I have been wanting to do this swap for years and finally the local self serve yard got a 6 lug awd astro van in. When gm upgraded the brakes on the astro van they made a knuckle with gmt800+ style brakes that bolts in place of a gmt400 style knuckle(what the astro previously used). So for $54 and an hours work I was ready to upgrade my suburban.
The old setup:
The new setup:
Side by side:
Everything bolts right in with a few exeptions.
The astro brake hose is 1/4if and the suburban is 3/16if. I just used conversion fittings for now I think I will probably replace the front lines with 1/4 when the time comes.
The calipers rub the original wheels slightly. Little grinding is all it needed.
The new hubs don't use inner seals and the dust sheilds rub the knuckle so i just eliminated the sheilds.
The last thing, which I didn't expect, was the track width grew by about 7/8" an inch on each side. After thinking about it a little' I think this is because the astro originally used a 5 lug 15" wheel with the 2wd/rwd truck offset on the awd vans. When the Astro went to 6 lug they went to the regular 16" 4wd truck offest wheels. This causes the axles on the suburban to stretch the inner joints out a bit more with the increase in track width. It is working fine but I will propably measure some axles next time I am out at the yard.
I also bolted up the 13" gmt900 style caliper and rotor. It looks to fit just fine, just need to find some cheap 17" wheels.
For the 2wd guys, if you are willing to go to 6 lug for the sake of decent brakes you might want to take a look at the 2wd 6 lug astro. Maybe swap in a 4wd rear axle since the track width will probably also increase on 2wd astro knuckle swap.
The old setup:
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The new setup:
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Side by side:
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Everything bolts right in with a few exeptions.
The astro brake hose is 1/4if and the suburban is 3/16if. I just used conversion fittings for now I think I will probably replace the front lines with 1/4 when the time comes.
The calipers rub the original wheels slightly. Little grinding is all it needed.
You must be registered for see images attach
The new hubs don't use inner seals and the dust sheilds rub the knuckle so i just eliminated the sheilds.
You must be registered for see images attach
The last thing, which I didn't expect, was the track width grew by about 7/8" an inch on each side. After thinking about it a little' I think this is because the astro originally used a 5 lug 15" wheel with the 2wd/rwd truck offset on the awd vans. When the Astro went to 6 lug they went to the regular 16" 4wd truck offest wheels. This causes the axles on the suburban to stretch the inner joints out a bit more with the increase in track width. It is working fine but I will propably measure some axles next time I am out at the yard.
You must be registered for see images attach
I also bolted up the 13" gmt900 style caliper and rotor. It looks to fit just fine, just need to find some cheap 17" wheels.
For the 2wd guys, if you are willing to go to 6 lug for the sake of decent brakes you might want to take a look at the 2wd 6 lug astro. Maybe swap in a 4wd rear axle since the track width will probably also increase on 2wd astro knuckle swap.
