder to grind down the outer surface of the old wheel bearing so it would be easier to remove after pressing the new bearing in.  I also used the thinner side of the old bearing as the pressing surface so that the wider part of the tapered bearing race could be gripped with  a pair of  vice-grips and hit out with a hammer and aluminium drift.  See the tools picture.  Be sure to fit the new bearing race to that the thicker part faces into the joint housing and the thinner part faces out of the housing towards the seal.

Once the bearing is in the housing you can press in the outer seal (A015 997 54 47).  Use something with a similar outer diameter to the seal.  I used a large block of flat wood to hammer it in.  I used a sealing compound on the outer bearing seal.

Clean/blow out with compressed air any debris.

2. Inner wheel bearing

Next I fitted the outer bearing race of the inner bearing to the joint housing.  Again using the techniques described above for fitting the outer bearing race.  Make sure the thinner part of the bearing race faces the inner seal (A015 997 99 47).

Fit the second half of the inner wheel bearing to the race and then fit the inner seal (A015 997 99 47).

In this picture, what did I not put in before the seal?

Clean/blow out with compressed air any debris.

Pack the bearings with the Castrol BNS.  The procedure calls for 80g.

Pack the joint housing with Castrol LM grease (800g per side).

3. Kingpin bearings

Once your joint housing and wheel hib is complete you can fit the upper and lower kingpin bearings on the axle housing.  First put in the tin cap bottom (A460 997 00 40), then the kingpin bearing (A000 981 59 05).  Pack with grease.  I used Castrol LM.  Finally the tin cap top (A460 332 00 33) goes on top.  You need to use lots of grease to get this to all stay in place with the lower kingpin bearing cap.

Wipe clean of debris.

4. Drive shaft

Before you can insert the drive shaft and CV joint arrangement you need to fit the axle bushing and the axle seal.  I used a similarly sized socket for the bushing and a flat piece of wood for the seal.  Tap them in with a hammer.  Coat both seal and bushing in Castrol LM grease.

Before going to the next step make sure to slide the wipe seal (A460 331 01 80) onto the axle housing.  The chamfered surface of the wipe seal  must point to the round part of the axle housing (i.e. towards you).

Next slide the inner steel ring (A460 331 05 58) over the housing.   The rounded edge of the ring should pint towards the wipe seal.  The sharp edge will fit into the joint housing.

Once these are in, insert the drive shaft.  When inserting the drive shaft on the LHS (sitting in the car) you may need to lock the diff or remove the diff lock cylinder.  I was lucky and could just pop the shaft back in.

5. Joint housing

Slide the joint housing over the drive shaft and CV joint.  Use the upper kingpin to locate the joint housing at the top.  Once located (make sure the top tin cap has not slid off) locate the lower steering knuckle kingpin into the lower kingpin bearing.  Again watch out for the tin cap.

The kingpings will have small shims on them.  Make sure you recdord their position.  There is a lenghthy procedure for setting the preload for the kingpin bearing in the Mercedes procedure.  My view is that if there has been no axle damage you can just use your original shims.  Otherwise you will need to set your preload again.

Tighten upper kingpin bolts to 170Nm-190Nm.

Tighten lower kingpin bolts to 250Nm-280Nm.

6. Outer steel ring

Once the joint housing is secure you need to fasten the outer steel ring/gasket reainter to the joint housing.  This is done using several M8x18 bolts.

First you need to apply the sealing compound/gasket sealer to the back of the joint housing.  Then it is good to loosley fit 3 or 4 of the M8 bolts into the outer steel ring and then drape the split paper gasket (A460 331 00 80) over these bolts.

Next press the inner steel ring onto the back of the joint housting.  Then press the wipe seal against the inner steel ring.  Then gently move the outer gasket retainer and paper gasket to the back of the joint housing.  With the bolts try and fix the gasket retainer to to the back of the joint housing.  You need to make sure that one of the 2 notches of the steel gasket retainer lines up with the lower brake caliper bolt.  Best to survey this before bringing them all together.

Now you can gently finger tighten all the M8 bolts trying to keep the wipe seal from being crimped by the steel gasket retainter.  I used a small flat screwdriver to do this.  Gently work your way around the bolts loosening, adjusting and then retightening the bolts until you have a decent fit of the wipe seal.  Once all is well tighten the M8 bolts to 20Nm-25Nm.

 A word on wipe seals:

There are 2 vaild wipe seals in the Mercedes EPC.  One is the split wipe seal (460 331 03 80) and the non-split wipe seal (460 331 01 80).  The split wipe seal is actually a throw back to the first 560 G wagen axles.  It is to be used in conjunction with what I call the “big staple”.  The split wipe seal is actually 3x more expensive than the non-split wipe seal.  Also the “big staple” is similarly priced to the split wipe seal so you end up paying 5x more for the split wipe seal solution.

I guess the reason this arrangement is still availble is because people don’t know better and the EPC doesn’t easily show this e.g. for my VIN in the EPC both arrangements are “valid”.

The other reason for this I suspect is that some people might want to change this seal without removing the joint housing so there is still a demand for them.

7. Wheel hub and bearing play

Slide the wheel hub over the the drive shaft.  Take one of the slotted wheel nuts and finger tighten onto the drive shaft.  (The chamfer of the slotted wheel nuts should point toward the locking tab i.e. towards the outside for the inner slotted nut.)  Now get a large block of wood and a hammer and use the wood as a drift to hammer around the wheel hub to set the wheel bearings.  Do this while turning the wheel hub.

Then you must tighten the slotted nut to 200Nm to “set” the wheel bearings.  Once you have done this you must slacken the nut off.

The Mercedes procudure calls for the use of a dial guage to measure the play.  Initially I tried to use this technique but found it very difficult to measure the required play consistiently.  The aim is to set the inner slotted wheel nut to measure a play of 0.1mm.

Then insert the locking washer and so the outer slotted wheel nut up to 170Nm-190Nm.  The final play should measure 0.03mm for used bearings and 0.01mm for “new” bearings.

As mentioned earlier I could not measure the required 0.01mm so I ended up tightening the inner slotted nut to measure the 0.1mm play and then with the wheel on tightening up the outer slotted nut so that there was the smallest amount of play that could be felt.

This requires an iterative process slackening off the inner nut and then tighteng the outer nut to the requred torque.

Once you have managed to achieve the final result bend the locking tab into one of the available slots so that the outer nut cannot work itself loose.  Very important!

Cover the slotted nut in Castrol LM grease and fill the grease cap with Castrol LM. 

Fit the grease cap and you are done!

Go back to the beeginning of the procedure and fit the rest of the items in  reverse order.
Aknowledgements:

I would like to thank the following people for making this possible:

My wife for allowing me whole harted use of the garage for a couple of weeks and being so understanding during the whole process.

Peter Merle for the use of his tools and workshop.  Also for all the words of encouragement, moitivational beers and friendship along the way.

Harlad Pietschmann for his very helpful website and his manual on how to get this job done.

Naeem Moolla for the kind use of his slotted nut tool.  I could not have done this job without it.

All the forum members from www.mb4x4.co.za and http://www.pointedthree.com/disc/forums/forumdisplay.php?f=57 for all their help.

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