How I deal with loose nipples...vacuum pump repair

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
Here is how I deal with the ALH's loose vacuum pump nipple problem. I have tried the peen-over method
and it works for a while but if it failed the first time then it probably will again. This will eliminate the o-ring's function that seals the joint. It seems like a weird failure prone, short term design to begin with and they keep doing it year after year.

I use JB Weld for this. It does take forever to set up....something like 10-12 hours to get firmed up.
This is a long time and maybe there is a shorter "kick-time" epoxy....I'm sure that there is but, this is my choice in this case. It is strong and the long set-up time lets it flow into crevices and level out. I wait overnight before putting the pump back into service.

Prepping the pump.

Clean the surfaces thoroughly with brake cleaner.

Create some tooth for the epoxy to "key" in onto the surface. I use a die grinder or Dremel to create small undercut notches on the 45* surface. The notches should be deep enough to hook the epoxy and prevent it from lifting up off the pump body. Finish off with a little rough Emery cloth on the bonding surfaces.



create a dam for the epoxy to settle in. I used 3/4" electrical tape here but, 1/2" is plenty and makes it easier to apply the JB Weld down into the trough.



Support the pump in a vice or other means so the the nipple is perpendicular to level. You will be relying on gravity to level the epoxy mix as it sets up.

Next, mix up some JB Weld. I have tried different ways to apply it and this one worked OK. Squirt both parts into a small plastic zip lock bag. A heavier weight bag is a good choice so that it does not break in the process. Seal the bag and squish it around until you get a uniform color. Nip the corner of the bag...just a small hole so that you can squeeze the mix out like a pastry bag dispensing icing.



Apply the mix first to the outer edge and drag a small tool like the end of a paper clip or a pick around the perimeter of the tape dam to work the epoxy down along the 45* edge.
Apply the rest to bring up the level about 3/32-1/8" above the surface of the nipple's flat.



After you have noticed that the epoxy has set up in the dispensing bag it is time to remove the tape. Trim off the edge with a razor while the epoxy is still semi-plastic.

Voila!:D

 
Last edited:

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS
Tucked in the brain for future reference/use. Thanks!
 

mrrhtuner

Veteran Member
Joined
Mar 29, 2011
Location
London Ont Canada
TDI
2003 Jetta Wagon TDI, 2015 Passat TDI, 2015 Touareg TDI
My question is...how well will this hold up with the engine vibration?

Keep us posted on how this works out for you.
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
My question is...how well will this hold up with the engine vibration?

Keep us posted on how this works out for you.

I have had about a dozen of these out there on cars so far over the last couple of years. It is getting to be part of the timing belt change procedure for me. Just about every MK4 that comes in has this going on to some degree.
Have I seen one come back a failure? Not yet. It is one of those things that, unless the nipple starts to leak grossly, it may not seem to be an issue to the owner/driver.

As for the longevity...
I don't picture that the JB Weld will be brittle and disintegrate. If anything, adhesion would be the hard part and that is where preparation comes into play. JB Weld does not stick particularly well to smooth flat surfaces.
You do have that 45* surface working against you and that is why I stress that some surface notching be used in that area to lock it in place.

We will see but, so far so good.
 
Last edited:

dweisel

Top Post Dawg
Joined
Jul 28, 2006
Location
Wheeling, West Virginia
TDI
dweisel isn't diesel anymore!
Use a product called "Quick Steel" it will set up fast and has a high temperture use rating. No waiting. I used it to patch a hole in a Beetle oil pan about 8 months ago. Still good.
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
I know that JB Weld is a 50/50 mix, but is there a mix that would err more to the side of adhesion? Maybe a little more white or a little more black?
 

Rembrant

Veteran Member
Joined
Oct 31, 2014
Location
Canada's Ocean Playground
TDI
2013 Golf TDI DSG
Excellent thread.

The procedure I've done is very similar...in that I use the tape in the same way, but used black high temp RTV silicone instead of JB weld. I may try the JB or Quick steel like this next time.
 

