Can anyone provide some tips on adjusting front wheel bearing on W124 chassis and checking the play?

I think I over-tightened the first time (went to finger tight) cause the grease behind the spindle washer was blackened some... Problem is even finger tightened there was still some play... Based on a few forum posts I tightened to where I can turn the washer with a finger with a bit of force...

No matter what I do it seems theres a bit of play up and down. Side to side the wheels just turn so not sure how to check that. The whole front end suspension is very old (possibly original), but idk if that could contribute.

Any help is much appreciated!

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1995 W124 M104 E320 Wagon. 175k Miles and Counting

If you haven't done or aren't doing them regular your best bet is to get yourself a suitable dial indicator and a magnetic stand for it.

The factory specs are pretty precise and the ability of the average wrench to determine if an installation is definatively within the specs is a serious challenge.

Doesn't cost much to alter the wheel bearing to what might be a better position but you've mentioned the vehicle is older and might be sitting on its original suspension parts. It might be worth it to get the car up on a lift and give the suspension a good going over before you start spending too much on any particular part/s. There are more that a few places that the front suspension can be worn and loose contributing to a sloppy steering feel.

Best advice is to access a Factory Service Manual which Mercedes at one point made available on line. That way you can get a basic idea of where you're going with addressing these kind of issues.

I have a 126 car and have cleaned/lubed/adjusted the front wheel bearings 3 or 4 times in the 20 yrs. I've owned the car w/o using a dial indicator.

I do it the old fashion way that many say won't work.

I must be lucky.

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

Not lucky, I do it exactly the same way and so do many others I know. Tighten until snug, back off, tighten finger tight. It's a wheel bearing, not rocket science.


If the bearing cannot be preloaded correctly, it's time for new bearings, they don't last forever.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

While the "finger tight" method gets plenty of people by, if you are unsure of yourself then get a dial indicator. Harbor freight sells a dial indicator and magnetic base cheap and it's definitely accurate enough to do a wheel bearing. While I haven't checked, I'm sure there are a dozen you-tube videos that explain how to use the dial indicator to check end-play.

Personally, I like to be absolutely sure it's within tolerance. I use the dial indicator every time.

Caveat: the Mercedes service manuals give the end-play tolerance specification in mm and the dial indicator that harbor freight sells reads out in thousandths of an inch. You will have to convert.

Are you checking for play with the wheel and tire back on it are you grabbing at the brake rotor and feeling this play?

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

I find the turn the wheel whilst tightening the nut until it gets difficult to turn and then back off to finger tight trick to work well if you are adjusting a pre-assembled and working bearing but for comfort's sake a quick check with the DTI is such a trivial additional step to make (if you happen to have the DTI of course).

If you are not careful new bearing seals not seated properly can give a false impression of bearing pre-load which you are more likely to detect with the DTI

So DTI is in my opinion safest and best

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

An easy trick is to use a flat blade screwdriver and use that to turn the nut whilst spinning the wheel - this will give you a nicer feel when you are tightening it screwdriver tight (I am imagining you are not the hulk in green mode).

once you are done with backing and tightening it about 10 times whilst the wheel is spun - you note the position of the nut, now loosen it and advance the nut just enough that you feel resistance (hold as strong as if you are holding a baby canary) - note this position. Advance the nut abt 20% ahead of the first position. and smack the snout of the spindle to test the freewheeling of the bearing.

I have done this a lot of times on a number of mercedes bearings and they always work silent. Dont worry too much about the grease going dark between the rollers, I have been told that its normal as long as the grease doesnt smell burnt and has not separated to oil and soap cake. (I used regular american red wheel disc brake grease - not the fancy minty german stuff) - I drove both my car tens of thousands of miles on a bearing service and they were silent as church mice in a library. (the mercedes FSM also speaks of the grease and bearing races turning dark)

using the correct amount of grease is also paramount too as the hub acts as a centrifuge as it turns

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Thank you all lots to address.

if6was9 - you make a good point, dial indicator is cheaper than I expected and maybe worth it for peace of mind given the age. I read through some of the FSM from the w124zone site but did not see too much on testing suspension. Is there anything I can physically tighten (rubber parts are degrading and need outright replacement) to get me through a few more months? Need to pass a safety inspection and december is a poor time for a suspension rebuild


Philly, I am checking both. i was more rotating the hub/wheel (push top pull bottom or reverse) instead of pulling in and out as the FSM indicates. I tried side to side as well but the wheels just turn...



As for the rest of folks, I did the finger tight, back it off, then just tight enough that the somewhat triangular washer can be moved by hand.

I don't hear any specific bearing noises while driving but it sounds worthwhile to get a dial indicator and measure the thing

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1995 W124 M104 E320 Wagon. 175k Miles and Counting

when testing with a dial gauge, the FSM is missing a few points.

You need to use some small bolts with the same thread as the lug bolts so the rotor sits tight against the hub, if you leave it loose and adjust the clearance, you will end up wrong as the rotor can flop a bit. Unless you are mounting the foot of the magnetic base on the hub.

Another point is to unload the brake caliper first (if the brakes are assembled)

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

I am amazed at that oversight in the fsm ...

axial play when pushing was good at between .005-.01mm on both rotors...hopefully not more when pulling once I find some smaller bolts or a large enough spacer I'll check both...

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1995 W124 M104 E320 Wagon. 175k Miles and Counting

There is a lesson in here somewhere, always use the newest information, WIS lists
Step 1 install a wheel bolt opposite the locking bolt to secure the rotor

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Paul

Wheel bolt doesnt stop the rotor from moving since the threads are 100% in the hub and 0% in the rotor....

This is clearly evidenced in my 1 rotor w/ no retaining screw..I can put all 5 wheel bolts in and it makes no difference, the rotor pulls right out.

Not sure what MB was getting at with that

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1995 W124 M104 E320 Wagon. 175k Miles and Counting

I'm surprised to hear you can remove a disc brake over a wheel bolt - I've never tried it but as the message you quoted doesn't specify "wheel bolt" I'm sure a M12X1.5mm bolt and a washer would suffice...

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Well you cant entirely remove it, but it pulls off until it hits the flange on the bolt... WHich makes the dial indicator measurement moot

I agree about the bolt, gonna pick a set up and give it a shot

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1995 W124 M104 E320 Wagon. 175k Miles and Counting