In my view at least, It had a great colour combination of Signal red with parchment interior.   Signal red is not a very common colour on the W126.     I also never found a spec of rust on the car.    It served me well for six years and 16,000km.

In the first year I had the car, I had fair few issues with it, culminating in the head coming off for service and rebuilding the entire HVAC system.   It was pretty reliable after that.   The strange issue had was the failure of the oil pump.   Luckily I caught it right away and everything was back to normal after a new oil pump was fitted.

I’ve found in the last year, I just haven’t been using the car like I was.   I only did 1,000km in the entire year.  It was time to find a new owner who will enjoy it as much as I did.    My kids are now older so they no longer need the attached child seats either.

The car has gone to an old friend who bought it for his son.   His son is about to start driving and liked the look of the red 300SE.  His dad liked how it had good crumple zones and a rigid passenger safety shell, along with ABS brakes.   Everyone wins.       It was a bit sad to see it drive out the driveway for the last time though.   Farewell 300SE!

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Over the six years and 16,000km I’ve owned it, I’ve sorted out a lot of the common issues with these cars including head gasket and head service, rebuilding the climate control system including new compressor, rebuilt climate control unit, blower motor and regulator, relays, temperature LCD and loads more. Tyres are still quite new. I’ve also taken care of the usual maintenance including things like engine and transmission mounts, fuel pump etc.  The car is fitted with an Alpine Bluetooth radio.

The car drives really well and I get a lot of comments from people about it.

For more details, see all the work I have done on the car over the years.

Update 20/1/23:  This car is now sold.

The post For Sale: 1986 300SE W126 appeared first on Classic Jalopy.

I’ve bled brakes many ways over the years.   The traditional two person method of pumping the pedal; various one man systems such as vacuum pumps or valves.    So far I had found the vacuum pump system the best.  However I had ruined two vacuum pumps by getting brake fluid in them.    The Motive Power Bleeder looked promising.

At first, it looked like it was going to be much harder than the videos suggested.  I couldn’t get the system to hold pressure.   There was a hissing sound, and it appeared that it was coming from the cap.   I tried to bleed the brakes anyway, and got one wheel done before fluid started gushing out of the reservoir.

Turns out the little rubber grommets above the fluid level sensor had gotten hard and were letting fluid through.   They were still available and quite cheap.   The reservoirs were also still available, an updated version without the grommets.  I got both, as I didn’t want to find the grommets didn’t fix the problem and have to wait another couple of weeks to get the reservoir.   Also in my mind was having a spare reservoir on hand given how little interest Mercedes-Benz has these days on suppling youngtimer parts. The picture above shows the reservoir with the grommets removed, and below shows with the new ones installed.

Once I had the leak fixed, Bleeding W126 brakes with the Motive Power bleeder was a cinch.   It took longer to get the car up in the air and take the wheels off.

I needn’t have put that old tee shirt around the reservoir to catch any overflow, as the new grommets did their job.   There was enough vacuum to do all four wheels.   This may not be the case if starting from scratch, as I had done one wheel last time.

Instead of buying the motive catch cans, I used an old coke bottle with a hole drilled in the lid.   It worked quite well. I drilled hole in an oval shape so it held the hose but let air get into the bottle.

Due to COVID lockdown, I didn’t get a chance to test drive the car.  The pedal felt firm so I am confident that all is well.    I also noticed that I have a miss matched set of wheels on the car, so I want to change some of the tyres so I have a set that match on this car and a set that match as my spare set.

Now I have the Motive power bleeder, I will probably do regular fluid flushes myself.  I don’t think I’ll be that keen to take on the replacement of the hoses though.

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I recently had the hoses changed on my 560SEC.   I was originally planning to do this job myself, but when I inspected the hoses under the car it seemed apparent they had not been changed since the car was imported from the UK in 2005.   After seeing this, I decided no to tackle this job myself and I’m glad I didn’t as the old hoses put up a good fight.    I figured since the 300SE was an Australian delivered car, the job would be much easier.

W126 brake hose replacement requires different hoses depending on the model.   Based on my 86 300SE and 87 560SEC and SEL, these were the required hoses.

