Brake servo vacuum line help please?

4Golf

Well-known member
Joined
Sep 30, 2015
Location
Ireland
TDI
VW Golf Mk4 Gt Tdi 130Bph
Hi,

Can anyone tell me what the symptoms would be if there was a collapsed section of the vacuum line coming from vacuum pump, in other words it sucked its self almost completely closed due to being the wrong hose used. It is a soft hose someone obliviously used as a replacement in the past but I believe it should be a hard plastic hose instead.

The reason I ask is my car failed the test due to being a vacuum leak according to the tester. He said the vacuum goes after one press hard of the brake pedal when it should be good for at least 4 presses. He said I’m basically manually pushing on the brakes all by myself instead of getting the assist by the vacuum. I think this squeezed closed pipe may be the cause of the problem. Can anyone confirm this or shine some light on this for me as tester said I prob need to replace the vacuum pump as he said it’s a common problem with them. Also if I need to replace this hose line how do I disconnect or reconnect the hose lines without damaging it or it’s fittings? My car is Golf GT TDI 130 PD


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joep1234

Veteran Member
Joined
Jan 2, 2014
Location
NC
TDI
former '04 Beetle TDI, now 2x '15 Audi Q5 TDI's, 2007 Dodge Ram 4x4 6.7
Check the barb on the back of the tandem pump for leaking and loose. Also check all of your vacuum lines for leaks. All it takes is one to cause problems with the brakes.
 

gforce1108

Top Post Dawg
Joined
Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 14 Audi A7 V6 TDI, 13 Porsche Cayenne V6 TDI
Wow... never heard of a test like that. Not a bad idea. I keep seeing people “deleting” the vacuum ball to clean up the engine compartment. Without it that test would never pass. Get yourself a mighty vac or one-man brake bleeder. It’ll let you test the whole system to find a leak and confirm the pump is generating enough vacuum.
 

4Golf

Well-known member
Joined
Sep 30, 2015
Location
Ireland
TDI
VW Golf Mk4 Gt Tdi 130Bph
Check the barb on the back of the tandem pump for leaking and loose. Also check all of your vacuum lines for leaks. All it takes is one to cause problems with the brakes.


Hi joep1234,

Thanks for your reply. If you mean the barb on back of tandem pump as the metal pipe insert that spins on the back of the pump that inserts into the hose where it begins coming from the pump then yes mine appears to be leaking there as I seen oily residue on that hose and it appeared to be coming from that little round metal pipe insert fitting that is fitted directly in rear of pump. I’m not sure though if it’s the source of my leak or is the hose itself failing and causing the leak.

I don’t know how to check all the vacuum lines for leaks. If I knew how to properly and had the tools I would do it. I do most my own work but I’ve never really needed a vacuum tester kit.

Plus there seems to be a maze if vacuum hoses on the bulk head on my car. Is there an easy way to test them? I have bought a used hard plastic brake service line and I can see straight away my hose is wrong. Is it hard to disconnect or connect the hose lines as I’ve heard they break often?


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4Golf

Well-known member
Joined
Sep 30, 2015
Location
Ireland
TDI
VW Golf Mk4 Gt Tdi 130Bph
Wow... never heard of a test like that. Not a bad idea. I keep seeing people “deleting” the vacuum ball to clean up the engine compartment. Without it that test would never pass. Get yourself a mighty vac or one-man brake bleeder. It’ll let you test the whole system to find a leak and confirm the pump is generating enough vacuum.


Hi gforce1108,

Thanks for your reply. I would like to have a mighty vac but I don’t know if I would get much use out of it as I only repair my own or family cars but always handy for brake bleeding I suppose. Will a one man brake bleeder confirm the pump pressure and van you recommend a good one?


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BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
I think you're spot on it. That soft hose (if we're talking the one to the brake booster) would cause exactly that symptom with the pedal. Get the proper hose or one from a wrecker, just be sure you plumb it up leak free. And of course the vacuum pump and other hoses should also be in good nick.
 

joep1234

Veteran Member
Joined
Jan 2, 2014
Location
NC
TDI
former '04 Beetle TDI, now 2x '15 Audi Q5 TDI's, 2007 Dodge Ram 4x4 6.7
That barb on the back of the tandem pump is supposed to be a pressed fitting and not able to move or rotate. You can clean it up and use silicone or JB Weld to lock the thing down. The vacuum leaks in the small hoses can be chased down by a good visual inspection. Remove them and check every inch. I had the loose barb and thought it was my problem with the brakes. My son fixed it for me and the brakes worked a little better but it wasn't until we changed all of the hoses that we found I had 5 leaks where the hose had worn through on the underside that had rubbed against something.
 

4Golf

Well-known member
Joined
Sep 30, 2015
Location
Ireland
TDI
VW Golf Mk4 Gt Tdi 130Bph
I think you're spot on it. That soft hose (if we're talking the one to the brake booster) would cause exactly that symptom with the pedal. Get the proper hose or one from a wrecker, just be sure you plumb it up leak free. And of course the vacuum pump and other hoses should also be in good nick.