Ed ke6bnl

Veteran Member
Joined
Aug 24, 2015
Location
High Desert So. Ca.
TDI
2002 TDI Jetta
I have used JB or similar on Dirt bike crankcases and usually sell them with the same repair years later, does have it limitation. On the oil pan good temp fix but need to remove and tig up the crack or hole
 

WT_Feng

Member
Joined
Jan 17, 2015
Location
SC USA
TDI
2000 Jetta ALH, 300k miles, 2nd owner
I bought an OEM new pump so I cut up the old one to show:






In retrospect:
I might have tried to press the nipple base tighter onto the seal e.g. with a 'C' clamp and re-peen the flange to hold it tight. I observed in the cutaway that there's still some 'squish' in the seal when I press the nipple base onto the landing in the pump housing.


...but with 300K miles I figured the vane was probably worn out of tolerance anyway.
 
Last edited:

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
I bought an OEM new pump so I cut up the old one to show:



I'm a newbie and the system won't let me upload pics. Sorry
Yea it will. You have to go to pics.tdiclub.com, log in again (same user/pass), upload the info, then get the url to paste with your post. More complete instructions in my signature.
For large photos, it's nice to post the thumbnail url, the link for that is at the bottom of the page once your data is uploaded.
 

keaton85

Veteran Member
Joined
Feb 26, 2011
Location
Camden, ME
TDI
Golf MK4
I have to do this on my Audi as well, since it has the same issue with it's vac pump.

JB weld actually does adhere to metal pretty well if it is clean and preped. If you wanted more surface area, you could wrap the tape lower around the base.

Great post! I also do a mod on the brake booster hard line. I wrap it about three times with rescue tape to fix the cracks. This makes for an excellent permanent fix for cheap! never have to worry about the hose giving out on you again and causing vac leaks.
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
I have since changed my way of mixing and administering the JB Weld to the trough.

I mix the two parts on a coffee can lid like you would normally. I am more assured that I get an even color that way.

Then, load the mix into the butt end of a 1.0 ml syringe that I give my cat his drugs with...needle removed.
i.e., pull out the plunger and drag the butt end across the mix to force it up into the syringe. It is much easier to apply it where you want it that way. Two syringes worth does it.
 

WT_Feng

Member
Joined
Jan 17, 2015
Location
SC USA
TDI
2000 Jetta ALH, 300k miles, 2nd owner
Yea it will. You have to go to pics.tdiclub.com, log in again (same user/pass), upload the info, then get the url to paste with your post. More complete instructions in my signature.
For large photos, it's nice to post the thumbnail url, the link for that is at the bottom of the page once your data is uploaded.
Thanks for the tip. I followed your directions. My screen differed from your your screenshots and I didn't find a "process" button. I selected the pics from my HD and got the message "4 files uploaded". The file names showed briefly on the screen then disappeared. After I clicked the "upload" button I got the following message:

/home/fred/photopost/data/uploads//432666: Error creating directory (check permissions).

Please notify the System Administrator.
 

AnotherPerson

Veteran Member
Joined
Oct 24, 2015
Location
New Orleans
TDI
1999 Beetle
Just a tip here. I use a product called "JB-Kwik" and it sets up alot quicker. To remove it from almost anything required a dremel so it would be strong enough also.
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagen, 2021 Atlas,2003 Jetta 261K Sold but not forgotten

smee907

Well-known member
Joined
Dec 4, 2014
Location
Alaska
TDI
09 Jetta Sedan
I usually just walk outside in the cold and they tighten right up! J/K great writeup.
 

WT_Feng

Member
Joined
Jan 17, 2015
Location
SC USA
TDI
2000 Jetta ALH, 300k miles, 2nd owner
It looks like a one way valve in there.
I was hoping there was a hole that could be drilled & tapped for a screw in fitting.

Rich W.
The internal check-valve just pulls out. They must've offset the port just to try and torpedo your idea. Maybe if you cut/machine away the whole nipple/check-valve flange...





...also, there's about 1/4" of metal to thread on the narrow side of the port. And it could get tricky if you happen to disturb the metal in the vane's raceway. Hope this helps you see a way forward with your idea.

Uh... I'm rethinking this! Does the check-valve have to stay in for the vacuum to work? When the vane approaches the port it would 'pressurize' and as the vane passed over and beyond the port it would 'vacuum'. Right?

Or... Does it always 'vacuum' because the vane's axis of rotation is offset in the housing (supposing the vane rotates clockwise in the bottom photo). The approaching (and pressurizing) half of the vane would be short while the retreating half of the vane would be at full lenght as it rotates. The relative difference in length between the vane halves (due to the offset) might create a constant vacuum.

