Changing the Exhaust pipes in the w123 280CE

There was this annoying hole in the exhaust from last summer. It was the thin sheet under front muffler that had cracked and I had it welded just before the MOT last year. Unfortunately the job was poorly done by the workshop. Another lesson learned on why we should fix our own cars…. The fix ended up costing almost as much as the new pipes, so that was also dumb. On the very day before this summers epic 3000 km road trip of crossing Norway I had to change the entire exhaust system. The pressure was on to get it finished before the trip!

The poorly welded exhaust only got noticeable few weeks before the upcoming road trip, but another car was planned to be used so there was no pressure initially. Then because of circumstances it was decided to use the 280CE after all and the exhaust leak needed to be addressed asap. I decided to swap out all the pipes since some rust was starting to appear in the pipe welds and its easier to just swap the whole thing at once.

I ordered the exhaust less than two weeks before from Germany and it arrived two days before the road trip was starting. Just in time. It only costed me 500$ which I think is a bargain for a classic car! The quality also seems very good as well.

Welded front muffler w123
Poorly welded front muffler. Now junk.

Stage 1 – Getting the car up in the air

You need some good space to wrestle with the large exhaust system under the car. I drove the front of the car up on ramps then lifted the back of the car on jack stands so the whole body was up in the air. I leave the tires on for extra safety and don’t lover the jack either. Also make sure to block the front wheels from rolling on the ramps. I’m a fan of redundancy and here I even placed a couple of jack stands in the front which is kind of unnecessary, but makes it feel somehow safer.

Car on jack stands
Car up in the air. Potentially dangerous and safety should be on your mind. Here I have redundancy by leaving the jack in place and using redundant jack stands. Not recommended to be under the car during an earthquake…

Stage 2 – Removing the old pipes

This is usually the most time consuming job involving rusted fasteners and wrestling with stuck pipes. I was planning to only change the pipes up to the down pipes, since the down pipes are in a really good condition compared to the rest of the exhaust. The issue then become separating the down pipes from the pipes underneath the car.

exhaust clamps
Front exhaust clamps

I started removing the clamps for the front pipes and loosening the system from the transmission mount. Then unhooking the four rubber donuts from the rear muffler. To avoid too much stress on the pipes I placed something under the rear muffler for it to rest on, in this case a tree stub.

rear muffler 280ce
Rear muffler resting on a wood stub

Then the issue with sliding off the exhaust system from the down pipes. They were extremely stuck and you’re not able to twist them since it’s a pair of dual pipes. I was first trying to push them out with putting my entire weight with my legs and kicking. Then I tried heating the outer pipes with a heater torch. After a while struggling with no success and them not moving at all I had to make a drastic decision. I needed to cut them out without damaging the inner down pipes. This would mean the old exhuast would be trash, but it’s old and not worth much anyway.

cutting the exhaust pipes
Cutting the exhaust pipes.

In order to get the old outer pipe off, it needs to be split and then removed. It would be impossible to try pushing them off otherwise. I started by cutting the pipes across a few centimeters before the mating point. Here I used an angle grinder with a thin cutting disk for about half the way, then a manual cutting saw blade for the rest. A bit tedious, but will get the job done. The best would be to use a hack saw which is much safer than an angle grinder and faster than the manual saw. However I don’t have one. Maybe now it’s a time to acquire one?

exhaust pipes cut
Pipes are cut and also a slit is made lengthwise with an angle grinder. Care is taken to not cut all the way through to th einner time.

After the pipes were separated I could remove the old exhaust system. The old stubs of the outer pipes are just as stuck and a slit have to be cut down the middle and care have to taken in order to not damage the inner tubes. The only tool for this is an angle grinder. Watch out for sparks in your face!

Split the pipes
Split the pipes with a sharp punch and drive it in with a hammer. Eventually the metal will split. Use ear protection since it tends to be very loud.

When there is a slit along the length of the pipe I could use a punch with a sharp end and drive it into the slit until it grew larger and eventually the pipe will split along its entire length. Then it was super easy to remove the outer pipe.

Splitting pipes with a punch
Splitting the pipes with a punch. Super easy!

I was surprised of how effective it was, and it was sour that I wasted so much time trying to free the pipes with different methods before I ended up doing this. I was also surprised to find that there was essentially no rust that was binding up the pipes, instead it looked like the metal had expanded into each other and exhaust coke had made this kind of glue between them. Now that the old exhaust was removed, I could mount the new system on.

Stage 3 – Fitting the new pipes

This was the fastest part of the job. It was basically lining up the three exhaust part components, putting on the clamps and tighten them. When the full length is assembled I could slide it under and mount it to the down pipes. Don’t forget to slide on the clamps before joining the exhaust pipes.

