R/C107 Differential Ratios

The R/C107 models had an extremely long production run – 18 years.   There were a variety of different models and specification changes.   This included the differential ratios that can have a big impact on the performance and economy of the vehicle.

In compiling the table below, I have tried to research the various country specific variants.   It is possible I have missed a few.  Please indicate in the comments below if that is the case.

The SL and SLC of the year had the same mechanical specification (at least during the SLCs production run).   The only exception was the 450SLC 5.0 where there was no equivalent 450SL 5.0 until the facelift and the 500SL model.   
R/C107 Differential Ratios

Many of the same aspects that were covered in the W126 table are applicable here.   As with the W126, the V8 models received the larger (1.3l) case.    Also, as with the W126 models, Mercedes-Benz went on a fuel efficiency drive during 1981 which is why the V8 cars got revised ratios.   The project was called the “Energy Program” and included other changes such as the revised Bore/Stroke of the 380 engine.

Early in the first generation production, the 450 models moved from a 3.07 ratio to 3.06.   This was achieved by changing from a 46:15 gear set to a 52:17 gear set.   This was more of a minor specification change than any real impact on the car.

From the long term ownership of a 450SLC, I think the chosen ratio works well for that car.   I’m not as sure of some of the other ratios.   My view is that some of the later ratios were too tall.   They probably worked a bit better for the home market on the Autobahn than in countries with lower speed limits.

Model / YearDifferential RatioSpeed at 1,000 RPM (4th)RPM at 100km/h
First Generationwww.classicjalopy.com
280SL (107.042)
280SLC (107.022)
5 Speed Manual (to June 1976)
RSA (to May 1976)
280SL (107.042)
280SLC (107.022)
350SL (107.043)
350SLC (107.023)
450SL (107.044)
450SLC (107.024)
To Dec 1973
450SL (107.044)
450SLC (107.024)
From Jan 1974
450SLC 5.0 (107.026)2.7244.52247
450SL (107.044)
450SLC (107.024)
USA 1980
Second Generationwww.classicjalopy.com
280SL (107.042)
280SLC (107.022)
380SL (107.045)
380SLC (107.025)
AUS, SE 1981-1985
500SL (107.046)
500SLC (107.026)
380SL (107.045)
500SL (107.046)
Third Generationwww.classicjalopy.com
300SL (107.041)3.4635.32833
560SL (107.048)
USA, AUS, J only
420SL (107.047)
500SL (107.046)

Mercedes-Benz Australia price list – April 1982

In April 1982 Mercedes-Benz was pretty much king of the hill when it came to mainstream luxury cars.   Rolls Royce was in a league of its own, and Jaguar was at its quality nadir.   BMW were just releasing the E30 which would propel them to a leadership position in the small, luxury market.  They still could not touch Mercedes-Benz in the mid or upper tiers.

As a result, Mercedes were able to charge premium prices for their offerings.    This was before the introduction of fringe benefits tax in Australia, so many of these cars were purchased as company cars with big tax benefits.

To put the prices below into perspective, at the same time AV Jennings were advertising a new three bedroom home that could be built on your block for only $29,950.   This was about the same price as a 230E before sales tax.

The 1982 range was quite small given how successful Mercedes-Benz were at the time.   The highly successful 230E had been able to effectively replace the 230, 250 and 240D in the line up.   They were also only offering three S class models.   I suspect there was a bit of complacency in this line up.  The grey market was thriving with private imports of the 500SE/SEL and SL models happening in big numbers during this time.

It wouldn’t be long before the lineup would be much expanded with the successful W201 190 series, and the expanded range of the W124 and second generation W126.   In the short term, the 380SE would also soon join the range.    For April 1982 though, you could only get the the V8 in the long wheelbase or the SL.   In addition, there was no manual transmission at all in the line up.   It would take the W201 to add this back.

The next 9-10 years would see significant price inflation.   Compare this to the 1991 price list.

