Identify which rear drum brakes

[Keith Seymore]

No, she's right. She has JB7, just like my 1980 8600GVW K25 with a 350.

Ah - I see somebody snuck another truck into the discussion.

That is correct for a 350 = JB7.

Diesel gets hydraboost, which is JDx. Gas gets vacuum, which is JBx.

K

 

[HotWheelsBurban]

Ah - I see somebody snuck another truck into the discussion.

That is correct for a 350 = JB7.

Diesel gets hydraboost, which is JDx. Gas gets vacuum, which is JBx.

K

14 bolt semi floating axle doesn't have the big hub and bearings coming through the middle. It's a regular axle hub, and the axle DOES NOT have to be pulled to pull the drum and service the brakes. My '90 R2500 Burb has the same rear axle and the rear brake service on it was very similar to the brake service on the Heavy Half ton trucks and Burbs. Just slightly larger and heavier parts....
I have a square body vintage 14B FF and you do have to pull the axles on it, to remove the drums. By the OBS trucks, in the later part of that generation, the 14B FF had slip on drums, so it's more like the 9.5 ring gear 14B.

 

[Bextreme04]

14 bolt semi floating axle doesn't have the big hub and bearings coming through the middle. It's a regular axle hub, and the axle DOES NOT have to be pulled to pull the drum and service the brakes. My '90 R2500 Burb has the same rear axle and the rear brake service on it was very similar to the brake service on the Heavy Half ton trucks and Burbs. Just slightly larger and heavier parts....
I have a square body vintage 14B FF and you do have to pull the axles on it, to remove the drums. By the OBS trucks, in the later part of that generation, the 14B FF had slip on drums, so it's more like the 9.5 ring gear 14B.

The original thread poster had a semi-float.

The post that started this thread back up, and was addressed to me, was in regards to a 1980 K25 8600GVW truck. She has the JB7 option on a 14BFF. The picture she posted is clearly for a full floater and she will need to pull the axle and use the parts list I posted for replacement parts for it.

 

[tophat36]

No, she's right. She has JB7, just like my 1980 8600GVW K25 with a 350.


Yes, for our year when you look up the brake hardware there are two 11" options and only the single 13" option. You will need the 13" ones. You have the exact same axle and equipment I do. I rebuilt the entire rear axle, brakes, hubs, etc... about 2 years ago. If you are doing the brake shoes, you might as well have your local oreilly's turn the drums and also replace all of the bearings/seals in there as well. If I remember correctly it was about $20-30 per drum to get them turned. The whole axle and drum has to come off to access the brakes. Here is all of the parts I used to rebuild mine(all from rockauto.com). You will need everything except for the Turn signal switch and Differential Rebuild kit in this list to do a full rebuild of the hubs/brakes.

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Thank you so helpful! Sounds like it’s worth it to just keep the drums. Any special tools I’ll need to remove everything, as well as the hub from the drum? Do you know which parking brake cable length fits our trucks, I haven’t measured that yet but would think it would be best to do that at the same time while I’m in there. Parking brake pedal doesn’t ever engage/click and stay when I press it down…just comes back up.

 

[Bextreme04]

Thank you so helpful! Sounds like it’s worth it to just keep the drums. Any special tools I’ll need to remove everything, as well as the hub from the drum? Do you know which parking brake cable length fits our trucks, I haven’t measured that yet but would think it would be best to do that at the same time while I’m in there. Parking brake pedal doesn’t ever engage/click and stay when I press it down…just comes back up.

Mine did the same. There's a little ratchet system on the pedal assembly, you need to just climb under there and spray some white lithium grease or silicone lubricant on the ratchet assembly and move it around until it starts working again. There is a 7/16" nut under the truck at a junction point that can be tightened up if the pedal doesn't actually engage the brake when the pedal is all the way down. You should be able to tighten it a bit, then move the pedal to feel how tight it is, then adjust more, etc... until you get it where you want it. It should start feeling tight about halfway down so that you don't have it partially engaged when the pedal is up.

 

[Chugalugg]

I have an OEM/NOS set of 13" rear shoes I bought for my '84 k20 and didn't use. I just cannot remember if they are gm or ac delco? I will look in the box if someone is interested as they need to go as I sold the K20. 50.00 obo plus ride

 

[Copymutt]

FYI on FF axles. If you intend to have a shop turn the drums you'll need to press out the wheel studs and the hub so the drum can be mounted in their lathe. Lucked out on my 11” drums. Still had enough to remain in spec.
Waiting on hardware & shoes from LMC.
If not a good circumference match to the drum I’ll glue up some course sandpaper on the drum & work the shoes down too match.

 

[Chugalugg]

Does anyone need a new nos set of rear 13 x 2 1/2" shoes? I bought a set years ago for my K20 and never used and sold the truck. 40.00 plus ride

 

[Bextreme04]

FYI on FF axles. If you intend to have a shop turn the drums you'll need to press out the wheel studs and the hub so the drum can be mounted in their lathe. Lucked out on my 11” drums. Still had enough to remain in spec.
Waiting on hardware & shoes from LMC.
If not a good circumference match to the drum I’ll glue up some course sandpaper on the drum & work the shoes down too match.

This is not necessarily true. Oreilly was able to do mine on their machine without pulling the hub

 

[idahovette]

@Bextreme04 is right. I can do them on my brake lathe, just use my cones in the races and go for it!