W126 Monovalve eliminator – part 4

I have now completed the installation of the Movovalve elimination kit on my 560SEC.   So far so good.  Most importantly, I don’t have heat when I don’t want it, but it is available when needed.   In the last installment, I completed the routing of the cooling hoses.    From there I installed the radiator and ensured the cooling system didn’t have any leaks.   The final step was to set up the vacuum solenoid so it could control the heater valve.

The very rough diagram below outlines how I adapted the kit for the W126.   Note the diagram is not to scale and in reality the vacuum lines do not have 90 degree bends.

There are a number of differences between the W126 and W123.  The two biggest are probably the inner firewall and multiple outputs for the heater core.   I have covered the coolants lines previously.   I also wanted to mount the vacuum solenoid inside the inner firewall.   In the end I installed it where the monovalve used to reside.   The movovalve elimination kit suggests putting a t-piece into the vacuum line for the climate control system.   The W126 is a big different in that it has one way valves in the firewall for the passenger compartment vacuum consumers.    Each vacuum valve provides 2-3 outputs for vacuum consumers.   Instead of cutting one of my lines, I just replaced a valve with two outputs with a new valve that has three outputs.     That way any vacuum leak should not affect other systems.

The photo below shows the new valve and the line I installed to the vacuum solenoid.   It is the new looking valve at the top.   The black vacuum hose connects to the solenoid located that the top centre of the photo.

Vacuum valve

Next step was to install the vacuum orifice line.   This line is essential according to the supplied instructions.    This is the clear line that can be seen in the bottom of the picture above.   One end of this line has a tiny hole that lets a small amount of vacuum bleed out.   This is poked through one of the firewall grommets.   It then links into a T-piece between the solenoid and the vacuum valve.    The diagram above shows how I have set it up.    It is shown in blue although the line is actually clear.

I decided to take the car for a test drive.    This had a surprising conclusion.   I assumed that when the vacuum lines were connected to the vacuum solenoid without power, the valve would be closed.   This is not the case.   The valve is actually open.   Still, it did prove that the valve works!   Once I disconnected the vacuum I could see the valve close.

The final step was to install the electrical connection.   The vacuum solenoid uses a more standard connection than the micro connection used by the monovalve.   The movovalve elimination kit provides the proper Mercedes electrical connections.   These require soldering.   The combination of the available space, only having two arms and my lack of soldering skill made this quite difficult.    I cheated and soldered the connections onto two short lengths of wire on the workbench and then crimped it to the wiring harness.


Monovalve elimination Kit

Back out for another test drive the car behaved exactly as it should.   Driving around normally with the climate control set around 20C, I had no intermittent heat.    Moving the temperature wheel to hot, and plenty of heat was available.    I omitted the auxilliary water pump so I have probably compromised my heat when the car is idling for prolonged periods of time.   However, I’ve never had any problem with any of the older models that do not have this feature in the warm Australian climate.

This installation has been more involved than I anticipated, but it would be much faster to do it again on another W126 V8.   I could have done it much faster by just mounting the valve on the outside of the firewall, but I wanted to make it a neater job since I plan to keep the car.   I also took the time to swap the radiator, coolant hoses, expansion tank, low pressure hoses, clean the cowl drains and install new seals and more.

Time will tell, but the Movovalve elimination kit seems like a good option for the W126.   Especially when the only monovalve available is the MTC unit.   I would also note that this installation was done in the way I decided to do it, and there are other simpler ways of doing  it.

Rear brake fluid leak on my 450SLC

I’ve used my 450SLC on a few spirited drives lately.    With the new injectors its been running really nicely.    However, on the way back from the most recent night drive, the pedal became really spongey on the way home.   Luckily it was late at night with few cars on the road so I was able to drive it home gently.

The next day I had a quick look under the car.  I noticed there was a lot of brake fluid on the drives side rear tyre.   Looks like I had a rear brake fluid leak on my 450SLC.

Rear brake fluid leak on my 450SLC

I was going to put the car up into the air and have a look, but it occurred to me that I had the lines and hoses replaced by a shop less than 12 months ago and it might be a better idea to take it back there and let them take a look.   Turns out it was as the rear brake fluid leak on my 450SLC was caused by a hole in one of the new brake lines.   The reason it had a hole was that the line was ever so slightly too short and when the suspension was on full travel it would nick the line and after some spirited driving and done so enough to create the hole.

