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Diary Of A 12 Bolt


Andy's Auto

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I was putting together the 12 bolt for the 68 Velle so I thought I would grease my camera for you all.

 

Started out with a seasoned 72 Monte 3.08 peg leg housing. Pressure washed it and painted it Satan black.

 

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I went with Moser axles and C Clip emininators so you have to chop off around 2 inches of housing. Do not forget to remove the old bearings and seals.

 

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I started out by installing the front pinion bearing and seal.

 

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The pinion seal is best installed with a large piece of wood and a big hammer. One whack gets it in straight. After that install the pinion, a new yoke and nut.

 

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After that drop your carrier in and check your contact patch and pinion depth. Refer to service manual. I can do this in my sleep but attention to detail makes these things last for years.

 

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My pretty Moser axles and eliminators.

 

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This particular setup requires removing the grooves for the stock C Clips. I used my trusty chopsaw Rex.

 

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Here is what they look like installed and ready for new brakes, hardware, lines, drums, and cylinders.

 

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I was wondering the same thing...and making the axle tube shorter gets the axle to fit, but doesn't that move the brake backing plate inboard and away from the axle flange? I'm just wondering if the brake drums cover the shoes when you are done.

 

I love the photos, but I'm still not fully understanding.

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Instructions say to leave an 1/8" past the flange the backing plate bolts to. The flange remains untouched. I just whacked it off with a Swazall. I left just enough to center the backing plate on the flange.

 

Andy

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I just whacked it off with a Swazall.

 

Ha Ha...for some reason...that statement is funny!

 

I know...I probably just "opened an account" with you...but it was worth it!

 

Are you OK after your encounter with this tool? You might need to use your "buffer" now, eh?

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Oh, ok. I guess the part of the tube that was cut off would be OUTBOARD of the backing plate flange? (I guess we were missing the "before" photo of that). That makes sense...you take some off and replace it with their assembly. You did such a good job I couldn't tell where it happened.

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French Clock Watching Wallaby, I will climb the ladder and get a shot of one of those virgin 12 bolts hiding on one of my racks. For the respect of my camera I usually skip teardown pics as I am not the cleanest working guy out there. But in your shoes I get the missing link.LOl.

 

Andy

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I have not dealt with those C-clip eliminator sets....do they have a barrell-bearing in them, and they are pressed onto the axle shafts?

The way I envision them, is like a Ford axle & bearing assembly bolted to the Chevy axle tubes. Kinda like a Ford axle conversion without the welding. Is that right?...so now the axle bearings take the side loads and retain the axle shafts?

 

Now the question about leaking: I have heard that these tend to leak oil when used on the street. Where is the leak coming from? Is it the area where the kit meets with the axle flange, or outboard of the bearing at the axle seal?

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The bearing is a sealed setup. It just presses onto the axle threaded side to the carrier. I used my flange setup on my exhaust bender and they went on very easily. What seals the gear lube is a liberal coating of high grade silicone between the axle flange and the backing plate then the backing plate to the eliminator. The instructions say that the parking brake idler bracket has to be bent to clear the eliminator housing but it looks like a straight shot to me. Just got the car off Towmater and we are inundated with cars right now so I hope to get the 8.5 Posi out of the Velle and the 12 bolt in. I am stealing all the brakes off the 8.5.

 

But the jist of how they mount is very similar to a 9 inch without the retainer plate, There are 4 threaded holes in the eliminators and they give you 8 high grade bolts and lockwashers. You just sandwich the plate between the elims and tighten everything together. It was alot easier than I thought it was going to be. I really did not want to chop off the axle ends but I was solidly 1/8" form meeting the flange.

 

The hardest part was usung a sawzall to cut the axle tubes outboard of the flange the backing plate bolts to. But I took my time and cleaned everything up with a 90 degree cookie wheel. You just leave just enough to center everything. Hard because if you screw it up, you just ruined a perfectly good hard to come by 12 bolt.

 

I will get better at the how to stuff. But I am Jules, not Winston Wolf. LOL. My wallet says BMFer right on it, seiously.

 

Laters Mark.

 

Andy

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What Mo's70MCs said...and ....

 

*dumb question alert!*

 

What does this do to the rim position once it is mounted? Moves the rim inboard correct? All things being equal 2 inches per side mean that both rims would now be moved in towards the center by the same amount? Or do you need to offset that 2 inches somehow with a different rim?

 

I guess that is a dumb question, so forgive me I don't know anything much about this sort of mod, just trying to figure out if it is something I want to look at down the road.

 

Assuming no mods like a set of wheel tubs, Seems to me that since it would move the rim inboard, wouldn't things like clearance with the inner wheel well come into play?

 

TIA

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Thanks Sam I now accept my dumb question of the month award... nutz

 

not a dumb question if you don't understand, if you understand now, it was worth asking wink

 

wacking off the end of the axle isn't as big of a deal as it seems. You take enough off so the bearing assem sit flushly to the backing plate, and enough must be left for centering the bearing assembly to the axle tube

 

when I did mine...the cuts weren't pretty, but it was good enough grin

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the two inches removed, are replaced by the c clip eliminator blocks, so nothing actually moves.

just a thought. for some of us that could use a 1/4 inch extra clearance on the outside, couldn't they make a thinner block so we can get that clearance? would save $ on new set of rims,

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I'm in the middle of putting c-clip eliminators on my car right now. I was looking at the same thing thinking that maybe I could press the bearings a little further towards the flange then it would make the rear end a little narrower. The only problem is like Bob said the brake backing plate is still in the stock location only the brake drum and axle flange would move in. I think that the brake shoes would bottom out in the drums if you tried to do that too much.

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if you have deep pockets, a 66-67 chevelle axle is slightly narrower then a monte axle, and will bolt right in.

 

IIRC, it's one inch shorter on each side... or it might be 1/2" on each side.. i can't remember off hand.

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  • 1 month later...
I was putting together the 12 bolt for the 68 Velle so I thought I would grease my camera for you all.

 

Started out with a seasoned 72 Monte 3.08 peg leg housing. Pressure washed it and painted it Satan black.

 

IMG_4568.jpg

 

Yikes, ya might want to consider having that thing blessed before you go driving. wink

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