m870a1 kingpin

[powersmoke18]

looking for the 2" king pin that fits an M870a1. any one know where i could get one or have a part number? thanks guys! Bart G.

 

[Castle Bravo]

looking for the 2" king pin that fits an M870a1. any one know where i could get one or have a part number? thanks guys! Bart G.

There is no part number, because there is no 2" M870A1 kingpin. That is, to say, there is no stock/OEM 2" kingpin. The trailer was designed for the 3-1/2" fifth wheel tractors. To my knowledge, all of the A1s were manufactured by Shoals American Industries, which no longer exists, so you can't go to them for parts.. I think armed with the correct dimensions and starting with an existing 2" kingpin, you could make (or have made) a working 2" kingpin assembly for the M870A1.

I have a 2" kingpin for my 870A1, but it was manufactured by someone. I could probably get you some dimensions of the kingpin that I have.

 

[simp5782]

Will bump this with some information.

Replacement kingpins for the 870a1 are as follows

For 3.5in and 2in
Overall length : 8.5"
Barrel thickness 4.5

For the Load King 870
3.5in kingpin Load king part# MP5-1639-1.
2.5in kingpin Load King part # MP5-1638

Spec diagram attached of both

 

[zebedee]

I saw there were 5 that came through Wed at the

Albany GA auction​

and 4 of them had no king pin. I would have jumped in if they were a lot closer to me and could have gotten dims to make one. Perhaps this is a sign of something to come - we can hope. Pre production of these may be prudent - anyone know if they are a higher grade steel?

 

[simp5782]

Kingpins are made of either 4320 or 8620 so hard enough

I am having a flip pin made. 4.5in diameter 8620 came in 2ft stock lengths. Going to have it as a 3.5in pin on one side and a 2in on the other with a raised weld in the middle as the hole catch for the pin. So you can simply use 1 pin for everything


3.5in pin is available from loadking for $460
2in pin is $650

 

[simp5782]

Total length of the pin needs to be 9-9/16" longer than the spec sheets provided. Attached are specs for the 3.5in pin from Castle Bravo.

 

[simp5782]

Worked great. Installed a bigger top catch though rather than using weld around the outside edge or the washer

 

[simp5782]

3.5 in kingpin. Main shaft specs call for 4.5in diameter but its an interference fit at that so 4.475 works.

I have a extra 2in pin for anyone who is looking for one.