1970 Blazer 4WD axle / brake conversion

[Jasko59]

I just bought a 1970 K5 Blazer 4WD and will be doing a frame off restoration. I'm interested in the best way to convert the drum brakes on both axles to disc brakes. I know I can swap a front axle from a '72 with existing disc brakes in place of the '70's front axle. Replies to other posts have said front axles from some years newer than '72 will also work, and others have said that they will not. I haven't found anything that addresses what will work best for the rear axle.

In order to get the best answer for this post I'll list several specifics that pertain to my truck and project plans.

- I might be able to get both the front and rear axles from a '72 Blazer, but there's no guarantee.
- The truck will primarily be used for road & highway driving, with some rare beach or light off road use.
- It currently has a 3.73 ratio.
- I'm going to work on the suspension while the frame is completely bare (no body, engine, transmission, transfer case, or gas tank).
- I'd like to be able to "drop in" the axles and / or brake conversions without cutting or welding the axle housing or shaft.
- The truck will run on 31"-33" tires when completed.
- If I lift the suspension it will only be 2"-2.5" using either a Skyjacker or Tuff Country kit.
- The existing 307 engine will be swapped for a 350.
- I'll probably swap the manual 3-speed (column) transmission for a 4-speed turbo automatic.
- I realize I'll have to get new brake lines & cylinder, and also a brake booster.
- I realize parts such as the axle shaft, steering knuckles, other steering components, u-joint, and drive shaft may have to be replaced.

Any and all info will be greatly appreciated. Thanks.

[1rippen6]

I have a 91 blazer I am parting out that has a disc brake dana 44 front I will sell for 150. I am pretty sure it is a direct bolt in and has 3:73s but would have to check again if you are interested. I have a 72 housing I can check measurements on but pretty sure it is the same. Looks like I am about 3 hrs away from you. You said change the 3 speed for a 4-speed turbo automatic. Did you mean a 3 speed turbo automatic or a 4 speed 700r4 which has overdrive? If you use a 700r4 you will have to get an adapter to use your transfer case or get one with the 700r4 but then you will have to do something with your driveshafts. There are articles on this swap on the forum if you search which will tell you how to do it. Why I ask is because I have a couple 3 speed automatics with NP205s for sale also. As far as the rear axle there is kits on the forum and plenty of write ups on how to do it. The rear would need brackets welded on to hold the calipers but I think the rest is just bolt on but you would have to confirm that with searching for the write up. I think you could do that with your original rear axle but be careful which write up you use because to pass inspection you will need to add calipers that have an ebrake set-up (which I think they use Cadillac calipers.) I see this is your first post but search and search the forum you will find all your answers someone has done it already and have listed the process you just need to find it.

[JNSM653]

I removed both front and rear axles from my 69 blazer and put axles from 1978 3/4 ton Chevy truck. Front axle was direct swap. Rear axle I had to move the spring perches. I used u bolts for the 3/4 ton due to the change in diameter of the axle tube on both axles.

[hemi43]

Not sure if you have machining capabilities, but I just converted my 70 Blazer drum brakes to disc using late model twin piston calipers.It's bolt in and other than changing the wheel studs to 1/2-20, all original Blazer components don't need modifying. Some pics on my build thread.
http://67-72chevytrucks.com/vboard/s...d.php?t=676080

[az1970k5]

Originally Posted by hemi43

Not sure if you have machining capabilities, but I just converted my 70 Blazer drum brakes to disc using late model twin piston calipers.It's bolt in and other than changing the wheel studs to 1/2-20, all original Blazer components don't need modifying. Some pics on my build thread.
http://67-72chevytrucks.com/vboard/s...d.php?t=676080

Hemi43 have you thought of making a conversion kit like this? I would be down for one for my 70

[hemi43]

Originally Posted by az1970k5

Hemi43 have you thought of making a conversion kit like this? I would be down for one for my 70

Not really.The liability alone would make it impossible.