How to change the front shocks and sway bar links in Mercedes w140 S-Class

Reading Time: 8 minutes

Changing out worn shocks might be most effective and cheapest fix that can transform the ride handling of your car for the better. My S600 had very noticeable up and down wobbling when driving over bumps and a quite large body roll making in tight corners. It was becoming a bit boat like there at the end. The S600 is a very heavy car and needs good handling when going fast. A flatter ride in corners also makes for a more comfortable drive overall, so your passengers don’t wake up from their naps.

Changing the shocks will reduce wear on other more expensive suspension components like bushings and tires, while overly worn might damage the suspension. Changing the shocks is in your interest to be an economical DIYer.

The front suspension uses normal a McPherson setup with separated gas shocks detached from the springs and can easily be removed. The rear suspension on the other hand uses the more complicated SLS leveling suspension setup and don’t use shocks at all. Instead it uses hydraulic rams along with pressure spheres. More effort and money is needed when doing maintenance on the rear suspension than the front. The SLS however normally lasts a lot longer if you remember to change the fluid once in a while.

When changing the shocks you should also use the opportunity to inspect/change some other wear items easily accessible in the front suspension. This could be sway bar links or the brake rotors and pads. The sway bar links wear down faster than the other suspension components due to their tiny ball joints and should be replaced whenever cracks appear in the sleeves or any slack starts to be noticeable. Worn sway bar links can make annoying sounds for you and your passengers. We all know expensive cars are known for being the most squeaky cars around, let’s change that!

Preparation

You should expect to use around half day to a day on this job, depending on your skill set, the amount of rusty bolts and your tools at disposal. It’s something you can do easily on a weekend. When doing the job I was even under time pressure since I had to catch a flight the same day. I managed to catch the flight and get the job.

If you want to bundle more front suspension jobs while doing the shocks, I recommend removing the front wheels and inspect the suspension such as the sway bar links, brake pads and rotors as well as the tie rods. Any more advanced jobs than that you will will require a lot more time invested so be sure to plan accordingly. Usually large front end jobs require a re-alignment of the suspension, but is not required here.

Parts needed (as described in the article):

  • 2x front shocks. I recommend premium brands such as Bilstein or Meyle
  • 1x Left front sway bar link
  • 1x Right front sway bar link

Tools needed:

I ended up using quite a tool collection because of rusted bolts on the sway bar links, but this might not be the case for you. I think this collection of tools goes into most home car mechanics tool box, but there might be a couple of them you should consider getting. Always better to be prepared than sitting there stuck without finishing the job.

  • Jack and 2 jack stands
  • Socket set
  • Long breaker bar
  • A set of long spanners
  • High quality hex sockets
  • Torque wrench
  • Hammer
  • Rubber/plastic hammer
  • Pin punch driver
  • Locking pliers
  • Long Hex keys
  • Propane blow torch (super handy when things are stuck)
  • XZN (12-spline) sockets (super handy when Hex nut gets rounded off)
  • Blue thread lock (for brake caliper bolts)
XZN socket set
This is how XZN Sockets looks like. They are always a savior when hex bolts gets rounded off.

Procedure

Start by raising the front of the car and remember to use the E-brake together with wheel stops. Place the front on jack stands. I also like to keep the jack in the up position as redundancy on the side I’m working with. You can lift the w140 with the jack on the rubber jacking pad and place the jack stands more towards the center of the car under the sub frame.

Jacking up a Mercedes w140
Jacking up the w140 with a garage jack and jack stands. Notice the rubber pad location is used with the jack and the jack stands are placed under the sub frame. Always use some padding between the car body with the jack and the jack stands, such as hard rubber or some wood to protect the under body from rust.

The shocks can be removed when the calipers are in place, but to remove the sway bar links, both the calipers and the brake rotors need to be removed to access it. I will first describe how to replace the shocks since it is a much easier job. Then I will describe how to replace the sway bar links.

Shocks

Start by removing the lower bolt. Use a long breaker bar and a large spanner to break the bolt loose. Then move to a ratchet to get the nut off. Use the jack to lift the lower suspension arm a little bit to relieve some tension in the bolt through the bracket hole. Then use a punch to smack out the bolt with a hammer. Be careful if the bolt catches too much, then try to relieve more pressure before continuing. Most shocks do not come with replacements for the lower bolt and nut, so try keeping these in good shape.

