W124 Rear Control Arm Links
 

Anyone here replaced their rear suspension links? How big a job is it for a DIY? Pretty sure all my links need replaced as the rubber joints are fairly rotted away on most of them. Thanks for your replies

Done it. Dropped the entire rear subframe and replaced everything all in one shot. Knowing what I learned from that experience I would say. If I were looking at replacing just the links I would just do them one at a time underneath the car.

Yeah, I haven't looked too close at the sub frame mounts but it's likely they aren't in too good of shape. I do have access to a lift so that would make it a bit easier getting to the nuts and bolts. I've seen a video or two of the full sub frame mounts rubber replacement and it looks like a big job!

Did you use Mercedes parts or after market?

I've done a similar job on my W201 - the hardest part was trying to get the rear alignment sorted afterwards - I ran out of time and had to pay someone to do it (oh the shame!)

I used a combination of TRW and Lemforder parts if I remember correctly

I ran across these on fleabay but they may be/probably are junk...


If possible I'd like to do this over the winter but will see how time goes...


https://www.ebay.com/itm/New-Control-Arm-Ball-Joint-Suspension-Kit-8-PC-Rear-Driver-Passenger-Side/281317614709?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

Replacing all the bones with the suspension in place is like building a ship in the bottle. Dropping the rear subframe makes access open and easy. It allows you to use power tools or torches on rusty fasteners without collateral damage.

I used mostly lemforder parts for everything but I did get a kit of the rear suspension arms from meyle. I have no complaints about quality of any of those.
Dropping the rear subframe is not that difficult with a good jack and an extra set of hands.

If I remember correctly years ago each strut was about 30 euros a pop so 80 USD for the set mmmm...


...special price

I did it too on my W201. Dropped the subframe as well. While I was in there, I refurbished just about everything in that area. Stripped and painted subframe, new subframe bushings, all new arms, cleaned spindles, new bearings, e-brake cables, brake lines, diff seals, etc. I don't think I would've been able to remove one link with all that rust. Even with the subframe off the car, I had to cut stuff and use BFH's. Now with everything cleaned, changing just one link is easy. But on an older car that saw salt for 25 years, just drop everything...
I also had a very hard time separating one bushing from the steel spigot in the underbody. I had to completely destroy the bushing to remove it.

"If I remember correctly years ago each strut was about 30 euros a pop so 80 USD for the set mmmm..."

If it's a wagon, the struts are not going to be $80 and it's going to be a lot more involved to drop the rear sub frame because of the SLS. Also, the rear wheel bearings in the wagons are PITA to get out because the bearing rollers are a larger diameter than the snap ring, so you have to pull the axle out of both inner races. There is no way to pull them with a slide hammer, ask me how I know.

It's actually for my 260E sedan... Thanks for your reply!

I did this job on my w201 and it was surprisingly very simple. I didn't remove the subframe and used all regular hand tools. You will need a 12 mm (or 10 mm, I forget which size) xzn triple square for the eccentric bolt. Also, get a 30 mm 12 point socket (the one to remove the axle nut). It just so happens that the 30 mm socket fits perfectly on the race of the rear control arm bushing and you can hammer it out right through the control arm and put the new one in without any damage to the bushing. A good tip to use is to get a small quart of white paint/primer and use it on all the bolts/nuts. I have made it a habit to use the white paint and starting from the center on a bolt, I will draw either a horizontal or vertical line extending to the surface of the vehicle (sorta like making a notch) to ensure that everything goes back exactly how it was. This will help with the misalignment issue. When torquing everything down, the wheel should be on the ground, but for this part I usually jack up from under the control arm to get the wheel where it would level if it were on the ground and I would torque everything to spec that way then I would put the wheel back on and take it for a test drive. Good luck.

W124 Rear Control Arm Links
 

Would you have a recommendation for a 'sequence-of-removal' of the various five links? IOW, should one remove say the upper-most link first, then another and so on....

Thanks for the tips!

Dale

For easier work and not dropping subframe, u can just unbolt subframe front bushings. Then subframe drops 2-4 inches.

Rear suspension removal
 

Start by jacking up the car and mark the nuts/bolts as I described. Then remove the 30mm axle nut (this is necessary in order to remove the rear control arm). Remove rear caliper from wheel carrier and support it out of the way, remove the rotor, and rear parking brakes. Undo, the 13 mm bolt that holds the brake cable to the wheel carrier. Next, break loose all the bolts connected to the rear wheel carrier (that way they are already loose and you won't need leverage later to get them off). Then compress rear spring and undo bolt on inside control arm, shock bolt, outside control arm, and the bolt for the sway bar support link that is connected to the control arm. Now you should be able to remove the entire lower control arm. Now you can replace the first bushing in the control arm. Next, remove the wheel carrier by undoing the loosened bolts and use a jack stand to support the rear axle end. At this point you can now remove and replace each link one by one and be sure to pay attention to the markings you made. When you are done with the links, use that 30 mm socket to hammer out the bushing on the wheel carrier.

