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welding/redrilling rear axle flanges #2737060
01/27/20 01:29 PM
01/27/20 01:29 PM
Joined: Mar 2003
Posts: 4,848
Memphis
HemiRick Offline OP
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HemiRick  Offline OP
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Memphis
I need to make a small bolt pattern A-body axle into big pattern, I bought a jig to drill the holes....The problem is my current axles have 3 holes in them all ready about where they need to be drilled. Has anyone ever welded up the existing holes? Do you think this could be done safely w/o changing the tempering/strength of the flanges?

Thanks for your thoughts
Rick

Last edited by HemiRick; 01/27/20 01:30 PM.

Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
Re: welding/redrilling rear axle flanges [Re: HemiRick] #2737084
01/27/20 02:22 PM
01/27/20 02:22 PM
Joined: Sep 2003
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north of coder
moparx Offline
"Butt Crack Bob"
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north of coder
if it were me, i would purchase a set of axles from Dr. Diff.
by the time you get done welding the extra holes shut and drilling the new ones, it's hard to tell what will happen to the flanges.
just my opinion. your mileage will vary.
beer

Re: welding/redrilling rear axle flanges [Re: moparx] #2737105
01/27/20 03:16 PM
01/27/20 03:16 PM
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Memphis
HemiRick Offline OP
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Dr. Diff does not sell replacement axles for the the 7 1/4 axle......


Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
Re: welding/redrilling rear axle flanges [Re: HemiRick] #2737120
01/27/20 03:42 PM
01/27/20 03:42 PM
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Posts: 701
Northern California
lilcuda Offline
super stock
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Northern California
Originally Posted by HemiRick
Dr. Diff does not sell replacement axles for the the 7 1/4 axle......


Just because it is small bolt pattern, does not mean it is a 7 1/4 rear end. 8 3/4's came with small bolt pattern too.


'67 is an abbreviation of 1967
67' is an abbreviation of 67 feet
They are not interchangeable.
Re: welding/redrilling rear axle flanges [Re: HemiRick] #2737121
01/27/20 03:43 PM
01/27/20 03:43 PM
Joined: Dec 2003
Posts: 22,695
Bitopia
J
jcc Offline
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
J

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Bitopia
Keep in mind, IMO no reputable shop would do what you are asking, no matter what you are paying. The deal breaker for me is you are only welding three, and that means uneven heating/tempering on a stressed high rational catastrophic non redundant drivetrain part. Only thing that could be worse, is you want to drive it on the street. eek biggrin


Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
Re: welding/redrilling rear axle flanges [Re: jcc] #2737149
01/27/20 04:48 PM
01/27/20 04:48 PM
Joined: Jan 2003
Posts: 20,356
Eagle, Idaho
Neil Offline
The Doctor is in.
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Eagle, Idaho
Stock axles usually have the access hole for adjusting the axle endplay so that might make this a bad idea as far as not having enough material to work with.

If they are 8.75 axles then sell them and use the money to fund a large bolt pattern set.

Re: welding/redrilling rear axle flanges [Re: Neil] #2737156
01/27/20 05:29 PM
01/27/20 05:29 PM
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Posts: 4,848
Memphis
HemiRick Offline OP
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This is a 7 1`/4 axle, yes the access hole to unbolt the bearing retainer will be welded up along w the other 2 holes and the flange redrilled. The axles will then be chucked in a lathe to make sure its still true and machine the welds flat. I will enlarge one of the old stud holes to make a new bearing retainer access bolt hole.


Last edited by HemiRick; 01/27/20 05:30 PM.

Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
Re: welding/redrilling rear axle flanges [Re: HemiRick] #2737164
01/27/20 05:54 PM
01/27/20 05:54 PM
Joined: Oct 2003
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W. Kentucky
justinp61 Offline
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Not a smart move IMO.

Re: welding/redrilling rear axle flanges [Re: HemiRick] #2737171
01/27/20 06:09 PM
01/27/20 06:09 PM
Joined: Jan 2007
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A Red State
SNK-EYZ Offline
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Are the flanges and holes on a 7-1/4 any different than the ones on an 8-3/4?

I had a shop that builds custom rear ends redrilll my small bolt 8-3/4 axles to large bolt and thread them to install 1/2 inch thread in studs.
He installed new axle bearings at the same time.

They would install press in (knurled) 7/16th studs (GM I believe) but said the outside diameter of the Mopar 1/2 inch studs was to large but said thread in 1/2 inch studs would be fine.


Kayse can't keep up at all now. lol
Re: welding/redrilling rear axle flanges [Re: SNK-EYZ] #2737173
01/27/20 06:14 PM
01/27/20 06:14 PM
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MI, usa
dvw Offline
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If its a 7 1/4 just use 4" to 4 1/2" wheel adapters. The adapters are stronger than the gear itself.
Doug

Re: welding/redrilling rear axle flanges [Re: HemiRick] #2737174
01/27/20 06:15 PM
01/27/20 06:15 PM
Joined: Aug 2009
Posts: 235
Central Mississippi
mopar97 Offline
enthusiast
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Central Mississippi
Originally Posted by HemiRick
This is a 7 1`/4 axle, yes the access hole to unbolt the bearing retainer will be welded up along w the other 2 holes and the flange redrilled. The axles will then be chucked in a lathe to make sure its still true and machine the welds flat. I will enlarge one of the old stud holes to make a new bearing retainer access bolt hole.


This has been done on dirt track cars for years. I know they fall off in the corner and place tremendous loads on the right-side wheels.


