Drivetrain
Thread Starter
ROTM Moderator
Joined: May 2007
Posts: 8,157
From: AL
Drivetrain
Ok I am doing my 5 lug and 8" rear end swap this weekend. I need some questions answered before I start.
Can I use my I6 driveshaft for the 8" rear end and just get a different u-joint or can I just use the driveshaft with no changes?
Can I use my 7.5" u-bolts and shock holder on the 8" or are the axle tubes larger?
Can I use my u-bolts that hold the u-joints in on the 8" rear?
EDIT: This is about brakes.
Are the brake lines and connections different between the 5 lug drums and 4 lug drums?
Can I use my I6 driveshaft for the 8" rear end and just get a different u-joint or can I just use the driveshaft with no changes?
Can I use my 7.5" u-bolts and shock holder on the 8" or are the axle tubes larger?
Can I use my u-bolts that hold the u-joints in on the 8" rear?
EDIT: This is about brakes.
Are the brake lines and connections different between the 5 lug drums and 4 lug drums?
Last edited by 1slow67; May 14, 2009 at 08:38 PM.
1st Gear Member
Joined: May 2009
Posts: 123
From: Florida
if the u-bolts arent wide/long enough, any car parts store should have them in stock. I had to get some longer ones when I added my under-ride traction bars to the car. O'Reilly had some nice 1/2" diameter ones that worked great. Test fit, then cut off what you dont need.
3rd Gear Member
Joined: Jun 2006
Posts: 528
From: Northern Virginia
[1] Existing I6 drive shaft will drop right into the 8" rear. No changes.
[2] The axle 7.5" U-bolts will probably work on the 8" axle, but I would replace them while you have them off.
[3] I'm not sure I understand your question abour the ubolts for the ujoints. Sorry.
[4] Brake line connections are the same. You can reuse the axle distribution block from the 7.5" (if the 8" doesn't have lines to the brakes). Check the condition of the flex hose while you're under there.
FYI - this is from my experience on a 67 coupe with a C4. Your mileage may vary!
[2] The axle 7.5" U-bolts will probably work on the 8" axle, but I would replace them while you have them off.
[3] I'm not sure I understand your question abour the ubolts for the ujoints. Sorry.
[4] Brake line connections are the same. You can reuse the axle distribution block from the 7.5" (if the 8" doesn't have lines to the brakes). Check the condition of the flex hose while you're under there.
FYI - this is from my experience on a 67 coupe with a C4. Your mileage may vary!
Thread Starter
ROTM Moderator
Joined: May 2007
Posts: 8,157
From: AL
[1] Existing I6 drive shaft will drop right into the 8" rear. No changes.
[2] The axle 7.5" U-bolts will probably work on the 8" axle, but I would replace them while you have them off.
[3] I'm not sure I understand your question abour the ubolts for the ujoints. Sorry.
[4] Brake line connections are the same. You can reuse the axle distribution block from the 7.5" (if the 8" doesn't have lines to the brakes). Check the condition of the flex hose while you're under there.
FYI - this is from my experience on a 67 coupe with a C4. Your mileage may vary!
[2] The axle 7.5" U-bolts will probably work on the 8" axle, but I would replace them while you have them off.
[3] I'm not sure I understand your question abour the ubolts for the ujoints. Sorry.
[4] Brake line connections are the same. You can reuse the axle distribution block from the 7.5" (if the 8" doesn't have lines to the brakes). Check the condition of the flex hose while you're under there.
FYI - this is from my experience on a 67 coupe with a C4. Your mileage may vary!
On question 3 you use them to bolt the driveshaft to the rear end. They look like small u-bolts.
That pic is an example of the parts I am talking about. I don't know their real name.
3rd Gear Member
Joined: Jun 2006
Posts: 528
From: Northern Virginia
Are you asking if you can use the U-joint bolts from the 7.5" axle to hold the U-joint on the 8"? If so, yes, they should fit. But again, I'd replace them too.
I always heard that Ubolt threads deform when tightened. Thus reusing them becomes impossible to obtain correct torque settings. As far as axle u bolts go, you don't any slippage/twisting of the axle on the leaf. That is the only place I've ever seen a leaf spring break. You might get away with it on the ujoint though.
I always heard that Ubolt threads deform when tightened. Thus reusing them becomes impossible to obtain correct torque settings. As far as axle u bolts go, you don't any slippage/twisting of the axle on the leaf. That is the only place I've ever seen a leaf spring break. You might get away with it on the ujoint though.
6th Gear Member
Joined: Oct 2006
Posts: 6,417
From: Cork, Ireland
not so quick!
my 6cylinder rear end hat a ridiculous small u-joint for which there was no conversion.
