Tired of these bad brakes and need advice

[88sclb350]

1988 k1500 5.7l with read 10in drums and disc brakes up front and rwal.

Bleed my brakes today for the second time still to no luck. I’ve adjusted the rear drums to be just barely rubbing, front brakes are good. Brand new fluid and I’m no expert but little to no air in the lines.

I even saw a bleeder nipple on the rwal dump valve and got all the old fluid and air out of that. Brakes still suck. I do notice that with the truck off the brakes feel okay after a bleed but once the truck is on the pedal is so soft.

I do have a brake light on sometimes it flashes 1,2,3,4 but when I jump a to h on aldl it is solid then blinks 1,2,3,4. If I unplug the rwal two wiring harnesses the light turns off.

I really want this truck to just have some brake pedal not like a new truck but I don’t like having to put the pedal to the floor to stop. What should I do? I’m leaning toward rwal dump valve delete and plumbing rear brakes right into proportioning valve. I’m sorry I’m new and I’ve seen similar posts in my research but I really wanted to ask for my specific issues. Thank you gmt400!

 

[evilunclegrimace]

What is your RPO for the brake system?

 

[Caman96]

I’ve adjusted the rear drums to be just barely rubbing

I adjust mine to just barely get drums back on. You probably have JB3, I’m guessing. What is overall condition of parts, meaning the whole system. If your still seeing bubbles, I’m thinking it’s sucking air somewhere.

 

[88sclb350]

Overall condition is rusty but there. It must be sucking air, im not sure how to find that.

As for the drums both the self adjusted we’re froze with rust I was able to free up both and adjust them maybe I’ll turn them out some more so I can just barely get the drum on there.

 

[Caman96]

Is it a 2500(LD 6 Lug)? Just noticed your avatar.

 

[88sclb350]

Is it a 2500? Just noticed your avatar.

No 1500.

 

[88sclb350]

What is your RPO for the brake system?

What is your RPO for the brake system?

To be honest I don’t know. I have a pic of the code but I’m not sure all I have for J codes is J50

 

[Caman96]

Take a picture of them and post.

 

[88sclb350]

Take a picture of them and post.

 

[GrimsterGMC]

J50 is the JB3 brakes and they don't like bigger tires like in your avatar. I changed my master cylinder for a smaller bore to compensate for my 33's and it brought them back to just reasonable enough.