379 peterbuilt hood hinge bolts?

hey guys, new member here, im not a truck driver, although my brother in law owns a trucking company. I am a machinist, my machine shop is AES Machine LLC in Shallowater Texas. my brother in law wanted to see if i could machine some hood hinge bolts? I took some measurements of the new bolts he bought. I have a few questions.
theres a steel sleeve that goes over the bolt, but the sleeve is only half the length of the bolt shank, then theres a black plastic sleeve over the steel sleeve. the plastic sleeve has 1/32" larger bore than the steel sleeve, it's a real sloppy fit!
so, should the steel sleeve be the length of the bolt shank? if yes, why not machine the bolt shank the size of the steel sleeve, which will yield a stronger bolt and no need for the steel sleeve.
should the plastic spacer be the length of the bolt shank also?
I was thinking of machining a larger bolt with a hex head and a grease zert in the head with a cross hole in the bolt shank. If anyone has any pictures that would help me. if i had the parts that these hood hinge bolt go into, it would make this process easier. I really think these bolts can be machined better for less than what most truck shops charge.

 

Lester, do you think a brass or bronze bushing would be better than the plastic? i think it would last longer, plastic parts should be reserved for cars not semi trucks.

 

Brass and Bronze are harder than plastic, softer than steel or aluminum. from the new hinge bolt that i measured, the plastic bushing had .032" larger ID than the steel sleeve. in other words, i could rattle the plastic bushing on the steel sleeve, so if truckers are noticing vibrations, that's where the vibrations are coming from. If you have machined parts that fit together correctly and are lubricated, no vibration will occur.
i think i will have to machine a few different bolts and bushings, have my brother in law try them on his trucks. maybe send a few of these to some truckers on this forum and have them try them as well to get some " real world testing and feedback".

 

almost finished with these prototype hood hinge bolts, i can't figure out how to post a image.
i did post some pictures on my business LinkedIn page, you can search AES Machinellc on LinkedIn, and I'll try to figure out how to post pictures on this forum .

 

these hood hinge bolts are finished, forum member Deere Hunter installed them on his truck last night, these bolts have a recessed grease zerk, so they can be greased. these bolts are cnc machined from stress proof steel. if any members are interested in these hood hinge bolts,
email me aesmachinellc@gmail.com

thanks