Issue with NBS 13" Rear Discs on GMT400

[davkenrem]

I finished up my Brakes yesterday morning on my 97 K1500 Suburban. I swapped in a 9.5" SF and used the disc package from a 2002 Suburban with the 13" rear discs. I go to put the wheels back on and they do not fit over the rotors.

I did my research and others claim to have used 16" wheels over the 13" NBS Rotors.

The difference appears to be that others are using after market wheels, and I'm using factory.

Question, does anyone have experience with this swap using 16" wheels?

I would hate to have to buy new 17" wheels and tires just to fit over the rotors?

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[Supercharged111]

You might try some good bolt on spacers. Does your e brake work?

 

[davkenrem]

I'll look into it but don't want my tires sticking out like a "brodozer". E-brake will work once I find correct length cables.

You might try some good bolt on spacers. Does your e brake work?

 

[Supercharged111]

I'll look into it but don't want my tires sticking out like a "brodozer". E-brake will work once I find correct length cables.

I think you need to wear a flat brim hat, never go off road, and roll coal to achieve full brodozer status.

 

[davkenrem]

I think you need to wear a flat brim hat, never go off road, and roll coal to achieve full brodozer status.

Kill me now...

 

[jdla140]

My Sierra Denali shares the same rear brakes as SUV's (dual piston calipers and 13" rotors). OBS 16" rims do not fit, just as you have discovered. SUV's and Silverado/sierra 1500 quadrasteer trucks had 16" rims and my truck has a 16" spare, so I know for sure that NBS 16" rims will fit. I think the OBS rims just have too much positive offset.

Curious how you did the rear disk swap, did you have to make a custom spacer to use the SUV parts?

 

[Nash]

http://www.cutthroat4x4.com/catalog/index.php?cPath=18_25&sort=2a&page=2

 

[davkenrem]

My Sierra Denali shares the same rear brakes as SUV's (dual piston calipers and 13" rotors). OBS 16" rims do not fit, just as you have discovered. SUV's and Silverado/sierra 1500 quadrasteer trucks had 16" rims and my truck has a 16" spare, so I know for sure that NBS 16" rims will fit. I think the OBS rims just have too much positive offset.

Curious how you did the rear disk swap, did you have to make a custom spacer to use the SUV parts?

I'm glad you asked, been wanting to share this. So when I began doing my research after betting my rearend I discovered that a 60mm spacer was needed to properly space the brakes on the axle. All my searching yielded parts for a 14bolt FF but not a 14bolt SF. I was looking on ebay one night and found these:

https://www.ebay.com/itm/14-Bolt-GM...775377?hash=item1ecdfaa8d1:g:RswAAOSwHoFXvOes

I contacted the seller and asked the spacing of the bolt holes and the diameter of the opening. He emailed me the measurements and the bolt holes perfectly matched the 14bolt SF. The 14bolt FF axle tube is slightly larger so the bore would fit over the 14bolt SF axle tube. I ordered them the next day.

Here is an early mockup of the spacer on the axle.

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There is a little space around the axle tube, but with guys running stacked nuts for spacers I figured this would be fine. Ordered some 4" or 5" Grade 8 bolts to put in all together and seems like it will work fine.



And here is a mockup of the brake parts.

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The Backing Plate , Caliper mount, caliper bracket and dual piston caliper came from a 2002 Suburban with the 13" Brakes.

hhLast night looking at the back of the factory wheels from the backside, they taper down to about 15" to the face of the wheel.

I ordered 1- Mickey Thompson Classic III from Amazon to test fit it. If it does not fit, I'll send it back.

 

[davkenrem]

I think the 14 bolt SF 4 wheel drive requires a 30mm spacer when using the set up he did. A 2 wheel drive requires a 6Omm spacer.

The pair shown at the attached site are a 30mm and what you would need but you will need to contact them to make a 60mm if you were to require a set for a 2wh dr.


http://www.cutthroat4x4.com/catalog/index.php?cPath=18_25&sort=2a&page=2

This is incorrect, a 4wd GMT400 9.5 SF 14bolt axle requires a 60mm spacer when using GMT 800 disc brake components.

My axle came from a 1996 Z71 truck.

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[Nash]

I did this a few years ago and have slept since then. I am sure you are right as the information on the swap is on the gmt400 site. Did not intend to mislead. My truck is a 2wh dr and I used the 60mm for the 14B SF 9.5. I think the 20mm is used on the 10 bolt 4wh dr rear. Probably wrong on that too.

I had my spacers made from steel and were $80 at that time from cutthroat.