Most of the hoses for the cooling system of the 300SEL appear to be original, or quite old.  I wanted to replace these hoses with ones that looked original, or at least were the current Mercedes part.  Searching through the EPC to gather part numbers was rather useless.  There were many different part numbers for hoses that appeared to be the same, and nearly all of the part numbers turned out to be bad.  With the help of the classic center, I was able to come up with some length of hose in the necessary sizes.  For future reference:

  • 38mm: N 900271 038025.  This 38x46mm hoses is used on the thermostat housing.
  • 18mm: N 900271 018038.  18x27mm hose used for the heater connections
  • 12mm: N 900271 012018.  12x21mm hose used for several connections, including the injection pump and fan coupling thermostats.
  • A 340 501 02 82.  The upper and lower radiator connections use this short funny hose with a large bulge in the middle.
  • 46mm+: The connection from the water pump to the radiator is larger than the 38mm hose I had.  I still need to figure out the correct size for this one.
12mm Hose
12mm Hose, old and new

Today I managed to remove all these hoses and replace most of them.  You begin to appreciate just how complicated the M189 when you work on it.  There are a lot of hoses.  There are several very short pieces of 12mm hose associated with the fan coupling thermostat which are very difficult to get to.

I ran into a snag when I realize I didn’t have the right size hose for the large water pump connection under the manifolds.  Since I had already removed the old hose and the car would now be laid up until I could get the right size, I decided to take things a little further.

Looking through the radiator cap, I could see the core was pretty crusty looking.  So I pulled the radiator out and will have it cleaned up at a local shop.  While its out, I’ll have easier access to change the belts and and address the oil leak at the front of the engine.  Still lots of work to do!

W109 Brakes

With the sale of the 300SDL, I’m motivated to start doing some serious work on the 300SEL.  Once the engine is running, the following things need to be done at nearly the same time in order to actual drive the car a bit:

  • Brakes (replace everything)
  • Suspension (new air bags in the rear, at the very least)
  • Tires (nice ones)
This is a short, but fairly expensive and time consuming list.  In order to get a bit ahead, I decided to pull off the calipers and send them off to be rebuilt.  I was happy to find everything came apart nicely.  The wheel bolts weren’t too tight and nothing was very rusty.  This further supports the low mileage of the car, and an easy life.  After about two hours, I ended up with this collection of parts:

It was nice to see the brake pads were original Mercedes parts.  The star was still visible on one of the rear pads.  I suppose the aftermarket parts business was non-existant in the 1970s and 80s, or these were installed at the dealer.  It was also worth noting that the brake hoses were marked with “Ate”, but had nothing else visible.  This makes me wonder if they’re original.  The hard brake lines broke free from the hoses and calipers up front easily, but things were not so eager to come apart in the rear.  I removed the calipers, but both ends of the brake hoses look as if they’re not willing to come free from the lines.  These lines are pretty short, so getting replacements won’t be such a big deal.
Once the calipers get back from the rebuilder, I’ll order up a new master cylinder, pads, rotors, hoses, hardware, and any hard lines I may need.  I don’t want to take any chances with the brakes, so replacing everything is the way to go.