SMason's 78 GMC K25 4x4 Build Thread

[Captain Swampy]

Nice truck! What gears are you running with the 44's? I hope you get around to painting it. It would look awesome in that hammered gray.

[Scott M]

Thanks man, I just have the stock gears which i believe to be the 4:10 since its not military or anything.  When I went to 44s I gave up on driving it down the road...thats why i purchased that trailer I had it loaded up on.  In 4 low gearing doesnt seem to hurt it much.  At the moment unfortunatly i put it on the back burner again but I will def keep this thread going as I do more... thanks for looking!

[Scott M]

So I picked up a rear pipe bumper for the truck that is actually made for an 73-87 truck. however the previous owner had welded the old bumper brackets straight to the frame so I am going to modify this bumper to mount to the outside of the frame instead of the inside where it should be.  I also picked up a welding machine.  This whole time I have always used buddys or brought stuff over to them to get it done. Pretty excited I wont have to rely on anybody anymore.  I am also going to fix up the front bumper a bit more and stiffen up the brackets me and a buddy welded up. Any suggestions on an easier way to take the paint and rust off the front bumper with minimal grinding and I dont have access to any blasting and dont really want to pay...I have been looking up different chemicals that are suppose to do the job...

forgot to mention I want to get rid of the rusted out rocker panels at the doors and want to weld in rectangular tubing in like rock guards or i think its called boat rights maybe? idk if thats right but thats my other plans.  now that i have this welder plan on getting back on this thing...

[Scott M]

Okay so I got the brackets rewelded on and i also adjusted for the 2" body lift.  I used this stuff called aircraft remover to take the old powder coat off in hard to grind places like the diamond plate and stuff.  Then i decided to just paint it with a couple of heavy coats of black bedliner.  Im pretty happy with the way it turned out.  I just finished mounting it this past weekend.

[Scott M]

making a little progress on the front bumper. By far not perfect or show quality but hopefully it will last a few years. i did learn my lesson after buying these to bumpers.  dont pay or even take for free a really rusty bumper.  i cant say that it has been worth the work.  Take and grind/brush as must rust as possible everywhere. chemical stripper to remove old powder coat (PITA) and then treat with ospho and then clean up and prep then prime.  next is bedliner then get it back on and hopefully be a tad straighter and stronger as i have worked on that as well.  Hopefully get it on this weekend and ill post a pic completed weather permitting.

[Scott M]

Finally got the front bumper back on. Pretty happy with the way it turned out. Im going to put the project on hold for the most part till the end of April but i might sneak in a few things if i have time.  Studying for the PE exam on April 21st. I might pick up military 46s between now and then....

[Scott M]

Picked up some 395/85R20.  found a good deal on a set of 20x10 XD chrome diesels going to pick up in the coming days. 

[Scott M]

Picked up a set of 20"x10" KMC brand wheels. I figure they are an older style (10+) years old or so. They have some pitting but I got what I think is a good deal on them and im not looking for perfection just a deal. hopefully get the tires mounted to them next week....

[Scott M]

Took a little longer than anticipated to get the tires mounted to the wheels and lots of stops at different tire shops until one did them for me.  I went to semi/ag places and one wouldnt touch them because the tires were older than 5 years old. another wouldnt touch them because they said the tire wont bead up on the truck rim cause its not made for it.  so finally after many other stops to auto tire shops found one that was willing to give it a shot.  the hardest part they had was getting the rim through the tire and they did it the old fashion way with lots of man power big crow bars and lots of jumping.  But got them on and tomorrow they are going to go on the truck to mock up were to cut the body. anyways here is a pic of one of them mounted and after this weekend I will have pics with them on the truck.

[Scott M]

Got the tires on the truck this weekend.  I did a little bit of trimming in the areas that absolutly needed it just to get the tire on.  I plan on trimming more right now its driveable with the trimming Ive done so far however riding up and down the beach it might still rub a bit so im going to go ahead and trim the rest soon. but for now they are on.  also I am only trimming to the max of the inner fender in the front for now.  If I rub bad I will modify and massage the inner fenders to get more clearance.  I dont plan on doing any extreme flexing. 

heres a few photos that I took....

[blazer74]

Looks like those rims are reverse cut from best I can tell from that pic.

If that's the case the tire goes on from the back side of the rim.

Is that what they did?

[Scott M]

Looks like those rims are reverse cut from best I can tell from that pic.

If that's the case the tire goes on from the back side of the rim.

Is that what they did?

I think I know what you are asking.  I only watched them mount the first one but when they did that one they layed the rim on the ground and put the tire on top.  so I would say that answers your question as no....  I know they had a hard time, but it was 90 degrees and it was at the end of the day when they mounted them.

[blazer74]

The fatter thicker portion of the rim on the outside perimeter between the beads with deeper dish style tend to be to the front making them reverse cut.

The thinner shorter portion is where the tire is mounted from.

Taking the tire off from the wrong side can cause damaged tire beads.


I know from experience.

Reverse cut ^^^^^^

[Scott M]

Does this photo help in determining what I have? Also the beads of these tires were at least 1/2" thick.  Tires are pretty darn thick in general weigh about 220lbs without the wheel.  If I ever have to take the tires off the rim it will be because im disposing of the tire at hazardous waste day haha.  As long as they hold air can go up and down the beach and the truck isnt rusted out I intend on leaving them on there. They are 14 years old the tires so this will probably be their final mounting/dismounting at least I hope.

Thank you for the info

[blazer74]

If it's facing up I would say yes reverse cut, wide portion is to the top because it is a deeper dish rim.

It's harder to install the tire from that side. The back side of the rim is easier to slide the tire on due to being narrow.

You will be surprised the # of places don't know.

I have old school slots and have to educate.