Bodywork, Paint, Interior, Trim, & Wiring

Just days from finishing MGB V6 (after 4 years). Today put wipers on and found one of the knurled drivers to be worn to the point wiper arm will not hold position.

I 've had that %&#*! dash off for the last time! Wiring is in, A/C vent hoses in... what's a viable "quick fix"?

Yes, I should have checked it out when it was off the car... I also should have bought IBM stock with my 1950s graduation money....
Knurled driver seems to be swedged or hammer fit. Anyone ever drill one off?

Thanks
Don B.

No great way to do this. Fix it right. I know- not what you want to hear.

You could try to use thin stock, even tin foil and push the wiper arm over this. Yes, when these fail, it is very frustrating. Our only cure is actual replacement.

-BMC.

Hi Brian,
Before I try to drown myself in Turkey gravy...

Couldn't get shim stock or alum. foil to hold... cleaned the individual grooves with dental pick & small wire brush on flex cable/ dremmel tool but continues to fail. What do you think of drill/tap a very small grub or set screw thru side of wiper arm base and into the knurling? (thinking of steering column attachment method) At this point, what do I have to loose?
your thoughts?

Happy Turkey day.
Don B.

Don, I'm assuming your wiper arms are new, right? If you look in the socket there are only a few ribs that engage the knurl. Usually it is the socket that goes bad rather than the knurl, and sometimes the socket is not as close of a fit as it should be even if the knurl is perfect and the socket is new. If the knurl actually is worn the tops of the knurl will be flattened and will be more shiny. I would always suspect the socket before the knurl, and would always try another arm on it, hopefully one that fits well on another knob.

Then if that doesn't help, and you may be there already, it becomes a matter of sticking the arm to the loose knob. I'd try to avoid putting a grub screw in it. I had one that a PO did on my car and it never worked very well anyway and I hated it every time I looked at it. Using shim stock can be made to work but is going to be very fiddly to get it right and may not hold very well. Obviously the right fix is to replace the bad parts but I can see why you'd want to put that off. I don't know if it's possible to R&R the offending stub without removing the rack but it may be.

But how to stick the bits together... First thing I'd do upon reaching that spot, is look around to see if I could find a thin plastic tube of some sort that could be forced into the socket. It might be possible to insert that and maybe heat the knob with a heat gun and force the pieces together and let them cool. Might even put a little green or red locktite in there while you're at it. That way it should stand a decent chance of holding and still look right and be removable.

Jim

I agree with Jim.
The knurled part is usually OK. It's the socket in the arm that wears.
If it is the knurled knob, it is replaceable.
You used to be able to buy them separately, maybe some old stock exists still. Or you can use a good used one.
Use a small puller such as a battery terminal puller to remove the knob.
To re-install, support the back of the shaft with something heavy, like a hammer head or large socket and have someone help to tap the new knob back on.
Use red locktite and repeen the shaft to lock it down.
Not easy but it is doable in place.
If it's an emergency. Coarse valve grind compound will hold it on for an amazing amount of time. (years for my 72 Suburban)

Cheers
Fred

My thanks to all who offered advice! After carefully reviewing the options....

Neither V/B or Moss offer the replacement for the knurled drive so didn't spend much time with the puller. Drove to VickyB (25 minutes from the house) and confirmed they had the "cranked" wiper arm needed for the 3 wiper 71B config. so took a chance.... knowing I could replace if I butchered it.

I drilled and tapped the underside of the wiper socket for a 10X24 slotted set screw. It took 5 minutes and seems to be working just fine. If it would subsequently fail, I'll re-post.

FYI, new arm sockets have knurling around the entire inside opening.

Thanks again
Don B.