D70 Drum to Disc Brake Conversion, Need Torque specs

LAmiller

LAmiller

THE KT-BOUNDARY
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Aug 17, 2006
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I put a d70 out of a 97 in my truck to replace my broken one and want to swap my disc brake over to the 97 axle. I need the torque spec for the big 2 1/2" nut that holds the hub onto the axle. Its tightens up against the wheel bearing so I assume it needs a specific torque sequence.

Lavon
 
Can you make some pictures of Your swap?

I have D80 disc brakes and I would like to swap to my D70 , but back plate is different.
 
LAmiller said:
I put a d70 out of a 97 in my truck to replace my broken one and want to swap my disc brake over to the 97 axle. I need the torque spec for the big 2 1/2" nut that holds the hub onto the axle. Its tightens up against the wheel bearing so I assume it needs a specific torque sequence.

Lavon
Click to expand...

120-140 lb/ft while turning the wheel.

back off 1/8 to 1/3 turn to allow .001 to .010" of bearing end play

tap lock tab into place
 
Rollin Coal said:
120-140 lb/ft while turning the wheel.

back off 1/8 to 1/3 turn to allow .001 to .010" of bearing end play

tap lock tab into place
Click to expand...

Thanks, that for the rear axle for sure? Taking the nut off it didn't seem like more than 40-60ft. lbs. I believe you, just want to clarify so I don't make it too tight and overheat the bearing.

AsTroSS said:
Can you make some pictures of Your swap?

I have D80 disc brakes and I would like to swap to my D70 , but back plate is different.
Click to expand...

I will try to remember to take the camera to the shop tonight and get you some pictures.

Lavon
 
it seems high to me too, but i think thats just to seat the bearing, then backing it off drops it alot.
 
I think its right, I'll know if its way off just by comparing how tight it was when I took it off.

Lavon
 
its right out of the 2001 FSM, for both the 70 and 80. most of the axles ive delt w/ in the past are finger tight + 1/8-1/2 turn to adjust bearing preload. So i think socking it down is just to lock the bearing in nice and snug.
 
LAmiller said:
Thanks, that for the rear axle for sure? Taking the nut off it didn't seem like more than 40-60ft. lbs. I believe you, just want to clarify so I don't make it too tight and overheat the bearing.
Click to expand...

The one you removed is probably looser due to the fact that the bearings have been run a bit and since you back it off after the torque sequence.
 
There's a 2001 FSM pdf file on the F: drive at my house- you're welcome to copy it to your laptop.
 
Well guys, I guess everything I heard about unbolting the drums and bolting the disc brakes back up isn't accurate because the bolt patter on the axle doesn't match the Disc brake pattern. What do I have to do to make it work?? I ended up putting it back together without any brakes on it at all. At least I saved about 100lbs. :)

Any Ideas?
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Lavon

ON EDIT: I found this link http://www.egrbrakes.com/pdf/4601_inst_5-06.pdf
 
Last edited:
the disc brake parts are off of my original 01 Dana 70 axle that broke. The Dana 70 that in there now is off of a 97 12V truck.

Lavon
 
LAmiller said:
anyone know what my options are at this point?

Lavon
Click to expand...

Ok, looks like we are facing the same problem. I hope D70(disck) back plate are the same as drum brake, but looks like it same as D80 disk brake

The back plate bolt pattern, location and size are different. Also drum brake axel tube are smaller diameter ithan disck axle.


My idea was to mill of back plate from disck axle and reweld it to drum axle correct location.(its approx 1/2 inch to diff side from original location).
 
either way it doesn't look like an easy job at this point. and I didn't want to spend a lot of time and money on this axle, as it'll probably break at some point and then I'll drop the bones on a Dana 80

Lavon
 
a 70 w/ a locker and shafts will hold more torque than can be run on the street. and is lighter than an 80.

but, is the caliper spacing and everything else right?
 
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