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brake whooshing sound 900 1995

posted by  muskox37 on  Mon May 15 08:02 CST 2017
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last visit: Wed Oct 8 11:54 CST 2014
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Having finally finished changing the rear shock absorbers and the left rear brake assembly I am now on the trail of an older problem that came with this car when I bought it four years ago.

When I push the brake pedal an obvious 'whoosh' sound emits from the area of the brake pedal master cylinder and booster. It is most clearly heard inside the car rather than when one is listening outside the car with the hood open.

The idle of the engine alters when the brake is pushed.

My strategy is to change the hose from the intake manifold to the check valve, this being the cheapest part to change, even though it appears to be in good shape. Then to change the check valve and then to change the booster if the previous efforts fail.

Local charge for the check valve is fifty Canadian dollars. If anybody knows where I can get one for less than that. I haven't yet costed out a booster but I expect it will be pricey. Not sure if it could be rebuilt.

I am assuming that if I go through this process the brakes will firm up. Right now they work well but the pedal feels mushy.

I tried to find some answers to this online and here but most replies are addressed to later model cars.








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    brake whooshing sound 900 1995

    posted by  Mr. Weekend on  Sat May 27 22:13 CST 2017
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    Go ahead and replace the booster assembly. I just went through this on my 960, if you hear it inside the cabin and not under the hood,it's the booster diaphragm. I bought a new Taiwanese made unit, the difference is amazing. When you remove the old unit be sure to adjust the clevis shaft on the new unit to the same length as the old one.








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      brake whooshing sound 900 1995

      posted by  someone claiming to be muskox3437 on  Sun May 28 06:57 CST 2017 [RELATED]

      I read a post somewhere else that said that there is some foam style packing around the clevis pin that is there for no other reason than to stop this sound inside the car. He even showed a picture of the packing.

      Since my brake system works fine, i.e., if I pump the brake and then start the engine, the pedal drops about a half an inch, I decided to leave the system alone and to live with the noise. It is not always evident and the brakes seem to work well. I asked about it to a mechanic friend of mine and he said that if the booster was not working I would indeed know it because the brake would be very hard to apply. This is not the case for my car.

      But I am interested that you found a Taiwanese version of the booster. I was seeing figures like five hundred dollars as a replacement cost.

      But then I bought a valve cover gasket for my 240 and it cost me $42 [Canadian, I admit but still . . .]. Maybe I am just out of date with my costing analyses.








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        brake whooshing sound 900 1995

        posted by  spook on  Sun May 28 11:20 CST 2017
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        last visit: Fri Oct 24 08:06 CST 2014
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        Dear muskox3437,

        Hope you're well. The "foam style packing" to which you refer, most likely refers to Part #3530985 (sealing ring), two of which go around the brake booster's shaft, that ends in a two-prong attachment point. Each of these seals costs about US$3.50 at a Volvo dealer.

        There's another part (#3530984; gasket; US$2), which fits around an attachment on the side of the brake booster, that is closest to the firewall, according to the parts diagram in Volvo VADIS, a superseded dealer parts/service database.

        So far as I know, these parts are available. Their emplacement - if missing - likely requires booster removal.

        Even if you do not plan to do this work right now, you might want to get these items. Parts for mid-1990s cars slowly go "NLA" (no longer available). The cost for the three required parts is under US$10 (C$13.50).

        Hope this helps.

        Yours faithfully,

        Spook








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          brake whooshing sound 900 1995

          posted by  muskox37 on  Mon May 29 13:52 CST 2017
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          last visit: Wed Oct 8 11:54 CST 2014
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          Hi spook,

          Thanks for your informative reply. Is it much of a job to pull that booster? I have ordered the parts but might wait for a bit before putting them in.








