ALH leaking vacuum pump

flee

Veteran Member
Joined
Sep 19, 2011
Location
Chatsworth, CA
TDI
2002 Jetta GLS wagon
BakoTdi, does your VW have anti-lock brakes? That sounds like it might be A/L brakes activating.
 

BakoTDI

Veteran Member
Joined
May 5, 2005
Location
Bakersfield, CA
TDI
Jetta, MK7
BakoTdi, does your VW have anti-lock brakes? That sounds like it might be A/L brakes activating.
Yes, that's correct.

I don't believe that to be normal though. It is a bit scary if you forget it can happen, and when it does, you can't stop momentarily, and once I release and press on pedal again, it's normal. ugh...
 
Last edited:

flee

Veteran Member
Joined
Sep 19, 2011
Location
Chatsworth, CA
TDI
2002 Jetta GLS wagon
Yes, that's correct.
I don't believe that to be normal though. It is a bit scary if you forget it can happen, and when it does, you can't stop momentarily, and once I release and press on pedal again, it's normal. ugh...
Find a VCDS and scan for codes. You may need a new brake module or ?
 

BakoTDI

Veteran Member
Joined
May 5, 2005
Location
Bakersfield, CA
TDI
Jetta, MK7
Find a VCDS and scan for codes. You may need a new brake module or ?

I have an intermittent wheel sensor code, but it doesn't necessarily happen when code is on. I've had to rewire the wheel sensor cables because they have gotten damaged, and I've changed the wheel sensors as well. Might have to revisit this.

brake module though??
 

runonbeer

Maintenance EnthusiastVendor
Joined
Apr 15, 2002
Location
Austin, TX/Chapel Hill, NC
TDI
'00 Golf 02M, '10 Golf 02E, '02 UTE 02M
Bako, search around here for slow down shudder. Many early ALH cars had/have this problem and it sounds kind of similar to what you are describing.
Inadequate brake booster vacuum will usually only manifest as a rock hard brake pedal coupled with very little actual stopping power. Makes me think of Fred Flintstone jamming his bare feet into the ground to halt his rock-mobile.
 

BakoTDI

Veteran Member
Joined
May 5, 2005
Location
Bakersfield, CA
TDI
Jetta, MK7
I looked at the “slow down shudder” posts and these seem to relate to IQ adjustments rather than with braking �� I could be wrong but since I last replaced my injector pump seals, i did do the hammer mod to adjust the IQ.
 

Solamia

Well-known member
Joined
May 26, 2010
Location
Kansas
TDI
2001 Blue Jetta TDI (380K mi)
Anyway, today I came across this video on youtube (https://www.youtube.com/watch?v=7aRX4gfcpek) and was wondering if anyone had come across this before, and since nobody mentioned it, I thought I would share it. The website the kit can be bought is this (https://www.rkxtech.com/products/vw-alh-tdi-vacuum-pump-reseal-kit). Some of you seem to have purchased the 2.5mmx74mm V75 Viton from the O-ring Store and seem to have no problems with it. I am thinking that if this is the right o-ring size, I might not have to get the kit I mentioned above since there are no specifications on the size of the o-ring included in the kit.

.
That "kit" is what, $24.50?? I ordered vacuum pump seal from IDParts and internal o-ring from O-Ring Store and even with shipping my total was $14.54.
 

BakoTDI

Veteran Member
Joined
May 5, 2005
Location
Bakersfield, CA
TDI
Jetta, MK7
That "kit" is what, $24.50?? I ordered vacuum pump seal from IDParts and internal o-ring from O-Ring Store and even with shipping my total was $14.54.
I figured that the convenience of the "kit" would beneficial, but I agree, not sure if $10 is really that much more convenient! haha

Thanks Solamia for the wake-up call :)
 

cvalentine

Veteran Member
Joined
Aug 7, 2003
Location
Anchorage, AK
TDI
2003 Golf, 2014 328d
How has the alternative size o-ring worked out? Staying leak free? I'm
about to order for my vacuum pump and am curious how the two sizes listed in this thread are working out. Thanks for any update you can give!
I tried the soft durometer in size -151 o-ring, and it started leaking after less than a year. The standard/harder durometer might seal better and work.
 

GEFP

Veteran Member
Joined
Jan 22, 2018
Location
Southern Alberta Canada
TDI
2- 2001 Jettas, 2 - 2002 Jettas (1 for parts) 2003 1.8t Jetta (parts) 2014 Jetta
I'm going to subscribe to this one. I'm sure I already have the same problem.
 

