Topic: 1964.5 Windshield Wiper Post Question

[jackhodges]

I am trying to install new chrome, wiper post bezels and nuts.  Although the new bezel nuts look exactly the same as the old, they won't screw down completely.  I have one of the good NPD bezel nut tools.  Only about two turns and they get really tight.  It doesn't really look or feel like a cross thread though.  I think the chroming process added material inside the new nut because, comparing them with the old, they look exactly the same and the thread count "looks" the same also.  Does anyone know what the size of the post is and what the thread count/pitch is?  I'm thinking of getting a tap and run it through the new chrome nut.

Any other suggestions?  I have a small bent pick and I've been scratching the chrome out of the threads of the new nuts, and it has helped, but what a tedious job! Anyone else had a similar issue and successfully gotten past it without scratching the car's paint?  Working on the post is stressful as I don't want to scratch the brand-new paint.

[jackhodges]

Not sure if it matters but I have the two speed wipers.

[CharlesTurner]

Sounds like the threads need to be cleaned out.

[jackhodges]

The correct size and thread count tap would be a HUGE help.

[jackhodges]

I ended up buying a digital caliper and thread gauge.  The answer to the original question is: 3/4-20 UNEF.  (UNiversal Extra Fine) 20 TPI. I have now ordered a tap to clean the chroming out of the threads.  We'll see how that goes.

[tim_morrison82]

Have you checked that both threads match up?

[Bossbill]

I had a slightly deformed end on one of my original ball joints. A thread file offered no joy. My tap and die set doesn't go this large.
A quick trip to the online store got me a reasonably inexpensive die.

Just a reminder that an under $20 tool can save aggravation and an expensive part.

[jackhodges]

The old bezel nut still screws on very easily and in addition, I cleaned the post threads which is pot metal up with a very small file. The new bezel nut is brass and a tap should clear out the additional chroming pretty easily.  I'll post how this works out in the end.

[jackhodges]

Tapping the new nuts worked perfectly.