I have been replacing the suspension components on my 1981 F-250 2WD (with 351M engine) over the winter.

The truck has the forged twin I-beam axles with kingpins setup. As I was replacing the axle pivot bushing I noticed that the bolt was 1/2" diameter grade 8, but that the center sleeve of the old axle bushing has an ID of slightly greater than 9/16". This was also true for the replacement Moog bushing (#K8621). Not completely sure that the old bushing (and bolt) was the original although it took considerable 'persuasion' to remove it , suggesting considerable age.

My question is should the axle pivot bushing bolt be 9/16" diameter grade 8? I tried a new 9/16" diameter grade 8 bolt and will fit, but fairly snugly. By contrast the 1/2" diameter bolt that came out allows the axle to 'move off-axis' a bit.

Thanks in advance for the guidance.

 

The OEM Pivot bolts I have from Ford have a shaft diameter of 14.0mm marked as a grade 10.9.
The Pivot bushings have a bore diameter of 14.5mm.
These are new parts I have on the shelf.

Rod

 

Thanks Rod.

This makes sense to me given the following conversions:
14.0mm = 0.55"
14.5mm = 0.57"
9/16" = 0.56"
1/2" = 0.50"

Not sure why the 1/2" bolt was in there, I guess that may be another PO story.

I will check with the local dealer for the OEM replacement part, or otherwise go to McMaster to source 14.0mm grade 10.9 bolts / nuts. If I need to go down the latter path, can you tell me whether the 14mm bolt has a flange or cap head? Also, is it partially threaded? Finally, is the nut a disorted thread flange nut?

I should have recognized that metric bolts were already making there way into Ford trucks by the early 80's. Thank you for the insight. Stewart.

 

My '85 Bronco had 9/16 pivot through bolts as did my '80 Bronco.Pretty sure the leaf spring bolts were also 9/16.

 

Ford part number on the bolt is N801079-S2
The nut number is N620604-S100

The bolt is a flange bolt with a 3 inch shaft. Threaded except for 3/4 inch before the head.
The nut is a non-flange lock nut.

I don't have the OEM package for the pivot bushings but it looks like the part number may be E6TZ-3B177-A.


Hope that helps

Rod

 

Most helpful. Thanks Rod. Stewart.