TheSamba.com :: View topic - Wiper arms slipping on shaft

Tue Nov 16, 2010 11:58 pm

The shafts appear to be fined with good splines, but the holes in the wiper arm are smooth. Am I correct that the arms are supposed to have internal grooves to mate with the shafts?

If so, what arms are folks replacing them with? I have not found any used ones, and I'm assuming the VW new parts are nutty. Open to suggestions. Looks like the P.O. tried to use an epoxy, which I cleaned out of the shaft splines with a dental pick.

I like the air foil on the driver's side.

DougM

Wed Nov 17, 2010 12:20 am

Quote: Am I correct that the arms are supposed to have internal grooves to mate with the shafts?
No.
Take off the nut holding the wiper arm on and put a washer under it so that it applies more pressure onto the wiper arm before the nut bottoms out on the shaft.

Wed Nov 17, 2010 12:47 am

Thanks - will definitely try that. So are the wiper arms supposed to be smooth on their side, or is this just a good fix for when they get like this?

DougM

Wed Nov 17, 2010 12:51 am

They are supposed to be smooth and the wiper shaft cuts in its own grooves.

Wed Nov 17, 2010 5:52 am

One thing, take a knife and clean out the grooves on the shaft side to get all the metal chunks out before reinstalling the wiper arm. It will make it grab much better.

Paul

Wed Nov 17, 2010 8:24 am

The arm hubs are unsplined for a reason, it saves your wiper motor when the wipers are frozen to the glass. Adding the washer does help to put more tension on the taper-fit so your positioning doesn't drift off with use, but they'll still break loose when they need to.

Wed Nov 17, 2010 8:44 am

Yep, the key is using a dental pick to really clean out the tiny grooves on the wiper shaft. The first time there is slippage, the splines fill up with the scraped off metal from inside the wiper arm, further reducing their ability to grab. Take the arms off, pick out the grooves, and you should be good.

Wed Nov 17, 2010 8:53 am

in addition to mentioned ive had good luck with a lock washer on top also, & a little loctite

Wed Nov 17, 2010 9:37 am

And be careful with the tightening of the shaft nuts. Too tight and the stud will snap off the shaft and you will be paying a visit to Major Pain's private office. 43 in. lb is all it takes.

Wed Nov 17, 2010 10:19 am

You don't need to tighten the nut very tight, that is not the problem. You need a washer with a big enough hole to slip over the end of the shaft so the pressure applied by the nut goes against the arm and nut against the shoulder on the shaft.

Recheck the torque on the nut after a couple of weeks and then once a year thereafter. I reapply loctite to mine each time I torque them. I also try to remember to pull the wipers away from the windshield when we are expecting anything more than a light snow. Anything more than 4 inches of wet heavy mung is going to cause the arms to spin on the shafts.

Wed Nov 17, 2010 12:25 pm

If you look at the shafts closely, you will see a small stop below the splines (at least they exist on my '90 Westy). If you've stripped the wipers already, it doesn't matter how tight you bolt them down ... the splines won't bite into the aluminum because of this stop. You must use an end mill on the underneath (large) side of the tapered hole. This will allow the wiper to sit deeper on the shaft, and the splines to bite into the cast aluminum.

Wed Nov 17, 2010 2:20 pm

Have a look at this thread:

http://www.thesamba.com/vw/forum/viewtopic.php?t=359352

I'd definitely use the wavy washers, and something to make sure you've got the proper torque rating.

Best!

Wed Nov 17, 2010 2:36 pm

gears wrote: You must use an end mill on the underneath (large) side of the tapered hole...
x2.

Mine were bottoming out (no matter the torque!) until I did this.
Small round file or countersink bit to get just a bit of air under it.
The splined shaft bites into the wiper assembly just like new.

Brilliant!

Wed Nov 17, 2010 10:19 pm

That's great news and thanks for the quick responses. The really, really excellent news is that I get to keep using what I assume are the original arms and my driver's side has a small airfoil on it. This vehicle was originally delivered in Germany, so it may have been a TUV requirement as I don't see these on US vans.

Cool. I'll get some air under the shaft hole if it's close to the stop. I got the shaft splines very clean with the dental pick one day while waiting for a VanCafe box to arrive. I noted the splines are actually quite sharp edged and this explains why.

On the loctite - I assume this is used on the nut atop the shaft, and NOT on the shaft splines, eh?

Doug

Wed Nov 17, 2010 10:41 pm

I have actually tried using Loctite on the splines as well as JB Weld before I figured out what I really needed to be doing. They both will help to some extent, but aren't really necessary if you keep the nut from bottoming on the shoulder.

Thu Nov 18, 2010 6:35 am

Quote: The really, really excellent news is that I get to keep using what I assume are the original arms and my driver's side has a small airfoil on it.
That D/S airfoil is normal on later model vans.

Thu Nov 18, 2010 9:50 am

Don't think the air foil does much for you. As a negative it kind of causes the water to blow funny across the windshield. When I finally felt rich and decided to replace my wiper arms the new one didn't have a foil and the foil hasn't been missed.

Thu Nov 18, 2010 11:06 am

IdahoDoug wrote: On the loctite - I assume this is used on the nut atop the shaft, and NOT on the shaft splines, eh?
Correct-a-mundo. Git 'r done.