Rear disc conversion

[Grit dog]

I've done 2-3 14BFF rear disc conversions and those calipers don't hold very well. I think the pedal/ lever needs more travel. I used a ratcheting lever on one and it was better. If I ever use Eldo calipers again, which I won't, I think the trick would be to use an e-stopp to pull it up tight.

Rear disc conversions aren't really worth it unless you are spending big money and racing. Rear drums work well and are reliable. If 30-40% of your braking occurs in the rear and a disc conversion improves it by 10-20%, you see less than a 10% improvement overall. Put the same money into larger drums in rear and better front calipers up front and you'll be way ahead

You won’t get “more” braking power with a simple disc conversion. Plus the drums will have plenty of braking power to lock the rear wheels even with some weight in the truck if they are operating correctly.
Now “racing” and high performance brakes are a different discussion. Nothing to do with your avg disc vs drum comparison which is what theOP is after.

 

[Keith Seymore]

Additionally - the rear brakes are "throttled" by the restriction in the proportioning valve by some percent (like 40%).

Why not bump the pressure up and let the existing rears do a little more work?

It's like having a carburetor sitting on a restrictor plate and then deciding you need a bigger carb.

K

 

[gerhed]

I haven't pulled them off yet, but they look huge, they almost completely fill the back side of a 16" rim.

How difficult is a swap to a 14 bolt full float rear axle? Is it a bolt on?

 

[Rusty Nail]

Don't do it.

 

[mummertj]

if you did it or decide to do the disc conversion, I would be interested in the backing plates you take off
Thanks

 

[75gmck25]

14 bolt FF should be a direct bolt on to the springs, but the driveshaft connection might be different. Many of them are also 4.10 or even 4.56, so it might not match your front axle. My ‘75 K25 8400 GVW has 4.10 gears and a 14 bolt FF with 13” drums. Front axle is a Dana 44 HD.

If you look for one you may want to find one without GovLock. You can upgrade and use most of the newer locking differentials with a standard 14 bolt carrier, but you can’t convert a GovLock carrier.