300SE

Front: 129 428 00 35

Rear: 126 428 03 35

560SEL/SEC

Front: 129 428 00 35

Rear: 126 428 01 35

I haven’t looked but I suspect the rear hose difference on the 560 models is due to the anti-squat suspension geometry.    I found that the attachments to the caliper were easy to remove, but I was only able to get one of the connections to the brake hard lines off easily.   Even after letting the other ones repeatedly soak in penetrating oil, they still wouldn’t move.   I was using the correct flare nut spanners but I still couldn’t get them to budge.

In the end I had a mechanic from up the road help me and we only got them off with vice grips.   This is not ideal, but the only way to get them off.    Cutting open the old hoses didn’t show any restrictions, but they were very hard and were starting to get some minor cracking on the outside.    I think next time I will not tackle W126 brake hose replacement myself and just send the car into a mechanic.

With the new hoses installed, the next step was to bleed the brakes.   I had bought a new vacuum bleeder a few months ago and this would have been its first use.

The power bleeder is quite easy to use, however I ran into another problem.   I couldn’t get my system to hold pressure.  At first I thought it was just a minor leak from the cap.   It turns out the rubber grommets on top of the housing for the fluid level were leaking quite badly and fluid poured out when I tried to bleed the brakes.    I’ve ordered a new set of grommets but also a new fluid reservoir in case there are more leaks.

As so many W126 parts are going NLA as Mercedes-Benz loses interest in the model, it will be good to have one on the shelf even if I don’t use it today.   The new housing is an upgraded part and it looks like it doesn’t need the rubber grommets.

In the short time I used the bleeder before I noticed the leak, I found it quite easy to use – the best system for bleeding brakes I’ve used so far.  I am confident it will be quite a simple job once I get the parts in I need.

The post W126 brake hose replacement appeared first on Classic Jalopy.

As I keep a spare Bosch fuel pump and filter, I figured I should change it ASAP.   In my view, it makes little sense to change out the pump and not do the filter at the same time.   I changed the filter when I did the accumulator about four years ago, and it was very dirty.   I think my car sat for some time, so the tank is probably a bit dirty.

My 300SE is an 86 model, so it has the single pump setup.   Obviously the first thing I did was disconnect the battery before working on the pump.   This job is not difficult but hard to do without spilling fuel everywhere.   I own some fuel line clamps, but of course I forgot to use them and sprayed myself with fuel.   This was rather uncomfortable as it soaked into my socks.    Its important not use vice grips here, as they will chafe the fuel lines.   I was able to push the handle of my ratchet into the fuel line to keep the stream of fuel at bay.

I am glad that I decided to change the filter.  After four years and about 12,000km, it was filthy.  I think this is also the reason why my fuel gauge flickers at lower levels.   I suspect after sitting for a while there is debris in the fuel tank.   This filter was not as bad as last time though.   Its also not been bad enough to affect the running of the car.   In my old 1988 560SEC, I ran out of Petrol.  The didn’t run properly until I changed the filter.   Given the debris in the bottom of the 300SE tank, I shouldn’t ever let it get too low.

Fuel pump replacement is one of my least favourite jobs.   I’m glad its sorted out, but I really don’t enjoy doing this one.   I’ll probably be doing the filter again in a couple of years to see if there is still debris in there.

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The length of the control rod that links the height corrector to the sway bar impacts the ride height.   However, the manual is quite clear that this adjustment is not there to compensate for the standard ride height (without load) being off.    When the car is sitting on the ground without load, the height corrector should be in the neutral position and this is baseline adjustment.

After reading this, I wanted to see the adjustment of my cars.   I can only keep two cars at my house, so as it happens I had the 300SE and 560SEL at home.   While on the ground, the 560SEL was in the neutral position.   The 300SE on the other hand was set up in a very strange way.   And to insult to injury, my fuel pump was seeping fuel.

I had replaced the control rod a few years ago, but I had just put it back where it had been before.   Based on the workshop manual, this was clearly not right.   The manual outlines a procedure where you can lock the car in the neutral position and then lower it back onto the ground.   This establishes the standard ride height without any SLS adjustment.

The manual then goes on to suggest the length of the rod should be set based on this neutral position with the car on the ground and no load.   I used a small drill bit as a substitute for the special tool that locks the height corrector in place.

There are two holes for the control rod.   The outer car is for cars without anti-squat suspension geometry.   This is basically M117 cars, excluding some USA models.   My 560s both use this hole.   The inner hole is for other models that do not have this suspension, i.e. all fives, sixes and M116 cars.   At the 300SE is a six, that is where it goes on this car.  On my car I had to shorten the rod about a centimeter.

