Here is my front driveshaft. I can't get the slip yoke to slip. (Lengthen) I have been spraying some Kroil on it for a couple of days. Any tips? I'll try unscrewing the collar when the outside temps drop a little.

It will take grease, but that doesn't loosen it up.

Also all of the replacements I look up have a cv joint (double cardan) on one end. Do I have an oddball?

78 F150
300
NP 435 transmission
NP 205 transfer case.

 

Pull the seal cap back and shoot oil in there. most likely it's just rusted and gunked up but there's always a possibility it's damaged.

You may have to force it to break it loose. if that doesn't work you may have to heat it with a torch , that will be a smokey mess with grease flames but if that doesn't work it's toast.

 

My 77 looks just like that. With 1 ujoint on each end.

DC cv on the rear. But not the front

Has it been off and sitting for a while? Causing it to rust up?

 

Hey John
Did you remove the shaft?
What seems a little strange is why is the slip yoke all the way up with no splines showing.
Should be about 1 to 1 1/2"s of spline past the dust seal cover.
My 79 front shaft also has a double cardan like you mentioned.
If you removed the shaft and it is as pictured the shaft is probably too long and bottomed out and jammed it up onto the taper.
If that is the case there could be other problems. Hope not
Measure from yoke to yoke on the truck to see the length then measure the shaft to see how much play you end up with.
Just lookin and thinkin.......

 

I finally got it. The cap unscrewed fairly easy. I shot some WD-40 in it to soften the grease and then used a tire iron and hammer to knock it loose.

I'm letting the remnants of the crusty grease soak now.

This is my father in-laws truck. He bought it new in 78. We put new u-joints in it a couple of years ago and it was a little tight, but we didn't think much of it. It collapsed when we ;pulled it and just couldn't get it expand back to the yokes. It needed about another inch to make it.

Once it get it back together and installed I'll snap a few pictures.

 

Glad you got it moving. A victory!
Some shafts do have the splines showing, and some do not. I don't know if it was a year-by-year thing, or if it depended on who the vendor to Ford was at the time, or something else.
In the case of the ones with no splines showing, the seal under the cap is simple and round and slides on the smooth shank of the shaft. Almost more like a wiper/scraper than just a seal.
In the case of the ones that have splines showing, the seal/wiper will have splined slots in it too, to match the shaft.

I would suspect that noting which type of seal you have on yours will indicate which type of shaft you have.
Either way yours is, it's nothing to worry about. They came in both flavors back in the day, so either way is correct. Now I'm curious about my '79. I think I have one of each, but it's been awhile. My '71 had no splines showing on either shaft.

In case you're not familiar with them, don't overfill the slip joint with grease. Clean the splines, slather some grease on them, stuff a little bit down inside or wait and just do it with the grease gun after it's back together. Whatever works. But you'll know if you over-fill it because the first time it compresses any it will hydraulic and shoot the grease cap right out the bottom of that section of the shaft!

have fun...

Paul

 

Here are some shots of it cleaned up. I used paint thinner. I've been using it lately as it is cheaper than brake clean and doesn't mess with the paint. It also gives a little more time to work with before it dries.
I used a toothbrush to clean the softened old grease.

I also hit the neck where the seal rides with some emory cloth.

I then used a toothbrush to get fresh grease into all the grooves on both pieces.

Here are shots with full extension and compression.

Notice no splines are showing. The seal collar limits that much extension.


Full extension

Full compression








Now I'll put new u-joints in it and bolt it in.

Note: pictures didn't sequence correctly.

 

Nice. Glad you got it apart.
I see that you have the older style, which means it's likely the original shaft. The aftermarket replacements, and perhaps the originals too I would think, went to a design where the grease fitting was up more by the seal and splines, rather than down low by the cavity and cap. I think the newer ones were better for getting grease up into the splines more quickly, but not sure if it was effective for all splines, or just the ones near the fitting.

I always had to disassemble my shafts to get new grease up into the splines more reliably.

Paul