windshield wiper question

[doogan]

My 49 B1B has electric wipers and everything works except the wiper arm.  The problem seems to be that the knurled inset inside the wiper arm doesn't go down far enough to slip on the splined section of the wiper mount.   So I bought a wiper kit with a knurled part that fits the mount but I don't know how it should be placed in the arm or if it should.

Is it possible the mount section on the truck is for the electric wiper arm and the arm itself is for the vacuum system.  The wiper motor works and the little splined stud that comes up through the cowl under windshield turn back and forth but the wiper arm will just sit there.  They were not working when I got the truck so I'm trying now to get them going.

Do you have any idea's or possible solutions?

[rb1949]

Correct wiper arm for the spline? Not switched. Not stripped. If it goes on far enough you would feel it engage the spline. Looks like it has the nut on the arm that tightens it to the shaft. Some things just annoy us.

[JBNeal]

Sounds like it's time to whip out the calipers and do some measuring... Splined shafts require an exact fit for proper function and eyeballing it will only be a guess an opinion

Edited October 18, 2016 by JBNeal
wording corrected for accuracy

[doogan]

On these wipers the arms will screw onto the stud on the cowl but do not turn.   There is nothing inside the arm that has anything that slips over the splined stud.   The only part in the arm itself is the nut that screws onto the threads at the end of the stud.   That is why I bought the repair kit shown in the top picture.   The second picture shows the inside of the arm but isn't clear enough to see nothing is in there to slip over the splined shaft. 
The repair kit has one of the round knurled nuts that does slip over the splined shaft but I don't know how it attaches in the wiper arm.  There were no directions with the repair kit and nothing seems to fall into place.  

It just seems to me the wiper arm is missing the part that slips over the splines.  

[JBNeal]

I took a few minutes to look at the wipers on the '48 and I cleared up a few things as I was a little confused.  Modern vehicles have splined wiper pivot shafts that mate with a keyed socket for an accurate indexing of the wiper blade arms.  The Pilot House trucks have shafts that are splined and tapered, and the tapered spline wedges against the surface of a circular plate in the wiper arm, with the hex nut securing the arm to the shaft.  So the tapered spline OD has to be greater than the circular plate ID for the wedging action to work

 

 

Edited August 20, 2021 by JBNeal
revised pictures

[wallytoo]

perhaps the repair "insert" has to be staked to the wiper arm cavity.

[ggdad1951]

arms and mounts are all the same between everything.  Only the driving force (vacuum/electric) source should be different.

[Merle Coggins]

I believe the post and wiper arm are different on the vacuum wiper setup. At least it was when I switched mine. I don't remember what the difference was now.

Merle

[ggdad1951]

Didn't change them on FEF when I went electric....arms MAYBE, but no reason to change the posts.  Arms really either....same distance travelled and such being the same and all, no reason to duplicate parts and all that.  A parts book look up would tell you.  Heading into the Wild game now so I can't look.

[JBNeal]

additional information - wiper pivots

Edited August 20, 2021 by JBNeal
revised link