Hissing Noise

neil p gaffney · Feb 16th, 2008, 22:40

Hi, I posted a message on the general site and nobody came back with a suggestion. Maybe the T5 owners might be able to help. I have a 2003 S60 T5 in pristine condition with 70,000 miles on the clock. In the last week I am getting a hissing noise when I press the brake pedal or let it go, like wise when I let go the accelerator? There is no difference in the braking, it still performs 100% as new. Please somebody tell me it isn't a knackered brake servo? I believe it is savage expensive to replace. I've had a grin on me since I bought the car, but it will disappear very quickly if this is true.

Clan · Feb 16th, 2008, 22:58

there is always a hissing noise from the servo when pressing the brake as the air goes in through the pedal push rod area but it is normaly very quiet .There is a foam air silencing/filter material inside the rubber boot where the pedal push rod goes through , but it does seem you will need a new sevo to cure from my experience with this noise :-(

CTCNetwork · Feb 16th, 2008, 23:00

Hi,

Registers is not the place for Technical questions. Have asked it be moved..
Your other post was actually in the "Blogs"...

However, some more detail about what model of car you have would help.

Hissing in the dash may relate to the heating system as that uses vacuums to open and close the heater distributor box.
Do you have AirCon??

Luck in getting this resolved...

Welcome to the forums and enjoy your time here...

Des. . .

s60ben · Feb 16th, 2008, 23:16

Quote:

Originally Posted by CTCNetwork

Hi,

Registers is not the place for Technical questions. Have asked it be moved..
Your other post was actually in the "Blogs"...

However, some more detail about what model of car you have would help.

Hissing in the dash may relate to the heating system as that uses vacuums to open and close the heater distributor box.
Do you have AirCon??

Luck in getting this resolved...

Welcome to the forums and enjoy your time here...

Des. . .

Vacuum for heater controls?

Since when?

Model of car clearly stated once again "" I have a 2003 S60 T5 in pristine condition""

15th Pint Des or spontaneous postwhoring?

CTCNetwork · Feb 17th, 2008, 02:42

Hi,

I can only assume Mr Ben has posted some derogatory comment but if you look at the below photo - top right hand part - you will see vacuum tubes to the heater distribution box.

If your hissing is definitely coming from the dash area then it may be (as already mentioned) a source of your hissing.
Tubes broken or removed or displaced will hiss.
But then, how the heater (and heater distribution box) works in your S60 could well be different to how it works in my 940 or V90.

Des. . .

IC · Feb 17th, 2008, 03:21

Quote:

Originally Posted by neil p gaffney

Hi, I posted a message on the general site and nobody came back with a suggestion. Maybe the T5 owners might be able to help. I have a 2003 S60 T5 in pristine condition with 70,000 miles on the clock. In the last week I am getting a hissing noise when I press the brake pedal or let it go, like wise when I let go the accelerator? There is no difference in the braking, it still performs 100% as new. Please somebody tell me it isn't a knackered brake servo? I believe it is savage expensive to replace. I've had a grin on me since I bought the car, but it will disappear very quickly if this is true.

Hi, the T5-R register is specifically for owners to register the details of their cars. Please do not post technical questions in the register as it defeats the purpose of the register - the technical forums are the place to post technical questions. I have moved your post to the S60 technical forum.

s60ben · Feb 17th, 2008, 10:38

Quote:

Originally Posted by CTCNetwork

Hi,

I can only assume Mr Ben has posted some derogatory comment but if you look at the below photo - top right hand part - you will see vacuum tubes to the heater distribution box.

If your hissing is definitely coming from the dash area then it may be (as already mentioned) a source of your hissing.
Tubes broken or removed or displaced will hiss.
But then, how the heater (and heater distribution box) works in your S60 could well be different to how it works in my 940 or V90.

Des. . .

Not derogatory Des, but it would appear you couldn't even be bothered to read the original post where he clearly stated he had an S60. Now you were either drunk or just didnt read it.

I'm also sorry, but I fail to see the relevance of comparing the heater distribution box in an old V90/900 to an S60, (even if you do have a USB cable in the way) It's like comparing a ZX spectrum to a current PC system, of little use, and likely to confuse the hell out of a new member once again.

Maybe it's just me, but I just find it pointless, misleading and bl**dy irritating, and it's just posting for the sake of it, ie postwhoring.

Anyway, back to a valid helpful post which Clan had already started on:

It sounds suspiciously like new servo time

Clan may be able to confirm but IIRC it's about 4 hours labour with a dealer as there is a fair amount of dismantling.

The only confusing point is the whistling occurring from the accellerator pedal also, I wonder if your boots have become misplaced/split hence allowing you to hear the noise.

John_C · Feb 17th, 2008, 10:47

Neil, if you do a search in the S60/V70 forum for "brake hiss" you'll find some threads which could be useful, you can compare them to the noise you are getting and go from there. As Clan says though they all seem to suggest a new brake servo is the most likely result.