Mopar born, Mopar breed, when I die, call me Mopar dead!
Re: welding/redrilling rear axle flanges [Re: justinp61] #2737175
01/27/20 06:16 PM
01/27/20 06:16 PM
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So Near, Yet So Far
topside Offline
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I'm no metallurgist, so if it was me, I'd ask an axle shop, but I'd bet they'd decline doing it.
Other options:
Look for a pair of 5x4.5 axles, if there's a B-body or later A-body application.
Have axles made (Yukon, etc), though that's like throwing good money after bad.
Swap in an 8.75 and (1) be done with it and (2) upgrade.
Adapters, if available, though that probably creates a problem with wheelhouse space.
Get matching pattern wheels.

Re: welding/redrilling rear axle flanges [Re: dvw] #2737194
01/27/20 06:49 PM
01/27/20 06:49 PM
Joined: Mar 2003
Posts: 4,848
Memphis
HemiRick Offline OP
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Adapters are an inch thick, then the wheels/tires wont fit inside the wheel wells.....no go


Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
Re: welding/redrilling rear axle flanges [Re: HemiRick] #2737212
01/27/20 07:35 PM
01/27/20 07:35 PM
Joined: Jan 2003
Posts: 1,798
McGregor,Iowa 52157
5
500ciDuster Offline
top fuel
500ciDuster  Offline
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5

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McGregor,Iowa 52157
Wish you were closer, I have a 7 1/4 big bolt

Re: welding/redrilling rear axle flanges [Re: 500ciDuster] #2737271
01/27/20 10:07 PM
01/27/20 10:07 PM
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Posts: 3,122
Auburn WA
Dave_J Offline
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Auburn WA
40 some years ago a shop made a 1/4 inch thick ring that they press fitted over the 7 1/4 hub and then stitch welded it to the hub.
They then heated the hub up very warn but not hot and TIG welded the 5 ea 7/16 stud bolt holes up using a copper backer plate behind the weld.
Then they redrilled and tapped them for 1/2 inch screw in studs on the LBP.
That car had 4.10:1 Suregrip and we ran G60 15's for years.

I also have a set of 1974 Dart Swinger LBP 7 1/4 axles somewhere out in the garage. But not sure its a easy swap. Wheel bearings or splines may be different.


Retired, US ARMY 1973-1994
ASE mechanic, Electrical 1994-1997
Retired GTE/VERIZON/FRONTIER 1997-2015


Posting cheap tech help (CRAP) here since Nov 97, 1000's of posts, some may be good.

03 Suzuki Burgman 650(Burger King) Scooter
65 Formula S Cuda
78 Little Red Express Truck
98 Buick Regal (wifes car)
Re: welding/redrilling rear axle flanges [Re: Dave_J] #2737285
01/27/20 10:53 PM
01/27/20 10:53 PM
Joined: Jan 2003
Posts: 1,798
McGregor,Iowa 52157
5
500ciDuster Offline
top fuel
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McGregor,Iowa 52157
They did do a bearing change so you couldn't just swap over to the bb axles

Re: welding/redrilling rear axle flanges [Re: 500ciDuster] #2737287
01/27/20 11:09 PM
01/27/20 11:09 PM
Joined: Jan 2003
Posts: 20,149
Park Forest, IL
slantzilla Offline
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Park Forest, IL
Originally Posted by 500ciDuster
They did do a bearing change so you couldn't just swap over to the bb axles


Spacing for the brakes is different too.


"Everybody funny, now you funny too."
Re: welding/redrilling rear axle flanges [Re: slantzilla] #2737294
01/27/20 11:39 PM
01/27/20 11:39 PM
Joined: Jan 2003
Posts: 18,389
UPPER MICHIGAN, MARQUETTE COUN...
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NITROUSN Offline
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UPPER MICHIGAN, MARQUETTE COUN...
Dutchman axle plugs and re-drills.

Dutchman

Re: welding/redrilling rear axle flanges [Re: slantzilla] #2737314
01/28/20 12:44 AM
01/28/20 12:44 AM
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Posts: 3,122
Auburn WA
Dave_J Offline
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Auburn WA
Originally Posted by slantzilla
Originally Posted by 500ciDuster
They did do a bearing change so you couldn't just swap over to the bb axles


Spacing for the brakes is different too.


The 74 Dart Swinger \6 Auto had LBP and 2.94 SG. I kept the axle for my 65 B-cuda that was LBP (using 68 RR 4 piston front and Ford 9 inch rear). I ran that 7.25 for years but had an issue so I built a 8.25 using a truck's 8 3/8's SG and 3.55 gears. I put the 7.25's rear backing plates and 2.5x10 drums on that 8.25 housing. They fit OK.


Retired, US ARMY 1973-1994
ASE mechanic, Electrical 1994-1997
Retired GTE/VERIZON/FRONTIER 1997-2015


Posting cheap tech help (CRAP) here since Nov 97, 1000's of posts, some may be good.

03 Suzuki Burgman 650(Burger King) Scooter
65 Formula S Cuda
78 Little Red Express Truck
98 Buick Regal (wifes car)
Re: welding/redrilling rear axle flanges [Re: Dave_J] #2737323
01/28/20 02:22 AM
01/28/20 02:22 AM
Joined: Jan 2003
Posts: 20,149
Park Forest, IL
slantzilla Offline
Too Many Posts
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The BBP backing plates and axles will swap around all 3 housings. They will not swap onto a SBP 7-1/4 housing. The tube ends and bearing sizes are different.


"Everybody funny, now you funny too."
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