Bleeding W126 brakes with a Motive Power Bleeder

I recently changed the flexible brake hoses in my 1986 300SE.   I wasn’t sure how old they were and they are a wear item.  The next step was obviously bleeding the brakes.  Bleeding W126 brakes is really no different to any other car.    I recently purchased a Motive Power Bleeder to make this job easier.

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.

Bleeding W126 brakes

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.

Bleeding W126 brakesOnce 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.

Bleeding W126 brakes

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.

Bleeding W126 brakes

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.

W111 Cabriolet rear seatbelts

I’ve always been a little surprised that my W111 Cabriolet rear seatbelts were lap only.   Mercedes-Benz were such pioneers of safety at the time that it seemed odd that they wouldn’t have fitted lap/sash seatbelts.   It hasn’t been a problem for me as I so rarely had passengers in the rear of the car.

That has started to change as my kids are getting old enough to want to ride in the back of the car.   I wasn’t so keen in a convertible with lap only belts.   I mentioned this when my car was at All Classic Car restorations being repaired from the ‘roo damage.   They said that if I removed the rear seats, they would take a look and were confident they could fit seatbelts.

I took out the rear seat and couldn’t see any obvious seatbelt anchors.   I removed the trim at the bottom of the parcel shelf where the soft top folds.   There was nothing obvious there.   Stranger still, was that there were factory anchors at the bottom, but my current lap belts were not using them.

I went on various forums, Facebook groups and checked pictures of cars for sale.  I found a couple of cars that had been modified during restoration to take inertia reel seatbelts, but as far as I could tell the W111 Cabriolet rear seatbelts were lap only.

On closer examination, my car did have rear anchors for lap/sash seatbelts.   They were covered up by some trim.   On the Cabriolet, there is a bulkhead between the parcel shelf and the rear seat.   On each corner of this bulkhead there was a seatbelt anchor.   They very much looked like factory anchors as this bulkhead section is not accessible from the boot or from the parcel shelf.   Adding the anchors later would have left evidence of cutting and welding into this bulkhead.

W111 Cabriolet rear seatbelts

Incidentally this bulkhead section is one of the many reasons why a coupe shouldn’t be ‘converted’ into a Cabriolet.   Not only is a beautiful coupe being vandalized, but the structures are quite different.

Getting the rear seats in and out of the Cabriolet is much easier than it was on my 450SLC.   Space is cramped on the SLC.   On the Cabriolet, you can mostly open the roof and stand up.   I found the easiest way was to make sure the bottom of the seat was below the level of the armrests and push it towards the bulkhead rather than sliding it down from the top.

W111 Cabriolet rear seatbeltsThe set back illustrates another difference between the coupe and the cabriolet.   The top of the seat back is narrower on the cabriolet to clear the soft top mechanism.

Getting the seat bottom in is fairly straightforward, but don’t assume you need to keep pushing it in to line up.   I had actually pushed it in a little too far on one side.  Pulling it back out 1cm meant the screw slid in no problem.

W111 Cabriolet rear seatbeltsI’m pretty happy with the result.  I now have W111 cabriolet rear seatbelts and I didn’t need to modify the car in any way.   I’m not fussed about not having inertia reel belts as they will not be used often.   But now when my kids ride in the back of the car, I’ll have a lot more peace of mind.

W111 Cabriolet rear seatbelts

W126 brake hose replacement

I’ve been meaning to change the brake hoses on the 300SE for a while.   I have no history for the car, so I don’t know how old they are.   As I also wanted to change the brake fluid, I thought it made sense to do both jobs at the same time.   I had noticed a slight pull to one side on hard breaking.   It may not have anything to do with the hoses, but they are a good place to start.   Brake fluid really should be changed ever two years.   Most people don’t do it that frequently, but regular changes are still important.   Probably even more important on cars that don’t see much use.

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.

W126 brake hose replacementThe 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.

W126 brake hose replacement

300SE fuel pump replacement

When inspecting the SLS in my 300SE, I noticed that the fuel pump was seeping fuel.    It wasn’t enough to smell fuel, so I am not sure how long it had been like that.   I’ve owned the 300SE for about four and half years and have not done the fuel pump replacement job.

300SE fuel pump replacement

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.

fuel pump replacementI 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 replacementFuel 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.

W126 Self-leveling suspension adjustment

On a recent drive with a few friends I noticed my 560SEC was sitting a bit low at the rear.   I had it parked next to a 380SEC, which I am pretty confident is at the correct height, and my car was lower.   Based on that, I started reading through the section on W126 self-leveling suspension adjustment to work out why.

