Howdy all, first post here. Just bought a high milage 83 300sd in decent shape to tinker with and keep miles off the other car.

Bought it knowing it shifted hard, and took a peak at the vacuum hoses. The line to the transmission had been temporarily fixed with a rubber hose slipped over the hard hose. Well age and nature killed the rubber, and finished off the pvc hose, or what ever its actually made of. I have access to pvc and hi temp poly tubing but I can find what size I need form searching the forums. Can someone help me out with that?

thanks

I went to advance stores and just tried different tubing,in the help section

__________________
1999 w140, quit voting to old, and to old to fight, a god damned veteran

Im at work right now, or else I would go measure it. Im sure its metric, but since Im more familiar with standard sizes, I think it was 3/16", maybe even 1/8". Just remember being surprised at how small it was.

Post some pics of the SD. How many miles? What works and what does not? We can help you get it back into fighting shape. My '81 SD has 262K miles and I do not consider that high mileage.

The most common size is 4mm.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

Thanks sd, and I'm guessing it's the modulator that runs in to right? It's been raining and snowing recently so it's hard to get out and confirm. I know it runs into the driver side of the trans.

Sent from my SM-G935P using Tapatalk

Yes, it runs to the modulator. Before you think about replacing the modulator, try all of your other options first as it is a bit of a PIA to replace correctly. One thing is replacement of the small rubber cap on the modulator, especially if it's cracked, as this can cause a vacuum leak.

I had intermittent shifting problems as well and most were eliminated by just replacing any kind of flex line under the hood. It will likely cost you ~$10 and save you a lot of frustration. All of the special fittings are available here at Pelican Parts, as well as the correct size of vacuum line.
Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

Yea, that's what I'm doing at the moment. I got new piping to install, but it look like some put rubber hose onto the modulator, and slipped the rubber over the hard line at the 3 way splitter. So I'm gonna run a new line and see what difference that makes.

Sent from my SM-G935P using Tapatalk