Need Help Advice On Rear Disc Conversion On DRW DUALLY

ForeverFalcon40

I'm Awesome
Joined
Oct 21, 2010
Messages
261
Reaction score
25
Location
Strong Island, NY
Looks like another flat-bracket "conversion" that stresses the caliper mounting pins. Over a thousand dollars for crappy engineering.
It just holds a caliper…torques down to spec I don’t see the issue here. Kit seems well made. I have a few friends running a lug nut kit on their SRW’s with no issues.

What do you suggest)
 

Schurkey

Supporting Member
Supporting Member
Joined
Jan 14, 2018
Messages
7,216
Reaction score
8,024
Location
The Seasonally Frozen Wastelands
You need an OEM caliper/bracket; probably with the OEM rotor as used on a GMT800 or newer 3500 DRW. You should look at how the calipers are mounted on the newer trucks.

I am not an expert on the newer-style discs except that they don't mount the caliper in a way that stresses the mounting pins. Either the caliper holds the pads, and caliper thrust is taken by an iron protrusion from the mounting system; (NOT a "flat bracket") or there's a separate iron bracket that holds the pads, and the caliper has no thrust. It just clamps the pads--the pad thrust is taken by the iron bracket that holds 'em.

Cheap-junk "conversions" use a flat bracket with no caliper thrust provisions; which means caliper thrust is taken by the mounting pins--a stress they were never intended to handle.
 
Last edited:

ForeverFalcon40

I'm Awesome
Joined
Oct 21, 2010
Messages
261
Reaction score
25
Location
Strong Island, NY
You need an OEM caliper/bracket; probably with the OEM rotor as used on a GMT800 or newer 3500 DRW. You should look at how the calipers are mounted on the newer trucks.

I am not an expert on the newer-style discs except that they don't mount the caliper in a way that stresses the mounting pins. Either the caliper holds the pads, and caliper thrust is taken by an iron protrusion from the mounting system; (NOT a "flat bracket") or there's a separate iron bracket that holds the pads, and the caliper has no thrust. It just clamps the pads--the pad thrust is taken by the iron bracket that holds 'em.

Cheap-junk "conversions" use a flat bracket with no caliper thrust provisions; which means caliper thrust is taken by the mounting pins--a stress they were never intended to handle.
I’m not familiar either at all with newer trucks as I don’t work on them. I posted a few years ago about converting and no one had something to say. I was going to go get a rear end from an HD with calipers. My buddy who helps with crazy projects over the years said he would do it but really wasn’t thrilled one bit. I can see it in his body language.

Basically said…without looking at it…

Axle will need a full rebuild and re-geared, new driveshaft made, brake lines made and routed. We don’t know if perches and mound need to be relocated. He said it won’t be cheap at all and will def take some time.

He advised to do some research and see what others have done. Really no one has done sh*t.

It appears I will be the first to convert in a dually and document it. People who have SRW using a same but different kit report no issues. Why is this kit any different?
 

Schurkey

Supporting Member
Supporting Member
Joined
Jan 14, 2018
Messages
7,216
Reaction score
8,024
Location
The Seasonally Frozen Wastelands
People who have SRW using a same but different kit report no issues. Why is this kit any different?
It may not be different. There's heaps of conversion kits that have terrible engineering; most of them make the SAME mistake. It's readily visible in your second photo.

You must be registered for see images attach


The only support the caliper gets from that dreaded "Flat bracket" is on the inboard side of the rotor. But the thrust on the caliper is centered at the middle of the rotor. So there's a leverage arm the distance between the center of the rotor--where the thrust SHOULD be taken, (and where it IS taken when GM engineers the caliper support)--and the bracket where it actually is taken using an aftermarket "flat" bracket. That leverage is trying to twist the caliper on the bracket. Those pins, (and the pads themselves) are resisting that bend and they were not designed to do that.

This is a REALLY COMMON aftermarket screwup because "flat" brackets are cheap and easy to make, and the old-style calipers are similarly cheap and readily available. Brackets that would take the thrust from cheap calipers in the proper place would require substantial additional thought, effort, and expense. Brackets and calipers like the newer GM products use--where the bracket holds the pads and therefore is designed to take all the braking thrust (the caliper squeezes the pads, but has no thrust load)--are more expensive than the older calipers.

In the end, it comes down to making the product as cheaply as possible. Don't get me started on the "kits" that omit the parking brake. At least you've got that going for you.
 

1998_K1500_Sub

Nitro Junkie
Joined
Jan 28, 2019
Messages
1,636
Reaction score
2,180
Location
Rural Illinois
Looks like another flat-bracket "conversion" that stresses the caliper mounting pins. Over a thousand dollars for crappy engineering.

Yes, the kit appears to expect the pins to sustain the braking forces.

They should have instead provided abutments for the calipers, like the OEMs did.

That’s why the calipers in the picture have those flat surfaces on either side, to press against the abutments (except the kit didn’t provide for them).

Let the buyer beware.

Here's what OP's aftermarket kit is missing: The caliper abutments aren't provided on the mounting bracket. The OEs include these for good reason (pictured), while many third-party retrofit providers assume they're unnecessary... or at least expect unsuspecting buyers.
 

Attachments

  • Nova brake knuckle - annotated.jpg
    Nova brake knuckle - annotated.jpg
    192.9 KB · Views: 28
  • Nova brake knuckle and caliper - annotated.jpg
    Nova brake knuckle and caliper - annotated.jpg
    131.6 KB · Views: 28
Last edited:

ForeverFalcon40

I'm Awesome
Joined
Oct 21, 2010
Messages
261
Reaction score
25
Location
Strong Island, NY
I finished up the swap last week! Everything went according to plane minus replace front calipers and pads. I went to bleed the brakes and the bleeders were frozen LMAO

Editing the video and will post it on the channel.

No mods needed! Closest to bolt on as you can get
 

ForeverFalcon40

I'm Awesome
Joined
Oct 21, 2010
Messages
261
Reaction score
25
Location
Strong Island, NY
Yes, the kit appears to expect the pins to sustain the braking forces.

They should have instead provided abutments for the calipers, like the OEMs did.

That’s why the calipers in the picture have those flat surfaces on either side, to press against the abutments (except the kit didn’t provide for them).

Let the buyer beware.

Here's what OP's aftermarket kit is missing: The caliper abutments aren't provided on the mounting bracket. The OEs include these for good reason (pictured), while many third-party retrofit providers assume they're unnecessary... or at least expect unsuspecting buyers.
Keep you updated as I drive my truck. Thanks for the concern!
 
Top