FNGs rear axle questions

[DaHateTank]

Hi All,

IIRC, I was on this forum, quite a while ago, but I lost the link, due to some computer problems. Glad to see its still here...

Anyway, I have a '72 Blazer, that mainly, sits around violating my backyard, but is intended for some off-roading and winter driving use.

Having ejected axles from the half-ass 12 bolt, in the past, I recently snapped up some 3/4 ton diffs, when a good deal came up.

The axles are out of a '76 3/4 ton 4WD. A 14-bolt full floater, and a Dana 44.

According to what Ive learned so far, the front is basically a bolt -in, as the spring pads are the same width...is this correct??

In the rear, I am gonna have to move the spring perches, I think. Anything to watch out for, when we do this?? Where can a guy buy the spring perches (the stock cast steel ones, will probly get wrecked, cutting them off)

Also, I am thinking of doing a disc brake conversion, on the 14 bolt. Does anyone have some good tips, or perhaps a website. that details this swap?? Id like to see some good pics, as I have access to some CNC equip, (including a laser) and I think I could make my own brackets, If I could get any dimensions...

Thanks, in advance, for any help!!

here's a pic, of the ole POS, violating my folk's yard


'72 Blazer, '66 396, SM465, NP205, 6" susp., 36 Swampers

[breeh]

Sounds like you have it all figured out already. You can buy the perches from Summit, Jegs, etc.

[Beast388]

Another Iowa guy!!.......what city?

You are correct, the front axle is a bolt up. The only thing to watch out for is the brake hoses may be different at the caliper end....that is ok as you can bolt on the calipers from your blazer. Also, you might need a hybrid u-joint (1/2 ton on one cross, 3/4 ton on the other).

You stated that the 14bff is from a 3/4 ton so the spring perch spacing is 42.5 on center. You will need to move the perches so they are on 40" centers to fit the blazer. As far as where to get perches, Summit, Jegs, Moser or any stock car parts house should have them for your 3-3/8" diameter axle tubes. Or you can make you own. Check out this link:

http://www.off-road.com/chevy/tech/perch/

Just make sure they are welded on so that you have the correct pinion angle. You will also need a hybrid u-joint for the rear and don't forget to move the shock mounts.

The 14bff disk brake swap is really popular. Lots of guys are doing it so brackets can be had for pretty cheap. Here is a link:

http://www.shakerbuilt.com/14_Bolt.html

I am in the process of gathering the parts to do a similiar swap so I have been researching this for a while. Another good site for Chevy 4X4 stuff is www.coloradok5.com. If you have any questions, just ask.

[DaHateTank]

Thanks for the links, Beast388...

The tubing spring perches might be a good idea. I had considered making my own, but had not thought of using tubing, yet...

the brake link I had seen before. Looks like he's using the style of brackets, which have tubing spacers between, the axle flange, and the caliper bracket.

like the ones shown in this link

http://www.a-tron.net/gm_14_bolt_dis...conversion.htm

Ive also seen this page, which shows a bracket, with a spacer made out of plate.

http://www.off-road.com/chevy/reviews/tsm/

My problem is, that it looks like the tubing spacers, as shown in the first link, are a bit longer, than the thickness of the plate, shown in link #2...

My preference is for the plate type, as Im somewhat wary of those pieces of tubing, and how stable they'd be (vs. torsion of the bracket). Further, it'd be dirt simple for me to laser cut the other style...

However, I need to know how thick the two plates are, or the thickness of the bracket/tube spacer combination. Maybe Ill just end up centering the calipers, on the rotor...

Ive seen guys just cut out the front caliper bracket/splash shield, from a donor front axle, and weld it to the back axle...IF that works, Im probly being too anal, worrying about the thicknesses...
(but Im an engineer, so I sweat those kinda things)

--------

As far as city...I currently live in Spencer, about 5-1/2 hours away from Clinton. (90 min. NW of Fort Dodge) However, Im originally from Clinton, and my folks still live there. I can't seem to remember seeing your 'burban, tho. How long have you had it??

My Blazer used to sit in the front yard of my parents house, until about 3 years ago... They live up by the old Target store (Farm & Fleet, now)

What do you do around Clinton??

-Marty

[Beast388]

I agree, the donut spacers look like a better option for the disk brake brackets instead of the little tubing spacers. Those don't inspire alot of confidence. On Ebay right now, someone has an auction selling blueprints of 14 bolt disk brake brackets that he designed himself. He is using tubing spacers but the length dimension of the tube could be used to determine the thickness of the donut spacer. In reality, it shouldn't be hard to design your own. I am a designer by profession and have thought that those would be easy to make.

One of these days when I get a 14 bolt and the parts I will take some time and draw it up.

I knew your Blazer looked familiar. I'm sure I've seen it around. My Suburban has been in the family for 20 years and has been mine for the last 10. It used to be yellow when I was in high school (class of '92) but as you can see it is primer black/grey now. I used to spend alot of time at my buddy's house which is right behind Farm & Fleet on 27th Avenue South.

[DaHateTank]

Now I remember that Suburban. It was pale yellow, sorta faded, like all the paint they put on these things???

IIRC, I started drving this Blazer, around '87 or so, it was chalky orange, with gold doors, & white lid, for a long time.

Its a piece 'o' crap, but Ive had it for so long, Im kinda attached to the ole heap

-M