They replaced the line at no charge and re-bled the system.  Once done, I was back to good breaks again on the 450SLC.   Pretty good customer service I think.  I still have a few more things to do on the 450SLC.   It feels like I have a bad transmission mount and I probably need a new fuel accumulator.   I have already purchased those parts.   The car also needs a pinion seal on the diff but I don’t think I will try that job myself.

Installing a W126 radiator

Today’s job was installing a W126 radiator into my 1987 560SEC.   I had previously sorted out the cooling hoses as part of my monovalve eliminator install.   I was just waiting on a few extra parts I had ordered to begin this job.

Firstly I decided to replace the coolant reservoir tank.  My current one is not leaking, but the plastic was quite discoloured and looked a bit white around the hose entry.  Genuine Mercedes coolant reservoirs are still quite inexpensive, and you never know how long that will continue.   Best to change it now.   I was already planning to replace the level sender as it never alerted me to my coolant leak.  It is a pretty simple job to move all the hardware over to the new tank.  Having a proper set of circlip pliers would have made changing the sender easier, but it wasn’t so bad with the a set of needle nose after the tank was out of the car.

Coolant reservoir

The old one will be useful as a temporary spare if I ever have a problem in the other W126s.   I also replaced the coolant hose between the tank at the bottom of the radiator.  I ended up having to cut this hose removing the old radiator as it was so rusty.

Coolant reservoir tank installed

It is easier to get the bottom radiator hose in place before installing the radiator.   I used a new hose here and new hose clamps.   I don’t know the age of the current one and hoses are not expensive and worth changing at the same time as the radiator.  The radiator slides in fairly easily, but the fan shroud must be in place first.

The clips that hold the radiator in place were a bit rusty so I purchased a new set.  I generally avoid Meyle parts unless there is no other alternative.   In my opinion they are poor quality.   I figured a simple clip would be fine, but I was proven wrong.   One of the clips snapped in two with just light pressure from my thumb.   The big challenge is that Meyle seem to be the only manufacturer of W126 transmission mounts that I can find.

The Nissens radiator that I have purchased does not have a drain plug like the IMI did.   I think the Behr radiators do, but I could not get one of those.   Other than that, installing a w126 radiator is the same regardless of brand.

Installing a w126 radiatorThe top hose is easy to install once the radiator is in place.  I also used a new one here.    While I was at it, I also replaced the clip that holds the small hose to the coolant reservoir tank against the front of the car near the headlight.

When I removed the radiator, the transmission cooler hoses were very crusty and I ended up cutting them.   They looked original and it was definitely worth replacing them.   The new hoses from Mercedes have metal spring protectors as they hang down quite low.


Installing a w126 radiator - Transmission cooler hoses

It is so much nicer installing new parts that screw together easily like those hoses than all the time it took to remove the rusty hoses and hose clamps.   Once these final hoses were installed it was now time to fill the coolant.  I used Penrite coolant, which is also to Mercedes spec.

At first all was well and I could see no coolant leaks.    However, after revving the engine a bit to get the water pump going and manually actuating the heater valve by sucking on the vacuum hose I started to get a bad leak from the heater hoses.   The puddle of coolant joined the puddle of transmission fluid under the car.   For some reason if I don’t use the SEC for about a month it dumps a big puddle of transmission fluid on the ground.   Its dry and then all of a sudden lake superior appears.   A problem to solve another time.

After removing and repositioning the hose clamp the leak seems to have stopped.  I have re-filled the reservoir and will check if it has gone down at all tomorrow.

SpillageIf the car is now working properly without coolant leaks, the next step is to take it for a test drive to make sure everything working properly, and I am getting cold A/C.   As I have not yet installed the solenoid, the heater valve should remain shut and I should have no coolant flowing through the heater core.   Overall, installing a W126 radiator is pretty simple.   More simple than removing one that has been there for a while.

500 posts on classicjalopy.com

The most recent post about the W126 cowl covers was the 500th post on this website.  I started the site in May of 2013 when I was doing a lot of work on my Citroen DS.   I had recently purchased the car and was fixing some of the problems with the car, installing a new radio and later re-upholstering it.   At that time I never thought it would still be going 7 years later and with over 500 posts.

