1984 245 stalls when applying brakes
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    1. #1
      Junior Member
      Join Date
      Nov 2008
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      2

      1984 245 stalls when applying brakes

      Just bought this 84 245 recently and am really liking it. It's a 4-speed (w/elec overdrive) and about 180k miles (on a complete rebuild at 140k for some strange reason). The car runs really well, except for this issue with the brakes affecting idle. The problem is only noticeable when the car is cold. It starts up fine, but as soon as I apply the brakes the idle starts to oscillate. The harder I push on the brakes, the wider the oscillation. Sometimes it will just plain kill the engine. When it's warm, there is/may be a slight effect on the idle when applying the brakes, but I'm not 100% certain.

      The obvious thing would seem to be a vacuum leak (which might also explain the high NOx numbers I was seeing -- but of course I fixed that by temporarily disabling the Chrysler vacuum ignition advance thingy), but I simply can't find any. Maybe I'm not looking in the right place. The one-way valve in the booster seems to work (I pulled it out and blew through it in one direction but couldn't in the other. Also, after the car has been sitting for a few minutes, there still seems to be a healthy amount of vacuum in the booster (sorry, no quantitative data on that).

      Anyway, for some reason I imagined this might be a common problem with these cars and one of you might be able to point me in the right direction.

      On a totally unrelated note, never having owned a Volvo before, I'm not sure what they're supposed to sound like. Mine has a bit of a breathy sound to it, like an exhaust leak or a bad manifold gasket. But if I stick my head under the hood I can't seem to localize the source of the sound. I'm wondering if a bit of that is normal, because I'm pretty sure I've heard other Volvos of the same vintage making similar sounds.


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    3. #2
      Senior Member
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      Aug 2004
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      Temple, Texas, USA
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      Re: 1984 245 stalls when applying brakes (dotrp)

      Welcome to Swedespeed, Doug.

      Very nice wagon - a keeper for sure.

      Indeed, you have given adequate info for us to troubleshoot the brake/idle situation.

      The "breathy" sound could be a failing manifold gasket which leaks more or less depending on engine load and vacuum (including brake application). As the engine warms the leak is minimized from heat expansion.

      Another area to check - vacuum lines, valves and junctions under the hood that lead to under dash-controls.

      BTW, do you have the maintenance history on the flame trap, fresh air box, throttle body, mass air meter, Ox sensor, etc?

      George Dill


    4. #3
      Junior Member
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      Nov 2008
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      Re: 1984 245 stalls when applying brakes (gdill2)

      Thanks for the reply. Yes it is a keeper. I love the car, but unfortunately, since I picked it up as a temporary vehicle while I'm away from home for a year, I'm not sure I'll be able to take it with me when I'm done. But that's for another day.

      I do have complete records. The MAF was replaced fairly recently, as I recall. The airbox and intake plumbing all look solid. I wasn't aware what a flame trap was, but I just found and cleaned it. I'm not confident that the whole apparatus associated with the flame trap is airtight, but I sprayed some carb cleaner around it while running without any effect, so I'm guessing it's okay.

      I assume the O2 sensor is working since the car did so well on smog ... well except for the NOx thing ... and it looks fairly new. No idea about the throttle body, but I'll check the records about that and the O2 sensor.

      I found my exhaust leak, by the way. The downpipe has some issues right where it starts going horizontal. I should probably look into getting that fixed, but don't really want to commit a lot of money to the project just yet.


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    6. #4
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      Re: 1984 245 stalls when applying brakes (dotrp)

      Give some thought to the Idle Speed Motor.
      This controlls the engine idle speed and can become gummed up with crankcase blowby. There are two hoses going to it and has a three pin plug. Try removing it and cleaning it out.

    7. #5
      Senior Member
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      Re: 1984 245 stalls when applying brakes (VolvoBob)

      Another area to look at is motor/trans mounting. If the engine is moving around on the mounts especially during rough idle electrical wires could be intermittently touching ground. This would also be true if the wiring harnesses are deteriorated inside the bundles and junctions.

      George Dill


    8. #6
      Junior Member volvostud's Avatar
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      Jan 2005
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      Austin, TX
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      Re: 1984 245 stalls when applying brakes (dotrp)

      A quick way to find a vac leak is to pop the hood, get a hose and slowly spray the engine and associated parts while the engine is idling. A vac leak should pull the water in which will cause poor combustion.You can start with a big spray down, soaking the entire engine and see if you get any reaction. If so, then start the slow search for the sweet spot.


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