Would the driveshaft need to be disconnected at the diff?



I will be referring back to this thread for sure when I get into this project. Your input will prove to be very valuable! Thanks...

U don't have to disconnect driveshaft. I did without loosening subframe. Those two upper links body side bolts are pain in the ass, others are easy. I had to cut those.

Just discovered this last evening when I had the wheels up off the ground. YIKES! If I had any idea it was THIS bad, I'd probably not taken it on a 1000 mile trip to ATL last week....

YouTube video

Well, I now have in my hands the control arms repair kit and am trying to strategize how best to tackle the job. I'm looking for guidance from those who have actually done this job and can comment from experience whether it is reasonably doable to R&R one or two of these arms (to each side) due to the time I have available to work on it. I have a garage/shop to work in where it will be done without a lift other than the standard floor lift and jack stands/concrete blocks. I can't simply take it apart and leave it there for days on end. As slow as I work, there's no way I see this being a 'start-to-finish-without-coming-up-for-air' project so I'm trying to figure the best approach.


This afternoon, I may take the time to get under there and apply more penetrating solution to all the connections - which I have done twice in the past 10 days. Might go ahead and try loosening some of them to see how easy/difficult they are going to be. All in all I'm looking for more good advice (and encouragement!) such as that from lsmalley and others! :)


Dale

Scratching my head here [emoji2957]

How to get the 'keeper' (cover) off the 30mm hub nut? Is it supposed to simply 'pull' off?

Dale

https://uploads.tapatalk-cdn.com/201...181a3107a3.jpg

Remove the 30 mm nut by bending out the small tab and then rotate nut CCW. Be sure to set the e-brake and if you have a jack stand try setting the ceter of the hub lip right on the jack stand so when you loosen the nut, the stand prevents the wheel carrier from moving up and down. Remove the 6 bolts mounting axle to diff, drop the axle-to-diff end of the shaft, then push axle out.

Thanks for your help lsmalley! I will indeed take your advice and twist that bad boy off there [emoji854]. I had already put things back together before I got your reply but that's ok!

So is that tab part of the actual nut or is it a cover for the nut? Thanks for clarifying.

Dale

It's part of the nut. It's just a break away tab

W124 Rear Control Arm Links
 

Somebody care to draw or take a picture explaining this procedure? Jeeesh, I'm a thick head at times [emoji58]

Thanks
Dale

EDIT: Is this at all the idea?

https://uploads.tapatalk-cdn.com/201...55a9f79cf0.jpg

Mark like this before you take out any bolts. Then when you are putting bolts back, the mark will line up exactly how it was. This will be most beneficial when dealing with eccentric bolts. Yes, your picture above is correct.

W124 Rear Control Arm Links
 

Hahahaha, Got it! So all the penetrating goop I've been shooting on them for the past few weeks will need to be sorta dried up so the paint will stick [emoji37]

I've started digging into this job this afternoon so I'll keep pecking away at it over the coming days (not weeks, hopefully) until done. I'll likely be back from time to time asking for guidance [emoji41]

Dale

I found it very helpful to use a 1/2 inch impact gun with about 125psi of air to spin that axle nut off.

Well, if I were to do that I'd have to go buy or rent a compressor and gun! If I can find one to rent, I might just do that. Otherwise I'm going to have to use breaker bar and a long pipe for leverage.

Thanks for the suggestion [emoji41]

Dale

Well, part of my issue was that I went a head and drop the sub frame with the axles and differential all attached. When I went to break free the axle nuts I didn’t have a good handle anywhere to back it up. If you are working on it still mostly put together usually use the brakes or put it in gear and give it hell with the long bar.

As for your debating on whether or not to drop the sub frame or work on the control arms in place... depends on how much you are replacing. Obviously, if you are going to be replacing the sub frame mounts been the sub frame will have to drop. If you are just working on the control arms then you might be better off working on it with the sub frame in place. Yeah, you may have a little more difficulty gaining access to both sides of the fasteners on each end of the arms but it will probably be less work all together.

Ah yes, I can see that being a problem.


Another issue for me is 'do I want to do my half-shafts now or not'. I purchased the diff bushings because mine are shot. So, the shafts need to be removed from the diff (I think) in order to install these.


Dale

Yes, you will need full front and back access to the diff bushings to get them out and in. Probably beyond what could be accessible with out having the diff completely removed.

When I did mine those bushings where the first new part that was swapped into the striped subframe after I cleaned it and painted it getting it ready to go back together. It takes a bushing press tool to do it the easy way. I made one out of 2” black pipe, threaded rod and fittings.