April 1982 price list header

ModelTransmissionTypeList PriceSales TaxRec Retail price
300TDAutoWagon 5 Seat$35,462.35$4,585.65$40,048.00
Wagon 7 Seat$37,287.10$4,821.90$42,109.00
280TEAutoWagon 5 Seat$38,147.62$4,933.38$43,081.00
Wagon 7 Seat$39,972.37$5,169.63$45,142.00

Yorkstar Motors – December 1969 Price List

I recently came across a price list from Yorkstar Motors, dated December 1969.   Yorkstar motors were at that time the main dealer in Sydney and I think they had something to do with the overall importation of the cars.  This era Australian delivery cars have a Yorkstar motors tag on them regardless of where they were sold.

Unlike in later years, nearly the whole range was offered in 1969.   It was only have the ADR regime became stricter in the mid 60s that Mercedes-Benz started to limit the vehicles they offered in Australia.   This was probably due to the cost of compliance.

The only models missing off the list were the 200 and 200D W115 models, and the 280SE 3.5 Cabriolet, which would be sold in later years.   The entry level W115 cars were probably considered too slow and really for the taxi market.  Mercedes were not a supplier of Taxis in Australia.   Locally built cars dominated the Taxi market.

One thing that jumps out to me is how much more expensive the 280SEL is over the standard 280SE.  No wonder they didn’t sell many of them.   While cars like the W109 were much more expensive than the W108, you at least got major differences to show for it.   The 280SEL was a simple stretch of the 280SE.   From what I gather, the body shells were modified manually, which might explain the higher price.

It is also interesting how much of the range was offered with the choice of an automatic or manual transmission.   It is extremely rare to find a manual transmission car from this era, outside the SLs.   Even the SLs are mostly automatic.   It was only the M100 cars that were not offered with a manual.

For other Australian price lists, please see November 1966 and July 1991.


ModelPrice (Manual)Price (Automatic)
280SL Roadster$11,163$11,741
280SL Coupe$11,340$11,918
280SL Coupe 2+2$11,422$12,000
280SL Coupe/Convertible$11,718$12,296
300SEL 3.5$13,908$14,486
300SEL 6.3N/A$20,850
280SE 3.5 Coupe$15,306$15,884
600 PullmanN/A$35,153

MBCNSW Drive to Bilpin

Today I joined an event with the MBCNSW for a drive to Bilpin.   Bilpin is to the West of Sydney and is half way up the Blue Mountains.   It is know for its Apples.   The purpose of the drive was to raise money for one of our club members, Sam.  Sam is the proprietor of the Bilpin Apple Pie Cottage, our destination.   He suffered quite a loss during the big fires last summer, losing buildings and part of his stock.   It was then a long time before he could start trading again due to clean up.   Finally, when things were getting back to normal COVID hit and there was even more impact.

This drive was actually rescheduled from earlier in the year.   On the day it was supposed to happen, there was a big storm and the power was out, causing the original event to be postponed.   I had gone to the meeting point and almost drowned in the 10 meters from the car to the McDonalds.

Today the weather was much better, if still a little wet.   This time I brought the whole family – Apple Pie and Ice Cream is a powerful draw card for small children.   The drive to Bilpin up Bells line of road is quite nice and the traffic was fairly light.    As I had the whole family, I brought the 300SE.   It was a good run for the 300SE as it normally gets used for very short trips around my house.

There was a pretty good convoy of cars for the drive to Bilpin, including a W108, a couple of W126s (my 300SE and two 420SELs), 107, 114 coupe, a W140 in a fairly unusual colour, an A124 and some more modern cars.   Also in the line up was a McLaren.

The whole family enjoyed the pie, and there was a raffle draw where I won a voucher for some car detailing.   As I’m terrible at car detailing, I am sure this will come in handy.

From there, the rest of the group did an extended drive up to Mt Wilson.   We peeled off and went for a walk in the nearby Blue Mountains Botanical gardens before driving back home.

Replacing CIS injectors on my 450SLC

This week I replaced the CIS injectors and the spark plugs in my 450SLC and the car is running much better for it.

