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These are the 4Matic fittings: Single piece bearing get pressed into the knuckle; and hub then gets pressed into the bearing. The process is straightforward (with the right tools, of course) but I have some questions I hope to get answered before I begin:
Where is the tone ring? (For the Speed/ABS sensor to read.)
Does this bearing need to be installed in a particular direction?
After checking with magnetic-sensing film (and paperclips) the bearing definitely is not magnetic on either side. Both sides are identical, except for lettering on one face. So that leaves the Hub -- which I will not have in hand until tomorrow.
In pictures, the hub does show a ring of some sort at the very tip; could that be the tone ring?? Also, in pictures, where the ABS sensor enters the steering knuckle seems to correspond to where the end of the hub would be.
Can anyone shed some light on this?
Last edited by ericsilver; Aug 25, 2022 at 02:12 AM.
These are the 4Matic fittings: Single piece bearing get pressed into the knuckle; and hub then gets pressed into the bearing. The process is straightforward (with the right tools, of course) but I have some questions I hope to get answered before I begin:
Where is the tone ring? (For the Speed/ABS sensor to read.)
Does this bearing need to be installed in a particular direction?
After checking with magnetic-sensing film (and paperclips) the bearing definitely is not magnetic on either side. Both sides are identical, except for lettering on one face. So that leaves the Hub -- which I will not have in hand until tomorrow.
In pictures, the hub does show a ring of some sort at the very tip; could that be the tone ring?? Also, in pictures, where the ABS sensor enters the steering knuckle seems to correspond to where the end of the hub would be.
Can anyone shed some light on this?
Find the ABS sensor on your car to be sure.
I would guess WIS for this vehicle or similar has been posted on this site, relative to the bearing orientation question. Try the search function.
Yes, there are two, which I am attaching. Neither document comments on a correct way to install the bearing so, apparently, it can go in either way.
Earlier today I also called SKF, the OEM supplier for MB, and they confirmed that this bearing does not have a magnetic encoder.
Then, when returning to the dealer for an extra snap ring and axle bolt, I asked the gentleman at the parts counter the same question about the bearing and got the same answer. Then I asked if there was an encoder in the hub and he said the abs sensor -- one of which happened to be sitting there waiting for pickup -- has its own magnet.
I did not ask for elaboration since there were people waiting behind me but what I conjecture is that it works on the same principles as a crank or camshaft sensors(?) Perhaps hiding somewhere in the hub, i.e., that ring-like end piece, is something akin to the teeth that are read by cam/crank sensors??
Originally Posted by chassis
Find the ABS sensor on your car to be sure.
I would guess WIS for this vehicle or similar has been posted on this site, relative to the bearing orientation question. Try the search function.
Last edited by ericsilver; Aug 25, 2022 at 08:33 PM.
Here is the view from the back, in photos I just found on an EBay auction for the same type of steering knuckle:
In photo 1, the sensor port is at the top.
Photo 2 shows where the cable enters the port
Photo 3 is a top view, showing the hub and bearing intact.
From the photos, it appears as if the sensor is too far from either the hub or the bearing to be sensing anything from them. It seems better positioned to be sensing axle rotation.
Sensor Port at top Sensor Cable behind dust shield Top view showing hub and bearing intact
e:
Here is the view from the back, in photos I just found on an EBay auction for the same type of steering knuckle:
In photo 1, the sensor port is at the top.
Photo 2 shows where the cable enters the port
Photo 3 is a top view, showing the hub and bearing intact.
From the photos, it appears as if the sensor is too far from either the hub or the bearing to be sensing anything from them. It seems better positioned to be sensing axle rotation.
Sensor Port at top Sensor Cable behind dust shield Top view showing hub and bearing intact
e:
Good job on the due diligence. Please keep us updated on the progress.
This went well, overall, and I will try to post some notes and photos over the long weekend.
I used a hydraulic puller to extract the old hub; and screw-style kits to extract/replace the bearings and to insert the new hub.
Unfortunately the new bearing and hub did not solve my root problem: A "whump-whump-whump" heard (and felt) at lower speeds. The faulty bearing certainly amplified it; but was not the cause. (The old bearing was unpleasantly audible when turned by hand on the car. And although the "whump" noise is more muted now, it is still present.)
I did notice the following (driver side):
* Outer tie rod is shot. The ball joint is as limp as a noodle. Passenger side must be as well, judging from the ridiculous outer wear on my tires, and the barely perceptible sideways shift I feel on some turns.
