# Drum VS. Disc spindle question



## gambit45 (Jun 12, 2012)

I have a 70 GTO and am converting to front disc brakes using the Stainless Steel Brakes A123-6 kit that converts from drum to disc. I found out through a lot of back and forth that my goat was ordered with "Heavy Duty" front drum brakes. Basically, I think they used a disc brake spindle instead of a drum barke spindle. This makes my disc brake conversion kit useless. So, I ordered drum brake spindles......

My question is this. Does anyone know the top to bottom difference in "height" between the spindles? 

The other problem is I have a Global West Suspension control arm and coil over system which I'm trying to figure out if the geometry is still going to be within specs with the drum spindle. Picture is below with the disc brake spindle.


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## likethat (Oct 5, 2007)

12" upgrade woes [Archive] - El Camino Central Forum : Chevrolet El Camino Forums


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## pontiac (Mar 6, 2011)

Pontiac factory stock drum and disc spindles are the same height.


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## gambit45 (Jun 12, 2012)

pontiac said:


> Pontiac factory stock drum and disc spindles are the same height.


Are you sure about that? I just got confirmation that they are in fact different heights from another source but he doesn't have a drum spindle in stock yet to give me a measurement. I was also told be a tech at Year One that they are different heights.


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## gambit45 (Jun 12, 2012)

OK "pontiac" was indeed correct the drum and disc spindles are the same height. The difference is the boss on the top portion that holds the drum brake cyclinder is flush with the bottom surface that holds the steering arm. The disc brake's boss is about 3/4" back. Problem solved and my the caliper mount now works as it should.


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## geeteeohguy (Feb 2, 2008)

No place to bolt the brake caliper to on a drum brake spindle/knuckle unit without an adaptor, etc. What you're dealing with is exactly why I always recommend used GM parts....cheap and a perfect fit. I'm glad your install worked out!!


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## gambit45 (Jun 12, 2012)

geeteeohguy said:


> No place to bolt the brake caliper to on a drum brake spindle/knuckle unit without an adaptor, etc. What you're dealing with is exactly why I always recommend used GM parts....cheap and a perfect fit. I'm glad your install worked out!!


Thanks geeteeohguy, it was a kit that was bought for me over 5 years ago but costs over $1,500 so I couldn't just let it go. If I had my choice I would have gotten Wilwood because I've set them up on other's Chevelles, Lemans and even GTO's and I truly believe in their machined hubs that they make. My problem with my own was that I've never done a drum to disc conversion. Live and learn.


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