1972 Build thread.

[A1971Blazer]

Originally Posted by prorat56

Hey I would Like to give my input on you building your rears (I do at least 20 rear diff overhauls and gear changes a year at my shop) Start with the original shims!, set your back lash then check your pattern. I don't own a depth gauge but I have used them and don't like them and think you will be chasing your tail. The gear marking compound will be your friend. Well that's my 2 cents and I hope this helps and makes your job a bit easier.

I agree with this^^^^
The gears are manufactured to a particular dimension as far as spacing and center line are concerned.....but.....the housings are manufactured with certain
± tolerances as well...which may or may not be the exact same as what the gears are.
The last set I put in my 12 bolt...I set the depth to exactly what was marked on the pinion gear......it wasn't anywhere close when I checked the pattern...

[kehstr]

Originally Posted by hemi43

And one more thing I've learned over the years is do not use synthetic gear lube because you will never get rid of the chatter regardless of how many bottles of additive you put in. On my Blazer I tried using Amsoil's synthetic gear lube because they claimed it was compatible. Well, they were wrong because it sounded like the rear diff was going to break in two. I gave it a few weeks hoping the noise would go away, but it never did. I drained it and put in standard gear lube and a couple bottles of GM limited slip additive, and the problem went away. That was an expensive mistake because Amsoil products aren't cheap.

Is this on a differential with some sort of locker?

[prorat56]

Originally Posted by hemi43

And one more thing I've learned over the years is do not use synthetic gear lube because you will never get rid of the chatter regardless of how many bottles of additive you put in. On my Blazer I tried using Amsoil's synthetic gear lube because they claimed it was compatible. Well, they were wrong because it sounded like the rear diff was going to break in two. I gave it a few weeks hoping the noise would go away, but it never did. I drained it and put in standard gear lube and a couple bottles of GM limited slip additive, and the problem went away. That was an expensive mistake because Amsoil products aren't cheap.

I think he is using trutracks diffs witch have no clutches so no additive needed but I've been leaning away from synthetic's myself. My favorite HD gear oil is Torco race oil GL6 rated. I use it in my Dragweek prostreet car and I've been using the same 9.5" pro gear for 4 season running 7.50s and 6 thousand street miles and they still don't make noise. Also try morpar posi additive is by far the best additive I've ever used.

[hemi43]

Originally Posted by kehstr

Is this on a differential with some sort of locker?

Yes ! I've had issues with both Auburn style (cones) and clutch style that come in our Blazers when using synthetics. I'm not a chemist, but I assume it has something to do with the friction modifiers much like the difference between Dextron and F type transmission fluid.

On my Blazer, I used Amsoil synthetic in the transfer case as well as the front Diff, but because the front is just an open diff, I had no issues.

What's odd, is that it claims right on the Amsoil tech sheet that their oil is compatible with locking differentials.

[kehstr]

Originally Posted by hemi43

Yes ! I've had issues with both Auburn style (cones) and clutch style that come in our Blazers when using synthetics. I'm not a chemist, but I assume it has something to do with the friction modifiers much like the difference between Dextron and F type transmission fluid.

On my Blazer, I used Amsoil synthetic in the transfer case as well as the front Diff, but because the front is just an open diff, I had no issues.

What's odd, is that it claims right on the Amsoil tech sheet that their oil is compatible with locking differentials.

Yeah, my dad had the same problem in his blazer with a Detroit, and he used Schaeffer's synthetic. As soon as he took the synthetic stuff out and put regular 80w-90 in it, it worked perfectly.

[Spf79]

Hi,

I finally got some time to myself in the garage.

Please take a look at the patterns on my gears, im looking for second opinions... should i run them or do some more shim work?

Pics of the 12 bolt

[Spf79]

... and the dana 44

[prorat56]

Pattern on both look perfect to me.

[Spf79]

Originally Posted by prorat56

Pattern on both look perfect to me.

Thanks for looking, the 12 bolt set up really easy... the dana on the other hand took 5 or 6 attempts.

I feel good about the contact patterns, i just wanted some other opinions. Thank you again!

[Spf79]

It has been a busy summer with the kids and work, not much done on the blazer. Over the last month or so I have been able to get back on the project a bit. I am hoping for a rolling frame with drive train by Christmas.

Here are some pics... five at a time.

[Spf79]

More pics.

I got the necks on the gas tanks switched out. Needs some paint.

My 12 bolt is done, I apparently needed more help with my dana 44, so that is at a buddies house. Hope to finish that up in a week with some more guidance than what I was getting off of Youtube

I got springs under the frame last night.

Starting the motor project this month.

[DeadheadNM]

Nice work. Thanks for the update.

[Spf79]

Originally Posted by DeadheadNM

Nice work. Thanks for the update.

Thank you sir! That means a lot coming from you.
I have been following your highlander build. It is amazing!!!

[Spf79]

Thanksgiving week is always slow at work, so I got some time to finish up my dana. Apparently I had it all messed up & I got educated... always good to have friends that know things.

I was able to have my father inlaw help me move my rear end onto some jack stands and get my front axle on the saw horses. I got my knuckles on tonight, and fitted the spindles. I need to bolt the spindles and caliper plates on. Hope to get the front end under the frame this weekend. Rear end next week. I am waiting on my tie rod and rear end u-bolt plates to get back from the powder coater Monday.

Happy face!!!, I got my rear end sway bar and front pumpkin cover today.

