farting brake pedal
Moderator: RichardW
farting brake pedal
Anyone else have this? When you press the brakes, the pedal buzzes for a second or so as it depresses. It almost feels like air escaping from around where the (now modified) piston enters the doseur valve under the dash, which kinda 'farts' and makes the pedal buzz as it goes.
Seems to only do it in warmer weather too and not every time you press the pedal, perhaps 8 times out of 10.
The brakes themselves work well and bite as they should. I have no LHM leaks and my accumulator sphere is brand new with a 2 min ticking interval.
Is this the doseur valve going kaput? Any ideas?
Cheers,
Chris.
Seems to only do it in warmer weather too and not every time you press the pedal, perhaps 8 times out of 10.
The brakes themselves work well and bite as they should. I have no LHM leaks and my accumulator sphere is brand new with a 2 min ticking interval.
Is this the doseur valve going kaput? Any ideas?
Cheers,
Chris.
So is it possible to replace the rubber bulb on it's own or is it the whole valve that needs to be replaced, assuming that's what is at fault? It made this noise a while ago, before I did the brake mod, and I never noticed any wet carpet down there at the time when I pulled the silly piston out to be de-springed.
Strange how it only seems to do it in warmer weather too.
Strange how it only seems to do it in warmer weather too.
Right, just had a good feel around under there. It's totally bone dry...no fluid or anything. I think I may know what's wrong though. The rubber bulbs edges go all the way out to the entrance of the valve. The piston that enters it (the one you modify with the bit of pipe) must rub against the rubber and make it difficult for the air to exit. In warmer weather I'd imagine the rubber expands and makes a tighter seal between the piston and the rubber bulb thus causing the farting as the air between them escapes when you press the pedal. If I push diagonally down on the pedal from the left, away from the clutch there is no farting/ buzzing. But if I push straight down on it, then it buzzes.
Just a theory mind.... I'm tempted to drill a hole in the middle of the piston the give the air somewhere else to go. We shall see if that fixes it! It's not affecting the brakes or anything, it's just annoying!
Just a theory mind.... I'm tempted to drill a hole in the middle of the piston the give the air somewhere else to go. We shall see if that fixes it! It's not affecting the brakes or anything, it's just annoying!
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I had a go at this liast night. I doused the rubber behind the piston canister in grease, but to no avail....it still does it. There is enough of a gap around the canister to allow air out so it can't be that sadly. This morning, in the cooler weather, it has hardly done it at all so it's definitely temp related. It does it only on the first bit of travel in the pedal and not if you press really gently.
So it could be air in the brakes? They don't feel spongy at all and are quite effective at all times. If there was air in the rear brakes I doubt this would make the pedal buzz as it does when you prod it. It almost feels like if there is air in the system, it's in the doseur valve itself. If you press the brake quite hard and let go there's also a 'Cha' noise like air being released under pressure. Is this normal?
So it could be air in the brakes? They don't feel spongy at all and are quite effective at all times. If there was air in the rear brakes I doubt this would make the pedal buzz as it does when you prod it. It almost feels like if there is air in the system, it's in the doseur valve itself. If you press the brake quite hard and let go there's also a 'Cha' noise like air being released under pressure. Is this normal?
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Yes, I also have a sort of rattling/farting as I first lay my foot on the brakes on my 97TD. It's become apparent after I changed the pedal spring for pipe, but that may be a co-incidence. I suppose it could well be air/gas. However, the old dear also has 5 ****ged spheres and intermittent ABS problems (momentary loss of brakes at walking speed). I thought I'd start with the fundamentals and take a run up to P......s in Sawtry (they're 20 minutes up the road, so it's hardly worth DIY) to get some new spheres fitted, then we'll take it from there with whatever problems are left.
Pete
Pete
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<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Chrispy</i>
If you press the brake quite hard and let go there's also a 'Cha' noise like air being released under pressure. Is this normal?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
That's normal. Or I should say, every Citroen I've had has done it. So it's normal for mine. [:)]
Cheers
Pete
If you press the brake quite hard and let go there's also a 'Cha' noise like air being released under pressure. Is this normal?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
That's normal. Or I should say, every Citroen I've had has done it. So it's normal for mine. [:)]
Cheers
Pete
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Chrispy</i>
So it could be air in the brakes? They don't feel spongy at all and are quite effective at all times. If there was air in the rear brakes I doubt this would make the pedal buzz as it does when you prod it. It almost feels like if there is air in the system, it's in the doseur valve itself.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
My Xantia does this every summer! On mine its always been caused by air (or maybe nitrogen from the spheres) getting into the osr brake line. Bleading the osr brake (there's never any in the other 3 on my car, no matter what order I bleed them in) seems to stop it - until the following summer when the weather warms up & it starts doing it again.
Don't ask me why its always only the off side rear that collects it......but that could just be peculiar to my car anyway.
So it could be air in the brakes? They don't feel spongy at all and are quite effective at all times. If there was air in the rear brakes I doubt this would make the pedal buzz as it does when you prod it. It almost feels like if there is air in the system, it's in the doseur valve itself.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
My Xantia does this every summer! On mine its always been caused by air (or maybe nitrogen from the spheres) getting into the osr brake line. Bleading the osr brake (there's never any in the other 3 on my car, no matter what order I bleed them in) seems to stop it - until the following summer when the weather warms up & it starts doing it again.
Don't ask me why its always only the off side rear that collects it......but that could just be peculiar to my car anyway.