Cheers,
John

Nunchukhamster · Feb 17th, 2008, 10:55

Quote:

Originally Posted by s60ben

I'm also sorry, but I fail to see the relevance of comparing the heater distribution box in an old V90/900 to an S60

Thank gawd for that, I thought it was just me that couldn't figure out why I was looking at parts of an older car when someone was asking about a modern S60.

kdst5 · Feb 18th, 2008, 13:51

I to have this hissing coming from the brake servo. I have never actually worked out where in the servo it comes from. Some suggest that a diaphragm is broken but I am not so sure.

When I start off in the morning there is no hissing, this only starts after about 15 minutes of driving. While pressing the brake pedal the hissing stops but starts again when the pedal is released, if you then press the pedal relay hard then the hissing will stop for a while. This to me seems more like case of the servo is coming apart and not the diaphragm.

I am sure on one of the forums (not sure it was this one) that someone managed to fix it without a new servo, the problem is I can not find it any more.

Feb 16th, 2008, 22:40	#1
neil p gaffney New Member Last Online: Feb 20th, 2008 19:58 Join Date: Feb 2008 Location: Dublin	Hissing Noise Hi, I posted a message on the general site and nobody came back with a suggestion. Maybe the T5 owners might be able to help. I have a 2003 S60 T5 in pristine condition with 70,000 miles on the clock. In the last week I am getting a hissing noise when I press the brake pedal or let it go, like wise when I let go the accelerator? There is no difference in the braking, it still performs 100% as new. Please somebody tell me it isn't a knackered brake servo? I believe it is savage expensive to replace. I've had a grin on me since I bought the car, but it will disappear very quickly if this is true.

Feb 16th, 2008, 22:58	#2
Clan Experienced Member Last Online: Today 09:37 Join Date: Jun 2007 Location: L/H side	there is always a hissing noise from the servo when pressing the brake as the air goes in through the pedal push rod area but it is normaly very quiet .There is a foam air silencing/filter material inside the rubber boot where the pedal push rod goes through , but it does seem you will need a new sevo to cure from my experience with this noise :-( __________________ My comments are only based on my opinions and vast experience .

Feb 16th, 2008, 23:00	#3
CTCNetwork Forum Support Team Join Date: Dec 2004 Location: Liège, Belgium View Photos By: CTCNetwork	Hi, Registers is not the place for Technical questions. Have asked it be moved.. Your other post was actually in the "Blogs"... However, some more detail about what model of car you have would help. Hissing in the dash may relate to the heating system as that uses vacuums to open and close the heater distributor box. Do you have AirCon?? Luck in getting this resolved... Welcome to the forums and enjoy your time here... Des. . . __________________ Density:- Not just a measurement ~ It's a whole way of Life.! ! ! I drive a Volvo, Please Don't Get In My Way! OldVolvos4Ever He shows up. People die. He vanishes. People should not be afraid of their governments. "He'll deliver more justice in a weekend than 10 years of your Governments should be afraid of their people... "V" courts & tribunals. Just stay out of his way." "I plan to."

Feb 17th, 2008, 02:42	#5
CTCNetwork Forum Support Team Join Date: Dec 2004 Location: Liège, Belgium View Photos By: CTCNetwork	Hi, I can only assume Mr Ben has posted some derogatory comment but if you look at the below photo - top right hand part - you will see vacuum tubes to the heater distribution box. If your hissing is definitely coming from the dash area then it may be (as already mentioned) a source of your hissing. Tubes broken or removed or displaced will hiss. But then, how the heater (and heater distribution box) works in your S60 could well be different to how it works in my 940 or V90. Des. . . __________________ Density:- Not just a measurement ~ It's a whole way of Life.! ! ! I drive a Volvo, Please Don't Get In My Way! OldVolvos4Ever He shows up. People die. He vanishes. People should not be afraid of their governments. "He'll deliver more justice in a weekend than 10 years of your Governments should be afraid of their people... "V" courts & tribunals. Just stay out of his way." "I plan to."

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Feb 17th, 2008, 10:47	#8
John_C Allons-y! Last Online: Jun 8th, 2020 15:32 Join Date: Dec 2004 Location: Winchester	Neil, if you do a search in the S60/V70 forum for "brake hiss" you'll find some threads which could be useful, you can compare them to the noise you are getting and go from there. As Clan says though they all seem to suggest a new brake servo is the most likely result. Cheers, John

Feb 18th, 2008, 13:51	#10
kdst5 Senior Member Last Online: Yesterday 12:53 Join Date: Jun 2007 Location: Horsham	I to have this hissing coming from the brake servo. I have never actually worked out where in the servo it comes from. Some suggest that a diaphragm is broken but I am not so sure. When I start off in the morning there is no hissing, this only starts after about 15 minutes of driving. While pressing the brake pedal the hissing stops but starts again when the pedal is released, if you then press the pedal relay hard then the hissing will stop for a while. This to me seems more like case of the servo is coming apart and not the diaphragm. I am sure on one of the forums (not sure it was this one) that someone managed to fix it without a new servo, the problem is I can not find it any more.

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