At the time, I wasn’t really concerned with how many views I got as I really created the site more for my own records.  Some of these jobs take me quite a while to do, and it can be invaluable to go back and review some things that I have done before.   A great example was when I crashed the Citroen and took apart the rear of the car.   It was over a year before I had it back together and I am not sure I could have done it without the notes and photos I took for this website.

Some people prefer forums and social media, and while these have their advantages, I’ve seen too many times content lost as forums come and go.   Social media is very transient so try finding something from last week let alone 7 years ago.

Over that seven years, the site has now grown to average about 100 visitors per day.      I only installed stats a couple of years after I started the site, but the 10 most popular posts on the site have been:

Of my own cars, The Citroen DS wins hands down in terms of the number of posts that have featured work on the car.

As well as work I have done to my own cars, I have also featured countless photos from car shows and museums, as well as various events I have attended.   In addition, there are articles that cover random subjects I have researched.   In going back to look at some of the older content on the site to create this post, some of the earliest posts are quite cursory and have poor photos.   Quality has slowly improved over time and there is room to improve further as I evolve the site.   I would like to try some more with video, although this is quite time consuming.

I would like to thank everyone who has taken the time to read the content of this site, particularly those who are regular readers and leave comments.  Hopefully you’ll still be around after the next 500 posts.

500 posts

Replacing W126 cowl covers

I had previously removed the W126 cowl covers to clean the drains.   Now they are clean and I have replaced the ABS module bracket, they were ready to be re-installed.

Before I did so, I had some new parts to install.   The first were the rubber boots that cover the windscreen wiper shafts.  On most W126 cars they are almost non existent.  On my 560SEC, I had the remains of one, and the other was completely gone.    The picture below shows the two new boots along with the remains of what was left on my car.

W126 Wiper shaft bootsSecond was the rubber seal that goes between the W126 Cowl covers and the windscreen.  These are normally cracked and perished.  The seal on my SEC wasn’t too bad, but it was covered with hairline cracks and no longer sitting flush against the glass as it had gone hard.   These are now available as reproduction parts.   I also purchased one for the 300SE and 560SEL as the postage was going to be about the cost of the seal if I only purchased one.

seal for W126 cowl drains

It is hard to see from the photo, but the one on the top is the new seal.   The old seal has many cracks as shown.

The W126 cowl covers go on fairly easily.   I found it easier to put on the bigger one first, starting with the windscreen side to tuck it under the glass.   The seal shown above is just pushed onto the plastic cowl cover once it is in place.   The windscreen wiper seals just slip over the wiper shafts.

W126 cowl covers installed

There are supposed to be five clips holding the covers on to the inner firewall, but for some reason I only have two.  I forgot to order 3 more in my parts order.   I couldn’t find a new seal for the inner firewall, so I just re-used the original one.   It wasn’t too bad.

The windscreen wiper just go on in the reverse of how they are installed.   I made some marks on the windscreen before I removed them to align.  This can be seen in the photo above.   I have not yet tested the wipers, but I am confident they are in the right position.

My final parts for the cooling system should arrive next week so I should be able to put the car together and test all the work I have been doing.

Cleaning W126 cowl drains

As part of the installation of the Monovalve elimination kit, I needed to remove the ABS controller bracket.   The bracket was in the way of the coolant hoses.  I order to remove it, I needed to remove the W126 cowl drains cover.   This is great opportunity to inspect this area and clean it.   Cars that have parked outside often have debris here that causes rust.

W126 Cowl drainsIn order to remove the W126 cowl drains cover, the seals at the firewall and windscreen must first be removed.   In the photo above, I have removed the seal on the firewall but not the windscreen.   Once I removed the firewall seal I noticed that some light rust had started at the top of the firewall.   Both of these seals just slide off.

Next step is to remove the wipers.   As can be seen in the photo above, the end caps push up to reveal the nuts that old them onto the splined shafts.    Once the nuts are removed, the wiper arms must be in the upright position to remove them from the splined shafts.

W126 Cowl drains covers removed

Once I got the W126 cowl drains cover off, I was pleasantly surprised withe the condition the drain area.   Other than the  surface rust in the first photo the area is completely rust free.   All I needed to do was vacuum out some of the larger debris and use some rags to remove the smaller dirt.

