Braking Issues

[Andrew Spratt]

Back story:
I have a 99 Chevy Express 3500 Dually. For a while it was having a random issue where the engine would just die for no reason or have a couple miss fires in a row. Thankfully I sorted out that it was just a crank positioning sensor and got that fixed. Although, before I had figured that out, I was cruising along at about 35 MPH and the truck died, and seeing as how the steering and braking systems are both hydraulic then naturally I had neither.. I used the E-brake to stop the truck (which I have used in the past) and got it started again and going. Well wouldn’t you know it, e-brake sticks on – just one side drum.

Now – over the recent weekend, I took the time to knock off the duels, pull the axle shafts and knock off the drums. While I was in there and replaced the shoes and springs, cleaned and lubed everything up, bled off the fluid a bit till the air was out. and put it all back together. This morning (7/5) everything was fine, no dragging no noise, I did how ever have a bit of miss adjustment where one side was grabbing a bit earlier then the other. But not a big deal, I figured I would take care of it after work. Bout 4 pm today I start to hear a bit of dragging coming from that same drum that locked up on me and it progressively gets worse till I can no longer drive forward with out serious RPMs. Backward the brake seems fine and operates, but soon as drive is engaged it locks up. Sadly I was getting ready to leave work and didn’t have the ability to tear into it right there so I had to have it towed.

Now on to my question: The only thing I didn’t really mess with was the wheel cylinders and that’s mostly because the brake line is steel and I couldn’t get it to break loose without it turning the whole line.. Do you all think the cylinder is bad? Maybe the proportioning valve? Crappy fluid? I’m at a loss at this point. I have a pretty fair amount of automotive knowledge but not real proficient in drum braking, and as I have to pull the axles every time to get in to them.. it gets tedious. Thoughts?

Topic

[Rob]

correctly you have to jack the car up and try to spin each wheel to see wich is locked up… it could be the parking brake or the wheel cylinder or even the master cylinder because there is a front and a back brake system on the master… also check the springs and the brake pad screw ( forget what they cal it) and see if thats set right..
to be honest it has been a while sense I have done drums.. most of the time you can tell the wheel cylinder is bad because its leaking… but you should be able to tell if its bad by trying to compress it and see how stiff it feels like you do with a caliper for disk brakes… but you might have to take of all the springs and stuff all over again…
to be honest the only way is to take the whole system all the wheels and check everything to see what is bad

[Rob]

also check the boots on the wheel cylinder.. if you see them torn .. then right off the bat you know its bad or going to be bad
also looks for like grease coming from it… brake fluid and brake dust will make like a grease

[Andrew Spratt]

Boots are in good shape. Wheel cylinder is working like it should. Master cylinder maybe but if it was bleeding pressure to the rear then both rears should drag instead of just the one. Star wheel is functioning as it should. All new springs and hardware, greased in proper locations. I’m at a brake shop now and even he is stumped.

[Justin]

Are the shoes adjusted properly? Since you say everything else looks good and is operating properly

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[Andrew Spratt]

So after about 2.5 hrs with the shop tech and pulling my axel in and out 3-4 more times we figured out the ebrake cable, tho the brake is off its slightly pulling. Enough to wedge the brake in place against the drum. But then when I go backward it would let go till I started going forward again. We just disconnected the ebrake for now so I could go to work but I’m guessing it’s linked somewhere.

[Author]

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