I am preping to put chevy springs is the back of my 04 ranger.

I will be doing away with the block and will need shorted u bolts.

I know they are 9 1/2" long but what diameter is the axle tube? Also what diameter bolts should i get 1/2"?

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04 Supercab 4dr 4.0 5spd 4x4 EDGE. Daily Driver
96 F350 Crewcab 460 5spd Vortech S/C 4X4 6" 35s
94 Lightning Bassani headers back CAI Underdrive Pulleys
86 F250 Reg Cab 6.9 4Spd 4x4 6" 35s (powerstoke,D60 5spd on the way)
80 F350 Reg Cab 429 C6 4x4 L&L headers F450 rear springs All Out Pulling Truck(D60 Laddered Frame, 540cid coming)

The main tube diameter of a 31-spline Ranger axle is 3.25", 28-splines are 2.80"

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I would hope i have the 31 spline

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04 Supercab 4dr 4.0 5spd 4x4 EDGE. Daily Driver
96 F350 Crewcab 460 5spd Vortech S/C 4X4 6" 35s
94 Lightning Bassani headers back CAI Underdrive Pulleys
86 F250 Reg Cab 6.9 4Spd 4x4 6" 35s (powerstoke,D60 5spd on the way)
80 F350 Reg Cab 429 C6 4x4 L&L headers F450 rear springs All Out Pulling Truck(D60 Laddered Frame, 540cid coming)

One way to tell is the 28 spline narrows toward the brake drums. 31 spline remains same diameter the whole way.

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I have 4:10s does that help?

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04 Supercab 4dr 4.0 5spd 4x4 EDGE. Daily Driver
96 F350 Crewcab 460 5spd Vortech S/C 4X4 6" 35s
94 Lightning Bassani headers back CAI Underdrive Pulleys
86 F250 Reg Cab 6.9 4Spd 4x4 6" 35s (powerstoke,D60 5spd on the way)
80 F350 Reg Cab 429 C6 4x4 L&L headers F450 rear springs All Out Pulling Truck(D60 Laddered Frame, 540cid coming)