[Spf79]

Finished the front axle tonight. Just waiting on the tie rod to get back from the powder coater. Hoping to get the front axle under the frame tomorrow.

[lks dcvn]

Very nice - where did you get the new 6 lug slot rims? Been looking for a used set for awhile - may just need to get new ones instead.

[Spf79]

Originally Posted by lks dcvn

Very nice - where did you get the new 6 lug slot rims? Been looking for a used set for awhile - may just need to get new ones instead.

Thank you!

I was in the same boat with the slotted mags, they are stinking hard to find in good shape. Seemed that anything I found in the $500 range was going to need a major polishing job..

I finally found these. I got them off of Amazon for $640. The wheels are a US mags, u101 Indy wheel. Mine are 15x10, with 3.5 back spacing. http://us-mags.com/indy-u101-truck-w-5493.htm. They even have a pic of a Blazer on their website, lol - sold!

I think Summit has them as well. I would assume that your local tire guy can get them. I had a mom and pop shop close to my house mount and balance mine. Note, they had to use a mag machine to put the tires one, one fella had to stand on the tire bead while the other guy ran the machine. They can't use a regular tire machine, because it will catch the lip of the wheel and make bad sounds. I used balancing beads as well so I did not have to deal with sticky lead weights.

The wheels appear to be of good quality, at this point. Hopefully they run out smooth.

Here is the pic of the Blazer off of their website.

[Spf79]

I had a buddy come by and help me get the axles under the frame tonight. Everything needs to be tightened... and I need to loosen the spring bolts and grease the bushings... hoping it settles out easily. I'm still waiting on my rear spring plates so I had to improvise the rear u-bolts until I get the plates. You have to take help when you can get it. This feels good, starting to look like a Blazer.

[Spf79]

1st of five 5125 Bilstien shocks showed up today... they were all due today.
The poor UPS guy looked like a train wreck... and I gave up trying to turn the two pics.

I did decide to go without the boots, and with them upside down from the traditional mounting style. Apparently the 5125 allows you to run them either way. I thought it was a cleaner look in my opinion. Also, since I am not running boots I figured it would help keep the seal clear from debris.

Now I impatiently wait for the rest to show up.

I am also waiting on my motor to come back from the machine shop. Yes!!!
I hope to see it in another week or two.

Funny item I ran into, more of an FYI. If you run the front 1-1/4" tie rod from Offroad Design without their add-a-leaf in the front it will hit the bottom of the leaf springs. Oh! And if you run the stock height steering arm it will hit the tie rod at full lock. So now I have to get rid of my drop pitmant arm, and buy a raised steering arm.

[Spf79]

2nd shock showed up tonight. Supposedly the rest tomorrow.

Happy dance!! My cam and rocker arms showed up a day early!!

Happy dance #2, my youngest got his next stripe, almost a purple belt!! Now... onto some homework with the boys tonight and then bed time... and then garage time. Hopefully I can get the rear shocks bolted in.

[hemi43]

Could you post a few more pictures of your front sway bar ? Do you know who manufactured it?
Also, how close is the rear sway bar from the diff cover? I'm asking because I would like to add one to my Blazer, but I only have around 5 inches between my diff cover and custom fuel tank. I'm also curious as to what that bracket is I circled in the picture. Thanks !!

[Spf79]

Originally Posted by hemi43

Could you post a few more pictures of your front sway bar ? Do you know who manufactured it?
Also, how close is the rear sway bar from the diff cover? I'm asking because I would like to add one to my Blazer, but I only have around 5 inches between my diff cover and custom fuel tank. I'm also curious as to what that bracket is I circled in the picture. Thanks !!

The rear bar is an Addco 202 1" rear sway bar for 2wd or 4wd trucks. It can be installed facing forward or backward of the axle. You circled it in its forward mounted position. I need to install the gas tank and then try changing the bar so that it faces rearward. Not sure how i like it yet. The front bar is a stock 73 & up 1-1/4" GM bar. The PO changed the front cross member out at some point. I can take some better pics tomorrow in the daylight. Sound good?

[6768chevylover]

where did you get your bilsteins from and for what year truck/blazer? Thanks

[hemi43]

Originally Posted by Spf79

The rear bar is an Addco 202 1" rear sway bar for 2wd or 4wd trucks. It can be installed facing forward or backward of the axle. You circled it in its forward mounted position. I need to install the gas tank and then try changing the bar so that it faces rearward. Not sure how i like it yet. The front bar is a stock 73 & up 1-1/4" GM bar. The PO changed the front cross member out at some point. I can take some better pics tomorrow in the daylight. Sound good?

Thanks !! After seeing your post, I spent lots of money today !! :-)
I went out this morning and bought an original 73 up front anti-sway bar from Bill's trucks which is just a few minutes from here. For some odd reason, I had a urethane bushing kit for it here which was a bonus. I will have to fab some front mounting pads, because I'm told the first Gen Blazers never came with front anti-sway bars.
While under the truck, I decided to buy new leaf springs also, and opted for the Tuff Country EZ-Ride with a 2"lift.
I like the idea of having the rear bar face forwards so I'll look into the one you used, because I may have fitment issues mounting rearwards. My exhaust pipes are in the way. Thanks for the info !!

Edit; I just checked the price for the Addco 202 here in Canada. $334.00 VS $186.00 at Jeg's !! FFS, I get fed up living up here. :-(

[DeadheadNM]

Solid work. Thanks for updates. Strong work on the stripe - kanpai!