I purchased some spiffy silicone vacuum hose to replace the aging lines on my '93 940 Turbo. It was pretty straightforward except in 2 cases:

1. Where does the vacuum hose running from the intake manifold through the firewall terminate? Under the dash? Is this accessible?

2. While tugging on one of the hoses, my hand slipped and broke the vacuum line that connects to that white check valve for HVAC on the firewall. This line is a solid black molded plastic with rubber connectors on either end. Is there a reason this is hard plastic? Can I just use a silicone or rubber hose here too (assuming it is a tight fit with the correct inside diameter?)

Thanks,

Chris
'93 945T (176K)

Dear slowboat,

May this find you well. The vacuum line that transits the firewall goes to the climate control system. A diagram on p. 54 of TP8701201 - the Volvo tech manual covering the climate control system - shows that this vacuum line connects to position No. 8, on the climate control unit's vacuum line connector. This vacuum line is designated by its violet color.

If I recall correctly, the vacuum line connector is a flexible polymer. I do not know if the vacuum hoses are glued to the connector, or are simply inserted into it.

There may be a connector, where the vacuum line from the engine bay enters the passenger compartment. If so, it will be behind the air distribution box, and so not easy to access.

to access the connector, you will have to remove the climate control unit. The procedure will be found in the 700/900 FAQs.

If the vacuum line, that supplies the climate control unit, seems to be in good shape, it might be best to leave it as is. Over the past three or four years, I do not recall any reports of trouble with this vacuum line.

Hope this helps.

Yours faithfully,

Spook

Where did you get the vaccum hose, and what size did you buy? I've heard/read conflicting reports on what the correct size actually is. 3.3mm?

Sorry I can't help with your questions. Good luck!