[Bill.H]

I ran out to the garage with calipers, but I couldn't get a good length measurement with my snowcaster mounted It's 5/8" diameter.

The pin is the easy part, replacing that spring is going to be more difficult. I'd toss in a 5/8" x2 1/2" bolt & nut for now and order a new pin and spring. The roll pin is 3/16 x 1 1/4, but the latch pin and latch spring have Case part numbers, no size listed.

 

[Bill.H]

Oh! the locator pins! That's totally different than the latch pin. You slide on to those, the latch pins snap in.

It's 1/2" thread according to the part list. Length shouldn't be critical but even with the snowcaster mounted you should be able to measure the one that didn't fall off close enough. I'd be tempted to see if I could find a steel pipe nipple with an OD the same size as the other pin, cut it to length, tack washers on both ends, then secure it with a hardened 1/2" bolt.

 

[99flhr]

Unless you change attachments frequently, consider removing the pins and substituting bolts with washers.
Locks the plate into the correct position and eliminates the slop caused by wear in the slots.
You`ll find it eliminates the issue of the front tires contacting the mower deck leading edge when the wheels are at full lock. The deck level adjusters tend to push the deck forward and the slots move on the stock pins
Also maintains more consistent belt tension.
JMO

 

[Bart]

If I needed a quick fix I'd get a 1/2" bolt to stick in the hole and tighten it in place with a nut and washer while waiting for a new, correct one to arrive in the mail.

 

[boomers_influence]

nutcase
if you compile all the answers you almost have it correct.
it is called a step, or shoulder bolt.
length 1.5"
dia. 5/8 "
now, leave the 5/8" dia. for 3/4" long. (inside length)
the other end is 1/2" dia. and threaded.
the stock ones have a allen hex inside on the big end.
as stated earlier the inside length can be way longer,
so you can use a vise grip to hold it when you tighten up the nut.
i hope you are not to confused at this time.
good luck. boomer