Type 4 alternator belt tension square nut

[airschooled]

Hi everyone,

I was assembling a Type 4 engine last week and came across a hex nut installed where the square nut should have been tucked in on the front of the alternator bracket. Since it's such a PITA to get that nut replaced, and we couldn't find a good used VW nut by our deadline, we made one.

If anybody else is struggling to find that special M8 square nut, one can be made out of a Unistrut nut and a few minutes of drilling/tapping.

The Unistrut nut came pre-tapped to 1/4x20, which was easy enough to drill out with a 17/64" drill bit. (An H bit would be better but we didn't have one.)

Follow with a well-oiled M8x1.25 tap…

And then you can carry on with the 96,832 other minute details that make the Type 4 engine such a pleasure.

We used PN P3006. For the over-achievers, pre-drilled M8 nuts can be found here: (clip the spring!)
https://www.amazon.com/Oglaend-Spring-Channels-Sta...annel+nuts

See you on the road,
Robbie
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[hazetguy]

How did you make the raised section that rides in the groove of the alternator bracket?

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[buckswilde]

Nice solution. I was dealing with a mangled square nut on my 79 last fall. Big PIA. If anyone is looking for a direct replacement without making one, Fastenal carries them. https://www.fastenal.com/. I took my old one in and they were able to find a match and order it for me next day. I'll try and find my receipt for the part number.

[airschooled]

[raygreenwood]

Great fix!

Anyone have caliper handy? What is the width of the slot in the bracket?

I ask....because you can buy these nuts at McMaster Carr.....

8mm x 1.25 thread....to fit a 10mm wide slot.
11mm total height with a 6mm thick flange
16mm wide
22mm total length...which you can trim shorter with a grinder

Part #: 90510A213.....black oxide....fully threaded ....$4.82 each

Catalog page 2661
Ray

[SGKent]

[airschooled]

Thanks Ray. I'll mic the slot this weekend. The length won't be an issue, there's about 10mm of dead space on the fan shroud side of the slot before you hit the M8 securing stud/nut. Our Unistrut piece was about 25mm long.

Ours is a NOS bracket too; the slot on the old one was so worn out I worried about it lasting another 40 years.

We had trouble sourcing a nut that had the correct flange that wasn't too deep. If the nut flange is taller than the bracket is thick, the assembly will never torque down. So if the flange is 6mm but the bracket is 5mm, I'm nut sure the replacement will work. Am I understanding the dimensions of the nut correctly?

Here is the page it's from, hopefully their links work:

https://www.mcmaster.com/catalog/125/2661

Robbie
_________________
Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com

[hazetguy]

[airschooled]

[raygreenwood]

I'm all for buying original stock when someone has it. Keeping new, corrct parts in circulation....and paying the seller a bit for the trouble of investing on that stock and storing it.

I also....HIGHLY appreciate when someone posts an EFFECTIVE....not crappy....way to fabricate or replace a part with a functional alternative....like was done here.

There is also somethingelse I try to do a lot (you may have noticed over the years).....I try to get people to think "descriptivly" about the alternate names and uses for hardware parts......and search for them in other places.

Do not always think that a VW hardware part is a unique automotive product. Yes...far too many times it is....unique to either automotive....and/or......even further unique to VW or even to one vehicle.

These particular nuts are an example. While unique in actual factory dimensions (they are short and shallow).....they really are just a "T" nut....like that used on mounting slots for mills and work tables.

This insanity on my part to always be thinking of where a usable, similar hardware, material metal or plastic product might also be used....comes from the huge range of industrial sites and factories I have worked in.

I cannot tell you how many times I have been in room with a handful of very skilled and experienced engineers, machinists and operators.....with a pile of broken equipment on the table....with all of the usual suspect catalogs out...grainger, Mcmaster, Fastenal (and many more)......looking for a part...and we cannot find it because no one knows the "real" or most common name for the odd fastener or part....so it shows up in no searches or catalogs.

Many times we saved our asses with a picture put into google image search....only to find a part or fastener....identifed by a name....we had never heard or thought of.

Always look for factory parts yes....but also...sharpen those description and searching skills! Ray

[Wildthings]