4x4 front axle swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BigBird05 · 11-03-2021, 07:22 PM

I am going to install a 1986 K-10 axle into a 1969 K-10. The 86 axle is the same gear ratio as they 69. I want to get a list of parts that will need to be changed for this swap. I already know I will need the proporsioning valve and disc brake hoses. What about u-joint size? Steering drag link and tie rod ends? Can I use the 69 pitman arm? Does the 86 proportioning valve use the same style brake lines as the 69? How about the shock mount location? What else am I forgetting? I just read that the 86 axle is 3" wider. Is that true? Thanks.

Mike C · 11-03-2021, 08:56 PM

U-joints should be the same. You also need a disc brake master cylinder. The disc brake rubber lines are different, but should bolt to the drum line.

On a 2 wheel drive truck, you need a T-fitting in the front brake lines to reduce down to the hard line from the proportioning valve which you probably will need to source. I would consider buying 71-72 factory from disc lines and replacing the drum lines in full.

The drag link on disc trucks is adjustable but the drum brake one should work. I would consider replacing it just due to age. And it’s not adjustable… Pitman arms should be the same.

I am not sure that the track width is significantly wider, especially 3”, but could be I guess.

b454rat · 11-06-2021, 07:14 AM

Not same truck, but I put in a D44 in a 62 burb I wish I still had. Driveshaft and D/L bolted up. I hooked brakes up, but dunno how I did it. Only thing I really saw was lower shock mounts, they were at a different angle. But maybe 67-72s mounts are lil different. Also the width is minimal, prolly won't notice it.

60sIron · 11-07-2021, 01:11 PM

I do believe they are wider. I just converted my closed knuckle 44 to disc brakes. It seem like the better solution to me. There’s posts on here that will walk you through it. Basically swap spindles on out with a disc brake 44. Need to turn down the axles to fit the newer bearings. Then up grade the master and hoses.

BigBird05 · 11-07-2021, 05:37 PM

60sIron, I don't think that will work for me because the 69 is a close knuckle and the 86 is open. I think the 86 is wider because the 71 is wider that the 69. But I don't see being a little wider as being a problem.

60sIron · 11-07-2021, 06:11 PM

I don’t like the look of the wider track. My 69 K20 is a closed knuckle 44. Now with disc brakes. Night and day difference.

11-03-2021, 07:22 PM	#1
BigBird05 Registered User Join Date: Aug 2019 Location: Cheraw Posts: 1,300	4x4 front axle swap I am going to install a 1986 K-10 axle into a 1969 K-10. The 86 axle is the same gear ratio as they 69. I want to get a list of parts that will need to be changed for this swap. I already know I will need the proporsioning valve and disc brake hoses. What about u-joint size? Steering drag link and tie rod ends? Can I use the 69 pitman arm? Does the 86 proportioning valve use the same style brake lines as the 69? How about the shock mount location? What else am I forgetting? I just read that the 86 axle is 3" wider. Is that true? Thanks. Last edited by BigBird05; 11-03-2021 at 07:24 PM. Reason: more research

11-03-2021, 08:56 PM	#2
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,727	Re: 4x4 front axle swap U-joints should be the same. You also need a disc brake master cylinder. The disc brake rubber lines are different, but should bolt to the drum line. On a 2 wheel drive truck, you need a T-fitting in the front brake lines to reduce down to the hard line from the proportioning valve which you probably will need to source. I would consider buying 71-72 factory from disc lines and replacing the drum lines in full. The drag link on disc trucks is adjustable but the drum brake one should work. I would consider replacing it just due to age. And it’s not adjustable… Pitman arms should be the same. I am not sure that the track width is significantly wider, especially 3”, but could be I guess. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

11-06-2021, 07:14 AM	#3
b454rat Senior Member Join Date: May 2004 Location: Binghamton, NY Posts: 3,469	Re: 4x4 front axle swap Not same truck, but I put in a D44 in a 62 burb I wish I still had. Driveshaft and D/L bolted up. I hooked brakes up, but dunno how I did it. Only thing I really saw was lower shock mounts, they were at a different angle. But maybe 67-72s mounts are lil different. Also the width is minimal, prolly won't notice it.

11-07-2021, 01:11 PM	#4
60sIron Registered User Join Date: Nov 2013 Location: Sebastopol California Posts: 151	Re: 4x4 front axle swap I do believe they are wider. I just converted my closed knuckle 44 to disc brakes. It seem like the better solution to me. There’s posts on here that will walk you through it. Basically swap spindles on out with a disc brake 44. Need to turn down the axles to fit the newer bearings. Then up grade the master and hoses.

11-07-2021, 05:37 PM	#5
BigBird05 Registered User Join Date: Aug 2019 Location: Cheraw Posts: 1,300	Re: 4x4 front axle swap 60sIron, I don't think that will work for me because the 69 is a close knuckle and the 86 is open. I think the 86 is wider because the 71 is wider that the 69. But I don't see being a little wider as being a problem.

11-07-2021, 06:11 PM	#6
60sIron Registered User Join Date: Nov 2013 Location: Sebastopol California Posts: 151	Re: 4x4 front axle swap I don’t like the look of the wider track. My 69 K20 is a closed knuckle 44. Now with disc brakes. Night and day difference.



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