Help Re-Installing 1973 450 SE Water Pump/Power Steering Pump V-Belts

Started by nblewi0, 16 April 2023, 03:59 PM


Hi all,
I removed all of the v-belts from my 1973 450 SE to replace them.  The two belts that I removed that drive the water pump and power steering pump were 10 x 1160 mm so I bought that size belt to replace the old belts.  I cannot get the new belts back on to save my life!  So far, I have tried the following:

I have tried to remove the water pump pulley.  This has gotten me the closest to being able to re-install the belts.  I cannot stretch the belt over the pulley and get the pulley back on.

I have access to all 4 bolts on the power steering pump.  I have loosened them all and even removed the lower bolt that allows for the option of placing it in either threaded hole to allow for belt stretch.

I even bought 10 x 1200 mm belts to see if some ninja had installed belts that were too short.  10 x 1200 mm is too long even if I switch the bottom bolt to the second threaded hole.

What am I missing?  Does anyone have any advice?

1973 Mercedes 450 SE "Goldie"
1973 Mercedes 450 SE "Blueberry"


Might need some pics to show your configuration on the pump.  On the 6.9 at least there is a toothed tensioning bolt which allows you to pivot the pump towards to engine once you loosen the bottom most bolt on the mounting bracket.  Without loosening that bolt the pump won't pivot.
1977 450 SEL 6.9 - Astralsilber


Thank you so much!  I was going out to take pictures of my power steering pump and your comment got me thinking about why I couldn't rotate the pump down more.  I discovered a couple of things:

1. The bottom slider bolt (fastening bolt 1 in 13-340) on my pump was not installed correctly.  It was not actually installed in the bottom slider bracket and was actually keeping the pump from rotating down far enough to put the new belts on.  It is kinda hard to see so I am assuming the last person to do the belts removed it and missed when they put it back on?  I removed it to help me install the belts.

2. I removed all the other bolts except for the top bolt (fastening bolt 3 in 13-340).  So, with 3 of the 4 bolts removed, the power steering pump rotated down far enough for me to put the new belts on.  I then re-installed the 3 bolts I took out.

I still haven't tensioned the belts back up.  I'm debating the best way to rotate the pump and tighten the bolts at the same time.  However, just getting the belts back on is great progress for me!

Thanks again,
1973 Mercedes 450 SE "Goldie"
1973 Mercedes 450 SE "Blueberry"