Fuel injection pump plug seal?

Hi,

There's a plug on the drivers end of my '99 ALH tdi injector pump that just started leaking. It's a little over an inch in diameter and needs a three sided socket for removal. Has a smaller hex bolt in it's center.

I need to know if removing it will disturb anything, and I need to know if it's seal is a plain "O" ring or some dedicated seal.

I'd sure appreciate benefitting from the experience here as I've been searching the past threads for hours and found nothing about this particular leak location.

Got a timing belt job due in 5000 miles so I will replace all other seals at that time. Just need to get this leak stopped.

Thanks,
Dan

I would not be surprised to find out that you need to have new seals done.

Just FYI, several experienced members here recommend having someone replace the seals for you...apparently it's pretty easy to trash the IP.

Buy the multi seal kit from dieselgeek. It has all the seals you are interested in for the reseal you are planning later also. About the only thing it doesn't have is the pulley side shaft seal, and that one requires retiming the pump after replacement anyway.

IIRC, it is the 810 kit. Somewhere, there is a diagram that has an exploded parts view, and some of those o-rings and seals have an 8nn number underneath them, indicating that there is a kit which has them. I could be absolutely certain if I could find that diagram, but I'm at work and can't spare that much time right now.

Anyway, since the most important and common seals are in DG's kit, I am sure you'll find what you need in it.

Thanks, I plan to get the kit, but I need the leak fixed right now and it looks like an "O" ring bought locally would do it.

I'll be retiming the pump in 5000 miles anyway when I do the timing belt change, so I'll probably do the shaft seal too.

All the diagrams I've found on the internet do not describe the seal and I can't tell from looking if it's a special seal or just an "O" ring.

I need to know the answer to two questions.

1. Will removing the plug will affect anything inside?

2. Is the seal for the plug an "O" ring?

Thanks,
Dan

One's an o ring and the other is a seal, probably a copper gasket. (i.e. for the plug and the larger bolt the plug goes into.) Removing the plug won't do anything except leak fuel and allow air in, so you'd want to try and bleed the pump before restart.

And no, I'm sorry I don't remember which. Google it and start looking, and you should find a appropriate diagram in 20 or 30 minutes.

I've spent hours and found several diagrams but none that show enough detail.

Just to be clear, it's the larger one, one inch plus in diameter, that's leaking. Is it OK to remove that one without disturbing internals?

Once out, I can tell what kind of seal I need.

Thanks for your help,
Dan

Update. In case someone in the future gets here searching for help, here's the rest of the story.

I called Dieselgeek.com and talked to Jim. He said the size of the three sided plug is 24mm, but 15/16" is a tighter fit. He also said the seal is an "O" ring, and removing the plug won't disturb anything.

I got a 6 point 3/8" drive 15/16" socket and removed every other flat by presenting it to the edge of my cutoff wheel.



It was a tight fit getting the socket in between the injector lines but from the engine side there was room. That way I didn't need to disturb the lines.
By turning the socket to index with the square drive, I was able to find a position for the 3/8" drive breaker bar to have room to break the plug loose. I then turned it the rest of the way out against the drag of the "O" ring using a box wrench on the bolt head in it's center.



Found a replacment "O" ring at the local tractor dealer and used Vaseline on the "O" ring to lubricate it going in. All is well thanks to Jim at Dieselgeek.com.

Dan

About to get started in replacing the head plug seal in my 2000 jetta. After making the three sided socket, any issues to be aware of? I assume a pretty decent quantity of fuel will spill out, but any details on the replacement seal/ring/gasket. Parts schematic says it's an o-ring. Any advice before I get way over my head quickly would be much appreciated. Thanks for this great thread. Yesterday I thought I was going to be in to this for several thousand from my mechanic, now I feel relatively confident that with you guys out there I should be able to do this in my driveway, myself.

It's been a long time since I did it but I don't remember loosing a lot of fuel. I think I just had a rag below to intercept any spilling fuel.


Still holding without leaking.

Dan

Just resealed my pump a couple months ago and the head plug seal just started leaking pretty badly this week.

Thanks to this forum and excellent members I was able to get a 15/16 socket from Autozone and modify it with my dremel. It is not as short as Dan's so required a reducer and extension through the fuel lines to get a ratchet on it.

Still had the o-ring from the dieselgeek pump kit, so it was about 1/2 hour to make the tool and 15 minutes to actually change the seal.

FYI - I only lost about a tablespoon of fuel, so I said WTH and started it up. Had a few bubbles pass through the line but they seem to have worked out.

Dan, you saved me from a headache that I had for weeks trying to figure this out. That leak was driving me crazy, I just performed this task and no leaks so far. Very easy fix.

I could only find a 1/2'' drive socket, had to remove the left two fuel lines, but everything went smooth. I did loose a decent amount of fuel, but did not have to prime anything.

This thread should be added to the entire build procedure on the injection pump for easier find. had no idea it was called the plug seal.

Thank you Dan for this post. I’ve never had to change the oring on that plug. I just had a friend that had a steady flow of fuel leaking out of that plug. Great info on the procedure and how to modify the socket.

Terry

Picking this back up. There are two rings that could theoretically be the replacement ring for the center bolt in the IP in that Bosch Dieselgeek package. It could be 1 of the 2 green ones or the black more traditional O ring. Can anyone please tell me which ring from the Bosch kit replaces the reddish one I am pulling out? Thanks.

Jim just said black one - for those interested. One coming out doesn't look like O ring but maybe it did 2 gazillion miles ago.

I used the diesel geek it, and replaced the top seals and the head seal. Follow the directions. I also bought the 3 sided socket from diesel geek. Also, make sure the the torx heads fit exactly, or you can strip the bolt heads. There is a video tutorial on diesel geek showing how to replace the seals.

Thank you for this post! I just replaced this O ring. Initialy thought one of the copper washers on the outlets had gone, then realized after replacing it maybe it was the center section. Luckily I had the seal kit, quick trip to home depot for a 15/16 socket and a little work with a dremeland I had the O ring out and the new one in. Have to say clarifying the black O ring was also super helpful, my old one was redishbrown and so flat and brittle it almost seemed more like one of the green O rings.