W126 B-Pillar trims

The W126 introduced a lot of new features for Mercedes-Benz. A small convenience feature is the height adjustable seatbelt for the front seat passengers. This feature brought with it a few problem. The W126 B-pillar trims. The MB-TEX on the B-pillar starts to separate from the pillar around the height adjuster. Its an endemic problem and common to the W124 as well. It was already occurring on my old 300E which was 15 years old at the time.

The W126 B-Pillar trims are quite easily removed. I didn’t attempt to fix this job myself. I would have only made it […]

W126 battery hold downs and Auxiliary fan resistor

When I restored the battery tray on my 560SEL, I noticed the W126 battery hold downs were missing. While the battery on the W126 sits quite snugly between the inner and outer firewalls, the hold downs are still important. On a serious bump the battery could short out against the bonnet for example.

These hold downs are the same as on the W123 and other models. I ordered a new one, thinking that at least having one in place would start, and I would look for a cheaper used one later. Turns out I needn’t’ have bothered as I found […]

My 560SEL’s selling dealer

My 560SEL was sold new by West Orange Motors, in Orange NSW. The original owner lived in Western Sydney, but had business in Orange and Dubbo. While it was sold new in Orange, it was serviced at Marshalls in Parramatta until 230,000km. Presumably, the car made a fair few trips up to Orange, Dubbo and the surrounding area over its life. The original stamp from West Orange motors is still in the service book. I can’t imagine that many 560SELs were sold outside the main dealers in Sydney, Sydney Eastern Suburbs, Melbourne City and suburbs like Toorak. The original owner […]

M117 Auxiliary fan cut-in modification

Under normal operation, the auxiliary fan on the M117 engine cuts in at 105C. It can also be triggered by A/C system pressure. These settings work fine to keep the engine at the correct temperature. The challenge is that most of these cars have been converted to R134A refrigerant. R134A is far less efficient than R12. The A/C system in the W126 was designed for R12 so is now under specified. Add in the hot Australian climate and stop/go Sydney traffic and you end up with a hot engine and poor A/C performance.

I’ve noticed that once the coolant temperature […]

W126 auxiliary fan replacement

Now we have hit summer here in Sydney, it was apparent that the auxiliary fan was not working. The fan is triggered either by high coolant temperature, or refrigerant pressure. High coolant temperature causes the fan to run at full speed. Refrigerant temperature can trigger a slower fan speed based on a resistor. Before I just jumped into W126 auxiliary fan replacement, I tested the existing fan.

The first test is to jump the wires at the coolant temperature probe. This should trigger high speed running. The next is the sensor on the A/C receiver/drier which should trigger low speed […]

560SEL EHA replacement

Today’s job was EHA replacement (Electro-Hydraulic Actuator) on my 1987 560SEL. The EHA is part of the KE Jetronic fuel injection system and makes minute adjustments to the air/fuel mixture. One of the sources for these adjustment is the oxygen sensor, if present. The EHA can leak either because the o-rings between the EHA and the fuel distributor have gone hard, or because of internal leaks in the EHA itself. In the case of my car, it looked like the EHA was leaking, not the o-rings.

The EHA is still available from Bosch, but it is not cheap. Still, I […]

W126 battery tray

The W126 battery tray serves a dual purpose. The first and most obvious is to keep the battery in place. The other is to protect the body work. Over time car batteries can leak acid and the removable tray catches all that. It is worth checking the condition of the battery tray each time the battery is replaced. If the battery tray becomes too corroded then it can no longer protect the body work.

It is also worth checking the W126 battery tray for another reason. It is easy for leaves to accumulate under the battery tray. This can cause […]

W126 power rear seat top trim

An obvious issue on my 560SEL was how the rear seat was mounted. There was an obvious gap between the parcel shelf and the rear seat. The 560SEL came standard with a W126 power rear seat. This either standard or optional on other W126 LWB models. It seemed clear that when the self-leveling rear suspension was removed, the trim was not put back correctly.

On a car without the power rear seat, the backrest is fixed into position so there is no need for an additional trim piece. On a car with the W126 power rear seat, there is a […]

M117 Fan clutch

The other day I was driving my 560SEL on a fairly hot (30C) day in heavy traffic. The engine temperature got quite warm when sitting in traffic. It was well over 100C in traffic, which would eventually cool down when I got moving. The car didn’t overheat, but I did hear coolant boiling in the radiator hose after I finished the drive.

While the temperature itself is well within spec, given the day wasn’t really that hot compared to days in the mid 40s we get here in Sydney, I wanted to do something about it. Additionally, the air conditioning […]

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 […]