I’ve been thinking about swapping the fuel injectors in the SLC for a while now.   When cold, the car wouldn’t run that well at first and you would need to blip the throttle a few times to get the idle to settle down.   This can be a sign that some of the injectors are not atomizing the fuel properly.   The car is less sensitive to this as it warms up, but proper atomization is important for smooth running and good power.   A really bad injector can also reduce engine life if it is squirting too much fuel and washing down the cylinder walls.

I was spurred on after I got the car out of storage post COVID19 lock down.   The car was really cantankerous when starting, almost stalling and not running properly and then it would eventually settle down to run on 7 cylinders.   My theory was that not being driven properly for 2-3 months had made this even worse and that it was fouling the spark plugs.

My other thought was that it was a good time to change them while they are still relatively inexpensive.   The parts are still available, but for how long?   D-Jet injectors are no longer available and the holders are no longer available for CIS-E injectors for the M104 engine.

New CIS Injectors

There are three parts needed when replacing the injectors.    The CIS Injectors themselves, the seals and the holders.    It is not strictly necessary to replace the holders, but they are usually in poor shape once the injectors need changing.   Mine definitely needed changing.

Replacing the CIS injectors is not difficult, just a little fiddly.   The injectors and their seals are held in by little metal tabs.   I  unscrewed the fuel line before removing the tab, otherwise the injector would just spin.   My injectors were still snug in the holders, but could be removed without tools.   I had to use pliers to remove the holders, but they all came out easily.  I had to use a dental pick to remove the hard and brittle o-ring.

CIS injector removed

The picture above shows one of the injectors removed, but the holder still in the car.   The injector on the left shows one with the locking tab still in place.

My injectors were absolutely filthy.   I guess the seals were not working as well as they looked as the injector sides and holders were caked with grime.    The contrast with the new injectors is stark.

CIS Injector - old vs newThe CIS injectors are still made in Germany by Bosch.   It is a pleasant surprise that they haven’t been sent offshore.    Before the new injectors can be fitted, the seal must be pushed onto each injector.  The new seals are quite tight and it can take a few tries to get the seal on and pushed up to the end of the injector.  The injector and seal then fits into the holder, and the whole assembly is held down by the tab.

I found cylinder 3, 4, 5 and 6 the most fiddly.   On 3 and 4 there is the fuel lines and throttle linkage.   I have heard that some need to remove it, but I didn’t.  For 5 and 6 there is the pipe work for the fuel pressure regulator.     I did my best to clean up the area before removing the injector, and the injector hole before putting in the new holders.   They were pretty dirty on my car.   The picture below shows the state of the holders after removal.

CIS injectors

As the injectors are held on with hard lines, I had to be careful not to kink them.  The hard lines mean the CIS engines are not as susceptible to engine fires as D-Jetronic.    It took me a couple of hours to do all eight.   After I had done the first four, I had to move the car briefly.    it ran even worse with four new and four old injectors.   It is definitely worth replacing all the injectors at the same time.

After completion.

After I had finished replacing the CIS injectors, the next step was the spark plugs.   I had forgotten how little room there is to work on the 107 chassis.   The 107 is basically a 114 chassis with a prettier body.   That means room is tight with the M117 V8.  Much tighter than the W126 and its cavernous engine bay.    A simple job to replace spark plugs is a pain on the 107.  The four rear cylinders being the worst.    It is easier to move the coolant expansion tank out of the way of the left hand side.   It may be easier to remove the battery on the right hand side, but i was able to get my hand in.

Having a ratchet with a hinged handle helped get into those last four.   I like to do most of the tightening by hand to make sure I don’t cross thread the plug, and only use the ratchet for the initial loosening and final snugging up.

Spark Plugs

The plugs on 1-4 were worse, and I think #2 was the cylinder that wasn’t firing at all.  That plug had a lot of fuel and gunk clogging it up.   I also noticed I had some strange non-standard suppressors on 2, 3 and 4 that I will need to replace.