Couple things:

To remove the stacked nut on the axle shaft without the benefit of an impact gun.

1) using a chisel and a hammer work the small staked portion of the 30 mm nut's collar out of the groove as best you can.

2) with rear jacked, blocked and on stands, the wheel/tire removed you can take a long pry bar or a section of rebar to counter hold the wheel hub from turning. Take a couple lug bolts and insert them into the respective holes in the hub. Now you can use the pry bar/rod inserted between the lug bolts and the hub center to brace the wheel hub from rotating. One end between the lugs and hub and the other end braced against the ground.

3) you'll need a 12 point 30 mm socket, the nut has a very short section that the socket interfaces with. This can make it easy for less than perfect interface between the nut and the tool. Most sockets have a rounded finish to their opening; in this case that rounded part will take up a bit of space when the socket is in place on the nut, thereby reducing the area of the socket that comes into actual contact with the nut. In the past I've taken a grinder to the socket and removed that rounded finished portion at the open end of the socket. That allows the socket to fit closer and more completely with its 30 mm 12 point interface area most completely on the shallow interface area of the axle nut.

4) Just before you tackle the axle nut use a propane or butane torch to heat the nut. It doesn't have to be red hot or even close but you should heat it top, bottom and sides to just a bit to hot to leave your finger on it. Temperature above 150 F will significantly soften and in turn loosen the blue threadlock that the axle nuts are treated with.

All that being done get your breaker bar and probably a section of black steel pipe as an extender, then while holding the socket straight and square on the axle nut on the braced wheel hub of the well blocked elevated rear you should be able to apply the pressure to unscrew the axle nut pretty easily once you break the initial bond free.

5) if you're planning on diff seals/bearings you'll need the diff dropped to get its back cover off in order to get access to the clips that secure the stub flanges the inboard axle ends bolt to.

Honestly if you're going that far and if you can somehow get a day or two with the car immobile I can't see how or why dropping the entire sub-frame isn't the best method. Only because once that's done you have infinately better access to every nut and bolt of the 10 bolts on each side you're going to be working on.

But everyone has his or her comfort level with that level of disassembly. Like R&R for the glow plugs, sometimes it's easier in the long run to remove the intake manifold to gain easier access than to spend much more time in multiples trying to work around things in order to get something accomplished. This is especially true when the R&R entails fooling around with things that can easily go wrong such as delicate parts or difficult parts like large strong suspension parts that might be 30 years in place.

You can get all the links replaced without disassembling the axle shaft from the diff, the axle stub usually pretty easy to drift out of the splined hub. If your determined to remove the axle from the diff I have found it easiest to do so when you can brace the hub and therefore the axle just like I've described for the axle nut removal. Brace the hub/axle, using a long extension you can reach into the axle/diff and after a thorough cleaning the bolt heads get that tool into the fastener and get it removed easier because the wheel hub/axle is counter-turn braced. You can usually reach at least one but maybe two of the axle/diff bolts before you have to unbrace-rotate-rebrace the hub/axle to get to the remaining of the six bolts connecting the axle and the hub. You have a later 124 so those six bolts might not be the original configuration XZM bolts and could be some variation of TORX head bolts that later 124 cars had originally.

If you disconnect the driveshaft at the diff mark the position of the drive shaft yoke to the diff yolk, keep track of the individual bolt/nut sets and where they where locked in relation to the yolks and the guibo. That way you can get everything back together the way it was. The 124 design can utilize a special heavier nut/s to help balance the drive shaft, if this part of the original installation you'll want to get all the parts and pieces back in the same place to avoid any potential mis-balance.

If you do work on the diff and need to drop it or pull it there won't be a better time to replace the two rear dif cover/sub-frame mounts and the single front diff mount. The front mount 8 mm Allen head bolt can be a bear and often rendered useless for reuse in the process. If you do drop the sub-frame of diff, get in behind the rear seat and unplug the ABS sensor wiring. Then you can pop the body seal, wiring and connector back through the hole and under the car. That avoids you having to remove the ABS sensor from the diff housing which can be a real bear sometimes, possibly resulting in damage to it in the process.

I've got a craftsman electric impact gun that I've used on this particular job in the past, and it got it done. I think Harbor Freight might have a ChiCom disposable version available. There should be some Sears Liquidation sale bargains available any day now as well!!!

The impact gun and a long extension is a very easy way to get the six axle/diff bolts removed as well, you don't have to get under the car, you can gain the access going in above the wheel carrier between the upper links.

