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Post Info TOPIC: 12 Bolt Diff Upgrade
Bobs_Place


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12 Bolt Diff Upgrade
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Last fall I ordered axles ,diff, ring and pinion, housing ends and some other miscellaneous other parts,  I have been planning to build up a stronger differential for some time now. Chris P. found the tool I need to center the weld on ends to the housing, he also new the right guy to weld the center casting to the tubs on both our housings, this strengthens them and on my housing, repair oil leaks. So we had them welded over the winter.

12 Bolt up grade 025.JPG

Well, I'm finally getting to it. The housing ends I,m installing accept the Impala backing plate and big ford Ford wheel bearings which gets me 11" over the 9 1/2" brakes, the axles will now be retained at the housing ends, no "C" clips.

Measured and cut the old end but left just a little to use to true up bring the tube to the correct dimension.

12 Bolt up grade 004.JPG.

12 Bolt up grade 009.JPG

Beveled the ends of the housing and started welding them on.

12 Bolt up grade 011.JPG

My first attempt at welding on the end did not go so good, it was to fare out of align. I had to cut the end off regrind it and the housing clean and star over,the second attempt went better but still had to grind and reweld to pull and shape the end. I found that putting to much to one side will pull the alignment and egg shape the end. It was a bit challenging. The other end I tack welded just like I did the first side, retacked to pull the end in align, then welded, I was able to weld all around and keep the heat up this time. I let it cool, the axle drop right in NO aligning or truing the end.nana

Pressure tested, no leaks

12 Bolt up grade 017.JPG

Blasted and painted the housing

12 Bolt up grade 021.JPG



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Bob W.

Lino Lakes
Lost in the 60s


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Looks mighty fine !!

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Mitch D.   River Falls, WI

Lifetime member of the "Cars apart Club"

Some Assembly Required

1966 Chevelle SS 396 M20

1970 Chevelle SS 396 M20

1967 Camaro SS 350 rs
Larry Lucast


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That is NICE.

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Larry L.

Coon Rapids
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Great, now that you figured out the welding technique you can give me pointers for doing mine. Hoping to get to it this fall. 



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Chris P
East Central, Mn

66 Chevelle 300 deluxe
Bobs_Place


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Well I hope I have it figured out.

The first side took a long time to get straight, after tack welding I welded about 1-2" segment and tried to check my progress, welded an other segment  at 180* apart from the first figuring that the second weld would pull the end back straight, this just caused the end to go out of round and not straight.  I suspect I let the welds cool to much trying to check for straightness. I also ground some of the welds to pull and or round out the housing end.I spent way more time on that end than I would like to admit!!!!!!doh

On the other side I tack welded the end on, found it to be off a bit, I welded about 3/4" to straighten, when I was satisfied it was straight I started welding, only stopped to reposition the housing, than continued the weld, not letting it cool. When done welding I let it cool, the alignment tool slipped right in, so i tried the axle, it also slipped in and the spline end centered up in the center of the housing. beers

Be glad to help.tiphat                       Hopefully I didn't just get real real lucky, but actually learned something.



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Bob W.

Lino Lakes
Lost in the 60s


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Is the alignment tool something you could leave in the end to hold alignment while tacking ? After 4-6 spaced tacks, it could probably come out, to prevent damage.

Yup, getting the opposite side tack weld on while the first is hot, allows the pieces to move back. Once that weld is cold, you're done.

Time spent making something right isn't wasted.thumbsup



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Mitch D.   River Falls, WI

Lifetime member of the "Cars apart Club"

Some Assembly Required

1966 Chevelle SS 396 M20

1970 Chevelle SS 396 M20

1967 Camaro SS 350 rs
Bobs_Place


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Lost in the 60s wrote:

Is the alignment tool something you could leave in the end to hold alignment while tacking ? After 4-6 spaced tacks, it could probably come out, to prevent damage.

Yup, getting the opposite side tack weld on while the first is hot, allows the pieces to move back. Once that weld is cold, you're done.

