AGR to LDA: Ready-made Expansion Joint Nipples

Hello,

for charge pressure connections on the EGR unit.
see https://community.dieselschrauber.org/en/viewtopic.php?t=3224
"So far, I've been using self-made threaded connectors, which might be difficult for others to replicate."

In a tuning forum, someone suggested using brake bleeding screws, for example, those available for Opel cars, which have the necessary M5 coarse thread (not fine thread).

I actually think that's a good idea (why didn't I think of it myself ?), provided that suitable parts are actually available somewhere.

So, if anyone in this group has access to spare parts catalogs, they could perhaps take a look and, if successful, post the part numbers and prices.

Thank you in advance!

Hm, so, the hobby shop around the corner also has plenty of those. Such little pieces are used for all sorts of constructions there; I still have some lying around in my basement from my airplanes and cars. A pack of 10 usually costs next to nothing.

Either Robbe or Graupner is fine.

Julian wrote:

Hmm, so, in the model shop around the corner, they also have endless amounts of things like that. These little pieces are used for all sorts of constructions, I still have some lying around in the basement from my airplanes and cars. A pack of 10 usually costs next to nothing.

Hmm, then they must have expanded their product range... Many years ago, I also used to do model building, but they didn't have anything like that back then (a hollow M5 screw with a hose nozzle).

While there isn't a hobby shop around the corner from me, I'll ask about it next time I pass one.

Do you happen to have your part numbers handy?

From Robbe:

PRESSURE TANK NIPPLE M4 VE10
1-6018

PRESSURE TANK FITTING M5 VE10
1-6019

I don't know if that number still exists... it's been a long time...

Graupner:

M5 quick connectors for hoses - 4 mm, product number 6800.3.
4mm quick connectors with threaded nipple (for tank fittings).
http://www.shop.graupner.de/stores/Graupner/images/products/6800.3gr.jpg

Julian wrote:

Graupner: M5 quick connectors for hoses - 4 mm, product number 6800.3. 4 mm quick connectors for hoses with threaded nipple (for tank fittings).

The photo looks good so far.
If the M5 thread is truly the "standard" one and not a fine thread (or is "fine thread" called something else?), then that could be a solution.

However, it seems to me that the thread length is a bit short -> if you tighten the part too much in the aluminum AGR housing, the aluminum threads could potentially strip.

My DIY solutions, just to be on the safe side, definitely have at least double the thread length.

It shouldn't actually be a fine thread. However, it's questionable whether more thread length would make a difference with only 1.5 bar of pressure. In model making, higher pressures are sometimes used, and in those cases, it's usually only installed in plastic walls (pressure tank).
You just have to try, it was just meant as a tip.

Julian wrote:

It shouldn't actually be a fine thread. However, it's questionable whether more thread length would make a difference with only 1.5 bar. In model making, higher pressures are sometimes used, and in those cases, it's usually only installed in plastic walls (pressure tank). You just have to try, it was just meant as a suggestion.

Sure. Thanks for the tip, on behalf of all AGR-Anzapfer as well.

I don't see the thread length as problematic due to the pressure, but rather due to the assembly process.
You need a fair amount of torque to get the connection tight.
On the other hand, the shorter the threaded portion, the more care is required to avoid cross-threading.

I've already made some short, round aluminum threads myself - although not on TDIs.


If you have experience with model building:

Are there brass tubes with an outer diameter of 5 mm and a wall thickness of at least 1.5 mm that are available as a standard product?
You could cut an M5 external thread of almost any length onto it, leave a smooth section of pipe as a "non-nipple," and then screw on a hexagonal nut and braze it in place for tightening.

What would be, in my opinion, less tricky than drilling a hole through the center of a screw...

You need a fair amount of torque to get the connection tight.



Loctite rules.

CU Gremlin.

You can find these types of fittings in all variations imaginable at www.festo.de.
Direct access to the catalog (it's best to use the "image selection" option there).
http://catalog.festo.com/deu/asp/start.asp

Apparently, Graupner also buys parts from there, as they are Festo parts.
M5 threads are standard, not fine threads. They also come in a cute M3 size!
By the way, you won't be able to torque the M5 to its full specification. It will break before that (it's hollow...). For the engine bay sealing rings, it's best to use aluminum sealing rings.

joegolf wrote:

You can find such fittings in all variations that you can imagine at www.festo.de. Direct access to the catalog (the "image selection" option is recommended). http://catalog.festo.com/deu/asp/start.asp.

H, I can't find any threaded nipples or similar items there.

I've tried different approaches, but I'm probably too stupid.

EDIT:
I finally did it.

However, an external thread length of a maximum of 4 mm (M5) doesn't seem very "foolproof" when screwing into an EGR housing...

...

An external thread length of a maximum of 4 mm (M 5) seems to me not to be very 'foolproof' when screwing into an EGR housing.

Hi Ulf,

It is even scientifically proven that screws smaller than M6 are usually tightened too much, while larger screws are usually tightened too little.
I would simply insert a split ring between them and then tighten it slightly (place the correct size wrench on it and tighten it by hand until it's snug).

What could possibly go wrong if the nipple starts to protrude during a ride?
The hole is so small that it makes a hissing sound, but the machine continues to run.
Since the part is attached to the hose, it first prevents rotational movement (which would cause it to detach) and secondarily, it prevents it from disappearing (in case it does detach).

So, put it on while it's lukewarm, and that's it – fish is ready.

Greetings.

Eike.

The thread length is sufficient, unless you're particularly clumsy. If you want to be absolutely sure, use some Loctite instead of a sealing ring, as Gremlin suggested. Or use Teflon tape. However, that can be quite fiddly with M5 screws.

If sourcing the parts becomes too complicated, please send me a private message.

Hello.

"Festo parts already have a micro-encapsulated sealant on the threads that briefly becomes plastic during assembly, providing a seal. However, I believe it's more important to have a reliable, flat surface around the threaded insert to ensure a defined tightening torque."

Best regards, Robert.

LZ wrote:

Hello, The Festo parts already have a micro-encapsulated sealant applied to the threads, which briefly becomes plastic during assembly and thus provides a seal. Best regards, Robert

No, that's Teflon tape. But that's only available for thread sizes starting at 1/8".

I have my threaded fitting from the company Legris: [link]
http://www-1.legris.com/webapp/commerce/command/ProductDisplay?prrfnbr=1248&prmenbr=361
Article No. 3101 03 19.
This is a standard M5 thread. This nipple is sealed with an O-ring (which is included with the nipple).
Use a 3mm hose (outer diameter) for this.
In our company, these nipples are used without any problems in pneumatic control systems up to 10 bar.
It's been running smoothly for 6 months without any problems.

Best regards, Jürgen.

Hi,

My tap is from the company Rectus http://www.rectus.de/dev/de/home.htm.

An alternative to Festo would be...
http://www.smc-pneumatik.de/Prod/DE/Contents/Pg_Produktuebersicht/EBP4-Schraub-Steck-Schlauch.jsp?ctry=3#Anchor-Steckverbindungen-37516