Next step was to remove the surface rust on the firewall.    I started using a wire wheel on my drill to prepare the metal for some rust guard paint.   The wire wheel creates a lot of small dust so it is important to protect sensitive areas with some rags.

W126 cowl drains

Once the loose rust was removed I painted some rust guard on the affected areas.    This should stop the rust that is already there and prevent it from spreading further.

Rust Removed

The rust guard paint is black vs the original Nautical Blue.  Luckily I still had some of the touch up paint from when I fixed the stone chips.   I used some of that paint to cover the black rust guard.   This area will be covered by the seal, but it is supposed to be body coloured and I had the paint on hand.

W126 cowl drains

The car is now ready for the W126 cowl drains cover to be re-installed.  Before I can do it, I am waiting on a few parts to be delivered. This includes a new seal for near the windscreen and the rubber seals that go around the windscreen wiper shafts.

Jaguar E-Type Fuel Hoses

While I was replacing the fuel pump on my E-Type I noticed some hairline cracks in the fuel hoses.   This was obviously a problem waiting to happen so I ordered a new set to replace them.   It is probably cheaper to buy the raw hose and adapt the original fittings, but SNG Barratt sell a kit with new hoses complete with fittings that is much easier to fit.  Postage is quite slow at the moment, so it was a few weeks before I finally got the hoses.

The cracks opened up even more as I removed them, so it was definitely worth it.   There are two E-Type fuel hoses the back of the car, with banjo fittings at each end.   One from the tank to the pump and one from the pump to a hard line at the front of the car.   There is an additional hose from the hard line to the carbies but I was not replacing this one today.

E-Type fuel hosesThe E-Type fuel hoses are quite accessible once the lining is out of the boot.  I already had it out to do the fuel pump.   It is worth buying new crush washers when replacing these hoses.  I didn’t think to order them and should have.    One of them was in quite bad condition.   I tried Supercheap Auto but they don’t sell this sort of thing.    There is a new Bursons near me where a very helpful lady found the exact match I needed.

Jaguar E-Type fuel hosesOne of the is a bit longer than is necessary, but there is room for the slack.    Once I sorted out the crush washers, I had no leaks with the pump running and the car idling.    I will take the car for a short test drive in the next couple of days to make sure that there are no further leaks.

The fuel leaks have damaged the paint in the spare tyre well.   I don’t need it to look pretty as this area is not visible, but I will have the paint repaired so I don’t get rust here.     I am looking forward to a nice long drive in the car without fuel leaks now the weather is nice and lock downs are finished.

W126 Monovalve eliminator – part 3

I have been working on a project to eliminate the monovalve from the climate control system in my 560SEC.   In the last part I had almost completed the cooling hoses required for the job.   I had mostly worked out hose routing I was looking for – which was combining the dual outputs from the heater core into a single hose where I could place the new heater valve.

Looking further my design wasn’t going to quite line up.   Once I put the elbow piece on the end, it was too long and the hoses were bent too much.     I didn’t have the clearance to have another join between the heater valve and the engine block.

My solution was to use some hose offcuts to try and find a single hose that would join from the engine to the heater valve and replace the factory hose.    I created this, tested it and based on it working, I went to Supercheap Auto to find a hose that matched as closely as I could.

In the end a hose from a Toyota Hilux LN106R 2.8 I4 Diesel fit well.    I just had to trim off the ends to use the bend that I needed.  The fit is not perfect, but it is close enough that it is not putting too much pressure on the hose.

Cooling hoseI didn’t want to use the joined up bends because the place where the join needed to go was where the hose went through the firewall.   The clamps may have chafed against the firewall.    The single piece should work much better.   Once I get a few more parts I will be able to re-install the radiator.   From there I can make sure I don’t have any coolant leaks.

MonovalveFrom there, I was able to install the heater valve  and join it to the engine block.    Next step will be install the solenoid and vacuum connections.      The hoses will be eventually hidden by one of the control boxes.  I think it is for either the ABS or the CIS-E system.

September 2020 night drive

A few friends in the Mercedes Club and I have been trying to get a monthly night drive going.    Last night was the third one and yet again we had a great drive.   This time we met up in Kirrawee and the drive was through the national park to Bulli.

