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Brake upgrades using factory parts for GMT-400(88-00 OBS), and 94-99 DODGE 2500/3500

Husker6.5

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But seriously, I believe that the 7° is the upper taper and 10° is the lower ball joint taper and is done because the diameters of the shafts of the new parts are larger. The taper reamer should already fit snugly into the bore, you are just carefully and slowly reaming a little bit deeper to widen the taper like another 1/16" to accommodate the larger tie rod and ball joint stud sizes. Besides, as far as the ball joint goes, FAR safer to bore the taper where the shaft is retained by a torqued and cotter pinned castle nut, than try to drill/machine/grind out an interference press-fit hole in a control arm to put the base of the ball joint into. The new taper should be the correct depth when a couple of threads are still below the surface, so the nut can pull snug before bottoming out on the tapered shaft.
 
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THEFERMANATOR

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The GMT800 brake upgrade is NOT an easy swap on a 2 wheel drive, it's not even really possible to swap 800 spindles onto a 2 wheel drive 400 without extensive modifications to the suspension and frame(just updated the op to clarify). Gmt800's all use a knuckle with a hub bearing as GM was cutting costs by making 2 & 4 wheel drives use the same parts. On the gmt400, 2 & 4 wheel drives used completely different spindles, a arms, geometry, even the frame width was different.

The single biggest reason you cannot do the gmt800 swap to a 2 wheel drive gmt400 is due to how the lower ball joints connect to the spindle. On 4x4 400's and all 800's the lower ball joint points down at the ground and the spindle mounts below the lower a arm, on 2 wheel drive 400's the ball joint points up at the sky and the spindle mounts pulling up on the ball joint. Some have modified the lower control arms to point the lower ball joint down, but then you MUST put an equal drop in the upper a arm to maintain suspension geometry, and you lift the vehicle doing it this way.

This is the only way to do it with a 2 wheel drive With stock parts. Otherwuse you can go with the wilwood calipers, but they're big $$$$.

And a shim to make up the 1/4" difference for the brake pads to drw calipers on a 1.25" rotor would make for one heck of a noise maker.
 
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Big T

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The GMT800 brake upgrade is NOT an easy swap on a 2 wheel drive, it's not even really possible to swap 800 spindles onto a 2 wheel drive 400 without extensive modifications to the suspension and frame(just updated the op to clarify). Gmt800's all use a knuckle with a hub bearing as GM was cutting costs by making 2 & 4 wheel drives use the same parts. On the gmt400, 2 & 4 wheel drives used completely different spindles, a arms, geometry, even the frame width was different.

The single biggest reason you cannot do the gmt800 swap to a 2 wheel drive gmt400 is due to how the lower ball joints connect to the spindle. On 4x4 400's and all 800's the lower ball joint points down at the ground and the spindle mounts below the lower a arm, on 2 wheel drive 400's the ball joint points up at the sky and the spindle mounts pulling up on the ball joint. Some have modified the lower control arms to point the lower ball joint down, but then you MUST put an equal drop in the upper a arm to maintain suspension geometry, and you lift the vehicle doing it this way.

This is the only way to do it with a 2 wheel drive With stock parts. Otherwuse you can go with the wilwood calipers, but they're big $$$$.

And a shim to make up the 1/4" difference for the brake pads to drw calipers on a 1.25" rotor would make for one heck of a noise maker.
Substitute Shim and sing along:

 

C30454

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The GMT800 brake upgrade is NOT an easy swap on a 2 wheel drive, it's not even really possible to swap 800 spindles onto a 2 wheel drive 400 without extensive modifications to the suspension and frame(just updated the op to clarify). Gmt800's all use a knuckle with a hub bearing as GM was cutting costs by making 2 & 4 wheel drives use the same parts. On the gmt400, 2 & 4 wheel drives used completely different spindles, a arms, geometry, even the frame width was different.

The single biggest reason you cannot do the gmt800 swap to a 2 wheel drive gmt400 is due to how the lower ball joints connect to the spindle. On 4x4 400's and all 800's the lower ball joint points down at the ground and the spindle mounts below the lower a arm, on 2 wheel drive 400's the ball joint points up at the sky and the spindle mounts pulling up on the ball joint. Some have modified the lower control arms to point the lower ball joint down, but then you MUST put an equal drop in the upper a arm to maintain suspension geometry, and you lift the vehicle doing it this way.

This is the only way to do it with a 2 wheel drive With stock parts. Otherwuse you can go with the wilwood calipers, but they're big $$$$.

And a shim to make up the 1/4" difference for the brake pads to drw calipers on a 1.25" rotor would make for one heck of a noise maker.

So the guff I got for being unwilling to convert my GMT400 C3500 2WD front brakes to a GMT800 setup was all for nothing?


Tom
 

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So the guff I got for being unwilling to convert my GMT400 C3500 2WD front brakes to a GMT800 setup was all for nothing?


Tom
Yes, it is not an easy swap, and requires custom machining to make work. I know I've said this elsewhere, but it wasn't in my original post on it(which I've remedied). The gmt800 brakes ARE far superior to the gmt400, but for 2 wheel drive guys, it is not an easy bolt on swap Like it is for 4x4 guys. I need to go through and clean this post up and add more to it that I have learned since I 1st made it.
 
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