The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 1970 3/4 ton 4x4 front drum to disc brake swap questions.

60sIron · 11-12-2016, 02:19 AM

The short answer is yes. To the best of my knowledge the disc axle is 3" wider. Not a big deal for most. Yes you will need to change the master. Also a new proportioning valve.
I'm currently adding discs to my 69 closed knuckle 44. Not the easy route...... Using parts from a 74 K20. Anything new I buy for a 72 K20. So far the brake lines were to short. Had to have some made. Also the master reservoirs were reversed. Smaller front goes to the rear brakes, larger rear goes to the front brakes. I'll have to make lines to correct the hook up to the pp valve.

11-12-2016, 02:19 AM	#2
60sIron Registered User Join Date: Nov 2013 Location: Sebastopol California Posts: 151	Re: 1970 3/4 ton 4x4 front drum to disc brake swap questions. The short answer is yes. To the best of my knowledge the disc axle is 3" wider. Not a big deal for most. Yes you will need to change the master. Also a new proportioning valve. I'm currently adding discs to my 69 closed knuckle 44. Not the easy route...... Using parts from a 74 K20. Anything new I buy for a 72 K20. So far the brake lines were to short. Had to have some made. Also the master reservoirs were reversed. Smaller front goes to the rear brakes, larger rear goes to the front brakes. I'll have to make lines to correct the hook up to the pp valve.