After this adjustment, the car seemed ever so slightly higher at the back.   I didn’t measure it first – probably should have.   Based on my W126 self-leveling suspension adjustment, I have not noticed any change in how the car rides.   I did hear a slight groaning noise on hard acceleration though, something to check.    I also don’t know the long term impact of my height corrector running with the arm backwards for so long.

While I was under the car I also changed the fuel pump and filter.   Luckily I had both on hand.   This will the subject of a separate article.

I will have to do some further tests on the car to ascertain the correct operation of the SLS.

The post W126 Self-leveling suspension adjustment appeared first on Classic Jalopy.

Due to the lost parcel, I had been driving around with the door card removed for weeks.   I was rather pleased to see the box arrive yesterday.   The new regulator looked identical to the old one.

I wasn’t looking forward to this job.  I expected it to be quite time consuming.   In the end, I was pleasantly surprised.   The workshop manual had a good step by step guide to removing the old regulator.   I had it out in a few minutes.   The most difficult part was removing the slide from the window channel.

Once I had removed the old W126 front window regulator, the next step was swapping the motor.   I carefully cleaned up the old hardened grease as best I could.   There is a metal plate that bolts on to hold the motor to the teeth and I gave this bit a good clean in brake cleaner.   I didn’t want to use that so close to the motor so I used rags for the motor and the window channel.

The new regulator came with two plastic spacers that were not present on my old one.   I used them on the two bolts next to the teeth.   That seemed the most reasonable place, although they were not mentioned in the workshop manual.   I’m not sure if this is right.

I put plenty of new grease on the moving parts of the new regulator.   Getting it back in was also quite easy.   The instructions had the usual (and useless) comment that installation is the reverse of the removal.   I found that the easiest way to do it was to first put the slide on the window channel (with new grease), then the bolt to the other side of the window, then the regulator to the door, then the other slide to the door.   While I still had access to the inside of the door I sprayed it with fish oil.

The most tedious part of the job was getting the door card on properly without breaking all the tabs.   The moisture barrier on my car was completely shredded, so I made a new one of out builders film.   It worked reasonably well.  I first cut a rough shape and then taped it to the door.  I then used a sharpie to work out where I needed to trim and some adhesive to stick it to the door.

Getting all the hooks into the door at the same time took me ages.   I hadn’t removed the upper window trim, so I found it easier to get the first tab on the left started away from the window trim then slide it across.   The bottom tab was also a pain.   The wiring for the light then needs to be pushed into a little hole which leads to the cavity where the light is.   I found the only way to do that was lying down under the door.   I also used a pick tool to get the door lock button through its little hole.

All this trim is now very brittle after 30+ years.  I managed not to break any of the door trim but the tab to hold in the lower light snapped off.   I’ll have to see if that light is still available.   After replacing the W126 front window regulator I now have a properly working front passengers window.   There is also a strip of glass I have never seen now it rises to the top.

The post W126 front window regulator appeared first on Classic Jalopy.

The W126 Outside temperature LCD repair is really easy.   It should be on the radar of any W126 (or W124) owner who has a failing outside temperature display.   It only took 30 minutes and is very easy.   Even better, the LCD illumination works when the headlights are on, when I thought it was broken.    I guess the old LCD was so cloudy the light couldn’t get through.

This is my second attempt to fix the W126 Outside temperature LCD.   The first time, I bought the wrong LCD panel and them mounted it upside down.    After seeing the preliminary results, I was confident enough to order two more displays in Celsius to fix the 300SE and 560SEC.   Last time I wasn’t sure which way up the LCD went.   On closer inspection, there is a small dot in the centre on one of the long sides.   I was able to reverse how it had it previously.    Considering the ease replacement and the impact it has on the car, the new LCD panel is very good value.

The photo above shows the two new W126 outside temperature LCD panels and the broken old one.   As with my prior attempt, the little back contact blocks need to be re-used in the temperature display unit.   As long as you’re careful, it is very easy to mount the new LCD panel.     It was a nice day when I fitted the panel today, but I can remember the display on my old 560SEC in Michican reading -20F.