Time spent making something right isn't wasted.thumbsup

 The alignment tool is a tight fit and it is aluminum so it will expand which makes hard to remove hot or if the end is out of round after welding, don't know if leaving the tool in place helps with alignment or not once it's tack welded.

The second end I did a continuous weld(stopped only to reposition the housing) not a 180* from the first pass, you might be right, if I had welded the 180* pass without stopping to check my work/ letting it to cool, the first attempt  may have worked.

"Time spent" Very true.  The alignment tools got the end centered with the differential side gears but the best tool to check the alignment of the end to the side gear is the axle shaft assy. Another words the end may be centered to the diff but inserting the axle will show the direction the end is pointing the axle. Getting the axle to come out centered at the differential is important for good wheel bearing life.



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Bob W.

Lino Lakes
Bobs_Place


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The welds are cool and the paint is cured time to get busy!Imgonna

First order of business, clean the housing. Soap and hot water to washout any sand blasting sand or grinding residue, rinse with hot water, dry with compressed air.12 Bolt up grade 028.JPG

Some of the part I'm installing. All 4 of my axle shafts from both of my housings are worn/pitted at the bearing surface, I also wanted to upgrade the brakes from the Chevelle 9.5" to the 11" Impala brakes from one of my spare Impala housings. There was no cost difference between the 30 to 33 spine so I opted for the 33s. So the axles and the housing ends and the brake I have cost less (I think) than a disc brake set. I could have stayed with the original diff/posi and 30 spline axle but the diff would have been the weakest link and I wanted something stronger, I will likely use the diff in the Impala so I upgraded to a Tru-Trac diff with the 33s and installing a set of 3.73s which should work well with the Gear Vender Overdrive I installed last year.

12 Bolt up grade 025.JPG

 



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Bob W.

Lino Lakes
Bobs_Place


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The first step in assembling the diff was to set the pinion height and preload. I installed a .015 shim, than pressed the bearing on to the pinion, I'm using an adjustable pinion spacer instead of a crush sleeve, so I shimmed the adjustable spacer to the same height as the crush sleeve, installed the pinion, space and outer bearing, checked preload and pinion depth. Well, the pinion was marked 2.855, that's from the center of diff side bearings to the end of the pinion as per the directions. I measured 2.510 that's a difference of .345 This means I have to drop the pinion, I only have a .015 shim to remove. The pinion is marked wrong, so I'll have to set the pinion height based on the pattern. I assembled the ring gear on to the diff case and installed it into the housing and painted the gears, the pattern showed that the pinion was very low. The preload was also loose, I pulled the diff case and pinion, remove the inner brg. added shims and reinstaled the brg to raise the pinion, removed all shims from the brg spacer. Assembled pinion and diff case into housing, checked pattern. Had to repeat this procedure several times to get the gear contact correct including resizing the pinion spacer, after removing all the shims from the spacer it was still to thick, so I used the belt sander to remove about .002" at a time, I eventually removed .007-.008" to get the pinion bearing preload correct.

12 Bolt up grade 030.JPG

Removing the pinion to add shims

12 Bolt up grade 002.JPG

Removing the brg

12 Bolt up grade 033.JPG

after adding shims

12 Bolt up grade 035.JPG

Checking after thickness after removing material from he spacer

12 Bolt up grade 006.JPG

Great patternnanabeershyper

12 Bolt up grade 017.JPG

 



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Bob W.

Lino Lakes
more ambition than brains


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I cannot even comprehend the patience and precision it takes to do what you are doing well.
Karl

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More ambition than brains,

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Bobs_Place


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more ambition than brains wrote:

I cannot even comprehend the patience and precision it takes to do what you are doing well.
Karl

 Compared to doing body work, this, is a walk in the park!!!!!!!!!!!!!!!!!



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Bob W.

Lino Lakes
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beersRemember I am the author of the chop-chop-chop-hack-hack-hack thread.

There are similarities between the craftsmanship required for both quality body/paint or mechanical.

There is a reason I am a bs-r not a technician.

