94 k1500 brake shoe and drum size

[Caman96]

You have 11” brakes. Buy your parts on RockAuto. I’d get Raysbestos Element3 brake shoes. Inspect your axle seals and wheel cylinders to see if they leak. Check drums out, brake hoses. Get it all fixed and along with front brakes, you’ll have JB6 braking. Which is good!

 

[Schurkey]

I didn't see anything screwy with the caliper mounting system.

Caliper is cantilevered off of the mounting pins/sleeves. Those pins were never intended to take braking thrust. An abuse of the mounting pins, potentially leading to metal fatigue and failure. GM designed those calipers so that braking thrust was taken directly by the iron mounting bracket, which braces the caliper BETWEEN the two pads...so there's no twisting force or thrust on the mounting pins.

I believe it's just a master cylinder out of an NBS truck. They bolt right up to the vacuum brake boosters on our trucks, but something having to do with the throw of the Piston I believe gives the pedal a much shorter stroke and much firmer feel.

The so-called "NBS" master cylinder is a two-chamber design. Quick Take-Up calipers use a three-chamber design, with the additional chamber having a huge piston moving a large quantity of fluid under low pressure. A "gush" of fluid to the calipers to push the pads up to the rotor, and then the smaller-diameter piston takes over, providing less volume but much higher pressure (more hydraulic advantage) to actually clamp the rotor, so pedal force stays reasonable even if the booster fails.

The "NBS" master just has bigger primary and secondary pistons, less hydraulic advantage, and therefore requires high pedal effort if the booster chokes 'n' pukes. Don't let your wife or daughter drive the truck, they'll never get it stopped.

Last I looked--and it's been awhile--even the Little Shop of Horrors explained that the "NBS" master cylinder was for use with non-low-drag calipers.

 

[scott2093]

You have 11” brakes. Buy your parts on RockAuto. I’d get Raysbestos Element3 brake shoes. Inspect your axle seals and wheel cylinders to see if they leak. Check drums out, brake hoses. Get it all fixed and along with front brakes, you’ll have JB6 braking. Which is good!

Thanks. Just want to be sure but, I think I need new drums...The front(leading) pad material is raised where rivets are and the back shoe material exposed metal must have been grinding grooves into the drum??? Or is that how these work?

 

[Caman96]

Thanks. Just want to be sure but, I think I need new drums...The front(leading) pad material is raised where rivets are and the back shoe material exposed metal must have been grinding grooves into the drum??? Or is that how these work?

I have no doubt it destroyed your drum.

 

[Schurkey]

You could measure the grooves to see if the drum is beyond it's machining diameter...but...I'm with Caman96. It's almost certainly "done".

Might as well get two. Ideally, from a local source. Lotsa folks complaining that their mail-order drums are warped, and then it's a hassle to return them for different drums that are also warped.

If you buy them locally, they're probably not counterfeit, and exchanges should be easy.

For the record, I've bought several sets of rotors via Amazon, and haven't had a bit of trouble with them. Maybe I've been lucky. OTOH, I also try to save "used" drums and rotors via a brake lathe to restore the braking surface. My Bear machine is ancient, but works "good enough" for me. There's a similarly-old drum lathe on the other end of the bench.

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[1998_K1500_Sub]

I didn't see anything screwy with the caliper mounting system.

Like @Schurkey said.

Be glad you have the 11" drums.

And as far as the master cylinder upgrade that he sells, I believe it's just a master cylinder out of an NBS truck.

Yup... and he sells that MC b/c it's got the large fluid reservoir that's more-or-less required for use with the disc rear brake kit which he happens to sell.

As noted by @Schurkey, if one installs that MC they need to pair it with appropriate calipers, i.e., those which have the requisite property of being non-low-drag. Where does one find them? They're used on the GMT400 JB7/JB8 brakes and readily available.

Low-drag caliipers are introduced to the reader in this brief tech bulletin from Bendix (attached); they're OE on GMT400s with JB5/JB6 brakes (and perhaps a few other RPOs... JN3?)

 

[scott2093]

Thanks for everything.
I would like to ask why , when my rear end was swapped to whatever this is, would my original parking brake cable not reach? And what I need to do to get it working again. I haven't gotten into it and studied but it's a bout a foot short to connect the front section to the rear where it all meets in the middle of the frame... Not sure it can be adjusted that far but haven't gotten into it yet.

Basically I guess I'm asking if I found what year truck this rear end came out of, would buying the parking cable for it make it work or are they the same and I just have some adjusting to do to get these to meet up?
Parking brake used to work with my old rear.....

 

[scott2093]

If you buy them locally, they're probably not counterfeit, and exchanges should be easy.

Jeez...can't even find any locally between Oreillys,Autozone or Advance.....can order from ***** for Saturday....$115 each for their house brand.......

tempting to order from Amazon AC delco....for $75 each..... damn counterfeits

https://www.oreillyauto.com/detail/c/acdelco/brakes/brake-drums---rotors/brake-drums/4b5c83cb9113/acdelco-brake-drum/acd0/18b255/v/a/3747/automotive-suv-1991-chevrolet-v1500-suburban-4wd...

 

[Schurkey]

why , when my rear end was swapped to whatever this is, would my original parking brake cable not reach?

I'm pretty sure that when I ripped-out my 8.5" axle in favor of the 9.5" semi-float, that I re-used my existing park brake cables.

I'm reasonably certain the cables are the same--they fit the vehicle (wheelbase) not the axle.

The last sets of park brake cables I bought came from O'Reillys. I just bought what was listed for my vehicle. Two rear cables, and a front cable, if I remember correctly. The front cable has different part numbers depending on vehicle wheelbase. I'm not thrilled with the O'Reillys cables, they are NOT "exact fit" but they're close.

I thought I had photos, but I can't find 'em.

And what I need to do to get it working again. I haven't gotten into it and studied but it's a bout a foot short to connect the front section to the rear where it all meets in the middle of the frame... Not sure it can be adjusted that far but haven't gotten into it yet.

Basically I guess I'm asking if I found what year truck this rear end came out of, would buying the parking cable for it make it work or are they the same and I just have some adjusting to do to get these to meet up?
Parking brake used to work with my old rear.....

Not much more than a wild guess, but I'm suspecting the existing cable(s) have seized in the sheath(s).

Try to pull ALL of the cables back and forth, see if they'll move freely. Once connected to the park brake levers at the rear wheels, I'd expect the other end to meet-up with the intermediate cable, maybe with some adjusting, maybe not. There's not a huge amount of adjustment in the system.

 

[scott2093]

I'm pretty sure that when I ripped-out my 8.5" axle in favor of the 9.5" semi-float, that I re-used my existing park brake cables.

Just messed around a bit and think that my body lift has something to do with it..hmm..

The finger clip that holds the front cable in a hole in one of the body mounts is just shy of reaching the hole...Don't recall what was going on before, just that it worked..

Anyway, I can bypass the mounting spot for the finger clip by just going around the body mount entirely and get the cable connected to the back section....
Don't have my rear brakes yet so won't be able to see how everything does...

seems like those finger clips are important and just leaving the cable hanging will alter the way everything works a bit ...
Was reading there are mounts that come with body lifts that are supposed to deal with this...Don't have anything like that on my truck...
It's a start....