W124 Rear Control Arm Links
 

@if6was9 - lots of useful info there! I'm probably going to go ahead and drop the sub frame. It's just been intimidating thinking about it but as I'm pecking away at it, I'm seeing how much easier it will be to access many of the connections - saying nothing about those rear diff bushings[emoji849]

Thanks!
Dale

I've actually got one of those HF electric impact guns and just didn't think it had enough butt! But now that I've read that you've used one for this job - I'll give 'er a try [emoji106]

Dale

Don't do it. HF will end up stripping your rear axle and then you'll need to replace the entire axle. I had to get axles from another member on the forum because one stripped and I could not get the collar nut torqued to spec and it ended up coming loose at some point and destroyed my rear wheel bearing. Use a breaker bar, 200 - 300 ft lbs isn't that hard to undo with a good breaker bar and some leverage....and I'm only 160 lbs and I did it with ease.

What part of the axle stripped? Are you referring to that 30mm axle nut? If that's what you're referring to, I'm not understanding why using a HF tool would be responsible. Just needing to have some clarity here [emoji846]

Dale

The threads on the axle stripped. My guess is the combination of vibration and turning must've caused the nut to jump a thread or something, I don't know, but I wouldn't do it again. Break the nut loose first, then try it. I definitely wouldn't use it to put the nut back on

W124 Rear Control Arm Links
 

So I've gotten started with this deal, a couple or few hours here, an hour there, so it's not going to be a fast one for me. I'm needing to remove my driver's side brake dust shield to replace it with a new one that I bought two years ago. Long story! But now is the time.

Does the hub need to come off in order to change iout the shield? Does the hub simply pull off? I think I recall several years ago when I put new half shafts in my 300D, the shaft pulled in toward the diff - then compressed to pull it from the diff. Any help will be welcome and appreciated if course [emoji851]

Dale

Unless you absolutely need to replace that dust shield and have all the proper tools and parts (i.e., another rear wheel bearing), then you are better off leaving that alone. In fact, I wouldn't even attempt it. I just replaced my rear wheel bearing not too long ago, and I had to have someone press it out for me. And even then it was sorta jury rigged to get it out. If I have to do the rear wheel bearing again, then I would end up spending the money on the MB special tool.

Crap! I was hoping I could do this while tearing into this rear end. I have a feeling that you know what you're talking about... Thanks

Dale

W124 Rear Control Arm Links
 

Question...

(Ref the attached pic) New arm on left with the hardware that was packaged with it - old arm on right with orig hrdwr as removed. New hardware has a triangular washer type disc - old one did not. Is it to replace the 'cupped' washer on the bolt head side of the old?

Thanks
Dalehttps://uploads.tapatalk-cdn.com/201...fac32b5be5.jpg

EDIT: Nevermind, it was easy to figure out since I had the printout of the FSM pages for this job...

This job is getting closer to finished. I just did the passenger side this afternoon so now I'll likely do the parking brakes, rotors, and calipers tomorrow. It wasn't nearly as bad a job as I was fearing, especially since I didn't drop the subframe. I will need to do the subframe bushings soon though..

Now, those pesky diff bushings, not looking forward to those too much. Anyone have words of wisdom on that job? The seals on the output shafts appear to be bad as well as the rear plate. Sure wish I could have replaced the dust shield [emoji37]

Dalehttps://uploads.tapatalk-cdn.com/201...1a0459c0d1.jpghttps://uploads.tapatalk-cdn.com/201...19b55489c8.jpghttps://uploads.tapatalk-cdn.com/201...66a2c8588d.jpg

Looking good, how did your project turn out? I know I loved the feel of my 190 when I dropped the subframe and did poly mounts and 8 new Meyle arms. It got rid of the axle hop and the terrible tracking at high speeds

It's still up in the air! Work and personal energy levels after working have slowed progress. I actually thought I'd mess around with trying to get those pesky wheel carrier bushings out this evening but I'm a bit whooped after work today [emoji58]

All the links have been replaced and torqued down to spec and have decided not to drop the SF at this time -saved for a summertime project perhaps!

Thanks for asking[emoji846]

Dale

ended up having to beat the Sheet out of those to get them out when i did mine. Heat helps. Don't be shy with the blue wrench

Yeah buddy, those puppies are tight! Ya know, I really didn't have a 'good look' at them (as I should have) before I removed the bolt/nut and set the carrier free from the LCA, and I took a map gas torch to it and the rubber was starting to burn of course. I THEN started looking at the bushing and I'm not 100% sure I actually needed to be replacing them! For whatever reason, I had ordered them along with all the control arms so I guess I'll carry on with putting them in.


I'm going to have to admit, I'm stumped trying to figure out what this "blue wrench" is you're referring to! Thanks for clearing that up for me :P


Dale

Nice looking 260E Dale! Looks pretty good especially being from Ohio.

Map Gas. You got it!

Thanks! It spent much of its life in the San Antonio TX area before I got it for years ago so it is still pretty dang solid and rust free. I try to get any road salts off it as soon as the roads dry up after we've had a snow event. This year, so far, it's actually not been driven in snow as it is up on jack stands [emoji854]

Dale