Karltiphat

 



-- Edited by more ambition than brains on Saturday 1st of June 2019 08:43:33 AM

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More ambition than brains,

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Lost in the 60s


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more ambition than brains wrote:

There are similarities between the craftsmanship required for both quality body/paint or mechanical.

There is a reason I am a bs-r not a technician.

Karltiphat

 Translation...Office Personnel..thumbsup



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Mitch D.   River Falls, WI

Lifetime member of the "Cars apart Club"

Some Assembly Required

1966 Chevelle SS 396 M20

1970 Chevelle SS 396 M20

1967 Camaro SS 350 rs
Bobs_Place


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I installed the brake backing plates, axle assemblies and brakes, had to drill the drums for the 1/2" wheel studs. 12 Bolt up grade 023.JPG

Removed the original housing/diff assembly.

12 Bolt up grade 014.JPG

I removed the upgraded housing/diff assembly from the stand, installed the rear cover, seal and yoke, brake lines and no hope bars

12 Bolt up grade 024.JPG

Then installed the assembly.12 Bolt up grade 026.JPG

The road test went well, the braking is good but should get better when the new shoes get seated to the drums, the diff works great (found that out during cornering), 3.73 ratio is just right for the GV Overdrive and the M22 1st gear.



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Bob W.

Lino Lakes
Lost in the 60s


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Having that fancy jack adapter is almost cheating ...laughing

Is that a '66 diff, or do you need the spring risers for tire clearance ?

I won't pick on your "no hope", bars...razz

Good to hear you are happy with the results, after all that work...thumbsup



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Mitch D.   River Falls, WI

Lifetime member of the "Cars apart Club"

Some Assembly Required

1966 Chevelle SS 396 M20

1970 Chevelle SS 396 M20

1967 Camaro SS 350 rs
Bobs_Place


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Lost in the 60s wrote:

Having that fancy jack adapter is almost cheating ...laughing

Is that a '66 diff, or do you need the spring risers for tire clearance ?

I won't pick on your "no hope", bars...razz

Good to hear you are happy with the results, after all that work...thumbsup

 The adapter might be cheating but but it sure worked nice to get around the hoist. Once it was unbolted I raised the car a bit and turned the diff he diff is out.12 Bolt up grade 017.JPG

The axle is a 71 or 72, just looked it up. The risers were on the housing when I got it, I don't know if there OE parts ,aftermarket/hot rod parts, used on El Cameno maybe, did 66 us them? The were 3", I cut them down to 1.5" The car was riding lower than I liked, I think both the front and rear settled since I finished the the car so front springs are also in the future. With the GV overdrive (shorter drive line) and the extra height the DL angles came in very good. No clearance issues just not a low rider guy.

Oh and on the no hops, thank you   whew cancan                laughing



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Bob W.

Lino Lakes
Lost in the 60s


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'66 was a flat plate and the spring is held on with a formed cup.
The risers are aftermarket, for sagging springs or more tire clearance. I have them on mine too and cut them in half also.

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Mitch D.   River Falls, WI

Lifetime member of the "Cars apart Club"

Some Assembly Required

1966 Chevelle SS 396 M20

1970 Chevelle SS 396 M20

1967 Camaro SS 350 rs
Derek69SS


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With those spring spacers, the no hop bars will certainly be necessary! No Hops are the only way to go with raised ride-height IMHO.

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Derek Kiefer - Mantorville, MN

69 Malibu Pro-Touring stroker LS1-383/T56 - 69 SS396-325/3spd project
Bobs_Place


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Lost in the 60s wrote:

'66 was a flat plate and the spring is held on with a formed cup.
The risers are aftermarket, for sagging springs or more tire clearance. I have them on mine too and cut them in half also.

 I also built the axle 1/2" wider, I have wheels with a 1/2" deeper backspace, that puts the wheel/tire back to the same wheel base as the std axle and centered backspace wheel, the more typical setup. The larger BS reduces the gap between the trim ring and spokes on the wheel, so the front and rear look similar. Also the weld for the axle ends were outside of the shock mount. Fronts are 7" rear are 8"

Wheels 002.JPGWheels 004.JPG

12 Bolt up grade 004.JPG



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Bob W.

