Carl Fausett

I now carry replacement solid vacuum tubing for the 928 and others. We were surprised how many hardlines had become brittle and how easy they were to snap or crack.

Here you go:

Description: Perfect replacement for the OEM solid vacuum lines that become brittle with age and often snap when moved. These vacuum lines are opaque black nylon, and UV and chemical resistant. They have a minimum bend radius of 1.5" without collapsing!

Two Sizes Used: Porsche used two different sizes of solid vacuum lines on these cars. We provide 8 feet of both!

Note: Each kit includes two 8' lengths of both 4mm and 3mm new black nylon vacuum line, which is enough to do an entire 928, 944, 951 engine bay. Rear-engined cars (914, 911, etc) may need 2 kits if re-lining their entire car.

The complete listing is here:

http://www.928motorsports.com/parts/...cuum_lines.php

Jim bailey - 928 International

If it is "solid" how does it flow ??

928autobahndreamer

Yeah, but its guaranteed not to leak.

ew928

Technicalmally, vacuum doesn't flow.

Jim, you're too much.
Wonder if the OP means rigid?

Jim bailey - 928 International

We deal in partial vacuum and if nothing flows then there is no potential for work /movement .....so something has to be moving flowing or the tubes might as well be "solid" as opposed to hard.

LightStriker

What's the difference between those and silicone vacuum hose?

Jim bailey - 928 International

These are hard "plastic" which fit inside rubber boots / elbows to connect to one another....

Carl Fausett

Bless you, Jim. Sadly, George Carlin has passed, but he lives on through you, the Great Bearded One

If you look into your engine bay (depending on model year) you will see some combination of vacuum hose (earlier cars) and solid vecuum tubing (later cars) with small rubber nipples on the end.

Many cars have sections of both. Generally speaking, from 85 and up there is much more of this stuff - nylon tube running the length of the circuit, and small sections of hose making the actual connection.

All years (even early cars) use this stuff under the dash for the HVAC controls. That tubing even after 25+ years is usually still flewxible and not brittle. But the under-hood sections become brittle owing to the heat of the engine bay.

Carl Fausett

I can change my description from "solid" to "semi-rigid tubing" if that helps. I just wanted to denote that this is not rubber or silicone hose.

aggravation

Do you have the rubber fittings available either as part of the kit or separately?

Jim bailey - 928 International

The elbows are 928 574 717 02 we stock them.

chrly924s

I bought the silicone kit from 928MS last year. Getting ready to install as soon as I get the manifold stuff finished. Wouldn't those be as good as these?

Carl Fausett

Different. The silicone hose replaces the hose you have. This is the ny;lon tubing to replace the tubing you have. (although, you can replace some tubing with hose if you like)

Tails

A vacuum is any pressure between atmospheric pressure and absolute zero pressure, in this instant.

A vacuum is created when the pressure within a "system" is reduced below the atmosheric pressure when the gas is partially removed. A "vacuum" cannot flow, the gas, "air" in this instance in the vacuum system of the HVAC, is removed by the air induction system of the engine on the inlet stroke in each cylinder acting as a vacuum pump.

Vacuum hose is usually some form of reinforced side wall, so that the hose will not collapse when a vacuum is induced due to the atmospheric air pressure being greater than the pressure within the hose.

A "solid" side wall thickness of a pipe or hose will prevent collapse where as some plastic or silicone hose will tend to collapse when the vacuum or pressure within the hose approaches absolute zero pressure. It is all a matter of differential pressure- so endith the reading.

Tails 1990 928S4 Auto

Jim bailey - 928 International

Ok so what we have here is solid wall semi-ridged hollow tubing designed to contain a partial vacuum and make all kinds of things like Auto transmissions , flappy valves , ignition timing , heater valves , cruise control , door locks , dash flaps , fuel vapor recovery , power brakes ; have a chance to work as they were intended. Since we are dealing with changing levels of partial vacuum there is flow ! And Carl just thought he was selling some plastic tube....