Removing lower bolt on damper
Remove the lower bolt on the damper.

When the bolt is loose, open the hood and locate the top nut. The top part of the damper can look different from each other. You have to keep the strut bar still with a hex socket or flat pliers while using a spanner to unbolt it. There exists a special tool to do this with a socket, but is frankly unnecessary except if you’re addicted to tools. This locking nut always comes with a replacement nut and you should throw away the old one. When the locking nut is off you can easily remove the old damper.

Location of top part of damper under the hood
Location of top part of the damper. This old damper uses a hex setup for keeping the damper still while loosening the locking nut.

Before installing the new damper, push it completely down a few times to relieve tension. The installation orientation has no influence if the brand does not specify it. Start by installing it with the top part and the top locking nut. When installing the new damper you must take of not letting the damper shaft rotate while turning the locking nut. Keep it secured while fastening the locking nut. This is to reduce the risk of breaking the internal seal of the damper so it will start leaking. The nut does not need to be extremely tight, but do tighten it until you feel it is secure. It is very important to make a re-tight after the car is on the ground. I will remind you of this again shortly.

Now you will probably notice that the new damper is quite shorter than the old one when you took it out. You therefore have to compress the spring by jacking up the lower suspension arm until you can align up the bolt hole. This might be a bit tricky and use a hammer to punch the bolt through since it is nearly impossible to align them up 100%. Again take care of not ruining the threads on the bolt. The lower bolt and nut should be torqued to 80Nm.

Front shocks w140
Old Vs New shocks. Notice the old one even leaks oil!

Front sway bar links

Now on to the more fun part where you can expect to meet more of a challenge. First you need to turn the wheel you’re working on all the way out to get access on the backside. Start by removing the caliper, it is held by two bolts. You may require some force to break them loose. Prepare some method too hook the calipers up in the spring to relieve tension on the flexible brake hoses. Never let them hang freely. I used long zip ties here and I could just to cut it off when done. But a simple S-shaped hook would have been even easier!

Front suspension and caliper
Turn the wheel out completely before starting.

The caliper might be difficult to get off if the brake rotor has a lip on the edge. Use a pry bar or the back side of a hammer to press in the outer brake pad by using the rotor for leverage. Be careful not to damage the pad material. When the caliper is loose, secure it up onto the spring.

Location sway bar link w140
Location of sway bar link. Notice only one accessible bolt. The other one is behind the disk rotor.
Brake caliper w140 removed and hanging
The brake caliper is remove and secured in a zip tie from the spring to relieve tension in the flexible brake hose and brake caliper sensor.

When the brake caliper is loosened you can start remove the break disk rotor. It is secured by a tiny hex nut, but you might find this lost or broken. Mine was broken off on the right side, but the left one was fine. Loosen the nut with a hex socket. If the brake rotor is sticking to the hub, try hammering gently on it with a plastic hammer. If it does not pop off, it can be quite frozen due to rust and you’ll need heat to loosen it. Ignite up your blow torch and heat the area just around the hub. This should expand the rotor just enough so it will pop off with a light hammer blow. Over heating the hub might make the hub grease melt and run out, so be careful with the heat.

Brake rotor locking nut w140
Brake rotor locking nut with hex. This might have broken off already.

Now it’s the time to locate the outer sway bar link nut. Cross your fingers for no rust. It is located right under the brake rotor. The locking mechanism is not the best engineering, since you’ll need either a special tool or trying to combine a socket with some magic tricks. I used a socket, secured it with locking pliers and then used a hex key sticking through it. After some fiddling I managed to get the nut off. You can usually loosen the bolt the first few turns by using just the socket normally.

The upper nut should be the easier of the two to get off, since the lower one usually gets all the rust and is easier to round off the hex bolt head. Soak it thoroughly with rust penetration fluid and let it work for 15 minutes. Then use a hammer and whack that nut good a couple of times.

Removing front sway bar link nut w140
Removing the lower sway bar link nut. Cross your fingers that the hex will not round out. I only got a 50% success rate.

