8.8 final questions
02-19-2012, 11:35 PM
#1
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8.8 final questions Will the f body axles fit the 28 spline track loc I have?
What measurements do i need from the 10 bolt to make sure I weld the tubes to the 8.8 axle tubes?
Is it better to mill the 8.8 inner tubes or the f body outer tubes? It would be best to mill both but that's not an option.
How much overlap should I leave?
Do I need to leave one side longer than the other?
Thanks in advance guys. I am hoping to get it welded up this week or next and installed
What measurements do i need from the 10 bolt to make sure I weld the tubes to the 8.8 axle tubes?
Is it better to mill the 8.8 inner tubes or the f body outer tubes? It would be best to mill both but that's not an option.
How much overlap should I leave?
Do I need to leave one side longer than the other?
Thanks in advance guys. I am hoping to get it welded up this week or next and installed
02-21-2012, 09:43 PM
#2
I'll try to answer your questions.
Yes, if your 8.8 has a 28-spline your 10-bolt axles will fit.
I'd make a complete diagram of the 10-bolt before you start cutting. Critical dimensions include - housing flange to flange, axle flange to flange, and housing flange to axle flange. Then measure the axles, I think they are 32". I think the carrier cross pin is 3/4" so the axle to axle dimension should be 64 3/4" or so (the axles ride against the cross pin).
Then do the same thing for the 8.8 (the cross pin on that is 7/8").
There are a number of ways to do the next step, you want to find the center of the axles. I hope this isn't too confusing, but what I did was to take each 8.8 axle dimension minus 10" to get a reference dimension to make a punch mark on the housing. Say the left side axle is 31", measure 21" in from that axle flange and put a center-punch mark on the axle tube. Do the same on the other side using that axle measurement. Then you have 2 reference marks on the housing when you cut the tubes off. The reference marks should be 20 7/8" apart which is your 10" offset on each side plus the 7/8" cross pin diameter. On my housing the ends of the cast center section weren't quite in the middle so I wouldn't rely on that to find the center of the axles. Then cut off the 8.8 tubes 1" out from the punch mark, leaving a stub housing 22 7/8" end-to-end. Do the math on the 10-bolt tubes, knowing you'll end up with a 64 7/8" axle flange to flange dimension, and allow for a 3" overlap of the 10-bolt & 8.8 tubes.
Machining the 10-bolt or 8.8 tubes depends on the 8.8 tube diameter. My Explorer tubes were 3 1/4" with 3/16" wall (2 7/8" ID) and the 10-bolt tubes are 2 5/8" so in that case you'd need a sleeve of some kind to fill the space. Some 8.8s have smaller tubes so you don't have that problem.
Before cutting the 10-bolt tubes make sure you find a way to record the radial orientation of the tube with respect to the housing.
I hope this isn't too confusing.
Yes, if your 8.8 has a 28-spline your 10-bolt axles will fit.
I'd make a complete diagram of the 10-bolt before you start cutting. Critical dimensions include - housing flange to flange, axle flange to flange, and housing flange to axle flange. Then measure the axles, I think they are 32". I think the carrier cross pin is 3/4" so the axle to axle dimension should be 64 3/4" or so (the axles ride against the cross pin).
Then do the same thing for the 8.8 (the cross pin on that is 7/8").
There are a number of ways to do the next step, you want to find the center of the axles. I hope this isn't too confusing, but what I did was to take each 8.8 axle dimension minus 10" to get a reference dimension to make a punch mark on the housing. Say the left side axle is 31", measure 21" in from that axle flange and put a center-punch mark on the axle tube. Do the same on the other side using that axle measurement. Then you have 2 reference marks on the housing when you cut the tubes off. The reference marks should be 20 7/8" apart which is your 10" offset on each side plus the 7/8" cross pin diameter. On my housing the ends of the cast center section weren't quite in the middle so I wouldn't rely on that to find the center of the axles. Then cut off the 8.8 tubes 1" out from the punch mark, leaving a stub housing 22 7/8" end-to-end. Do the math on the 10-bolt tubes, knowing you'll end up with a 64 7/8" axle flange to flange dimension, and allow for a 3" overlap of the 10-bolt & 8.8 tubes.
Machining the 10-bolt or 8.8 tubes depends on the 8.8 tube diameter. My Explorer tubes were 3 1/4" with 3/16" wall (2 7/8" ID) and the 10-bolt tubes are 2 5/8" so in that case you'd need a sleeve of some kind to fill the space. Some 8.8s have smaller tubes so you don't have that problem.
Before cutting the 10-bolt tubes make sure you find a way to record the radial orientation of the tube with respect to the housing.
I hope this isn't too confusing.
02-25-2012, 08:15 AM
#3
For mine, the only measurement I used was axle shaft flange to brake flange on the tube from the 10 bolt. Everything else changed or didnt make any difference
After that I built a quick jig from scrap metal to locate the angle and approx position of the suspension points and approximate the diff angle
I chopped the 8.8 tubes 3" after the step down where the ID was similar to the OD of 10 bolt tubes. There was an interference fit of about .040" which could have been turned down on a lathe, but i used an angle grinder. Slip the 10 bolt axles in and measure how much tube you need to cut from the old housing. Id suggest a min of 1/4" overlap, but the more you have the easier it will be to get the tubes straightened
Set pinion angle, put one small tack weld on each joint, then ensure the tubes are strait. I used a digital level on top and strait edge/caliper combo off the rear to ensure straightness. Put more tacks to hold the joints solid, then weld. Control the weld so the heat doesnt warp the tubes. I did 1" beads on opposite sides of the tubes then switched sides while the other cooled. I tried to recreate the TA mount in the same location as the 10 bolt but the 8.8's diff is too big, it had to be moved approx 1" to the drivers side
IIRC my Fbody tubes were within 1/2" of each other. Not the drastic 4" difference the 8.8 had
Pic of my jig with the welded axle tubes to give you an idea how simple they can be
http://i150.photobucket.com/albums/s...t/DSC02624.jpg
After that I built a quick jig from scrap metal to locate the angle and approx position of the suspension points and approximate the diff angle
I chopped the 8.8 tubes 3" after the step down where the ID was similar to the OD of 10 bolt tubes. There was an interference fit of about .040" which could have been turned down on a lathe, but i used an angle grinder. Slip the 10 bolt axles in and measure how much tube you need to cut from the old housing. Id suggest a min of 1/4" overlap, but the more you have the easier it will be to get the tubes straightened
Set pinion angle, put one small tack weld on each joint, then ensure the tubes are strait. I used a digital level on top and strait edge/caliper combo off the rear to ensure straightness. Put more tacks to hold the joints solid, then weld. Control the weld so the heat doesnt warp the tubes. I did 1" beads on opposite sides of the tubes then switched sides while the other cooled. I tried to recreate the TA mount in the same location as the 10 bolt but the 8.8's diff is too big, it had to be moved approx 1" to the drivers side
IIRC my Fbody tubes were within 1/2" of each other. Not the drastic 4" difference the 8.8 had
Pic of my jig with the welded axle tubes to give you an idea how simple they can be
http://i150.photobucket.com/albums/s...t/DSC02624.jpg
04-16-2012, 12:09 PM
#4
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Gonna start on it again here soon, had other priorities to deal with first plus lost interest in the car for awhile. Is the pinion angle extremely critical with welding the new ends on since I'm ditching the torque arm and doing a mini ladder?