During the plug change I dropped one of the plugs and could not find it.   I had purchased a cheap boroscope on Amazon a few weeks ago, so that was a good test to find the plug.   While i was at it, I had a look inside the cylinders.   You can still see the factory cross-hatching on the walls, and other than some carbon build up on the pistons, the engine looks in great shape for 300,000 km.


Finally I was ready for my test drive.   Initial start up was a bit choppy but once I got going there was a lot more power than before and the engine ran much better.   I now had 8 cylinders again!   The engine needs a fine tune, but my annual roadworthy is due later this month, so I will have that done when I got to get the pink slip.    So far this looks like it has been a really worthwhile repair.   I’ll soon be doing the same on my 560SEL as it needs a set of injectors too.

Mercedes Club drive to Peats Ridge

The Mercedes Club organized a joint drive with the Rolls Royce Owners club to the Corrugated Cafe in Peats Ridge.   Peats Ridge is about 90km north of Sydney.   This was one of the first drives after the COVOID19 restrictions were eased.   A couple of the members of the club were trying to organize a line up of W126s at the event.   The event seemed like a good opportunity to see some Rolls Royces and give the 560SEL a good long drive after I got the car back from some preventative maintenance.

Taking the 560SEL also gave an opportunity to take two of my kids along and see if they enjoyed the day.   They are not yet old enough to travel in the W111 due to lack of lap/sash seatbelts and child seat anchor points.

The lineup of W126’s was quite impressive.   It was also a good illustration of the sort of cars that get preserved, and the sort that (sadly) don’t.   On display were 8 W126 cars.  Of those cars, all by one were V8s, all but one were long wheelbase, and all but one were second series.  There were 5 420SELs showing the popularity of that model in club circles, my 560SEL, a 300SEL and a first generation 500SE.   This is pretty typical in classic cars that were produced in reasonable volumes.  Most of the cars saved are the later and high specification models.  Of these, there was about a 400,00km difference in the odometer readings from the lowest to highest model.   You would never know by looking at the cars.

W126 Line Up

If you assembled 8 W126 models based on the most commonly sold variants, and only included those original offered for sale in Australia, your line up would be rather different.   Two 280SEs, Two 300SEs, and one each of the 300SEL, 380SE, 420SEL and 560SEL.

As well as the W126 line up there were some other lovely cars.   From the Mercedes Club that included a 190SL, 280SL Pagoda, 280SE 3.5 W108, Adenauer, W116,  450SLC and more.   The SLC was a recent purchase up from country Victoria and it looked great.   There were also a pair of A124s, quite unusual to see two at the same time.

Of the Rolls Royces, there were some nice Silver Shadows, Silver Spirits (and derivatives).  There was also one older model, perhaps a Silver Dawn?

The drive up the old Pacific Highway to Peats Ridge is always enjoyable.   Being a Sunday it was pretty busy and there were cyclists and highway patrol aplenty.   The food at the corrugated cafe was good, and the route back was through Central Mangrove over Wisemans Ferry.   I take regular late night drives up the old highway and I have never thought to come back that way.

I was happy with how the 560SEL performed after its service.  The new thermostat kept the temperature right where it needed to be, the new motor mounts smoothed the ride and the good used steering wheel is much nicer to hold.   I also start the car with impunity now the guides have been replaced.   The previous owner spent good money having the chain and tensioner done about 25,000km but inexplicably the guides and sprockets were not replaced as a matter of course.   It’s the guides that are the main problem in these engines.   I also had the camshaft oiler fittings replaced at the same time.

There are still a few more things I plan to do to this car, but chief among them is to re-instate the self-leveling rear suspension.   The ride from the rear is unpleasant on all but the smoothest roads.   My other option would be to remove the pedders springs and shocks and put in Mercedes springs and shocks.  If I am going to this trouble I might as well do it properly and put the self-leveling back.

Overall it was a good drive and the kids were not too bored!

Leaking SU fuel pump

I took my E-Type out for a couple of drives this week.   The state of NSW has been in lockdown due to COVID19 since March.   Until last week, it was illegal to be out and about without a valid excuse.    This precluded the use of the E-Type as unlike some of the more modern cars it isn’t so suitable to use to do a shopping run.   For starters the boot is minute and the car doesn’t like stop/go traffic very much.