I got lucky with one side, but the other side I had to drive in an over sized XZN socket with a hammer so it’s surely stuck in there. Then I could get enough torque to loosen the rusted nut. This will obviously destroy the part, but it’s thrown out anyway. Unfortunately I did not get any pictures of this process since I was struggling a bit and running out of time.

Broken sway bar link sleeve
The sleeve was broken on the sway bar link. This does not take long until squeaking starts!

Now you should be able to remove the sway bar link. Go fetch the one that fits depending on the side you are working (hopefully you order the correct ones). Fit the top side first, then you move on to the lower side. It can a be a bit tricky to fit the lower side onto the sway bar again. Get a long bar or a long spanner and wedge it between the spring to get leverage to push down on the sway bar.

Use leverage to fit the sway bar link to the sway bar
Use leverage to fit the sway bar link to the sway bar.

It is not necessary to tighten the sway bar links very hard, just snug with enough force so they sit on. Remember these will probably rust tight faster than you can say cheese and the hex bolts will round off again.

old vs new sway bar links
Old vs New Sway bar links.

Caution: Before assembling the rotors, make sure you brush off any old rust off the hub face and the inside of the rotor. This is to prevent rumbling while braking and that the rotor sits on straight! You can use a steel brush and a rough pad to do this. Also brush off any surface rust on the front side of the rotor where it meets the wheel.

The front caliper bolts need a layer of blue thread locker on them since there are no shims or similar. Use 115Nm torque when tightening the caliper bolts.

It can be a bit tricky to mount the wheel if the little rotor locking nut is missing, so a replacement might come in handy here. Otherwise you have to align the hub with the rotor first and then with the wheel when sticking in the bolts.

Now I hope you will take on this task without paying stupid amounts of hours for mechanics to figure this out at a workshop. Go do it yourself!

Cheers, Robs out!

Thinking of w123 – Reputation of a classic

Reading Time: 4 minutes

Currently we think of the Mercedes-Benz w123 as the perfect Mercedes model which is pretty much a flawless classic. It is a car that resides in the super league of renown young classic cars. It is true they outlasted most other cars from that era and have a reputation for “superior” build quality and “reliability”. The w123 has indeed a large place in many people’s heart and often bring about memories and stories when nice examples roll by on the street. However the cult status of the w123 has maybe become a little skewered and starting negative discussions of the model is frowned upon in quite ideological ways. In hindsight this classic’s reputation might have become a little biased, as with most renowned classics (read: Ferrari).

Don’t worry I’m not trying to discredit the w123, but trying to convey a more realistic perspective of the model as a car looking away from the icon status. As any car or man-made object, the w123 is not perfect and comes with its quarks and weird engineering.

I was looking through an old review from 1977 of the 280E in Motor Sport Magazine written when the w123 was brand new. This is the perfect time to look into an unbiased opinion for the times and comparison to other cars at the market. If you want to read the full article, it can be found at https://www.motorsportmagazine.com/archive/article/march-1977/37/mercedes-280e-w123

I’ll give some of the highlights opinion from the review under with my own comments on the matter:

Complaints

Complaint 1: One complaint is that the car is too expensive for the time, you could get more luxury and more performance in a Jaguar for less money. Also the extra equipment is expensive and 280 base model without electrical windows or sunroof starts at £8495 which is roughly £52700 in today’s money. Quite a lot!
Comment: This makes sense in 1977, but as time has shown, the Jaguar had many issues especially with QC and the electrical system. Mercedes is a better built car overall, but is not as sporty with smaller (more boring?) engines and less equipment in general. In hindsight when you look at how long many of these cars have lasted, maybe it was not so expensive after all?

Complaint 2: Another complaint in the article is the low power of the 280 engine (remember this early version had only 177hp compared tot he 186hp of later models) and the author misses a bit the V8 power for this top w123 model which only clocks in 0-100km/h in 10s. The kick down is pointed out to be bit slow and the author recommends to keep in S when overtaking. Fuel efficiency was also not the best at its time where the author also points out that the engine is quite thirsty with 16-18mpg (12-14 L/100km).
Comment: I quite can understand the lack of performance when compared to cheaper Jaguars and BMWs at the time, but Mercedes never wanted this to be a sports car. That was reserved to the SL and top of the line S-class. The upgrades to the M110 engine in 1981 did increased its power and probably lowered fuel consumption a bit. I run mine 280CE from 1984 usually around 10 L/100km. The kick down is indeed a bit slow to react, much faster to manually stick in S with the auto transmission.

