98 k3500 Rear Drums

[454cid]

This whole job is getting me closer to putting in a rear disc brake conversion. As Schurkey said this is a nightmare of a design. Got it all back together, and went to replace the diff fluid as part of this whole mess, and am now looking at methods to get the diff cover off as it was RTV'd and is mightily stuck on. What I thought was a Saturday afternoon job has now leaked into 14+ hours of cursing and smashed knuckles.

Thanks for the info to everyone who posted, it was a big help, and I've definitely learned more than I cared to know about drum brakes, especially on these trucks, but knowledge is power.

I ended up buying new hub assemblies, with new drums, and will look into bearing replacements. Hopefully a month or so down the road I can get the new pieces pressed together and get the whole new drums/hubs on as that was my original plan. For now I'm reusing the drums/hubs/bearings with new shoes and hardware.

You don't have what Shrurkey described. You have the better setup, and buying new hubs is a waste of your money unless they're damaged.

I'd try a putty knifle and a rubber hammer for the cover. Then use a wire cup to strip all the RTV off. I always use paper gaskets, but some guys here do use RTV in a more controlled manor instead of trying to use as much as possible.

 

[Schurkey]

Yep, it appears that your drums are not on the back-side of the hubs. It might be that they're intended to slide off the lug-studs. The drums on my '97 aren't like that.

Be VERY careful about buying new bearings. There's a lot of Chinese/import junk out there.

It would take an enormous rear disc set-up to match the braking power of what you already have. Be sure you don't DOWN-grade your brakes with a disc conversion.

Me? I'm gonna open up the drums once; do whatever it needs, and forget about it for as many years as possible.

 

[1998_K1500_Sub]

It would take an enormous rear disc set-up to match the braking power of what you already have. Be sure you don't DOWN-grade your brakes with a disc conversion.

I'm glad @Schurkey said this. In fact I was planning on him saying it, to save me the effort of doing-so myself.

It's good advice.

 

[AuroraGirl]

I'm glad @Schurkey said this. In fact I was planning on him saying it, to save me the effort of doing-so myself.

It's good advice.

did anyone get my sarcasm about the rear disc.

because without a prop shaft brake it would not uh... be wise to rely on the parking brake on a converted rear lol.the self energizing drum has a few innate qualities that are wonderful for big trucks

 

[1998_K1500_Sub]

did anyone get my sarcasm about the rear disc.

Well, I didn't, but that's just me.

I suspect an equivalent-capacity rear disc brake conversion is possible.

I just took a brief look on RockAuto and saw that a disc rear was available on GM K3500 SRW and DRW trucks in recent history. Upon inspection it appeared the rotor had the integral drum parking brake, as seems popular these days.

See BENDIX PRT6076 - 14" dia 1.6" thick
on RockAuto under GMC > 2016 > SIERRA 3500 > 6.0L V8 > Brake & Wheel Hub > Rotor

So the parts are "out there". Enabling them on a GMT400 might take some work, but if one is so inclined...

OTOH, if OP isn't really using his K3500 to its potential then a brake downgrade might be an option... but one I won't entertain.

 

[Schurkey]

The JF9 brakes on GMT400 C3500HD had rear discs. I don't know if that included a tailshaft brake or not.

 

[stutaeng]

Well, I didn't, but that's just me.

I suspect an equivalent-capacity rear disc brake conversion is possible.

I just took a brief look on RockAuto and saw that a disc rear was available on GM K3500 SRW and DRW trucks in recent history. Upon inspection it appeared the rotor had the integral drum parking brake, as seems popular these days.

See BENDIX PRT6076 - 14" dia 1.6" thick
on RockAuto under GMC > 2016 > SIERRA 3500 > 6.0L V8 > Brake & Wheel Hub > Rotor

So the parts are "out there". Enabling them on a GMT400 might take some work, but is one is so inclined...

OTOH, if OP isn't really using his K3500 to its potential then a brake downgrade might be an option... but one I won't entertain.

The only GMT400 that had rear discs was the C3500HD (GVWR = 15,000 lbs) with the huge 19.5" wheels. If I recall correctly, those have the weird e-brake drum on the tailshaft of the transmission, just the like the RVs. https://www.ebay.com/itm/264658590549

Maybe swap a 14 bolt from the 99-06 2500HD/3500 trucks that came with rotors is easier? It's been done before, but I don't know the details.

 

[1998_K1500_Sub]

Maybe swap a 14 bolt from the 99-06 2500HD/3500 trucks that came with rotors is easier? It's been done before, but I don't know the details.

I should add that I'm not trying to dissuade OP from a disc conversion, but I felt it appropriate to acknowledge the concern for retaining braking capacity.

It would be great to see a completed project write-up using, e.g., the parts noted by @stutaeng.

 

[AuroraGirl]

Well, I didn't, but that's just me.

I suspect an equivalent-capacity rear disc brake conversion is possible.

I just took a brief look on RockAuto and saw that a disc rear was available on GM K3500 SRW and DRW trucks in recent history. Upon inspection it appeared the rotor had the integral drum parking brake, as seems popular these days.

See BENDIX PRT6076 - 14" dia 1.6" thick
on RockAuto under GMC > 2016 > SIERRA 3500 > 6.0L V8 > Brake & Wheel Hub > Rotor

So the parts are "out there". Enabling them on a GMT400 might take some work, but if one is so inclined...

OTOH, if OP isn't really using his K3500 to its potential then a brake downgrade might be an option... but one I won't entertain.

I believe most rear disc kits tend to go the way ofthe lever and ratchet out piston for a park brake. works fine for my park avenue but of course thats way different than 1 ton truck with a trailer esp park oon a hill

 

[1998_K1500_Sub]

I believe most rear disc kits tend to go the way of the lever and ratchet out piston for a park brake.

Yes, and most I've seen (but not all I suppose) use those cheezy mounting brackets that don't do a proper job of maintaining caliper orientation or managing the forces during braking. See exhibits A & B at the links below.

I need to look at some of the better disc conversion kits, assuming they exist, just to learn a few things. I might imagine they're a bit more pricey.... and the best "conversion" is an OEM designed system retrofit onto the vehicle. Wait... didn't we just talk about that???

Summit Racing SUM-BK1629-DS Summit Racing™ Rear Drum-to-Disc Brake Conversion Kits | Summit Racing

Free Shipping - Summit Racing™ Rear Drum-to-Disc Brake Conversion Kits with qualifying orders of $109. Shop Disc Brake Kits at Summit Racing.

www.summitracing.com

GM 88-00 K1500 Rear Disc Brakes (6-lug, for 10" Drum Axles)

1090303

www.littleshopmfg.com