Hey folks,
I just realized that the black, rubber vacuum hoses in my '89 765T are crumbling - especially the one that lays across the head and hits a T at the firewall (left goes to the pressure switch and right goes inside the drivers side, probably the Cruise control?). Also, my concern is yesterday I realized I can feverishly pump the brake pedal and bring the idle to a stall. Ideas? I know I must have a vacuum leak because I'm having an engine braking problem. The tach bounces from 1000 to 1800 while decelerating - touch the brake and the bouncing stops. Vacuum related problem?

I'm very confused as to what kind of vacuum hose to buy. I can't find a "kit" online nor the local AutoZone/A&A Auto Parts/NAPA know what I need. They want to see a piece of the hose to match.

Also, should I replace the "hard, yellow" vacuum hoses? There is connectors for these on top of the intake manifold - should these need replacing?

The hose for the brake cylinder is much larger than the little one to the pressure switch. I'm assuming that might be broken?

If anyone knows part numbers or outer-diameter,inner-diameter specs I would much appreciate it. Also, how long of hose should I buy? 5 meters? Should I replace all the clips or can I reuse them? I'm betting the old clips will break from age/weathering.

Thanks for any feedback.