Hi BobnOH, thanks for your reply. I have bought a used vacuum pump brake servo line from breakers and I can see the hard plastic hose on it instead of my soft one in the location of my sucked in hose. I want to check all hoses for leaks but it seems like such a maze of hoses and it looks a bit confusing/awkward to do! I also am afraid if breaking some of the fittings/check valves. I will tackle it myself but just a bit cautious. Can anyone tell me the procedure for replacing the vacuum pump to brake servo hose on my car as it looks like I have to remove a few bits to do it?


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4Golf

Well-known member
Joined
Sep 30, 2015
Location
Ireland
TDI
VW Golf Mk4 Gt Tdi 130Bph
That barb on the back of the tandem pump is supposed to be a pressed fitting and not able to move or rotate. You can clean it up and use silicone or JB Weld to lock the thing down. The vacuum leaks in the small hoses can be chased down by a good visual inspection. Remove them and check every inch. I had the loose barb and thought it was my problem with the brakes. My son fixed it for me and the brakes worked a little better but it wasn't until we changed all of the hoses that we found I had 5 leaks where the hose had worn through on the underside that had rubbed against something.


I thought I read somewhere where that barb as you call it was supposed to be able to rotate, don’t know why and doesn’t make sense to me. I think I will try what you say as I can’t see it needing to rotate and shouldn’t be a problem sealing it up. It really just looks like a maze of hoses to check for leaks but if I can find an easy way of doing it for me I will check them all. I am afraid of breaking something though! But it does sound like its worth checking over.


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gforce1108

Top Post Dawg
Joined
Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 14 Audi A7 V6 TDI, 13 Porsche Cayenne V6 TDI
Hi gforce1108,

Thanks for your reply. I would like to have a mighty vac but I don’t know if I would get much use out of it as I only repair my own or family cars but always handy for brake bleeding I suppose. Will a one man brake bleeder confirm the pump pressure and van you recommend a good one?


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Even a cheap one will have a gauge on it and will work nicely. I used one for years and don't think I spend $20 on it? I recently bought the mighty vac, which still wasn't too expensive - just higher quality. I sucked brake fluid into the old one a couple too many times and clouded up the gauge face :)

This is similar to the old one I have: https://www.amazon.com/HFS-Brake-Bl...862290&sr=8-19&keywords=one+man+brake+bleeder
 

wonneber

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Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
I want to check all hoses for leaks but it seems like such a maze of hoses and it looks a bit confusing/awkward to do! I also am afraid if breaking some of the fittings/check valves.
It is a maze of hoses.
I did mine (twice now) by doing one at a time and marking the replaced ones.

First time I used white out (from stationary).
It has a small brush in it and dries quickly.
A bit sloppy.

Second time I used short pieces of telephone wire, Wrapped two or three turns around each hose replaced.
 

4Golf

Well-known member
Joined
Sep 30, 2015
Location
Ireland
TDI
VW Golf Mk4 Gt Tdi 130Bph
Even a cheap one will have a gauge on it and will work nicely. I used one for years and don't think I spend $20 on it? I recently bought the mighty vac, which still wasn't too expensive - just higher quality. I sucked brake fluid into the old one a couple too many times and clouded up the gauge face :)



This is similar to the old one I have: https://www.amazon.com/HFS-Brake-Bl...862290&sr=8-19&keywords=one+man+brake+bleeder


Thanks for the link. I think I will purchase one of these as I always hate bleeding the brakes on my own using a half full bottle of brake fluid with a hose in it and the other end attached to the brake caliper bleed nipple. Its also a bit awkward so I know this would be much easier/faster. And I’ve had to repair a vacuum system before on a 4x4 as the 4 wheel drive wasn’t engaging due to vacuum leaks but I never had a vacuum pump and I can see it being useful in the future considering all the things that are assisted/controller by vacuum. This vacuum system on my Golf also looks a lot more complicated than the old 4x4 did.


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4Golf

Well-known member
Joined
Sep 30, 2015
Location
Ireland
TDI
VW Golf Mk4 Gt Tdi 130Bph
It is a maze of hoses.

I did mine (twice now) by doing one at a time and marking the replaced ones.



First time I used white out (from stationary).

It has a small brush in it and dries quickly.

A bit sloppy.



Second time I used short pieces of telephone wire, Wrapped two or three turns around each hose replaced.


Hi wonneber, thanks for your reply. That’s reassuring to hear and some great tips there. I have a white paint marker that i got before for marking things like this and for marking alignment parts etc so this would be handy but the telephone wire sounds even better and maybe much easier to spot as being done and also can be removed when done without leaving any marks.


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4Golf

Well-known member
Joined
Sep 30, 2015
Location
Ireland
TDI
VW Golf Mk4 Gt Tdi 130Bph
Can anyone tell me what size vacuum hose I need to replace all hoses on my car? I can only find 3.2mm and 5mm vacuum hose in the stores. Is 4mm supposed to be better to provide enough vacuum for braking power?


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BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Not terribly familiar with the PD, but I'm reading it's the same as the VE. Below are 2 links with detailed info, MoGolf's with the part nos. is really old-
#19
#12
I remember buying 3mm silicone, firm and 4mm silicone, medium. I know the 3 was factory 3.5mm, but the 3mm works nice. The 3.2mm and 5mm vacuum hose ar likely what you need, just don't get flimsy windshield washer type product.
 
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