Rear Brakes not Working

[Transom Jack]

Hello All,
I'm new to the board and this is my forst post.

I got a 1990 C1500 Silverado 4x4 today and when driving it home from the sellers house I dang near slide through a stop sign because the rear brakes are not working at all. I was on snow so it was easy to tell there not working. When I got to my house I checked the brake fluid and its full but kinda dirty which I plan on flushing and replacing in the very near future.

Any ideas before I dive in on this problem.

 

[Johnbalderas90k1500]

Check your wheel cylinders for leaks. Sounds like a hydraulic problem

 

[Fobroader]

Also the shoes and drums could be gone, Ive noticed when buying drum brake vehicles that most people dont like working on the damn archaic things.

 

[Swims350]

well fyi if it's a c then it's a 2wd and if it's a 4wd it's a k.

Next up if the wheel cylinders are working and not leaking, the brakes are adjusted out properly and nothing is wrong, could be the dump valve for the abs system.

 

[Transom Jack]

Is there a way to test the dump valves before just replacing parts and hoping for the best?

 

[Swims350]

yep, but I would check the brakes out back first, pull of a tire and drum and make sure it's in good shape.

you have to unhook the lines from the dump valve, hook the proportioning valve straight to the rear brake line and line from the MC to the prop valve, bleed the whole system and try it. I think the dump valve requires a fitting to work too. meaning in order to remove it you need the fitting to make th eline work to the prop valve.

Most of the time the dump valve makes for a soft pedal or alot of travel if it's bad. That is because it is bypassing the fluid going to the rears inside itself.

You also need to make sure that fluid is getting to the back, a clogged up rear line could stop fluid from getting there, the rubber hose on the rear end.


So again I would pull the drum and check things out, and if nothing else try to bleed each side and see if fluid comes out before looking into a dump valve and such.

It could just be a simple adjustment, stuck wheel cylinder, clogged hose, anything.

 

[darren250r]

The first thing I would check is the rear drum adjustment. They have self adjusters that are supposed to adjust when you hit the brakes in reverse, but when they get dirty or corroded they won't work right or at all.

Jack the whole rear end up and remove the tires. Spin the drums, one at a time. You should hear interference between the drums and the pads. If you don't, they are out of adjustment. Start by properly adjusting the brakes and cleaning them out, paying special attention to the adjusters at the bottom. You should remove the adjusters, clean the threads well and lubricate them.

 

[Mike]

also bleed the rears REALLY well, could just be a big bubble

 

[Transom Jack]

Finally got around to checking to see what the problem was. Turns out the dumb a** PO removed the rubber hose that leads down to the brake lines on the axle. Figured something was up so I pulled the rear drums and found nothing and I do meen nothing.....no brakes shoes, no springs, no wheel cylinders...... nothing. My thinking is that the dumb a** previous owner had a leaking wheel cylnder or something and took out all the hardware, pulled the brake hose, forced a pipe plug in the hose block(had to replace it to) and just drove around on the font brakes only.

Soooo..... after a bunch of parts runs and day of putting everything back together I now have rear brakes.

Thanks to all for the replies.

 

[Fobroader]

Finally got around to checking to see what the problem was. Turns out the dumb a** PO removed the rubber hose that leads down to the brake lines on the axle. Figured something was up so I pulled the rear drums and found nothing and I do meen nothing.....no brakes shoes, no springs, no wheel cylinders...... nothing. My thinking is that the dumb a** previous owner had a leaking wheel cylnder or something and took out all the hardware, pulled the brake hose, forced a pipe plug in the hose block(had to replace it to) and just drove around on the font brakes only.

Soooo..... after a bunch of parts runs and day of putting everything back together I now have rear brakes.

Thanks to all for the replies.

Wow....a whole new level of ghetto engineering. Good thing you got it sorted.