Lino Lakes
Bobs_Place


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Derek69SS wrote:

With those spring spacers, the no hop bars will certainly be necessary! No Hops are the only way to go with raised ride-height IMHO.

Derek

You are right. Lower control arms should be level, mine are not. But when I land on the peddle with my right boot, the rear of the car rises, with or with out the spring spacers.



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Bob W.

Lino Lakes
Lost in the 60s


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Bobs_Place wrote:

 I also built the axle 1/2" wider, I have wheels with a 1/2" deeper backspace, that puts the wheel/tire back to the same wheel base as the std axle and centered backspace wheel, the more typical setup. The larger BS reduces the gap between the trim ring and spokes on the wheel, so the front and rear look similar. Also the weld for the axle ends were outside of the shock mount. Fronts are 7" rear are 8"

 

 I'm getting you a bumper sticker...thumbsup

ocd_or_cdo_bumper_sticker-r0366b00d98f64



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Mitch D.   River Falls, WI

Lifetime member of the "Cars apart Club"

Some Assembly Required

1966 Chevelle SS 396 M20

1970 Chevelle SS 396 M20

1967 Camaro SS 350 rs
SShink


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Lost in the 60s wrote:

Having that fancy jack adapter is almost cheating ...laughing

 

Bob where did you find that jack adapter?  

I've got some axle work coming up in the future, and that would sure make it easier than wrestling it on the top of the jack and trying to balance it.



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1972 Malibu Convertible 2nd time around 

1999 SS Camaro LS1-6 speed

Forum influenced terms: 'Link Paste', 'Stanitized', & 'Revolving garage door...' 

 
Bobs_Place


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Lost in the 60s wrote:
Bobs_Place wrote:

 I also built the axle 1/2" wider, I have wheels with a 1/2" deeper backspace, that puts the wheel/tire back to the same wheel base as the std axle and centered backspace wheel, the more typical setup. The larger BS reduces the gap between the trim ring and spokes on the wheel, so the front and rear look similar. Also the weld for the axle ends were outside of the shock mount. Fronts are 7" rear are 8"

 

 I'm getting you a bumper sticker...thumbsup

ocd_or_cdo_bumper_sticker-r0366b00d98f64

 That's pretty "Trick" isn't it.   thumbsup

Oh and by the way, I think you should order two stickers, I know someone else that might need one.            rolleyes                                            Mitch    laughing

 



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Bob W.

Lino Lakes
Bobs_Place


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SShink wrote:
Lost in the 60s wrote:

Having that fancy jack adapter is almost cheating ...laughing

 

Bob where did you find that jack adapter?  

I've got some axle work coming up in the future, and that would sure make it easier than wrestling it on the top of the jack and trying to balance it.

 The adapter came from Bob's Surplus Steel and Supply House.      Some assembly required,              and cutting        and drilling        and welding,         etc. etc.

Your welcome to use it,. dose your jack have a removable plate with about a 1 1/8" stub?

Jack 003.JPG



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Bob W.

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Bobs_Place wrote:

Having that fancy jack adapter is almost cheating ...laughing

 

Bob where did you find that jack adapter?  

I've got some axle work coming up in the future, and that would sure make it easier than wrestling it on the top of the jack and trying to balance it.

 The adapter came from Bob's Surplus Steel and Supply House.      Some assembly required,              and cutting        and drilling        and welding,         etc. etc.

Your welcome to use it,. dose your jack have a removable plate with about a 1 1/8" stub?

I was wondering if you built that yourself!  tiphat

That looks like the same size as my floor jack opening.  I'll check it and will let you know when I get ready to tear into the rear of the car. 



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Stan S.-Twin Cities 'South Metro'

1972 Malibu Convertible 2nd time around 

1999 SS Camaro LS1-6 speed

Forum influenced terms: 'Link Paste', 'Stanitized', & 'Revolving garage door...' 

 
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