W111 Becker Grand Prix Stereo

The choice of radio for my 1965 Mercedes 250SE Cabriolet was not an easy one. I don’t know what radio the car had in it’s early years. It is a diplomat delivery car, that was picked up from the factory in Stuttgart. The original radio would have either been a slimline model, or perhaps a radio delete plate. At some point, some butcher enlarged the opening and fitted a DIN radio. When I purchased the car it had a ghastly 90’s CD player.

A few years ago, I removed the 90’s CD player and installed a Becker Tribute Radio. This […]

M129 Heat Exchanger

My 250SE Cabriolet had a feature I was not aware of. Underneath the injection pump is an oil/coolant heat exchanger. This was also an option on late 230SLs. Instead of a separate cooler that the M130 engined cars have, the heat exchanger helps warm up the oil when the engine is cool and cool it down when the engine is hot.

There are lines from the oil filter housing that go to the heat exchanger, as well as coolant lines that come from the side of the block. An example is pictured below. The picture is not my heat exchanger. […]

New tyres for my W111 250SE

I recently drove down to Canberra in my 1965 250SE. This was the first time I had taken the car on a longish trip in a couple of years. The main reason for that was the running issue had been experiencing with the car over the last few years. I finally solved this issue last year by fitting a new electronic distributor.

On the way down I noticed how bad the ride was. The car was quite bouncy and not very enjoyable to drive. While the car didn’t do any long trips, I was using it quite a bit on […]

W111 123 ignition – part 2

In the first part of this series, I installed the 123 ignition distributor and got the car running. This part focuses on test driving the car and fine tuning the install. I should note that the 123 ignition distributor has nothing to do with the W123 Mercedes. A couple of people assumed I was fitting a distributor from a W123. The 123 ignition is a brand new electronic distributor that fits many makes and models.

My first step was setting the correct advance curve for my engine. Luckily the workshop manual has all the specifications I needed. The first specification […]

W111 123 ignition – part 1

A couple of weeks ago, I posted an update about my W111 running issues. A reader who is an expert in these cars suggested I fit a 123 ignition distributor. His feedback was that even if it doesn’t solve my current running problem, it is a very worthwhile upgrade. My mechanic also thought the issues were probably ignition related. Based on that, I decided fit one.

I spoke to the local agent for 123 ignition, and based on that discussion, I checked the distributor in the car. My car being an early 250SE (10/65) has ‘0 231 116 047’. This […]

W111 poor running issues and becker update

My 250SE has been suffering from poor running issues for almost two years now. It started not long after I got the car back from being repaired from the impact with the Kangaroo. Despite a lot of work to try and rectify these issues, they are still plaguing the car.

The challenge is that these are intermittent problems, and so hard to diagnose. I started by checking the basics – the fuel filter, tank and so on. I also changed the plugs. This had no impact. My mechanic thought it was ignition related, so we’ve changed most of the wear […]

W111 alternator upgrade

This last week my 250SE has been at the workshop having an alternator upgrade. Back in 2020, my alternator gave up, and I replaced it with a rebuilt 35A alternator. Ever since then, that alternator has struggled to charge the car. It would charge the battery when driving along during the day, without any accessories. But as soon as the A/C was running or the headlights were on, it would barely make enough power. The charge warning light would come on at idle, and even faintly glow when driving.

The W111 alternator is supposed to be a 35A model, and […]

Troubleshooting the Classic Auto Sound Becker tribute radio

I installed the Classic Auto Sound Becker tribute radio in my 250SE a couple of years ago. The W111 series are supposed to have a slimline radio instead of a DIN size. Unfortunately, a previous owner cut my dashboard to DIN size. This meant putting the correct radio for the year was now practically impossible. Instead of putting a 70s Becker instead, I went with this tribute radio which is based on a Retrosound radio with an actual Becker faceplate.

I’ve been happy with the radio in the car, and would recommend it to anyone who had their dashboard modified […]

Rebuilt Mercedes brake calipers

I attempted to attend the MBCNSW May night drive with two separate cars. Coincidently, I had the same brake issue with both cars. On both cases I experienced a soft brake pedal, and on further investigation a very hot drivers side rear wheel. The rear caliper was not releasing properly causing it to drag and boil the brake fluid.

I knew the hoses were only a year old on the 560SEL, so the issue was likely to be with the caliper. The hoses were probably due for a change on the 250SE, so could have been either issue there. Based […]

250SE refusing to start and the importance of not jumping to conclusions

The other day I had to move the 250SE out of the way to access the 280SE. The 280SE was parked in a fairly inaccessible spot until I had sorted out the fuel injection. With that looking promising on the test gauges, it was time to take it for a proper test drive. I had not been driving the 250SE of late, as the rear brakes are sticking and its booked in to have that repaired in June. There are also a few other minor issues to look at, such as the bonnet being stuck closed.

To get the 280SE […]