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braking problems S40-V40

posted by  someone claiming to be dpn on  Fri Aug 29 09:17 CST 2003 [RELATED]

I had all front and rear brake pads and rotors replaced and I'm still having problems stopping my '00 S40. When I first bought the car, the brakes were awesome. What could be wrong?

thanks,

-D








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    braking problems S40-V40

    uid 35's pic
    posted by  arno on  Sat Aug 30 03:59 CST 2003
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    last visit: Fri Dec 8 01:10 CST 2000
    [RELATED]

    Did you replace them with the OEM rotors and pads or did you use different brands?

    How long ago were these changed? Have you bedded in the brakes yet?

    Bye, Arno.








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      braking problems S40-V40

      posted by  someone claiming to be dpn on  Mon Sep 1 14:46 CST 2003 [RELATED]

      My S40 has 47k miles. The rotors and pads were not OEM, but a different brand. I believe if you're asking if the brake lines have been bled. The answer is NO. I'm taking it to the dealer this week to see what they can find out.

      thanks,

      -D








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    Check fuse S40-V40

    posted by  someone claiming to be Frank on  Fri Aug 29 10:28 CST 2003 [RELATED]

    Check the 10 amp fuse (15 amp in newer cars) under the hood for the "vacuum pump". It's probably blown. That's the vacuum pump for your brake booster which is an electric pump and there's a TSB on how Volvo wants it fixed by removing moisture and re-sealing BUT if it's an older, high mileage car, you'll probably need a new vacuum pump. When that pump is inop, you almost have no brakes and it's dangerous IMO.








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      Check fuse S40-V40

      posted by  someone claiming to be Mike on  Wed Sep 3 07:03 CST 2003 [RELATED]

      I just had the same problem- and yes it was the fuse-they replaced that and then I had to bring it in again for them to replace the vacuum pump.








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      Check fuse S40-V40

      uid 35's pic
      posted by  arno on  Sat Aug 30 03:57 CST 2003
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      last visit: Fri Dec 8 01:10 CST 2000
      [RELATED]

      But this pump only works/helps right after startup. After about 30 seconds it's turned off and the engine vacuum powers the brake booster.

      Bye, Arno.








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        Check fuse S40-V40

        posted by  someone claiming to be Roy on  Wed Sep 10 09:57 CST 2003 [RELATED]

        The vacuum pump runs all the time, the vacuum off the engine is not strong enough to run the system (was informed by a volvo service manager).








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          Check fuse S40-V40

          uid 35's pic
          posted by  arno on  Thu Sep 11 08:02 CST 2003
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          last visit: Fri Dec 8 01:10 CST 2000
          [RELATED]

          Definitely not the case on euro S/V40's like my 2.0T.

          The reason it only needs to run a little while is that the variable valve system used by Volvo that causes the reduced vacuum only operates on a cold engine and is only used to reduce emissions (and not for power gains like VTEC, VVTi and other such systems). Once the engine warms up it returns to 'normal' operation and enough vacuum is produced for the brake booster.

          You can hear the pump start when you discharge the stored vacuum in the brake booster by repeatedly pressing and releasing the brake pedal until it goes 'hard' and then start the engine. (You need to do this as the pump won't even start if there is enough residual vacuum in the system.)

          The pump makes a low booming/buzzing noise (not to be confused with the fuel pump, which can be noisy too) and it switches off after a while.

          Because of this it will usually only run at the first start in the morning. This is also what causes the problem as it 'sucks in' a lot of cool/cold air that's often loaded with water vapour. Once the pump shuts off the vapour condenses inside the pump.

          This can then cause the pump to either seize up after a while or generate a short. In both cases it will first blow the fuse and after a while it often needs replacement.

          It's a bit like old EGR and air-pump systems that also suffer from similar problems with water collecting in the valves/pumps.

          Bye, Arno.