* Ball Joints: Inconclusive. But I will replace with the tie rods. I did notice that he only way I could detach it was to raise the control arm to make space. I had only the left side jacked up, however, and I wonder if that had something to do with it(?)
* Inner axle boot is cleanly torn off at the clamp. I was able, therefore, to pull the joint out and have a look. No visible indication of wear but the ball bearings did seem to have some play (not sure if that is normal or not). I cleaned everything and repacked with Redline CV grease as it is less inclined to sling out of a boot, while I prepare to replace the axle.
Either the whump is coming from the passenger side; The tie rods/alignment is causing it somehow; or, most likely, the axle is bad, which is infuriating since it is a barely two years old GKN Loebro that cost me $2,000 to install (left and right) at an MB-specializing shop. (Then again, I did not see the box it came it so it could very well be substituted junk.) Also, the passenger side was replaced a year ago under warranty, for the same type of boot tear.
Now that I see how accessible the axle is, I will simply do it myself.
I got caught up taking care of the things I discovered in need of attention during the bearing/hub change, specifically:
* Replaced Left/Right-side Ball Joints;
* Replaced Left/Right-side Outer Tie Rods;
* Replaced Left side axle. Right side to follow, once I decide best method to remove it.
Regarding the Hub & Bearing, here is what I did:
1. LOOSEN AXLE BOLT. REMOVE WHEEL, ROTOR, CALIPER, ABS SENSOR
* Pry Off Center Cap, Loosen Axle Bolt (XActo blade; 27mm Socket)
* Jack up Car, Set Jack Stands, Remove Wheel (17mm Socket)
* Remove Caliper Assembly & Secure (21mm Socket; Short Bungee cord)
* Remove ABS Sensor & Secure (E10 Torx Socket; Tape)
* Remove Rotor (T30 Torx Socket)
* Remove Axle Bolt (27mm Socket)
NOTES: Loosen the axle bolt with the wheel on the ground. The impact driver did it in about 2 seconds. But you can use a breaker bar just as well.
NOTES: The ball joint removal tool works well. Hit the *Tool* with the hammer for best results, as it is in direct contact with the tie rod's threaded stud. While you are at it, check the condition of the tie rod. Mine is shot, as shown.
3. SEPARATE BALL JOINT
Support Control Arm with Jack & Separate (22mm Wrench; Ball Joint Remover; Sledge)
NOTES: As with the tie rod, the removal tool works best when hitting it with the hammer.
4. PUSH OUT AXLE
Push axle out and secure
Axle freed from hub.
NOTES: My axle came out with thumb pressure. If yours is stuck, partially reinsert the axle bolt and tap with a rubber mallet or small sledge hammer. And yes, I did bend the dust shield at that crazy angle but don't recall why.
5. REMOVE HUB
Reconnect Ball Joint (without nut)
Extract Hub with puller Hydraulic Puller. I used a 24" Pipe placed through hub and butting against subframe for the Puller's piston to press against with the jaws grabbing the hub flange.
NOTES-1: This extraction method was not originally intended. My plan was to attach the Hydraulic Puller on the backside of the steering knuckle and push the hub out from the back. There was not, however, enough clearance in the wheel well for the tool to fit. But this method worked just fine and was more direct. I did, however, waste about 90 minutes devising it when Plan A proved unworkable. NOTES-2: Removing the snap ring/Circlip took a while, perhaps because my snap ring plier's prongs were too narrow(?) for such a large, stiff circlip. Spraying and wiping with acetone helped a lot by degreasing and drying the ring. NOTES-3: The axle boot was not just torn; it was separated and the inner joint slid cheerfully out of its "can," so I removed. You can see the dark cavern in the hub extraction clip. I was lucky that day; the inner joint slid through the strut without fuss. When I did the same thing when I replaced the axle a few days later, three of the six ball bearings fell out.
Hub Out. I may be one of the ten people on the planet who pulled a hub like this without destroying the bearing.
Clean/Degrease Circlip/Snap Ring to make it easier to remove
6. REMOVE OLD BEARING & INSERT NEW
Press Out Bearing (101mm Sleeve Front; 81mm Drift Back)
Clean & Lube Steering Knuckle Bore
Position New Bearing and Press In. (83mm Drift Front. 101mm Cap Back) INSERT NEW SNAP RING
It is critically important that you insert a new snap ring before proceeding. Write it down 10 times and perhaps even tape the new snap rig to your fender, so you cannot miss it. If you start to insert the hub without it, you will not be able to back it out without destroying the new bearing. (Ask me how I know.) I would strongly suggest having a second bearing standing by, as I did. If you don’t need it, just return it for a refund.
