I have a few questions on my 87 300 SDL. I bought O rings and copper seals from Peach Parts. Followed directions for proper torque on installation at 30Nm twice then final at 35 Nm, or I tried to. On first pressure valve holder was getting tighter than it was when I removed it and I hadn't made it to 20Nm yet. Long story short, it broke off inside IP but I was able to remove all of it. Not sure what I did wrong unless my torque wrench is fault. How important is it to get the torque just right? Now I see that copper seal is same OD but different ID than the old one, making the copper portion wider than the old one. Is this ok? Also I see that the new O ring is a true O ring but the old one was a flat type ring instead of round like the new O ring. Is this right? Lastly, I haven't found any pressure valve holders from Peach Parts but I did find one from Mercedes-Benz of South Atlanta on line. Does Peach Parts sell these? I'd like to buy from the place that supports the forum that has helped me so much. Has anyone used that place in South Atlanta. Sorry so long but had to get it all in.

Sounds like you cross threaded it. Bad mojo. Are the threads in the IP still OK?

The old oring came out square because it was squished flat for almost 30 years. The replacement is circular.

You can get a new delivery valve at a junk yard or buy it from MB.

The tightening sequence and amounts are absolutely CRITICAL. DON'T deviat from the procedure in the FSM

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'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
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The threads are all ok. It went in smoothly and backed out smoothly so I don't think it was cross threaded. I'll double check my torque wrench. Any thoughts on the copper seal?
Thanks for the info on the O ring, thought that might be the case but I didn't want to take any chances.
Have a great day.
Anyone else?

You can verify your torque wrench is calibrated correctly by using a accurate digital portable luggage scale. Measure exactly 12 inches from the center of the socket holder and mark the handle. Now secure the socket end into a vice gently and attach the scale somehow onto the handle at your mark. When you pull the other end of the scale the two numbers should match exactly. Example 20 ft lbs set on the torque wrench at a distance of 1 foot the scale must read 20 lbs. Modify the length if you like for a 2 foot mark the scale would read 10 lbs etc. I like to do this before torquing as my torque scale is difficult to read.

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92 e300d2.5t
01 e320
05 cdi
85 chev c10

Thanks for that tip dieselbenz1. I'll work on that calibration.

I am more familiar with foot/lbs. that Nm. The instructions said to torque to 30 Nm twice then to 35 Nm. My smaller torque wrench has foot/lbs on one side and daNm on the other with Kgm down below. I set the wrench to the Kgm setting which I now know is 10x more than I needed. I feel really stupid for doing this but now I know.

Any other feedback on a good source for the pressure valve holder for my 87 300 SDL, not many Mercedes in salvage yards around here, or info on the difference of the new and old copper seal would be much appreciated. Hope everyone has a good day.