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.

W126 Self-leveling suspension 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.

W126 Self-leveling suspension adjustmentI 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.

W126 Self-leveling suspension adjustmentThere 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.

W126 Self-leveling suspension adjustmentAfter 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.

W126 front window regulator

Back a few weeks ago I identified the problems with my power window was the W126 front window regulator.   In particular, the passengers side front.   The regulator was missing some teeth.  I had bought a new one some weeks ago, but the regulator was in the shipment that FedEx lost.    I went with a VDO regulator as I expected it to be higher quality than a Meyle unit.

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.

W126 front window regulator

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.

W126 front window regulator

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.

Builders filmGetting 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.

door card done

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.

Reinstalling W126 self-leveling rear suspension

The previous owner of my 560SEL had the self-leveling rear suspension removed.    He told me that he was having problems with it, and the suspension shop he took that car to (Pedders) advised him to remove it.   This was pretty bad advice, but he wasn’t to know that.   A 560SEL should have a supple ride, but my car rode like an old pickup truck.   The Pedders springs and shocks were overly firm and caused the rear to bounce around.   It may have been better with three heavy adults in the back but my children are six, four and four, so even with them in the car, the ride was no better.

Obviously a W126 can ride well without self-leveling suspension.   It was only standard on the 560 models and all models sold in Australia.    The models originally not equipped with self-leveling suspension had specific springs and spring pads to ensure a good ride.   In the workshop manual there is a rather complex table where you work out the number of points you car has based on the model and installed options and that determines the springs and spring pads that should be used.

Instead of reinstalling W126 self-leveling rear suspension, I could have procured the right springs for my car.   560SELs were never sold without SLS, but 500SELs were, so I could have extrapolated the number of points and used springs for a heavily optioned 500SEL.   The cost of this approach probably wouldn’t have been a great deal less than putting back in the correct suspension for my car.

The main reasons why I decided reinstalling W126 self-leveling rear suspension was the best approach was that I really like the way this suspension rides; It is the correct suspension for my car; and the system had been removed in a way that made reinstallation reasonably straightforward.   In a previous article I went over this and the parts I would need.  If the pump had been removed and blanked off, and leveling valve removed, this would have made things much harder.

I found a set of good used struts and springs from a local Mercedes dismantler.   They were not cheap.   I am still on the look out for another spare set.   At the time, I considered having them rebuilt but they were not leaking and seemed in good condition.

I had the work done about a year ago.   At the time I was quite busy with work and forgot to write up the article.   I also hadn’t been back under the car to take some photos.   I didn’t attempt this myself as I wasn’t comfortable compressing the springs, and reinstalling W126 self-leveling rear suspension is quite different from just simple component replacement.    Down the line, If I have a bad accumulator or leaking strut, I would probably do this myself.

reinstalling W126 self-leveling rear suspension

The photo above shows the re-installed strut and spring combination.    The spheres and hoses are all new parts, as are the rubber bushings.   I also needed a new control rod to set the height.   Used accumulator sphere are available, but I would advise against them. They are a wear item.

reinstalling W126 self-leveling rear suspension

After the system was installed, I took the car for a long drive.   What a difference.   It really is transformed.   It now drives like an S-Class should.   Even thought it ended up being expensive, I do not regret reinstalling W126 self-leveling rear suspension.   The main advice I would give anyone who has one of these cars is not to remove it.   Most of the time it is removed at significant expense, the issue can be traced back to worn out accumulator spheres.   They are not that expensive and easy to replace.   The struts can be rebuilt, pumps re-sealed, hoses repaired and so on.   I’ve now driven the car another 5,000km, and I really enjoy the ride in this car.

I’m still on the hunt for another set of struts.  I recently found a set for a very good price in the USA, but Fedex lost my package.  It also contained some workshop manuals I had been searching for a long time as well.

MBCNSW June Night Drive – Berowra Ferry

Today was the June MBCNSW night drive.   This month, we had planned to do the route originally planned for March.   Back then, Sydney had just experienced the worst storms in 60 years.  Our route was not going to be possible after all the storm damage.   We also had to postpone our planned route tonight.   We were supposed to drive over Berowra ferry, but as we got close to it there were signs indicating the ferry was closed for urgent repairs.

Instead of taking the Ferry, we headed up to Peats Ridge via the Old Pacific Highway.   We took the old highway back as far as Mooney Mooney and then the motorway to Thornleigh McDonalds.