Now the fix is done for my 300SE, next is to remove the instrument cluster and also repair the 560SEC display.

Update – 27/4/21:  I have now completed the job on the 560SEC too.   See that article for more details, especially how to ensure the display is not too bright.

The post W126 Outside temperature LCD screen repair appeared first on Classic Jalopy.

I had purchased a good used W126 window regulator a couple of years back.   Yesterday I decided to try and fit the regulator.   To get to the W126 window regulator, the door card must be removed.     To do so, there a few screws holding it in place.    Two holding the little chrome embellisher near the door striker,  one behind the plastic backing for the door pull and three for the arm-rest.     Once the screws are out, the door card lifts up and out.   Many of these are damaged when people attempt to just pull it outwards.

Behind the door card is a moisture barrier.   Mine was in a sorry state.

I will replace this after I get the window regulator working properly. Next step was to check why the regulator wasn’t working properly. A quick test confirmed the behavior I had seen.

When I took a closer look at the mechanism, it was pretty clear why the motor was jumping like that.   The regulator was missing multiple teeth.

I wasn’t able to replace the regulator as the used unit I had was quite different to what was installed in the car.   Doing further research, it turns out it is for a coupe.    This isn’t so bad as having a coupe spare is quite useful as they are now hard to come by.

Looking at the parts catalog there are two regulator types possible for my car.   The first type was made by Brose and has part number 126 720 13 46.   I have this type on my car.   The second was made by Reitter & Schefenacker and has part number 126 720 17 46.   I understand the main difference is the number of teeth on the motor.   Therefore the difference doesn’t matter if you’re going to swap the regulator and motor as a unit.

While I was doing this job I noticed another wiring harness in the door.   It even had the little Mercedes-Benz pin connectors, so it was unlikely to be aftermarket.   Most aftermarket radios and alarms I have found in these cars were quite sloppily installed with the wires just twisted together.

I started a thread on the ozBenz forum and it turns out that it is likely from option code 551, which was the anti-theft system.   An unusual option for a low spec 300SE like this one.

I’ll leave the door card off while I source the new regulator.   It sure makes a difference to road noise though.

The post Bad W126 window regulator appeared first on Classic Jalopy.

I was especially keen to do this on my 300SE as water would get into the passengers foot well in the rain.   This would only happen when the car was parked nose up on an incline.   My theory was that debris may have been preventing this area from draining properly.

This job can be done in about two hours, even assuming a lot of cleaning time.   It is certainly worth doing on any W126.     As covered previously, the first step is to remove the wiper arms.   The little plastic covers flip up and the 13mm nut is behind.   The arms will only come off if they are raised.

The drain covers are next. At least on right hand drive cars, the cover is in two pieces. There is a plastic fastener that holds the two pieces together that is just pulled out. The top seal is available for purchase, and these are often in poor shape after 20 years. The picture below shows the edge of the seal on my 300SE. The middle wasn’t quite as bad.

The lower seal is generally in much better shape as its covered by the bonnet. I was not able to find a replacement for this, but could re-use both of my seals. Once the seals are off, there are metal clips that hold the cowl drain covers to the firewall. Once those clips are removed, the drain covers can be gently lifted up. The metal clips hold it to the outer firewall and the covers have molded edges to clip in under the windscreen. I found an old toothbrush to be useful to clean the mesh part of the covers.

Unlike the 560SEC, which had debris from leaves in the cowl area, the 300SE had fairly thick dirt. No rust had started that I could see. The drain holes were open, but the thick dirt may have prevented the water getting to the drains in all circumstances. I’m hoping this cleaning of the 300SE cowl drains will stop water getting into the cabin and prevent rust.

I’m not sure what it is fore, but there was a wiring harness that looked factory coming through the firewall into the cowl drain area.   Instead of being plugged into anything, it had just been taped up.   Please post in the comments section if you know what this is for.

I was actually expecting more debris and some blockages here, so I guess it is possible that something like the windscreen seal is also leaking.   It’s certainly a lot cleaner than it was.

Once cleaned, its quite easy to replace the covers and the two seals. I used my new upper seal and the new wiper shaft seals.

This is the sort of job that is good to do at home as it would be expensive to get a mechanical to properly clean out this area.   Removing these covers really is very simple and the whole job takes about two hours, taking your time.   Having owned this car four years, I really should have done it sooner.

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