I am looking to upgrade the rear axle on my 72 to disc and wanted to know if anyone has done this using a factory axle out of a newer truck. I have already invested in a new set of 35" tires with new rims (6 lug) and want to be able to use them. I would like to get a 12bolt or 14bolt unit with a 6 lug bolt pattern and with a WMS to WMS length around 67.5" to match the front axle. The front axle has 3.73 gears in it now so I would like to get the same ratio so I can use the axle for a while until I can afford to upgrade both axles with new gears and lockers. I was also thinking about trying to pick up all the braking parts from a newer truck with hydrualic assist brakes (master cylinder, brake booster, and power steering pump) to increase the stoping power. Would these parts have any chance of working with some minor modifications or would I be better off spending my money on an after market disc brake system and just rebuild my exsisting 12bolt? It would be nice to have a rear axle that is closer in length to the front then the orginal so the rear wheels don't set in so far.
CK5
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factory disc brake axle swap
- Thread starter 72 K5
- Start date
fordtruggy
Registered Member
To mu knowlage (and quote me if i am wrong) Most all chevys are wider in the front and you prolly wont find a wider one for the back.However you could use a wheel spacer for the back to gain the extra wanted width.
fordtruggy
Registered Member
PS 14BFF are 8 lug.Just do disk upgrade to what you have and run your drum lines to your diske .We do this on our fords and it works great.
I thought I read somewhere that chevy had a 14bSF with 6lug on some of there 1500HD trucks. Also I thought the new trucks have an axle length of 68". Is any of this true? I can get a newer axle with disc brakes for the same price I can upgrade my old axle with disc, but would still have an old axle.
72 K5 said:
2500LD's could be had with 6 lug 14SF, and I was told the same about the 1500HD.
Problem is, as far as I can tell, there are no 14SF disk braked rears.
The later axles are 3" wider than the 73-87 stuff, so they match the front width exactly. No idea how this plays on pre-'73 stuff.
There is a pretty decent 14SF tech post in this forum that I started, with a fair amount of data. But I could never find any factory documentation that said 14SF's ever came disked. GM typically doesn't bother saying which axle is under which truck in their online brochures.
IIRC, the 8.5" axles never used the same axle flange bolt pattern as the 14SF/FF, so those aren't useful donors either.