On the first drive, I noticed a bit of a fuel smell.  It seemed like it was coming from the front of the car, so I spent quite a bit of timing examining the fuel connections to each of the three carbies to see if there was any dripping.   There wasn’t.    The other night I took the car on an extended 150km drive up to Gosford via the old Pacific Highway.  On the way back, I could start to smell the fuel again.    Just in the time it took me to open up the roller door. I saw dripping from the back of the car.

Looking in the boot, it was obvious that I had a leaking SU fuel pump.   It was almost raining fuel down inside the boot.   I wonder if this started this week or if it has leaking a little bit for a while.   As I drive the car with the roof down most of the time, it is possible that I may not have noticed some minor fuel smell.

Leaking SU fuel pump

Today I went back to have more of a look and remove the fuel pump.  It is only a 15-20 minute job to remove it.    Firstly the two fuel lines are removed.   I marked them top and bottom to make re-assembly easier.   I was surprised to see two washers per fuel line.    Then, the power and ground can be disconnected.   There is a fair amount of room to get a hand into the rear wing where the fuel pump is located.

Leaking SU fuel pump

Finally, the three nuts that hold in the pump and its bracket can be removed.   While it does not seem like it, it is actually fairly easy to get a hand around behind the pump and remove the rear nut.   I made a mistake in removing the front two nuts first.   It would have been easier to remove the rear one.   The pump is mounted to the car body through rubber mounts.   One of mine was completely perished (probably accelerated by the fuel) and the other two do not look far behind.

Looking carefully, I can see some plastic or rubber debris in the outlet pipe.  Probably the remains of a perished gasket or diaphragm.     In addition, the leaking fuel has dissolved some kind of black sealing material that has been used in the body of the car.   There is black residue in the spare tyre well that I will need to clean up.

The pump leaking SU fuel pump in my car is the original points type.   Specifically it is an AUF303.   It must have been rebuilt when the car was restored.  This pump is now known as the AZX1307.    There is now a fully electric replacement available, or the rebuild kit EPK300 can be used to rebuild it.

I have not yet decided if I will rebuild the pump I have or move to the fully electronic version.    It looks like an all new pump is about 3x the cost of a rebuild kit.

W126 reclining rear seat

Long wheelbase models of the W126 could be equipped with an electric reclining rear seat.   From the factory the W126 reclining rear seat was standard on the 560SEL and optional on other models.   local subsidiaries may have ordered other models with this feature as standard in their markets too.    At least here in Australia it is always seen on the 560 models, commonly seen on the first generation 380SEL and occasionally seen on the 420SEL.   Privately imported cars vary, but it is more commonly seen on the higher specification models like the 500SEL.

The W126 reclining rear seat was not working on my 560SEL when I purchased it.   I bought the car from the original owner and he could not remember when it ever worked.   The seat was stuck in the reclined position, which was not ideal to fit a child seat.

Back in May, I did some initial troubleshooting.   There was not a blown fuse, there was nothing jammed in the mechanism, and the motor did not run when the button was pressed.   It is fairly common for the control cables to become dislodged, which means the motor runs but the seat does not move.

W126 reclining rear seat

Today I looked at the system in a bit more detail, as I wanted to fit a child seat.     The diagram above shows how the seat works.   Its quite simple really.   The two switches send voltage in the direction the motor must run to move the seat.   Using my power probe, I had voltage on one pin and nothing on the other.   This seemed odd, as I would only expect to see voltage when the button was pressed.    When I pressed the button, the voltage was no longer present.

The next step was to test the motor directly.   The power probe allows for voltage/ground to be applied easily.   As soon as I applied power, the mechanism moved in the correct direction.   I was able to easily move the mechanism into the non-reclined position with the power probe.    Confirming that the motor, cables and mechanism worked highlighted that I likely have a switch, wiring or ground problem.    With the mechanism in the right place, I bolted the seat back into place.

