Topic: 1975F Rear Wheel Hub Threads

[RodSOHC750]

I removed the rear wheel bearing retainers.  I drilled the retainer having 4 punch marks.  This retainer seized up after a few turns out and I had to resort to cutting the retainer.  The threads in the hub appear to have some damage.  Is this hub salvageable? Does anyone make a thread tap to cleanup the threads?  Thanks.

[colvinry]

Next time stick a punch in there and wack it with a hammer. It will spin. Or get the specialize tool l. Might be okay still but I imagine it's gonna be a heck of a time getting that cap to thread right


Sent from my iPhone using Tapatalk

[NobleHops]

Nope - bad advice deleted.

[RodSOHC750]

I omitted a lot of details on how I tried removing the retainer.  I first bought a special tool with four prongs to fit the retainer.  I tried loosening the retainer with the tool and it wouldn't budge.  I then tried whacking it a few times with a punch and it still wouldn't budge. I then drilled the four factory punches.  Using the special tool and spanner attached, the retainer backed out effortlessly for 2 or 3 turns then it bound.  I turned the retainer back in a full turn then backed it out one turn and it bound again. I redrilled the four punched holes again and got another turn out of the retainer before it bound up again.  I sprayed the threads with penetrating oil and worked the retainer back and forth repeatedly.  I then attached an impact driver to the special tool and forced it out 2 or 3 turns before the retainer seized up.  Then I had to resort to cutting the retainer into four pieces to extract it. 

[riffman12]

I had that happen to my comstar hub. I paid a machine shop to fix the threads but it cost me more than I would have liked to pay.

Saves having to buy another wheel I suppose.

I've also heard if it's not too bad you can find a bolt with the same thread pitch and drag it around the mangled threads. Didn't work for me, but worth a shot before you resort to more drastic measures.

[NobleHops]

I omitted a lot of details on how I tried removing the retainer.  I first bought a special tool with four prongs to fit the retainer.  I tried loosening the retainer with the tool and it wouldn't budge.  I then tried whacking it a few times with a punch and it still wouldn't budge. I then drilled the four factory punches.  Using the special tool and spanner attached, the retainer backed out effortlessly for 2 or 3 turns then it bound.  I turned the retainer back in a full turn then backed it out one turn and it bound again. I redrilled the four punched holes again and got another turn out of the retainer before it bound up again.  I sprayed the threads with penetrating oil and worked the retainer back and forth repeatedly.  I then attached an impact driver to the special tool and forced it out 2 or 3 turns before the retainer seized up.  Then I had to resort to cutting the retainer into four pieces to extract it.

Not to bust your balls, but in the interest of not getting tortured next time, you made a couple of mistakes. I've made them too.

The indentations made by the factory on their punch spots go no more than 3/16" deep, or even less if you could measure them. Think about it - they're just taking a pin punch, laying it in there, giving it a whack to bend a few threads together to stake it in place. Primitive, fast, effective. The error you (I) made was drilling too far. That resulted in a lot of swarf in the drill hole, and as soon as you started backing it out, inevitably the sharp edge grabbed some swarf and carried it into the threads. The bearing retainers aren't like taps with a big recess every 90 degrees to capture and store swarf, so it just balled up and bound up the bearing retainer till you were fooked.

You're actually better off drilling too shallow than too deep, because the damage you may cause is limited to the last few threads and you'll be past that pretty quickly, and the bottom 90% of the retainer will probably chase them sufficiently to reinstall. Just drill 1/8" or so down next time, blast out the hole with compressed air, fit your tool and back it out. A few drops of TapMagic or light oil (eg 3-in-1) can't hurt either.

N.

[RodSOHC750]

Thanks!  I suspected drilling too small or too deep was an error although I thought I had initially drilled about 1/8 to 3/16 inch deep. QUESTION: I have new retainers ordered.  After reassembly, do I punch these in?

[NobleHops]

Thanks!  I suspected drilling too small or too deep was an error although I thought I had initially drilled about 1/8 to 3/16 inch deep. QUESTION: I have new retainers ordered.  After reassembly, do I punch these in?

Yes, screw them in till they bottom onto the bearing, then lay a pin punch in the groove, give them one good whack to smash some threads in a few spots, done.

[RodSOHC750]

I successfully repaired the damaged internal threads in the wheel hubs.  I first purchased a thread file but realized this tool is only for external threads.  I then purchased an rethreading tool and it worked slick.  Saved me a bunch of time and money.  One of those tools you used once every 30 years, but man it is nice when you need one.   

[754]

I had that happen to my comstar hub. I paid a machine shop to fix the threads but it cost me more than I would have liked to pay.

Saves having to buy another wheel I suppose.

I've also heard if it's not too bad you can find a bolt with the same thread pitch and drag it around the mangled threads. Didn't work for me, but worth a shot before you resort to more drastic measures.

Drag a tap around it, not a bolt..use it like rake to clean up the bad stuff. Easier if you hold it with a good tap wrench so you can lean into it a bit .