Then why the internal check valve? Perhaps that internal valve only makes sense if there's a relatively short duration pressure-pulse to clip.
 
Last edited:

hey_allen

Veteran Member
Joined
Nov 25, 2006
Location
Tacoma, WA
TDI
2000 Jetta TDI
I suspect that the only reason the check valve is located there is that some engineer thought it would be convenient.

Personally, I'd try tapping the larger check valve bore, and install a threaded hose nipple. There is plenty of wall thickness to support the threads, and little to no chance of damaging the pump bearing surfaces.
Then it would be easy to mount a generic vacuum booster check valve in line in the hose.

Any chance you have measured the diameter of the larger area where the check valve seals, above the offset hole into the vacuum pump chamber?
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagen, 2021 Atlas,2003 Jetta 261K Sold but not forgotten
The internal check-valve just pulls out. They must've offset the port just to try and torpedo your idea. Maybe if you cut/machine away the whole nipple/check-valve flange...





...also, there's about 1/4" of metal to thread on the narrow side of the port. And it could get tricky if you happen to disturb the metal in the vane's raceway. Hope this helps you see a way forward with your idea.

Uh... I'm rethinking this! Does the check-valve have to stay in for the vacuum to work? When the vane approaches the port it would 'pressurize' and as the vane passed over and beyond the port it would 'vacuum'. Right?

Or... Does it always 'vacuum' because the vane's axis of rotation is offset in the housing (supposing the vane rotates clockwise in the bottom photo). The approaching (and pressurizing) half of the vane would be short while the retreating half of the vane would be at full lenght as it rotates. The relative difference in length between the vane halves (due to the offset) might create a constant vacuum.

Then why the internal check valve? Perhaps that internal valve only makes sense if there's a relatively short duration pressure-pulse to clip.
I'm sure they put the check valve in for a reason.
Also blocking that port on the side will probably cover the vacuum.
A short fitting would pass the cutout and not cover the hole.
Maybe a bigger check valve on the outside.

Rich W.
 

WildChild80

Veteran Member
Joined
May 30, 2016
Location
Nashville, AR
TDI
2001 Jetta TDI 2000 Jetta TDI 2000 New Beetle TDI ALL 5 speeds
I know this thread has been dormant for a while but why not thread the outside and make a retainer cap for the nipple, tape a piece of pipe and use the same tap and die to make your threads, weld in a small washer that will lay on the nipple base to a larger washer and use red loktite and don't look back

Sent from my Pixel XL using Tapatalk
 

WildChild80

Veteran Member
Joined
May 30, 2016
Location
Nashville, AR
TDI
2001 Jetta TDI 2000 Jetta TDI 2000 New Beetle TDI ALL 5 speeds
Or multiple thread inserts jb welded together or tack welded together but for isolation on the nipple and to help seat it

Sent from my Pixel XL using Tapatalk
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagen, 2021 Atlas,2003 Jetta 261K Sold but not forgotten
I know this thread has been dormant for a while but why not thread the outside and make a retainer cap for the nipple, tape a piece of pipe and use the same tap and die to make your threads, weld in a small washer that will lay on the nipple base to a larger washer and use red loktite and don't look back
Interesting thought.
I will have to look at it.
I might have a die around the size.
 

WildChild80

Veteran Member
Joined
May 30, 2016
Location
Nashville, AR
TDI
2001 Jetta TDI 2000 Jetta TDI 2000 New Beetle TDI ALL 5 speeds
I'm in Arkansas and my tubs of vdub parts is in VA but when they get here I'm going to begin some R&D on nipple repair. Hopefully a week or 2, I feel naked without my spare parts...

Sent from my Pixel XL using Tapatalk
 

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 here has been my experience. I tried to just twist the nipple out so I could see what's underneath. That broke a good part of the flange off. So after looking it all over I decided to drill a hole for a small screw the replace the broken off flange. When I tightened that up the aluminum just cracked away. So those of you who are thinking to thread the hole and turn a nipple in be careful. The aluminum housing isn't very strong.

So on my spare housing I just peened the flange down more and used JB Weld. We'll see how long that lasts.

I like the idea of threading or just JB welding a nipple in and using an external check valve.
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
So far, zero problems with the original design, (JBWeld collar). ;)
 
Top