RPR Posted December 11, 2005 Share Posted December 11, 2005 This is just plain stupid. For the life of me, I cannot seem to convince myself one way or another. The vacuum line from my manifold out to my remote servo has a one-way valve. What I cannot onvince myself of is that the one way valve should allow flow from the servo to the manifold, i.e. vacuum. This makes perfect sense, but then..... Can someone please confirm? Abuse deserved and accepted.... Quote Link to comment Share on other sites More sharing options...
western Posted December 11, 2005 Share Posted December 11, 2005 (edited) Shouldn't it be from the manifold to the servo, my servo has a one way [non-return] valve on it which is connected to the vacuum pump. so the pump [vacuum] sucks the servo diaphragm. Edited December 11, 2005 by western Quote Link to comment Share on other sites More sharing options...
RPR Posted December 11, 2005 Author Share Posted December 11, 2005 You see what I mean??? Let me try again. Am I correct that the valve should be set up such that the vacuum created in the manifold is "pulling" air from the servo to the manifold, i.e. flow from servo to manifold rather than from manifold to servo..... Quote Link to comment Share on other sites More sharing options...
Lars L Posted December 12, 2005 Share Posted December 12, 2005 Yes! Quote Link to comment Share on other sites More sharing options...
landi41 Posted December 12, 2005 Share Posted December 12, 2005 Shouldn't it be from the manifold to the servo, my servo has a one way [non-return] valve on it which is connected to the vacuum pump. so the pump [vacuum] sucks the servo diaphragm. RPR, I wonder will this help? from the WWW somewhere "The automobile engine produces vacuum as a by-product of normal operation and is freely available for use in powering accessories such as the power brake booster. Vacuum enters the booster through a check valve on the booster. The check valve is connected to the engine with a rubber hose and acts as a one-way valve that allows vacuum to enter the booster but does not let it escape. The booster is an empty shell that is divided into two chambers by a rubber diaphragm. There is a valve in the diaphragm that remains open while your foot is off the brake pedal so that vacuum is allowed to fill both chambers. When you step on the brake pedal, the valve in the diaphragm closes, separating the two chambers and another valve opens to allow air in the chamber on the brake pedal side. This is what provides the power assist. " Quote Link to comment Share on other sites More sharing options...
02GF74 Posted December 12, 2005 Share Posted December 12, 2005 well this is confusing since you are discussing the flow of vacuum. someone will correct me but the vacuum (i.e. lack of air in the manifold) varies according to engine rpm load etc. the valve is so fitted so that once the air is sucked out of the servo, i.e. it has vacuum in it, when the vacuum in the manifold decreases i.e. more air in it, this air does not get into the servo to reduce the vacuum. Quote Link to comment Share on other sites More sharing options...
Lara Posted December 12, 2005 Share Posted December 12, 2005 Absolutely. The one way valve should allow air to be drawn out of the servo and into the manifold, i.e. Vacuum in the servo. and not the other way round. Lara. Quote Link to comment Share on other sites More sharing options...
RPR Posted December 12, 2005 Author Share Posted December 12, 2005 well this is confusing since you are discussing the flow of vacuum.someone will correct me but the vacuum (i.e. lack of air in the manifold) varies according to engine rpm load etc. the valve is so fitted so that once the air is sucked out of the servo, i.e. it has vacuum in it, when the vacuum in the manifold decreases i.e. more air in it, this air does not get into the servo to reduce the vacuum. Thanks. This is actually a very clear explanation. My blond moment is over... Quote Link to comment Share on other sites More sharing options...
landi41 Posted December 13, 2005 Share Posted December 13, 2005 I think this all like playing Bagpipes...are those guys sucking or blowing to produce these "orrible" sounds.... Quote Link to comment Share on other sites More sharing options...
RPR Posted December 14, 2005 Author Share Posted December 14, 2005 Well, on the coldest night of the year so far (derision from the Canucks neither requested nor welcome) -9* nubbins here decides to put the servo line in so I can get it to pass inspection before heading off road this weekend (rethinking unless a heatwave is on the way!!!). Despite the loss of vast quantities of skin and potentially one ear to frostbite, I was successful. Bloody hell it makes a difference to the braking!!! I have no idea what application the remote servo I have was intended for. It's fairly large! Anyway, with 11" twin leading shoes all round on the Volvo axles, it stops fairly sharpish!!!! It's pulling a bit left but I'm hoping it will pass inspection. The charming thing here is that the MOT is done by private garages and if you know the chap, he can tell you whether it will pass or not so that you don't get a quick deadline for redress and a fine if you can't meet it... Quote Link to comment Share on other sites More sharing options...
02GF74 Posted December 14, 2005 Share Posted December 14, 2005 Bloody hell it makes a difference to the braking!!! well done! Yes, the servo makes a big difference and is very noticeble if you should be lazy like me and roll your down the drive instead of driving it., then you press the brake to find that nothing happens and it takes a few milliseconds for that to register, hopefully before you roll one of your cars into another! Quote Link to comment Share on other sites More sharing options...
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