8" rear should be 1310 style with either 1-1/8" or 1-1/16" cup diameter. The lenght is 3-1/4". I believe you probably already have the rear end so just get a vernier caliper and measure between the tabs (is probably 3-1/4" and the diameter where the u-jopint will sit. is either 1-1/8 or 1-1/16"
what you need to do is to measure the cup dia of the u-joint axis stuck in your DS.
I guess that to be 1"
as well measure the overall length for this axis. if you don't have a vernier caliper you can judge it quickly with a tape measure. less than 3" length-> you cannot use your driveshaft
More info on this:
there are 3 stlyles common (apart from biugblock 1330):
1210-> only used in 6cyl. cup dia is 1" and length is around 2.33"
1250-> used in V8s sometimes. seen it in front of driveshaft as well
1310-> most common one in Ford SB V8. as said the length is 3-1/4" but the crap with them is that there are some with 1-1/8" cup and some with 1-1/16" cup.
1250 to 1310 conversion exists, 1210 to 1310 does not! It's too tiny to handle a V8 anyway
What caused me most headache is the fact that 1310 style inside snapring is 2.33" apart. so some people give you that as measurement. I always believed that would be the total length and therefore got the wrong u-joint. I ordered 3 times, then bought a second hand driveshaft and then got the correct u-joint. 3 months well wasted.
I can't say if the axle u-bolts will fit as I changed to 9". but surprisingly the u-joint bolts i was able to re-use
To not confuse the crap out of you:
- see if it fits. If yes you are a lucky man. If it doesn't you will need to measure so we can sort you out with the correct u-joint
you will need to measure the following from BOTH (the u-joint axis in shaft, and the yoke of the rear axle)
1. overall length (for the yoke measure between the tabs that hold the u-joint)
2. is it inside or outside snapring
- if inside measure length between snaprings
(for the yoke you won't use any snapring as it's clamped)
3. the cup diamter
(for the yoke measure you can measure the half circle diameter where the joint will be sitting on)
hope it's any help
my 6cylinder rear end hat a ridiculous small u-joint for which there was no conversion.
8" rear should be 1310 style with either 1-1/8" or 1-1/16" cup diameter. The lenght is 3-1/4". I believe you probably already have the rear end so just get a vernier caliper and measure between the tabs (is probably 3-1/4" and the diameter where the u-jopint will sit. is either 1-1/8 or 1-1/16"
what you need to do is to measure the cup dia of the u-joint axis stuck in your DS.
I guess that to be 1"
as well measure the overall length for this axis. if you don't have a vernier caliper you can judge it quickly with a tape measure. less than 3" length-> you cannot use your driveshaft
More info on this:
there are 3 stlyles common (apart from biugblock 1330):
1210-> only used in 6cyl. cup dia is 1" and length is around 2.33"
1250-> used in V8s sometimes. seen it in front of driveshaft as well
1310-> most common one in Ford SB V8. as said the length is 3-1/4" but the crap with them is that there are some with 1-1/8" cup and some with 1-1/16" cup.
1250 to 1310 conversion exists, 1210 to 1310 does not! It's too tiny to handle a V8 anyway
What caused me most headache is the fact that 1310 style inside snapring is 2.33" apart. so some people give you that as measurement. I always believed that would be the total length and therefore got the wrong u-joint. I ordered 3 times, then bought a second hand driveshaft and then got the correct u-joint. 3 months well wasted.
I can't say if the axle u-bolts will fit as I changed to 9". but surprisingly the u-joint bolts i was able to re-use
To not confuse the crap out of you:
- see if it fits. If yes you are a lucky man. If it doesn't you will need to measure so we can sort you out with the correct u-joint
you will need to measure the following from BOTH (the u-joint axis in shaft, and the yoke of the rear axle)
1. overall length (for the yoke measure between the tabs that hold the u-joint)
2. is it inside or outside snapring
- if inside measure length between snaprings
(for the yoke you won't use any snapring as it's clamped)
3. the cup diamter
(for the yoke measure you can measure the half circle diameter where the joint will be sitting on)
hope it's any help
Banned
Joined: May 2008
Posts: 1,049
From: Maryland
Are you asking if you can use the U-joint bolts from the 7.5" axle to hold the U-joint on the 8"? If so, yes, they should fit. But again, I'd replace them too.
I always heard that Ubolt threads deform when tightened. Thus reusing them becomes impossible to obtain correct torque settings. As far as axle u bolts go, you don't any slippage/twisting of the axle on the leaf. That is the only place I've ever seen a leaf spring break. You might get away with it on the ujoint though.
I always heard that Ubolt threads deform when tightened. Thus reusing them becomes impossible to obtain correct torque settings. As far as axle u bolts go, you don't any slippage/twisting of the axle on the leaf. That is the only place I've ever seen a leaf spring break. You might get away with it on the ujoint though.