Complaint 3: Plain interior and cheap plastic is used. The author points out the spartan interior, sparse use of real wood and really nasty cheap plastic used for the side door pockets. Also the boot has a cheap looking tool kit compared to a BMW.
Comment: The interior is very plain, but has kept the styling somehow timeless and looks nice too this day. I personally really enjoy the large air vents int the dash. The cheap looking plastic used on the doors rarely breaks. This is another story for the notorious glove compartment-lid. It always breaks and is definitely cheap plastic. The author credits the seats for being quite firm and good, but I think the seat comfort can be quite uncomfortable on long rides. I wonder how other cars were at this time?

Complaint 4: Road and engine noise. The complaint is that Jaguars are superior in this department. Especially the wind noise from the large and flat non-aerodynamic mirrors. Poor engine noise insulation is pointed out too.
Comment: Agreed, quite some wind noise especially in the coupe version. The wheel sills can clearly be heard on gravel roads. Also the engine valve tick is clearly audible in to the passenger compartment. They should have put a bit more sound proofing, but it does save weight in the end.

Recognition

Recognition 1: Rev happy engine. The straight six is very rev happy going up to 6500 before the red-line. The author also points out the engine has superior smoothness to V8s at the time.
Comment: A bit contradiction to the first complaint, but I see the point since you need to get the revs up since it lacks the low end power of a V8. I think the M110 feels fast and can keep up with modern traffic pain free. The straight inline 6s have perfect balance and are superior to any other engine configuration. It’s one among the economic reasons why Mercedes has reintroduced them in their new cars and is planning to discontinue V6 production.

Recognition 2: Brilliant suspension and road handling. The w123 utilizes the latest technology from the S-class at a cheaper standpoint. There is little body roll and the ride feels more comfortable than harsh BMWs while still being agile. Also the car has wet weather stability than the S-class. Super maneuverability with the recirculating-ball servo. Also impeccable braking with large disk breaks on all four wheels.
Comment: This I totally agree with! You can toss the w123 around mountainous roads at full speed without being daunted, there is a clear indication when you are pushing the limit with the classic wheel whine without the car going sideways. There is a reason why there were so many w123 Taxis going around back then, they can easily turn on a dime in the city. I was not aware that the ride was better than the S-class (w116) in wet. KUDOS!
NOTE: I should point out that you can get two different dampers to w123: Comfort and Firm. I will highly recommend the latter due to less body roll. I also recommend to go for the Bilstein dampers!

Recognition 3: Business as usual with effortless automatic door locks, boot and filler cap. Simple control of the functions such as lights, wipers and mirror adjustment. No fuzz about. The headlights can be adjusted with a single knob.
Comment: This makes Mercedes so easy to operate so you can focus on the driving without getting lost trying to find the door knobs. It makes the car a bit spartan and have a modern compared to other classic cars. Many do indeed enjoying the weird features and quarks of old Porsche and Italian classics.

There is much more details in the magazine. I hope this gives some more nuances of a classic car such as the w123. Happy reading.

Cheers, Robs out!

1990 Mercedes 230TE w124 added to the fleet

Reading Time: 2 minutes

You might ask how can you go from 6.0L V12 to a 2.3L dull station wagon? Good question! This car will be a workhorse car for all year use, hauling trailers and transporting stuff.

It’s a bit scruffy looking when you get up close and have the impression of standing outside too long without a decent polish.

Lets start with the pros:

  • It’s a Sportline version – Oh yes Sport with 132 HP
  • It has ADS (automatic differential lock), so usable in the Norwegian winter
  • Mechanically the car runs fine, engine and breaks etc.
  • No significant rust to speak of
  • The black metallic color is quite nice and more easy to sell than for example green
  • No electric windows, so less things to break
  • AC seems to work OK
  • It has an electric sunroof that can be opened and closed
  • Comes with a DAB radio – FM is obsolete in Norway
  • It is face lift 1 – looks better than the 85 original and does not have the rust paint problems of face lift 2

And then to the negatives:

