Rear Disc Brake swap for 97 K3500

[John Cunningham]

I purchased this beautiful untouched stored gmt 400 in heated garage for 21 years. Its showroom new.

I found out I dont like the steering or brakes so I will make some changes in those areas to see if I want to even keep the truck. 1997 Silverado crew cab 7.4 4x4 k3500 and stops for crap.

After reading various threads I pretty much decided that a rear brake swap to discs was a waste of money and since all new trucks have them I never really gave much trust to the these comments.

I had bought all the stuff to re transfrom the drums with bigger wheel cylinders and the right shoes etc I decided it to be a waste of time.

And that is is when I called the folks at "LUG NUTS 4X4 and talked to him. He claims he has sold 1000's of these kits and they definitley will make a difference buying the JB7 calipers and cermac pads.

I want to either dispel this non verified modification or prove it to be true. I need to do it for myself on my truck and by tommorow I will now for sure. I am not touching the front for now. I want to see what the rear will do and do understand it will not really stop the truck for more than maybe 30%

I was told not to worry about porportioning valves etc and if I have a hydroboost dont do a thing, which I do...I will flush the brake fluid

If this does anything at all I will be happy then move to the front....had this truck been not so perfect I would not be doing a thing.

So stay tuned and lets really find out what it can do....by the way the company Lug Nuts 4x4 were really sincere and helpful.....the entire kits runs about 400 dollars which means I do not have to figure out which parts I need and end up with mismatched parts....maybe somebody on this forum has bought his kit and installed it.......if I get some satisfaction from this I will go to the front and use either the dually rotor and caliper kit with good brake pads or go the gmt800 route...either way this truck needs to stop as good as a gmt800 truck or its going to be sold...mew double din dash with a kenwood as well as new tires...

Lets just get the facts now since I have been hot rodding and modifying for 40 years...I wonder what will happen...any bets?

 

[letitsnow]

I installed a lugnut 4x4 disc kit on my truck this past weekend. My rear axle is a semi float, but yours might be a full float being a 1 ton? I got the cheaper JB6 calipers and stainless steel brake lines.

The kit didn't have any real directions, so be prepared to figure things out as you go. Little things slowed me down like the brake lines - they can only go on the caliper one way (and seal) because mine had fittings with a lip on one side that the crush washers wouldn't make up for. One big thing that slowed me down was that the brake rotors didn't fit on my axles. I called Shawn and he explained what I needed to do. I spent a couple hours grinding on my axles get the rotors to fit. It was great that Shawn answered the phone and helped me, but having to grind on my axles was a pain. If I weren't set up to do stuff like that, it would have stopped the project. Just once it would be nice to install something like this that doesn't require the use of a sawzall/torch, or grinder... Hopefully yours go on easier than mine did.

With the upgraded rear calipers and you having hydroboost, your brakes should work pretty well when you get everything together. My truck stops very well now, and I went for the standard calipers. I don't have hydroboost, but have ditched my abs and replaced with a willwood prop valve. My stock rear brakes were messed up from before I bought the truck, so I don't know how well the stock (in good working order) set up would work in comparison.

 

[John Cunningham]

I installed a lugnut 4x4 disc kit on my truck this past weekend. My rear axle is a semi float, but yours might be a full float being a 1 ton? I got the cheaper JB6 calipers and stainless steel brake lines.

The kit didn't have any real directions, so be prepared to figure things out as you go. Little things slowed me down like the brake lines - they can only go on the caliper one way (and seal) be99 00 SILVERADO 2500 R. FRT SPINDLE/KNUCKLE 4X4cause mine had fittings with a lip on one side that the crush washers wouldn't make up for. One big thing that slowed me down was that the brake rotors didn't fit on my axles. I called Shawn and he explained what I needed to do. I spent a couple hours grinding on my axles get the rotors to fit. It was great that Shawn answered the phone and helped me, but having to grind on my axles was a pain. If I weren't set up to do stuff like that, it would have stopped the project. Just once it would be nice to install something like this that doesn't require the use of a sawzall/torch, or grinder... Hopefully yours go on easier than mine did.

With the upgraded rear calipers and you having hydroboost, your brakes should work pretty well when you get everything together. My truck stops very well now, and I went for the standard calipers. I don't have hydroboost, but have ditched my abs and replaced with a willwood prop valve. My stock rear brakes were messed up from before I bought the truck, so I don't know how well the stock (in good working order) set up would work in comparison.

Mine is the semi float too.....will start and finish tommorow

 

[John Cunningham]

Mine is semi float...........why did you get rid of the abs?
do you have any photos...........was the diam needed to be gound or the length?

I find that kind of lame that he did not explain this in the directions.....thats crazy because that should be in bold letters ..making you figure this out takes time...I am sure Ill have the same issue....but talked to him twice and he never mentioned a word

 

[John Cunningham]

are we talking the inner diametor of the rotor.........would not the indder have to be put on a bridge port and cut out even or the axle dia cut down..how could you grind down anything even?

 

[letitsnow]

The inner circle of the rotors needed to either be bigger, or the machined surface on the axle (where the factory wheel studs went through) needed to be machined about another 1/4" towards the center of the axle. Shawn said that he had heard of this before, but it isn't common. It seems like GM mixed and matched parts on occasion.

 

[letitsnow]

I don't have any pictures. You maybe know this, but with the SF rear end you need to remove the cover off of the dif and take the clips off (and that center pin and bolt) to remove the axles. The axle seals are next - they have a lip on them that bottoms out on the end of the axle. You can get them loose by tapping a flat blade screwdriver on that lip and prying - Look at the new seals and that might make sense. Then pound out the factory lugnut studs The new disc goes on the inside of the axle, with the new studs going through the discs, then into the axle. If your discs sit flat on your axles, you don't have to grind.

 

[John Cunningham]

all great info...! thanks..but still figuring the grinding
part out..how you grind it out? machine shop?

 

[John Cunningham]

I know I have a SRW 1 ton k3500 4x4
truck is unmoleted from new......its funny that I have a semi floating axle more like a 3/4 ton
its a siverado loaded up but I dont know what month it was built

 

[John Cunningham]

so do you still need to upgrade the front brakes to gmt800....That does not sound like a big deal to do either..I was going to find some used 99 to 200 steering knuckes and modify the bal joints...supposed the tie rods fit....you just have to adapt the extending adjusters