mj1pate

In anticipation of of finding a loss of vacuum, when I test for vacuum at the A/T vacuum modulator, I may need to run another vacuum line. Vacuum hoses at engine top side have all been refreshed. I don't know what the state of vacuum lines are between the engine and transmission. What is a good vacuum line stock for this purpose and what is a good source? I assume something rigid or semi-rigid would be appropriate.

Mike

BrianG

I have found that the semi-rigid line used by Porsche on the 928 does not deteriorate very quickly and should be found in pretty decent condition.. I suspect that you will find that the terminal flexible (rubber) section requires replacement. I have found that thick-wall silicon tubing works very well for this application. It is very tolerant of heat and hydrocarbon based fluids.

WICruiser

I ran a seperate line from the engine compartment to the trans area because I couldn't find the original line once it went down the firewall area.

I used steel brake line and ran it parrallel to the existing metal brake line that runs down the drivers side (at least on my '85) and used the open side of the brake line retension clips to hold the line in place.

On the engine end I ran the line up the firewall and over toward the middle where I uses a piece of flexible vaccum line from the local auto parts to connect to the original vacuum system.

On the transmission end I ran the metal line over the top of the muffler / exhaust shield and pointed it back toward the front above the vacuum module. Then connected the steel line to the vacuum module with onther piece of the local auto parts source flexible vacuum line.

The steel line should be fine but I will check the flexible lines over time to make sure that they are handling the heat.

borland

If you need the rubber vacuum line coupler that goes between the plastic tubing and the metal tubing near the bell housing, here's the part (not shown on the 928 PET) and price from Sunset Porsche ..

928.574.747.03 connecting piece $1.94

gbarron

Do you happen to have the P/N for the rubber section going from the steel tube to the modulator at the rear of the torque tube?

Randy V

Any heavy gauge vacuum line should work for that application - available at any auto parts store.

borland

gbarron, Randy,

Most auto parts stores don't carry metric vacuum hoses.

For that run to the vacuum modulator, what you need is 3.5 mm I.D. vacuum hose. I believe the plastic vacuum lines in the engine bay are 4mm O.D.

I sourced this from a seller of German cloth braded vacuum hose (identical to what the factory used) on eBay.....

http://cgi.ebay.com/ebaymotors/VW-3-...spagenameZWD1V

For my 90' S4, I needed 3 feet in length. You might find it from a Euro or VW parts house... locally or on-line.

gbarron

Thanks borland, you the man!