'86 190D - brake line from reservoir to clutch master clyinder
 

Finally got around to replacing brake booster, everything went well until I tried to bleed the brakes. The rubber hose from the brake fluid reservoir through the firewall to the clutch master cylinder basically disintegrated and is leaking like crazy. Can't put pressure on the system. Does anyone know the part number for this? Is it just regular 7mm hose? Is there a special connection in to the clutch master cylinder?

It's number 26 on this diagram. Can't find a part number.

Should be just cloth braided cut to length hose. As you're probably aware there isn't any pressure on it, it just connects the fluid reservoir to the clutch master. Pressure is on the other side of the clutch master.

Good luck!!!

Yeah, knew it's not under any pressure. Right now I'm trying to source brake fluid safe hose and connect with a barb splice in the meantime just so I can move the car out of the driveway.

This looks pretty close to what I need. https://www.*******.com/products/bmw-clutch-hydraulic-hose-21521163714

Can't open the link but any braided cloth hose from a foreign car repair shop, BMW, VW, Volvo, Benz dealer should be fine. Completely understand and respect your concern for brake fluid safe hose but haven't seen it. Please post back if you dig something up on that I'd like to know.

Good luck!!!

Quick update. Good news! Was able to track down the real part number for the clutch hose - 2039972752. I also ordered the w123 clutch reservoir line mentioned by Party since it was cheap enough. The new plastic pipe works great and seals perfectly! Brakes feel a million times better than before. I ended up removing the pedal cluster completely in order to access the hose on the clutch master cylinder. The bolts holding on the master cylinder to the clutch pedal are nearly impossible to access. My bent wrenches were too long, needed to be about 1 cm shorter at the bend. Removing the pedal cluster wasn't a big deal at all since I was already down that deep. Bleeding was super straight forward with a pressure bleeder.

Unfortunately the new brake booster didn't solve my shut off valve issue as I had hoped. Upon further investigation it's not holding vacuum at all even though the lever does drop when I apply vacuum. Just not for long. So, that's next. Picked up a few new fuel hoses do tackle while I have the intake off. They won't show up for a week or two.