ALH IP leak

Hi, I have a MK3 with an ALH IP. I have a leak and it appears to be coming from the plug that is in the center of the the IP and is surrounded by the for injector lines. It looks like a plug with a bolt in it. Anyone have an idea what this is? I know there's a seal on it but just wondering what it is before I go removing it to change the seal.

I think it’s a left over part from the idi pumps that used a dial indicator, to set timing. They serve no purpose on TDI pumps.

The center part with the hex head used to have a copper seal, but I think it’s been done away with, on the TDI pumps.

The large triangular plug is sealed with an o-ring. Good luck getting this off while on the car, if you don’t have the special socket.

Both can be removed, with no worries.

-Todd

ToddA1 said:

I think it’s a left over part from the idi pumps that used a dial indicator, to set timing. They serve no purpose on TDI pumps.

The center part with the hex head used to have a copper seal, but I think it’s been done away with, on the TDI pumps.

The large triangular plug is sealed with an o-ring. Good luck getting this off while on the car, if you don’t have the special socket.

Both can be removed, with no worries.

-Todd

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My AHU tdi pumps have had the copper washer on the timing port but perhaps some might not have that, I have only seen three or four TDI IP's so can't say for certain.

The large triangular plug can be removed with a 6 pt 24mm socket with three sides ground down to allow for the rounded portions. It took me a while to make it but it's been used several times now so I don't consider making it a waste of time.

Steve

It's a lot of torque on that 3 sided bolt. It has a knife-edge seal on the inside to keep the high pressure fuel from escaping into the case pressure. You can almost always re-use them though. It also has an o-ring to keep case pressure from leaking out of the pump. You can get the proper tools on amazon/ebay for pretty cheap.

The 12mm bolt in the center is still used for timing with a dial indicator, but it's preset at the factory with the hub.

So the big question would by why that dial indicator plug would be leaking fuel? I thought the fuel would be isolated from the body of the pump?

RabbitGTI said:

https://cdn.shopify.com/s/files/1/2...ead_Seal_Replacement.pdf?15651934029198646224

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I resealed it a couple years ago using those instructions and has been fine since. The leak I'm referring to is coming from the large plug surrounded by the injector line fittings.

Because stuff wears out......?

Like Steve said, grind a large socket. I’ve always tapped on a large open end of a 24 or 25mm wrench. You’ll need to pull the lines and delivery valves, though.

-Todd

Dieselfiend said:

So the big question would by why that dial indicator plug would be leaking fuel? I thought the fuel would be isolated from the body of the pump?

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Because it has 2000 psi or better behind it?

Try tightening it. The ones I've had out had a copper gasket as has been mentioned.

More likely it's the o-ring on the big plug but you might get lucky. For a while.

KLXD said:

Because it has 2000 psi or better behind it?

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The o-ring I was referring to only holds about 100 psi. The copper washer and the knife edge do hold over 3000 psi but they are unlikely to be the problem.



The fact that you already replaced some seals on this pump is a give away as to why this is leaking. Bosch expects around 15 years out of a pump before it starts leaking. You're past the design expectations. Consider resealing the complete pump or you're constantly going to be chasing leaks until all the seals are replaced.

I was responding to this:

Dieselfiend said:

So the big question would by why that dial indicator plug would be leaking fuel? I thought the fuel would be isolated from the body of the pump?

Click to expand...

Any of you guys know the OEM number for the socket that fits that big cap?

Dieselfiend said:

Any of you guys know the OEM number for the socket that fits that big cap?

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Sorry, I don't happen to have a list of the special tools, that's why I make most of these items myself, that and it's far more expedient to just make the item if you need it.

You might call the dealer and see what they say, and if you find out something post back here so others will have that info if they need it.

Steve A

I've been known to make my own tools in a pinch but sometimes it just causes more problems than which you started with. That said, I try to exhaust all options to get the right tool for the job first before fabricating. I'm not in a huge hurry. The leak seals itself after the car warms up a bit. There's a place here in town that carries specialty tools but they need the OEM number to make sure it's the right one. That's why I was asking.

