All GM switch axles f/r 4x4

[motovate]

I have a 1971 Chevy K20 4x4. Right now it has what I think is a Dana "Old" style 44 on the front. It has the big long hubs on the front. Pretty sure they were not original to the truck and I am not real sure at least the cab isn't a k20. Pretty sure the rear is a Corp 10 inch (?) in the rear. I seem to have too much play in the drive shaft rear end and while the front is disc the disc /hub's are worn pretty bad.

I have access to a 1989 Chevy "V" model Suburban 3/4t 4x4 complete all stock. I believe the front axle is a chevy 10 bolt and the rear is a Corp 10". It is all stock and in good shape. I'm thinking it might be a smart up grade to the 71.

Before I get all excited and start pulling things apart I'm trying to be sure it is essentially a bolt off bolt on situation. Both trucks are leaf springs front and rear. Am I right in thinking I can just drop both axle sets and bolt up the 89 Sub to the 71 K20? The spring width and mounting plates are essentially the same. I will use the springs on the 71 because they are new comparably and are a 4" lift . I'm wondering if there might be a difference in the brake line connections - if the 89 might be metric????? Any issues hooking up the steering linkage, etc.

Since the sub diffs are basically free I think I'll be saving $ even if I do need to replace the U joints??

Any thoughts, info will be appreciated. FYI I don't live in a "run down to the local junk yard/parts house kind of place". They are a 40+ miles one way kind of trip.


Thanks LBM.

 

[b454rat]

If ur truck has the original axles, it would be a Dana 44 big hub, might be open knuckle disc brake but can’t be certain. Rear should be the Eaton HO52, not up on these axles but know what they are looking at it. It’s sorta like a big 9”, drop out center section. The burb will be a 10 bolt front, rear could either be a semi float 14 bolt or full float. Brake lines will be metric, the 71 SAE. But if ur current axle IS disc brake, won’t have to change it, caliper will bolt on. I believe the front will bolt in, it’s the lower shock mount that may be different. The rear will need perches and shock mounts moved. Both should use a 1350 joint, same with front, bolt in.

 

[motovate]

Thanks - helps a lot. Just to clarify in my mind. If I use the 89 axles I may need to find adapters to fit the metric Sub to SAE 71 connections or make some new brake lines with SAE on one end and metric on the other. If I use the existing 71 calipers on the front 89 rotors if they will bolt up to the 89 front end. Or go ahead and use the existing good 89 sub calipers. Thinking about it the only connections I may have to adapt or change on the front is the connection from the master cylinder down to the junction block on the 89 axle - or the single(?) rubber brake hose that connects @ the junction box correct? Since I can just leave everything as is on the 89 front disc brake 10 bolt. ????? But it will bolt in place on the front with out moving axle perches. The perches on the rear will need moved in or out on the rear axle tubes to match the frame width???????? or if they need to be on the top or bottom of the axle to fit the existing frame. Seems fairly simple??

 

[motovate]

I have a real character flaw. I can't go look at these things when it is during the daytime I have to do it at night when I have to use a flash light and it is cold! I verified the front is an open knuckle on both of the rigs. Front is definitely a "Big Hub". Both mount on top of the axle. Question - which front axle is the best one. Or does it matter. I was thinking the 89 would be better because it is 18 years "younger" and the rears are comparable as long as it isn't broken. Thanks again.

 

[b454rat]

This is still a huge debate which is stronger, but they are both pretty much the same. Some argue that the 89 is stronger, believe that year they went to 30 spline non tapered inner shaft. But GM designed the 10 bolt after the Dana 44. As long as you have good brakes now I’d just reuse the existing calipers. I’d swap out the big hubs too, put them on the 10 bolt. Everything from the knuckle out will swap. Just need to swap spindles, the 44 uses a smaller bearing on the inner. It sure if mentioned but why swap em out?