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            brake whooshing sound 900 1995

            posted by  Mr. Weekend on  Mon May 29 19:51 CST 2017
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            Muskox, I just did this job. It's not too difficult, but it does require patience and care. If your unit is making that whooshing noise it's not long for this world, and when it decides to go south it's very disconcerting, very hard to stop. You can find that booster on Ebay for about $140 delivered. It comes with the check valve installed.








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            brake whooshing sound 900 1995

            posted by  spook on  Mon May 29 17:27 CST 2017
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            last visit: Fri Oct 24 08:06 CST 2014
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            Dear muskox37,

            Hope you're well. I've not had to replace a brake booster. Based solely on its location - towards the top of the firewall - I'd have thought the main difficulty is access to the connection between the brake booster's actuating rod and the brake pedal assembly.

            I've spent a fair amount of time "under the dash" on the driver's side. In that area are: the ignition computer; the brake system (ABS) computer; the cruise control module (small and not "in the way"); the switches for brake lights and cruise control disengagement.

            Also, I do not know how the brake booster's actuating rod is connected to the brake pedal and so what tools are needed. The FAQs do not address this subject in much detail.

            I wish I could be of more help.

            Yours faithfully,

            Spook








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        brake whooshing sound 900 1995

        posted by  jwalker on  Sun May 28 09:19 CST 2017
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        last visit: Fri Jun 6 08:39 CST 2014
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        That's crazy money for a valve cover gasket! Even in Canadian dollars.

        Have you tried FCP Euro or other U.S. Volvo aftermarket sellers?

        https://www.fcpeuro.com/Volvo-parts/240?year=1990&e=914&m=20&keywords=valve%20cover%20gasket








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    brake whooshing sound 900 1995

    posted by  rstarkie on  Thu May 18 15:32 CST 2017
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    last visit: Fri Oct 24 10:14 CST 2014
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    The check valve is fairly easy to test.

    Removed from the booster you should be able to suck air through the "engine side" but not be able to suck air through the booster side.

    Randy








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    brake whooshing sound 900 1995

    posted by  1pocket on  Mon May 15 10:28 CST 2017
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    you have a leak, obviously

    hose for check valve to intake manifold
    check valve
    brake booster diaphram itself internal

    the first 2 are cheap and easy to fix the booster itself is more costly and a bit of pain to change

    since you have been driving this way for years clearly the problem for you is cosmetic in an aural sense and not a driving safety issue

    i likely have a dozen sound check valves in a box. send me you address and for the price of postage you can have one.








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      brake whooshing sound 900 1995

      posted by  muskox37 on  Thu May 18 08:51 CST 2017
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      last visit: Wed Oct 8 11:54 CST 2014
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      Hi trichard,

      Address:
      Bob Pellow
      295 Jensen Ave W
      Parksville, BC
      V9P1K3

      Please send and I will remunerate for postage in a return letter.

      I am now thinking that it is more likely the seal in the booster unit because the sound is very obvious within the car but not so much when one is listening under the hood. I had a look at various diagrams but it would appear that I cannot get any seals for the aft end of the booster. I am assuming that I am losing some braking force with a leaking booster.

      But these things are damnably expensive. I will have to talk to my auto wrecker supplier but he in turn is not so cheap. Mmmm. is a conundrum.

      Bob







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        brake whooshing sound 900 1995

        posted by  jd620 on  Thu May 18 10:53 CST 2017
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        last visit: Fri Oct 17 07:42 CST 2014
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        If the booster is leaking and needs replacing it can be replaced from many older 740s or 940s. I replaced the leaky booster on my 1995 940 with one from a 1991 740 last Fall and it works just fine. No modifications were needed.
        --
        Mine:5-940s running, 2-740, 2-940 parts, dtrs:3-940s running








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          brake whooshing sound 900 1995

          posted by  muskox37 on  Mon May 29 13:43 CST 2017
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          last visit: Wed Oct 8 11:54 CST 2014
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          That is good useful information. If I have further troubles it is good to know that other vehicles can supply the needed part. For now I am going with what I have but if the booster worsens I know where to turn. Thank you.







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