240 Vacuum Leaks and Wrong Hoses?

Hi All,

I've been getting pickier with the car's (1989 245) functionality, and the intermittent cruise control has really been driving me crazy. I replaced the cracked vacuum lines which solved some problems, but the cruise control is still very erratic. Sometimes it won't hold speed going up hills which means it certainly won't accelerate either. This tells me that I'm probably dealing with a small vacuum leak.

This is where I want to start pulling my hair out. I used my hand vacuum pump to see if the pedal actuator was working as intended. It pulls the spool all the way to the detent and holds vacuum. Cool. Then I checked the reservoir. It holds strong vacuum as well. Then I went back to the intake manifold. If i suck down everything, I can't draw more than about 10in/Hg and it drops quickly after I stop pumping.


This means that something is up with the HVAC controls or the hose between. After fiddling with enough stuff, I made the system hold vacuum. Two things seemed to make a difference. The exducer fitting that adapts the little metal elbow to the reservoir seems to be touchy. I'd like to replace that as well as the one that's connected to the check valve on the intake manifold. Does anybody know where I can get one? What would you call it?


The other part in question is the re-circulation switch. If I press that button, the system holds vacuum. Otherwise, it does not. Is there any way to fix this? Do you I need a new HVAC panel? Thanks!

The only unchecked part in question is the tiny hose coming off the intake manifold check valve. Is that even large enough for both the HVAC and the cruise control to work right? They both have their own vacuum resrvoirs which leads me to believe that it would be fine, but all the cruise specific hoses are bigger which has me thinking "maybe not". IF I end up finding a replacement for that reducer off the check valve should I swap it with a bigger fitting and reduce for HVAC after the cruise control? I feel like it can't hurt. I just don't know where to get those! For reference, here's the part I'm asking about. Thanks again.

I've only seen that used for the hvac controls. That little hose splits and leaks vacuum. Never saw cruise control connected to that as well. Maybe the cruise control should go to another port on the plenum?

dl242gt said:

I've only seen that used for the hvac controls. That little hose splits and leaks vacuum. Never saw cruise control connected to that as well. Maybe the cruise control should go to another port on the plenum?

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I kinda think it would. The whole thing was a mess full of adapters before, and it still doesn't seem right to me. I know cruise control is not a very common thing for these cars, so pictures of original installation is hard to find.

Does the cruise work if the recirculate button is pressed in?

Repairing a busted recirculate actuator thingy requires removing the whole HVAC box. I just did mine, the diaphragm was blown off its plastic body due to a bad check valve and boost.

volvowagoon said:

so pictures of original installation is hard to find.

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Diagram from 85-87 parts book any help?

Cwazywazy said:

Does the cruise work if the recirculate button is pressed in?

Repairing a busted recirculate actuator thingy requires removing the whole HVAC box. I just did mine, the diaphragm was blown off its plastic body due to a bad check valve and boost.

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That's no good. If it's the actuator, then I'd just let it stay broken for a while. lol I'm not prepared to dig that deep into this car right now. However, I think it's just the button because I'm drawing my vacuum from the hose in the engine bay that goes to the whole system. If it was the actuator, then I should only have a leak with the button depressed. Instead it only leaks with the recic off.

MasterBlaster said:

Diagram from 85-87 parts book any help?

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A little! Thanks! First of all, it appears that cruise is not supposed to T in with HVAC, so that's something I'll have to figure out. I'm not sure of the best place to tap in for that. It also looks like 23 is a reducer which is the opposite of what I have and explains my symptoms. I wish I could get the hose sizes. That would tell me a lot more.

I'm looking at pictures of other manifolds and diagrams. It looks as though I should have some plugged vacuum ports that could allow the cruise and HVAC to draw from separate sources. However, I think a Y-fitting with a reducer nipple right off the check valve would work about the same while looking less ridiculous that multiple nipples, check valves, and reducers. I'll play a little more this evening.

hiperfauto said:

Smoke test the system to see where it's leaking from. It could be a switch, actuator or hose leaking.

The part number for the reducer/connector is 1215591.

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volvowagoon said:

Thanks! Could it be the actuator or hose leaking if the leak only occurs with the recirculation turned OFF though? It would make more sense to me if it happened when it was on, but the switch should be making a dead end for supplied vacuum and venting the actuator side. Instead, it's venting both.

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The vacuum switches need to do 2 things, pass vacuum when on and not leak when off. It sounds like the switch is bad.

Both the installation instructions and this illustration from the greenbook show the cruise control vacuum source is tee'd into the HVAC vacuum.

hiperfauto said:

The vacuum switches need to do 2 things, pass vacuum when on and not leak when off. It sounds like the switch is bad.

Both the installation instructions and this illustration from the greenbook show the cruise control vacuum source is tee'd into the HVAC vacuum.

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Thanks. I guess that axes my separate source theory. I still have the issue with the HVAC leak eliminated though. Bad check valve? I never tested it. I suppose if I loose all my vacuum whenever the throttle gets opened up too far, I would have very poor cruise function. I'll take that off later too.

So I finally was in a situation where I could actually hear the hiss of the leak with the recirc. off. I also took the car on a test drive through some hilly and less traveled areas to test the cruise control. I think I just got a bit too used to modern all electric cruise control, because the car behaved exactly how it remembered it. It kicks down when it starts losing speed uphill and regains it in a reasonable amount of time. Therefore, I'm going to put all the blame on that recirc. switch.

Has anybody attempted to rebuild or repair these before, or should I just try getting a good used one?

volvowagoon said:

That's no good. If it's the actuator, then I'd just let it stay broken for a while. lol I'm not prepared to dig that deep into this car right now. However, I think it's just the button because I'm drawing my vacuum from the hose in the engine bay that goes to the whole system. If it was the actuator, then I should only have a leak with the button depressed. Instead it only leaks with the recic off.

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It's the opposite, pushing the button in blocks off vacuum and lets the spring push the door open. Button out uses vacuum to close the door and suck air from the cowl. (I think this only applies to recirc, the other two pass vacuum through when pushed in)

During the 2 years it took me to get around to fixing mine I left the button pushed in and used a bolt wedged against the firewall to prop the door closed so recirculate wouldn't be stuck on.

Cwazywazy said:

It's the opposite, pushing the button in blocks off vacuum and lets the spring push the door open. Button out uses vacuum to close the door and suck air from the cowl. (I think this only applies to recirc, the other two pass vacuum through when pushed in)

During the 2 years it took me to get around to fixing mine I left the button pushed in and used a bolt wedged against the firewall to prop the door closed so recirculate wouldn't be stuck on.

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Thanks for the info! So your saying that I WOULD need an actuator or a hose to fix my leak. That sounds a lot more reasonable to shop for. That's in the center of the HVAC box though isn't it? Is is tough to get to?

volvowagoon said:

Thanks for the info! So your saying that I WOULD need an actuator or a hose to fix my leak. That sounds a lot more reasonable to shop for. That's in the center of the HVAC box though isn't it? Is is tough to get to?

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I don't think it's possible to fix/replace the recirculate thing without entirely removing the box. I only fixed mine because I was doing the blower motor.

Cwazywazy said:

I don't think it's possible to fix/replace the recirculate thing without entirely removing the box. I only fixed mine because I was doing the blower motor.

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Dang. My blower motor and resistor pack are only a couple years old. Figures.