  • No electric windows – I need to please my luxurious ego
  • The sunroof tilting function is not really working at the moment – not the end of the world
  • There is a leak from the hose of the rear window washer reservoir – needs to be fixed
  • The cables and vacuum hose of the right front door have been cut
  • The driver seat is quite worn and needs a new sitting pad
  • Door check straps needs to be changed
  • Switch for the rear wiper needs to be replaced
  • Front plastic bumper has cracks – needs replacement
  • Fabric interior, where is the luxury?
  • Ugly unoriginal rims – Needs to be changed for sure. Good thing I have some original w126 rims that can be bolter straight on
  • Worn winter tires
  • The key for the door and ignition are different

So is this a lemon car? Not really, but not a show car either. It has some issues and the age shows. The price also reflected that. The mileage is not low either at above 350.000 km, so at least its driven in properly.

Many of will might ask how I can drive 3 cars simultaneously around. Well obviously I don’t. Mostly my father will use it as his daily driver. I can though see some nice articles come out of it. And having the opportunity to drive a classic w124 can be fun!

This is just a quick teaser. A full review will be posted at the end of the summer! So stay tuned.

Cheers, Robs out

How to adjust the valves in the M110 engine – Part 1.5

Part 1.5 of valve adjustment of Mercedes M110 Engine. Stuck valve adjusting nuts require a DOHC valve compressor tool, which is hard to obtain for this engine.

Reading Time: 3 minutes

Christmas came early..

Notice the part 1.5 nonsense, what is that all about you might think to yourself? Have I gotten mad over New Year’s? It’s rather just because of the half usefulness of this article. Since you readers are mostly DIY mechanics and Mercedes enthusiasts, I want to convey a story of the journey toward valve adjustments of such an old engine. In this way we share the ups and downs, the challenges and successes, and maybe learn something on the way.

Remember in Part 1 https://mercbenz123.com/posts/valve-adjustment-m110-engine-part1/ where I ended with 4 different options listed with increasing price and pain? Well since Christmas came early (2018) I ended up somewhere with a solution in the middle of option 1 and 2. After trawling the used car tool market, mostly ebay, I managed to find a seller which sold a late 70s vintage Mercedes valve compressor kit for DOHC engines. Although not specific to the M110 engine it is close enough, that with a few modifications it might just work. Let me just say it was the most expensive vintage tool I have ever bought. Lets hope it can come to good use!

Mercedes late 70s DOHC valve spring compressor tool.
Mercedes late 70s DOHC Valve spring compressor tool for several engine models.
M110 DOHC valve compressor tool
This is the M110 engine specific tool which is out of production. Looks similar right? Although not the same, I’m sure we can adjust the obtained one to do the same job with some modifications.

I almost did not buy due to the high asking bidding price, but after the deadline was reached it was still for sale. I decided to go for it as a Christmas present for myself and bid on the tool for a little less. Chance happened that we compromised and reached a fast deal. Two weeks before Christmas it landed in the mail box.

Valve spring compressors
It came with 4 different valve compressors. I might use the second from the left with some modifications.

It comes with 4 different valve compressors, although I’m not sure if any of them fit right out of the box. I might need to adjust one of them. The lever bar has a simple screw on attachment to swap out the compressor ends. The Hook is not attached, but can be placed in different grooves. I might also need to adjust the arrangement here as well.

Under I have tried to visualize how the tool is operated on the valve head. The idea is to compress the valve just enough so I can slide off the rocker arm. Since the valve clearance adjusting nuts are so tight we need a socket over the nut which is naturally blocked by the rocker arm.

I tried to overlay this tool over the valve and camshaft arrangement in the M110 engine. Here The sizes are not 1:1 but illustrates the point. Already here we can see that there might be clearance issues between the engine wall and the compressor. Also the circular edge for the compressor surface has to be cut, so it can slide onto the valve top under the rocker arm.

I’m excited to see how the tool can be used in real life, but since it’s winter and the car is hidden away, this have to wait until spring. I’ll keep you posted on the progress in this journey as soon as possible.

Cheers! Robs out


Other news: I tried to sell the S600 in the autumn, but was unfortunately little interest which is hard to believe when regarding the current economics and huge interest in classic cars. Norway is a weird country.. The car is in mint condition with low mileage so I will not give it away for free. I will instead keep it and enjoy it, make some good articles about the w140 and let time mature it into a true classic.