I just did this work three weeks ago, on mine that plug was leaking a lot! i bought the bosch seals kit on ebay (2 467 010 003 is the bosch number of the kit) and then i fabricated the needed tool with a dremel (it's a 24mm three-sided socket), then i cleaned the pump and the surroundings areas to prevent dirt entering the pump, then i disassembled injector lines and with a t-shaped wrench i managed to remove the plug (it required me a lot of effort, it's very hard to remove!). Then i changed the o-ring with the one in the kit and reassembled everything. Now it doesn't leak anymore and it's perfect!

I don't think a dealer will have a P/N for that tool since they would replace the pump before removing the plug to replace the seal.

Not a criticism of dealers on this. They aren't equipped to rebuild pumps since it's a clean-room type job.

DFIS might have a P/N for the tool. Might be available on Amazon or eBay.

I'm pretty sure this is the kit I use



https://www.ebay.com/itm/Socket-Wre...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

thats a nice socket find. looks to be for a '99 tho mk4s.
it looks to me there are 3 special sockets/tools needed in total(not including a one for the center 'plug'). one is on the very top of pump, in the older idi's it was for the vac hose, i forget the term for the top of the pump. the other looks like it fits in your pic tool #3, its the next 'level' of the pump down, opposite, in back of the inlet hose connection. on the 'front' of the pump is the electronic panel entrance, a smaller tool is needed. i dont think your pic has this tool, although the site your link takes us to has a compatibility selection, may lead to the right set of tools for our AHUs needed here.

i clicked on post so much i lost sight its a topic on an ALH pump in a mk3. ^.

burn_your_money said:

I'm pretty sure this is the kit I use



https://www.ebay.com/itm/Socket-Wre...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

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That looks like a nice set, I've made all of them but as you know they are often crude. So far they work.

This is for the triangle on the distributor head.



Steve

Just for future reference, there are 26mm triangle sockets all over ebay. However, I didn't want to wait so I ground down 3 flat sides of a 6 point 24mm socket as someone here suggested. Didn't really take me that long in all honesty and it worked well. Swapped the seal on the plug and back in business.

iluvmydiesels said:

i clicked on post so much i lost sight its a topic on an ALH pump in a mk3. ^.

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haha! Yes, my car was upgraded to an ALH IP pump. Used to belong to drivbiwire and I know he tinkered a lot with it before I got it.

iluvmydiesels said:

thats a nice socket find. looks to be for a '99 tho mk4s.

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AHU and ALH pumps are basically the same except for the case and the connector. All the bolts will interchange. In the eBay ad, the socket they show taking off the side of the quantity adjuster (don't actually do this, it's not serviceable) is used for the top bolt on the quantity adjuster. I'm going from memory, that side bolt is not removed.

I'm quite sure that's the kit I have and it does everything on these pumps.

yea well, i ve seen for myself in being curious -'like a cat'- that that panel is unserviceable. then a few years later i had one need a gasket. learned how to do that gasket if needed. what got me is i didnt see that gasket in the reseal gasket set. well that car has one and works good for now(at least there).

Dieselfiend said:

haha! Yes, my car was upgraded to an ALH IP pump. Used to belong to drivbiwire and I know he tinkered a lot with it before I got it.

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as my AHU runs quite good, not high mileage, but 20+ years old, and still going good. in the future to keep 'er running, among other continuing and improving plans, is a m-TDI pump and ('basic')set-up put in. the other web site has a lot and seemingly quite a bit of good info on this. get a pump and send it to whats his name, the pump shop, have him do a complete over-haul of pump and set it nicely. not too aggressive, but some -at least, to say the least.
the only thing i have a question of, for the most part is turbo, as i want to do away with electronic as much as i can. for the purposes of the A/C i ll need to keep the ecm to run it. hey its post-1990s, gotta have the convince, and luxury. its nice to run down the road, with little effect on performance, in a 90+dg day and be nice and comfy. but the thing i was saying is i want to put in a mechanical turbo at that time. i gotta do studying up on this and such if i want to do that.