Rick97213

New member
Joined
Aug 2, 2006
Location
PDX
TDI
2003 TDI GLS Wagon 5 spd
measured RKX kit O ring

measurements with micrometer of .100" of the O ring in the RKX kit is right at 2.5MM.
The custom seal between head was about 3mm.
I just had to know.


Rick
 

apple4ever

Well-known member
Joined
May 22, 2006
Location
Coatesville, PA
TDI
2002 Jetta TDI, 5sp manual, 280K miles
So speaking of leaking oil and the vacuum pump:

I've been having loss of power issues, which I tracked down (so far) to vacuum issues.

About 5 years ago (and only 30K miles if my records are correct) I replaced the all the vacuum lines including the brake booster line and N75 (because I broke a connector off of it). I also had the nipple fixed, though the garage did a weird fix with some green stuff (bondo?).

Anyway, I got a Mitavac and only got about 15" at the N75 inlet line, and I eventually get 25" at the line right off the break booster. If I press my brake pedal about 4 times, I lose vacuum until it has time to rebuild, and I can see the vacuum going down.

Then I noticed cracking ing the green stuff and the nipple could rotate. As a temporary fix I put some RTV on the nipple, but that didn't really help.

So I went to check the brake booster line, and there was a bunch of oil in it! Mostly on the vacuum pump side, but a little on the booster side too.

So options I've done research this:

1. This suggestions the valve is bad in the booster line. So I could replace that, but it looks good otherwise and its $60 right now from IDParts.
2. Pull the vacuum pump off and open it open. Make sure it looks good inside, replace the two o-rings, and do the JB Weld method of sealing the nipple. A bunch of work that may not fix the oil issue, but would fix the vacuum issue most likely.
3. Buy a brand new pump, which is what was implied on this thread .

Thoughts?
 

apple4ever

Well-known member
Joined
May 22, 2006
Location
Coatesville, PA
TDI
2002 Jetta TDI, 5sp manual, 280K miles
Just a note, I tracked down my boost issues to a bad Turbo Vane Actuator - it was not holding vacuum and not moving.

Still got to figure out the oil part.
 

Qui-Gon_Gene

Member
Joined
Jan 29, 2012
Location
Texas
TDI
2000 Jetta TDI
So, has anyone come up with a fix for the loose vacuum pump nipple that actually works? I tried JB Weld and that was a waste of time. I have enough of a vacuum loss with that thing to rob me of braking power.
 

GEFP

Veteran Member
Joined
Jan 22, 2018
Location
Southern Alberta Canada
TDI
2- 2001 Jettas, 2 - 2002 Jettas (1 for parts) 2003 1.8t Jetta (parts) 2014 Jetta
So, has anyone come up with a fix for the loose vacuum pump nipple that actually works? I tried JB Weld and that was a waste of time. I have enough of a vacuum loss with that thing to rob me of braking power.
JB Weld worked for me. I tried to fix the sloppiness with a punch and ended up breaking the housing. I cleaned up the housing with brake clean and JB Welded the fitting.

Make sure you clean it up good and let the JB set for at least 24 hours.
 

Qui-Gon_Gene

Member
Joined
Jan 29, 2012
Location
Texas
TDI
2000 Jetta TDI
We'll, I spoke too soon. I got ready to take things apart again, and discovered that the JB Weld did hold after all! the wobbling I saw this time turned out to be the hose attached to the port, and that hose needed to be replaced. I chased down a few other minor leaks and replaced a few pieces of hose here and there, and my brakes are a lot better. I think my vacuum pump is just getting worn out.
 

jeffpepin

Member
Joined
Oct 8, 2017
Location
canada
TDI
1.9 ALH jetta 2003
Here is a simple drawing showing a section through the nipple. During manufacture, the nipple is set into its hole, then the lip of the hole is rolled over to secure the nipple.

As the engine rocks back and forth during acceleration and deceleration, the booster hose tugs on the nipple. This, over time, pulls the lip up slightly and you get a loosey-goosey nipple. Whatever seal is underneath the nipple will tolerate a bit of looseness, more than that and you get a vacuum leak

The pump needs to be off the car as you just can't get good access with a hammer if it's on the car.

Chuck it in a vise. Don't clap the vise on the area where the o-ring goes, you don't want to mar that surface or you could get a oil leak.

Take a punch and put it on the edge of the lip, parallel to the nipple as per the red arrow. Give it one good whap with a hammer. Go around the lip with the hammer and punch, I do 10 or 12 hits all around the lip.

SO MANY THANKS !! the Tappy-Tap method you have mentioned worked like a charm
gratz from Qc Canada
 
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