June Night DriveWe’ll try and reschedule our original route for later in the year.   A few of us did the route as a dry run back in February and it was quite good.    Being Winter, the popularity of the night drives drops off.   Still, we had seven cars and despite the threat of rain, and COVID19, the drive was a big success.

I took my 560SEC and it ended up being the oldest car there.   That is somewhat amusing since it is the newest car I own.   There is normally a good variety of cars at the night drives.   As well as my SEC, there was a 420SEL.   It was also nice to see a W140 in the form of an S420.   It is quite rare to see W140s at club events.

June Night Drive

As well as the three older cars there was a good selection of late model Mercedes including an E400 Cabriolet, an AMG GT, CLA45S and C300.  Both of the AMGs are not garage queens – they are regularly used by their owners which is great.

Despite a second failed attempt at our route, the June night drive was still a lot of fun.

450SLC rear windscreen screen rust update

A couple of weeks ago I discovered rust around the rear windscreen in my 450SLC.   At the time, I was having the 450SLC rear windscreen changed for a unit in better condition than mine.    The rear screen seal was replaced back in 2006, but no sealant was used.   Even though the car has been garaged the whole time, water had gotten stuck between the seal and the metal.   While the cars were originally built without additional sealer, it is generally a good idea to use it.   It stops the water getting stuck behind the seal like it did on my car.

I took the car in to All Classic Car restorations who do all my body work.  They have now scraped back all the rust and it was even worse than it appeared.   As well as the two major rust areas, rust was starting all around the lower part of the seal.

450SLC rear windscreenAt some point, probably before I owned the car, a very rough hole was drilled for the heated rear window connection.   You can see there is a factory hole on the inside of the cabin of the car.  On my car, somebody had drilled a very rough hole for these wires.   Since this area of the car has to be welded, it will be fixed along with the rust holes.

450SLC rear windscreenIts amazing how many hacks and shortcuts you find when you own these old cars that have been left from previous repairs.   The two major holes are the ones that were already evident.   There was a lot of smaller surface rust that would have turned into additional holes if left untreated.

450SLC rear windscreenThis is a really common area for rust on these cars.   The 450SLC rear windscreen traps water under the seal and then rust invariably forms.   This then causes the rear window to delaminate.   A delaminating rear window was the reason why I was changing mine out.

Next week the paint should go on and then I can have the good used rear screen fitted.   With plenty of sealer of course.

560SEC performance exhaust

Last year I had the exhaust replaced on my 560SEL.   At the time the exhaust was rubbing on the drive shaft and had a few holes.   I had a custom stainless system built that I am really happy with.    This year I saved up to do the same thing on the 560SEC.   While the SEC’s exhaust wasn’t rubbing, it was starting to get a few rust holes.  It was also sometimes scraping on the ground even after replacing some hangers.  In addition, somebody had previously removed the back box and welded in an oval tip I didn’t think suited the car.   It’s been bugging me since I bought the car back in 2018.

As the SEC is the 10:1 compression ECE model, it has a different exhaust system as standard than my 560SEL.    The exhaust manifolds are two piece on each bank and go through longer headers. This is illustrated in the picture above that can be compared to picture in the 560SEL article.    This is often referred to as the ‘tri-y’ system.    Based on this, I was looking for a 560SEC performance exhaust.

As can be seen in the picture below, my new exhaust retains this feature. It is now in stainless steel 2″ pipe. I’ve saved the original pieces to remain with the car too.

560SEC performance exhaustThe system continues as dual 2″ pipes to a single centre muffler that replaces the factory kidney mufflers.    I’ve not seen stats, but the kidney mufflers seem very restrictive.    My straight through centre muffler should work much better.    The rear muffler is also much smaller than the factory rear box.   I was looking for something with a bit more presence, but without droning at speed or being obnoxious.

560SEC performance exhaustIn having this system built, the other thing I was basing this off was the contemporary AMG systems.   The main difference is the AMG systems came straight out the back.   I didn’t want to modify my rear bumper or have the exhaust hang low, so I used the factory cut out.    You can see the AMG system in the centre and the tips on the bottom left.

I had actually bought some AMG style tips, but due to the curvature required in the exhaust, I had these tips made up.   I think its a pretty good compromise to make sure the exhaust doesn’t impact any curbs.  My 560SEC performance exhaust sounds great and it should last a long time

560SEC performance exhaust