i ve always been of the opinion that the industry in succeeding years(since the '70s) has made (in our case) vehicles made to be limited, for the industries benefit and thats not all. i always have felt the electronic involved in diesels add to that 'limiting factor' and tend to be an achilles heel.
the old mechanical versions are more solid state to me and much more reliable, even in the long run economical, as they work longer for (seemingly)less, with less problems, and such.

iluvmydiesels said:

as my AHU runs quite good, not high mileage, but 20+ years old, and still going good. in the future to keep 'er running, among other continuing and improving plans, is a m-TDI pump and ('basic')set-up put in. the other web site has a lot and seemingly quite a bit of good info on this. get a pump and send it to whats his name, the pump shop, have him do a complete over-haul of pump and set it nicely. not too aggressive, but some -at least, to say the least.
the only thing i have a question of, for the most part is turbo, as i want to do away with electronic as much as i can. for the purposes of the A/C i ll need to keep the ecm to run it. hey its post-1990s, gotta have the convince, and luxury. its nice to run down the road, with little effect on performance, in a 90+dg day and be nice and comfy. but the thing i was saying is i want to put in a mechanical turbo at that time. i gotta do studying up on this and such if i want to do that.
i ve always been of the opinion that the industry in succeeding years(since the '70s) has made (in our case) vehicles made to be limited, for the industries benefit and thats not all. i always have felt the electronic involved in diesels add to that 'limiting factor' and tend to be an achilles heel.
the old mechanical versions are more solid state to me and much more reliable, even in the long run economical, as they work longer for (seemingly)less, with less problems, and such.

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Ya know, there are a lot of performance advantages to things being electronically controlled. I'm a former jet aircraft mechanic and automated digital jet engine trimming in-flight was a performance game changer. I say the same for TDIs. The real difference between aircraft digital components and auto components is quality and environmental protection. It's kind of a shame that circuit boards in cars aren't manufactured or protected in the same way aircraft circuit boards are thus making them susceptible to wear a whole lot sooner. But, we are a small sliver of the auto buying population that keeps cars way passed their intended service life. Why would auto manufacturers cater to us when the majority of the population only keeps a car for 2 years on average.

ya well, im not the biggest enthusiast of over-electronic. esp on/in a mechanical need. then again i ve been chided in the past some for my open-minded view.
i have interest in jet propulsion, and well realize the need for the electronics. and the performance aspect. i just never had a chance or really a reason, other than being very interested in such stuff, to really get into aspects like school or studying.
as far as a diesel its mainly mechanically based, one of my points the mechanical pumps pressure doesnt really benefit from having internal electronics and 'wires' entering the pump. and like you point out, and i know well, our car, industry electronics are not made to the highest reliable standards. then again if electronics go in a plane, it comes up as a disaster. certainly is 'tragic', and a loss, of life.
and from the onset of diesels oh early 1900s the only real electronic is the shut-off solenoid. thats a matter of reliability, and cost effective. the only other electronics needed, are like a secondary electric system. its idiot lights, and gauges. other than that is such as A/C sensors, not directly related.
and some mTDI information have power out put being quite good.
i think in the past i ve seen where mr.waldon states he has/had the last available of performance pumps, hopped up by giles i think.
its not that im looking for a lot of performance, but some pump performance, along with a balance of economy, some head work, this im not sure of all i can do on it, just yet. maybe some extra turbo, with a mechanical type of turbo, and some injector nozzles. even until i do something like this, perhaps sending an ecm to kermatune and seeing how some of these upgrades work. will be fun. already is, as long as i dont get stranded, havent yet, so lucks with me! or things just work out, in either case.

In removing the three sided plug, is there any risk of internal parts of the pump coming out or getting dislodged? And how much torque is required? Thanks!

Nothing will fall out but make sure nothing gets in. That's the heart of the pump with a very tight tolerance on the piston in the bore. Next stop from there is the injectors that don't like dirt either.

I've found it takes a lot of torque to remove it but don't recall the tightening torque. Wasn't too tight. Some searching should turn the number up. That plug is supposed to be a one timer but many have reused it, myself included.