1/2 to 3/4 axle swap. Please help guys..

[dasanii19]

Current specs: 1976 K5 blazer 350, 3.06 gears 12 bolt rear 10 bolt front, th350 transmission. I want to run 35's, my tranny needs to get rebuilt so that will come next after I get this gearing thing taken care of.. GRRRRR

Im just going to do it!!!!... I need some help though, first I found these 3/4 tons axles for sale http://reno.craigslist.org/pts/286595801.html first off, do you recommend I get these?

If so, next..........

I need to know if they will drop right into my truck?

will I need to modify anything like my brake lines?

will I have to re locate the the leaf spring perches on the 3/4 tons axles? "perches", as in what the leaf springs sit on.

Will these 3/4 tons axles be the same width (side to side) as my 1/2 tons axles?

Can I use my stock leaf springs?

Will I need different drive lines or do I just change out my U joints?

Will my stock steering bolt right up or will I need to change anything like the pitman arm?

These 3/4 tons axles will be 8 lug right?

Please answer these questions completly, these are the questions that are eating me away at night.... Thank you!!

 

[boz42]

hard to tell what the axles are, by just saying they are chevy 3/4 tons. could be semi float rear, could be from earlier model & be a less desirable. i would contact the guy & see what they are before i got too excited about them. get some pictures e-mailed to u or go look at them to see what they are. if they are from 73-86 3/4 ton truck i think $500 is a little high, but it may not be for your area.

i really can't answer any of your other questions w/ out knowing what the axles are from?

 

[dasanii19]

I just wrote and aksed what year truck they are out of. Here is a reply from some questions I has asked before..

""I have had them for about five years and as far as I know they are original, although in very good condition, the brakes are about 75%, rear end still has both E Brake cables, not sure of the mileage, When I bought them they had been stored inside and have been stored inside since I got them, Not sure on the condition of the bearings. I got them for a 1969 4x4 conversion I was working on. Ran out of time. Still have the 1969 4x4 frame but not the 2x4 truck. I am in Fallon, NV. I’ll try to get some pics if you still need to see them."

 

[Avery4jc]

http://coloradok5.com/forums/showthread.php?t=194562


Have fun reading...although there is a TON of crap it also has a lot of good information that'll help you out.

 

[Avery4jc]

will I need to modify anything like my brake lines?

nope, I didn't have to modify anything...just be sure that you don't loose the blocks that the bolts screw into for the front calipers...the bolt is hollow and screws into this block then into the back of the caliper and then the brake line screws into the block...I had issues w/ this b/c I didn't realize I had lost the blocks so again...just swap everything over from your old 6 lug 1/2 ton 10b and you'll be set.

will I have to re locate the the leaf spring perches on the 3/4 tons axles? "perches", as in what the leaf springs sit on.

If these are out of a 3/4 ton then nope. The spring perches all align without any modifications...

Will these 3/4 tons axles be the same width (side to side) as my 1/2 tons axles?

I believe they are 2ish inches wider (someone help me out here). But I haven't had any problems...I went with 4" of back spacing on my new rims to help offset this...

Can I use my stock leaf springs?

Yep and be sure that you check out your centering pins that run though the leaf springs into the spring perches on the axles...if they need to be replaced be sure to use the correct hardware
But yeah you won't have to change anything...

Will I need different drive lines or do I just change out my U joints?

The front will be good to go as far as joints/length go...
The rear will either need a conversion joint (Napa part #447) which has s44 on two ears (for the 1/2 ton d-shaft) and 1350's on the other two ears (for the 14ff yoke).
Oh wait...crap I just remembered you have a 12b so it might be different...ok help me out on this one guys...I forgot what a 12b has...
One thing for sure is the rear d-shaft length...if everything was perfect (as in your old d-shaft wasn't being pulled out of the transfercase because of your lift) then you'll need to shorten the d-shaft (or maybe this would be a good time to have a new correct length shaft made up by a local shop with the correct ends so you don't have to use a conversion joint). BUT if you were like me and your d-shaft was too short already b/c of the lift then this'll push the slip yoke back into the transfercase a little bit.

Will my stock steering bolt right up or will I need to change anything like the pitman arm?

It'll bolt right up...check and see if you have a raised steering arm, drop pitman arm, dropped draglink...w/e and it'll help us figure out what you'll have to do.
Like on my truck I have a stock pitman arm, dropped draglink and a raised steering arm so I had to have that raised steering arm swapped over onto the new axle b/c the new axle had a stock height steering arm which was too short to reach to my draglink.
Either way it'll bolt up regardless of how you have to mix and match...

These 3/4 tons axles will be 8 lug right?

iono...lets hope so b/c sometimes you can even get the 14sf in an 8 lug so its hard to tell unless you just see them or ask the dude...




I hope that helps a little bit dude...but check out my thread that I posted a link to above...