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            Check fuse S40-V40

            posted by  someone claiming to be Roy on  Fri Sep 12 04:03 CST 2003 [RELATED]

            Thanks for that info! It makes me feel better about a possible pump failure while driving. My problem was that the actual hose fitting on the pump housing snapped off (made of plastic) so I had an actual hole in the vacuum system. The pump was running like crazy trying to keep up. I would like to find some sort of a one way valve that can be put on the line running to the pump so if it ever snaps again I won't lose the brake booster. Something to alert me to a loss of vacuum would be nice also (I'm looking for the right pressure sensor right now).








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        Check fuse S40-V40

        posted by  Eese on  Mon Sep 8 00:00 CST 2003
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        Hi!

        I donīt have any fuse in my -99 T4!!!???








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          Check fuse S40-V40

          uid 35's pic
          posted by  arno on  Mon Sep 8 19:55 CST 2003
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          last visit: Fri Dec 8 01:10 CST 2000
          [RELATED]

          Does your T4 have a manual or automatic gearbox?

          This pump is only on cars from late 1999 onwards with an automatic gearbox as far as I know and not present on manual transmission cars.

          European automatic gearbox S40's before that time didn't have this pump. It was introduced when the S40 was brought to the USA. (just like the 'shift lock' system which is not present on european models until that time either...)

          Seems like americans are incapable of pressing the brake pedal hard enough :) :)

          (For the humour-impaired: It's a JOKE people!!! Although I do wonder....)

          Bye, Arno.








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            Check fuse S40-V40

            posted by  Eese on  Thu Sep 11 00:12 CST 2003
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            Itīs a manual.
            I heard that cars in Europe has bigger brake discs than US models.
            I talked yesterday with finnish importer.

            Yeah i guess so...maybe it takes too much energy to press it!?

            ByTheWay...do you know is there any clear tail lights for V40 in Europe?

            Thanks!

            -E








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            Check fuse S40-V40

            posted by  someone claiming to be Roy on  Wed Sep 10 10:12 CST 2003 [RELATED]

            While the joke is funny, I just had this happen to me while going down the road, the plastic fitting on the vacuum pump cracked so no vacuum was going to the brake booster. I am a big guy and I had to stand on that pedal to get the car to stop. There was no way I could stop that car in a hurry. Luckily I was the only one on the road otherwise I would have been trying out the air bags. There is no way that my wife could have stopped the car had she been driving. What annoys me is that no trouble indicator came on at all, since this vacuum pump supplies all the vacuum for the everything, why didn't the OBD system give me a warning? The OBD knew about the problem when queried. In my mind there is a single point of failure in the barke system; you can crack a fitting or blow a fuse and lose your brakes. I have now lost confidence in the most important safety system of this car, the brakes. I am considering replacing the vehicle.








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              Check fuse S40-V40

              uid 35's pic
              posted by  arno on  Wed Sep 10 22:11 CST 2003
              Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
              last visit: Fri Dec 8 01:10 CST 2000
              [RELATED]

              > since this vacuum pump supplies all the vacuum for the everything,

              Umm.. No actually...

              The pump *only* runs for the first 30 seconds or so after engine startup. The variable valve timing on the engine causes it to have low vacuum in the intake manifold during that time.

              After that time the vacuum for the brake booster is supplied 'as normal' by the engine and the pump is not used anymore.

              A bad pump (or fuse) usually shows itself in that it's somewhat more difficult to stop the car when it has just been started (reduced vacuum, so less assistance), but will brake fine after that.

              The situation you describe (pipe breaking, complete vacuum loss) could have happened on any car wether it has an auxiliary pump or not.

              I agree that it's a very bad situation though as it really shouldn't fail like that. Didn't the engine start to run rough too? Would have been a major vacuum leak in the intake system.

              Still I find it odd that you had such a difficult time to stop the car. I have driven many cars, including S/V40's, while being towed (no engine running => no brake assistance and no power steering) and they still braked fine. You just needed to press a little harder.

              Makes me wonder if Volvo's in the US are perhaps supplied with harder (longer lasting, lower friction) brake pads than here in europe?

              Bye, Arno.







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