W126 reclining rear seat

As I will have a child seat installed, it is actually better that the seat does not work.  I don’t want one of the kids pressing the button and damaging the motor or mechanism as it tries to fight against the child seat.    I would like to fix the seat in a couple of years once I remove the child seat.   This will be early 2024 when my youngest child no longer needs one.   The W126 only has a lap belt in the middle rear, which is incompatible with a booster seat.   The booster seat requires a lap/sash seat belt.

It is not clear right now where the problem lies.   If it is a switch or some wiring or ground problem.   A switch seems more likely.

With the seat in the non-recline position, you can see the huge leg room available in the back of a long W126.   If only the airlines could provide something comparable.     I have now fitted the child seat, in preparation of a club drive I am planning to join in a couple of weeks.

560SEC stone chip touch up

Over the years my 560SEC has acquired quite a lot of stone chips on the front of the car.   I understand the previous owner was in semi-rural Queensland so there may have been some gravel or unsealed roads in there.   Today I applied a stop gap fix until I can address the problem properly.   Most of the stone chips were in the front panel under the headlights.   These panels are removeable, so eventually when I have the rust under the rear screen fixed, i’ll have this panel repainted too.    That repair will be a couple of years away, so today’s task was some stone chip touch up.

Stone chip touch up

Autobarn will sell a little pot of touch up paint with a small brush that is matched to the car’s original colour.   This was the perfect solution for my stone chip touch up job.   While the pot will not match perfectly due to fade, it will make the car look better close up.    I own two cars in 929 Nautical blue, so the little pot of paint is a good investment.

Recently I fixed one of the cladding panels with a colour matched aerosol from Autobarn.   You can have the colours in either format, depending on what you need.

stone chip touch up - Autobarn paint

I started by masking off the bumper bar near the affected area.   Later on, I found that it probably wasn’t necessary as I didn’t spill any of the paint.   I suspect if I had not masked off the area, I would have though.    There is a little brush inside the cap that I used to gently apply paint to each chip.   I don’t think I did the greatest job in the world.   My skills are not in fine work like this.   I still think it is better than all those chips.

Stone chip touch up

I found that pushing backwards against the normal direction of the brush was better to get the paint into each chip.   When I used the brush as normal, it left more of a brush mark and not all the paint went into the chip.   The worst ones did require a little brushing due to their size.

As well as this panel, there were quite a few areas that needed stone chip touch up around the grille.   I used the same method and fixed those.   Again, if you look closely you can still see where it was fixed.  From 1-2 meters away you can hardly tell.


I will check again in the next couple of days to see how it has dried and if I need to touch up any of my touch ups.   Overall, for an hour’s work and a $20 paint pot I am pretty happy with the result.

stone chip touch up

Flashback: 2012 Sydney German Auto-Fest

They Sydney German Auto-Fest is now a major event in the Sydney car show calendar.   There are hundreds of cars to choose from including Mercedes-Benz, BMW, Porsche, Audi and some of the smaller brands.   It has even replaced the separate Mercedes-Benz concours event.    However, this show had quite humble beginnings.   I attended the 2012 Sydney German Auto-Fest, back when it was a couple of dozen cars in a parking lot.   I recall that this was the inaugural event, but I could be off a year.

I went there in the 250SE, but I wasn’t sure if you had to register before, so I didn’t display the car.   The original event clearly did better than the organizers had hoped for as the small parking lot where it was held was soon overflowing.    I only had a short time available, but I was able to snap some of the photos that you see there.

Some of the cars that were on display at this event are now favorites to be seen at subsequent events.   This includes the dark blue Pagoda, the red 190SL and the Adenauer.   Compare these photos to the last time I was able to attend – in 2018.   That year was so big it completely filled Gough Whitlam park.   I would imagine the event will need to move to a larger space at some point.

The event continues this year on the 25th of October. Due to being late in the calendar is unlikely to be impacted by COVID-19.   For more information on the 2020 event, please see this link.    I will likely be displaying the 250SE.    I am pretty confident that the 2020 event will easily surpass the 2012 Sydney German Auto-Fest.