Hangers different from old system
Shape of hangers different from the old system.

I found having some help with the assembly part is useful due to the quite heavy and large part that needs to be aligned, but also doable alone if you plan all the moves ahead in time.

The exhaust kit came with four new rubber donut muffler hangers. These rubber hangers crack at an incredibly fast rate due to the heat of the exhaust and they rarely lasts more than 1-2 years before they break.

New exhaust system
New muffler being very shining, almost looks fake.

Stage 4 – Road trip

Luckily I managed to sort it out the evening before and could leave the next day.The road trip went fine and went without issues all the 3000 km. The tail pipes of the new exhaust have a slightly different shape and the heat reaches the rear bumper a bit more making a subtle bluish tint on the chrome which is quite cool.

280CE in Lofoten

I have the habit of doing jobs in hurry lately where I needed to travel shortly afterwards. Unfortunately this introduces a lot of stress and takes the joy out of fixings cars a bit. I need to plan better indeed.

Cheers, Robs out.

Thinking of w123 – Reputation of a classic

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!

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.

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.

AC Part 4: Changing the Expansion valve in w123

Changing the AC expansion valve

An old and defect expansion valve will decrease performance in your AC system. That can result in either the commonly too warm air, or in fact too cold air causing frost on the vents! The air can also alternate between these two modes. The more expensive consequence is that it can also wreak havoc on the AC compressor since coolant will always flow (unless the compressor has a shut-off clutch).

In the final part of this “AC 101” series we will look at changing the expansion valve. If you need to read upon how the expansion valve works in an AC system look at Air Condition Systems 101.

The Ac expansion valve is quite accessible under the passenger side dashboard, but you will need some large spanners to loosen the AC hoses.

Preparation

Before you do anything, make sure the AC system is completely emptied of refrigerant at a workshop. I repeat what I have written earlier in this series; The AC refrigerant is a highly volatile greenhouse gas. And if you have an old R12 system, the system might contain old freon gas which will deplete the ozone layer as well as being a volatile greenhouse gas.

So do that and then go shopping.

Parts:
  • New Expansion valve
  • New AC gaskets – You should change these to avoid leaks.
Tools:
  • Philips Screwdriver
  • Little flat screwdriver
  • Large open ended spanners

Procedure

Removal

Start by removing the passenger side lower dashboard cover. It is held in place with three screws at the top under some brittle plastic covers and a plastic screw on the lower right hand side. Remember when dealing with old interiors you have to take extreme care to not breaking any parts or loosing them. Replacement parts are long out of production by now and are not available except used ones (if you can find them) at often very high prices.

Passenger side dashboard ccover MB W123

Use a narrow and thin flat head screwdriver to carefully pry off the three small plastic covers.

Removing lower passenger dashboard cover MB w123

Then  unscrew the three philips screws on top and the lower right plastic screw. The left side and back side of the dash cover is held up by tabs in the floor and wall construction.

Removing lower dashboard cover w123
Weird plastic screw location

With the cover off. You can immediately locate the AC expansion valve. You should detach one end of the ventilation hose so you can access it. Detaching it from the left side is much easier and you don’t end up breaking stuff.

AC expansion valve w123
The Expansion Valve was covered in some very old foam that is disintegrating.

The expansion valve is covered by some foam that is long past its lifespan. Touch it and it disintegrates. So be prepared to get some styrofoam replacement (which you have to fabricate yourself). The only practical function of this foam is to protect the other plastic from the very cold valve.

Start by unscrewing the hoses, they might site quite hard and getting to them is a bit of a grind. Start by removing those who you find easiest and remove the other ones as you go.

AC expansion valve w123

Note the orientation of the old valve before removing.

AC expansion valve removed w123
AC expansion valve is removed

After the expansion valve is removed you should change the old gaskets with new ones before you install the new expansion valve.

The new expansion valve also says R134 on the side so it can in fact work fine with newer AC systems. The old one was for the obsolete R12 system.

AC Expansion valves Mercedes w123
New vs old AC Expansion valve

Installation

Remember to change the  gaskets and then start to screw in the hoses making really sure not to cross thread them. Take your time here. The hoses should go on quite tight to make a tight seal under the pressurized gas.

AC Expansion valve R134 w123
New expansion valve installed. It says R134 on it so it will work better with the R134 systems since R12 is obsolete. Notice the styrofoam placed on the backside.

Then install the dashboard cover again and your job is done, for now at least.

I highly recommend to perform pressure testing of the AC system before filling it with new gas, since many workshops do not even do this before they fill. You basically have to demand it before they fill. An AC leak is quite nasty since you will get a dirty cleanup job, not mentioning the greenhouse gas effects…

Cheers, Robs out!