New Circlip In
7. INSERT NEW HUB
Lube Bearing & Hub. CAREFULLY Position Hub & Press In 955-17 (77mm) Inner Race Support Drift on Back;
Any snug-fitting Ram on Front
NOTES: It is even more critically important to position the hub perfectly straight before inserting it. Secure it with the ram/receiver as shown, using just enough hand tightening of the nut to hold it in place. Then rotate it. If is skewed or wobbles, straighten it until it rotates straight and true. Then you can hand tighten a little more and check again any misalignment. If all is good, begin cranking the nut with your socket wrench to drive the hub in.
Support Inner Race on back of bearing when pressing in new hub
** You MUST support the inner race on that back of the of the bearing with a drift of the same size or slightly larger. If you do not, and press in the hub in without one, you will destroy the new bearing.**
Unfortunately the new bearing and hub did not solve my root problem: A "whump-whump-whump" heard (and felt) at lower speeds. The faulty bearing certainly amplified it; but was not the cause.
Either the whump is coming from the passenger side; The tie rods/alignment is causing it somehow; or, most likely, the axle is bad, which is infuriating since it is a barely two years old GKN Loebro that cost me $2,000 to install (left and right) at an MB-specializing shop. (Then again, I did not see the box it came it so it could very well be substituted junk.) Also, the passenger side was replaced a year ago under warranty, for the same type of boot tear.
* The whump is from the tires. I have some great Continental Extreme Contact DWS rubber on the front, which were destroyed by the worn tie rods -- in a year!
* After replacing the driver side GKN axle with a Cardone remanufactured one, which is behaving very nicely I should add, the heavy vibration I endured for the past two years with the GKN axle, is gone. It was a problem from the day it was installed and I honestly do not know why that brand is so hyped. Even I bought into it, based on what I read online, but never again.
It's twin on passenger side also vibrates but not quite as strongly as the driver side did. That boot is also torn and I will be replacing it with a genuine MB (about $300 at dealership) as soon as I settle on the best removal method. Removing the left axle was easy: I positioned a 6-inch, 1/2" diameter pipe behind the inner joint housing and three or four taps with a small sledgehammer knocked it right out. The right side won't that simple from behind; but there is plenty of space in front (I can literally reach in and wrap my hand around the inner housing), which it where I will be focused.
Last edited by ericsilver; Sep 14, 2022 at 09:40 AM.
Reason: Corrected pipe diameter from 3/8 to 1/2 inch
GENERAL TOOLS (used for)
32mm/Socket (FreeTec Bearing Kit Nut)
27mm Socket (Axle Bolt)
27mm Wrench (FreeTec Bearing Kit Bolt)
21mm Socket (Caliper Bracket Bolts)
22mm Ratcheting Wrench (Tie Rod Nut)
21mm Ratcheting Wrench (Ball Joint Nut)
19mm Socket (Ball Joint Remover Tool Bolt)
17mm Socket (Lug Bolts)
5mm Allen/Hex Wrench(es) (To secure Ball Joint when re-tightening nut)
E10 Torx Socket (ABS Sensor Bracket Bolts)
E10 Torx Box Wrench (Dust Shield Bolts)
T30 Torx Socket (Rotor Bolt)
Breaker Bar (If you are not using an Impact Driver)
Torque Wrench (For tightening bolts Properly on Reassembly)
Snap Ring Pliers (To remove & insert bearing snap ring/circlip)
Ball Joint Removal Tool (To detach Tie Rd and Ball Joint)
Rubber Mallet, Small Sledgehammer (To tap on ball joint removal tool to speed process)
Wheel Chocks, Floor Jack (To secure and lift car)
Grease; Liquimoly LM-48 (Bearing Kit threads; Hub & Bearing insertion)
Wire Brush/Wheel (De-Rusting & De-Griming rusty/grimy parts)
Gloves, Microfiber Cloths (General Cleanup)
Brake Parts Cleaner, Acetone (General Cleanup)
ESSENTIAL MEASUREMENTS * 955 prefix items are from the FreeTek kit.
Wheel Bearing: 49mm ID. 88mm OD. 46mm Length
Bearing Removal | Receiver Rams: 955-18 (81mm) Front | 101mm + Plate Back
Bearing Insertion | Receiver Ram: 955-19 (83mm) Front | 101mm Plate, flat side on knuckle, Back
Hub Insertion | Support Ram: Any Fit Front | 955-17 (77mm) Inner Race Support
Last edited by ericsilver; Sep 15, 2022 at 09:29 PM.
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