We started out with 5 cars and based on the cars that participated, it was a celebration of the Mercedes M116 and M117 V8.    There was at least one of every generation represented.    We had a 280SE 3.5 with the original iteration of the M116 – in 3.5 liter form with the D-Jetronic fuel injection.    Then there was my 450SLC with the second generation of this engine, a K-Jetronic 4.5 liter M117.    For the third generation we had a 380SEC with the 3.8 liter M116 – the first of the Alloy engines.    Finally we had a pair of 420SELs sporting the fourth and final generation of the M116 with the CIS-E fuel injection.    Interestingly all of these cars have pretty much identical peak power figures of around 200hp, although the torque figures and gearing vary greatly.

The M116 was Mercedes first mass production V8 and ran from 1969-1991.    The M100 came first but it was always a low production, specialty engine.    The M117 is identical for each year other than a longer stroke and hence larger capacity.   
Mercedes V8s - M116/M117We then proceeded towards waterfall before entering the national park for a nice windy drive to Bulli – taking in the sea-cliff bridge along the way.    At Waterfall we managed to corral a BMW 735iL (E32) along the way.    I’ve done that road a few times, but never at night.    Doing the road at night is a totally different experience, less traffic and more concentration on the road.

Mercedes V8s - M116/M117  We met up at Bulli before coming back via the motorway.   The motorway was completely empty on the way back.    My 450SLC performed well for most of the drive, especially on the twisty bits and the motorway.   The new injectors have really made a huge difference and they will probably pay for themselves pretty quickly with the vastly better fuel consumption I am now getting from the car.

For the second time on these night drives I had car trouble on the way back.   I had to stop suddenly suddenly when I was going through Ramsgate.  After that I had a very spongy pedeal.   My cars are dropping like files and the only one I have available to use now is my 1986 300SE.     I won’t be driving the 450SLC until I can investigate further.     I hope to have the 560SEC ready for next month’s night drive.

MBCNSW Mid-Week drive up the Putty road

The Mercedes Club hold a mid-week drive pretty much every month.   I’ve been a member for more than 10 years but never managed to attend one.   I had a free day today and the drive looked really good.   This months MBCNSW mid-week drive was up to the Hunter valley.   The route was via the Putty road, which I’ve done a few times before.   Mid-week is a great time to do this route as the Putty road gets very busy with motorcycle groups on the weekend.   These also attract highway patrol.

MBCNSW Mid-Week drive

Attendance was pretty good for a mid-week event.   I took my 450SLC.   The 450SLC is well suited to this route, but the choice wasn’t really much of a choice, as only the 300SE and 450SLC are up to a longer drive at the moment.   The 250SE is not charging so would promptly run out of electricity.    The 560SEC is currently without a radiator or coolant hoses, and the 560SEL is having some minor panel damage repaired.    Exacerbating this situation is the long shipping times due to Covid19.

As well as my SLC, at the MBCNSW mid-week drive there were two other 107s – a 380SL (with a 5.0 engine) and a 350SL.   Sadly the 350SL failed to proceed early on.   It was belching out black smoke and the owner thought he might have a batch of bad fuel.  I sure hope it was only that!   There was also a 380SEC and a manual 190E, which are quite rare in Australia.    As well as the classics there were three moderns, a C Class, an E class and an SLK.

The route started out taking us west, towards Richmond.   From there we turned off at Comleroy road, and then at Blaxland ridge road.   These are both roads I am quite familiar with, using them to come back from the mountains and avoid the M4 or M2.   We then joined the Putty road, the original way to the Hunter.   The Putty road has some twisty sections and some long straights.   It is nice to drive it without bikes up your tail every few minutes.     We took the Putty road right up to the hunter and then turned for Broke.   There is a slightly faster way to go for Broke, but the road is not as good.

We had a rather nice lunch at Harrigans Irish Pub and then a few of us took a rather spirited drive back via Wollombi and Central Mangrove.    It was really good to get the SLC out and stretch its legs.   I suspect both my SLC and the 380SL 5.0 will need new fuel accumulators as they both struggled to start when warm.    I’ll probably need to replace the transmission mount.   I have not yet inspected it, but from the vibrations I was feeling I am pretty confident it is collapsed.