Question First: Does anyone know the thread size of the FD output lines? I need a bolt to plug the outlet.

I want to plug 7 of the 8 FD outlets (leaving one empty at a time) to flush the FD, one port at a time.

Project:

1979 Mercedes 450SLC. After diagnosing and fixing several components, I am attempting to cleanout a spare Fuel Distributor by filling it up with Yamaha Carburetor Cleaner - widely used in motorcycle fuel systems due to its effectiveness in dissolving fuel varnish while NOT attacking any of the rubber or plastic components.

My method of filling the FD was to:

1) remove FD from car

2) remove fuel line outlet filters

3) inject Y-Cleaner into the threaded towers (empty of fuel lines) on top of FD

4) slowly extend the plunger until the fluid is drawn in (this of course is possible only when the plunger exceeds its normal range of travel)

5) even more slowly move the plunger to the very top position, avoiding pressurizing the interior and ejecting cleaner

6) repeat the injection / plunger operation 3 or 4 times until the unit is full of cleaner

7) leave alone to soak for as long as practical (Yamaha Cleaner is so effective in undiluted form it would act in as little as 30 minutes)

Next I plan to install this FD on the car and flush it using the car's own fuel delivery system. I plan on connecting the high pressure and return hoses and capping the rest of the outlets, except one (at a time) of the FD-to-injector lines. The WUR control and return lines will be plugged by a spare WUR. The Cold Start valve, by a spare CSV.

I am a bit in the dark about the FD-to-injector output lines. I hope someone can help me properly ID the size of the bolt with which these ports can be plugged. All I know is that the thread pitch is 1.0mm.

Back to the FD cleanout: I would like to flush the FD chambers one by one, mostly to observe what comes out. I am under no illusions that if serious contamination (rust) is present, that it would flush out, but I know from years of experience that all of the fuel varnish will certainly be gone.

I would appreciate any comments and especially if someone can help me to ID the correct thread size.

Bostonmish

PS I have restored a completely plugged WUR, back to 100% spec. by injecting it with the Yamaha Cleaner and drawing it from the inlet to the return ports by alternating vacuum and pressure with a mityvac. At first the unit was plugged completely with fuel varnish. I filled the inlet cup and the fluid stayed there. No amount of vacuum (within reason) would draw the fluid in. After about 20 minutes (at room temp) I was able to transfer some pressure from the outlet and observe an air bubble in the fluid on the other side. I applied a bit more vac/pressure over the next few minutes. After 1 hour the fluid appeared in the output side and the level equalized between both ports. I knew the diaphragm was now covered. 12 hours later the unit was transferred to the vehicle and confirmed to be 100% in spec, from absolute cold through the warm up cycle and beyond. Keep in mind, the unit was completely gummed up when I started!