Brake scare while driving today / any ideas?

[cameronsaddress]

Hey guys,
I was driving the k5 today and when I went to brake at a stop light, my foot went right to the floor. I panicked and started pumping it and it began to build pressure and stopped the truck. I went straight home very cautiously. It never did it that bad on the way home, but the braking felt pretty week most of the way.

Where do I start to get this fixed? I checked the fluid and the reservoir is full. What other info can I provide to help troubleshoot?

Bummed now because I won't be able to drive it until I know that I'm not gonna die in a no-brake crash...

Thanks a bunch!
Cam

 

[ashman]

I assume you checked both front and back reservoirs are full. if so, maybe the lines need to be bled? did you mess around with that trailer brake thing at all yet? maybe something you changed there?

its also possible your rear brakes are almost gone, or need to be adjusted. I assume you still have drums in the rear. I've seen them get out of adjustment before and behave similar to what you experienced.

 

[cameronsaddress]

Hey there ashman,
I haven't dealt with the trailer brake yet, thankfully. I checked one reservoir, the one that is in the front right of the engine compartment that sits in front of the booster. is there another to check?

I do have drums in the back, how might I check to see if they are out of alignment?

I have not changed the fluid or bled the lines since I purchased it last month.

 

[63chevyll]

Check for leaks at every connection, check wheel cylinders and adjust rears, but could be a bad master cylinder

 

[ashman]

Hey there ashman,
I haven't dealt with the trailer brake yet, thankfully. I checked one reservoir, the one that is in the front right of the engine compartment that sits in front of the booster. is there another to check?

no, just 2 areas in 1 reservoir. I'm sure you looked into both (under the same cover), but just wanted to mention it.

I do have drums in the back, how might I check to see if they are out of alignment?

honestly, its been a long time since I checked mine (one of the things I'm doing this winter. ) they should adjust automatically, but it doesn't always work. I'm sure you can google "adjust rear brake drums" and get a much better answer than anything I could write up.

 

[cameronsaddress]

I checked the reservoir again, is it full enough?:

I didn't find any leaks. Here are some pics, let me know if you see anything out of order:

Adjustment for the Drum brakes?

Any idea what this electrical connection is for?

emergency brake cable? ...shredded

 

[kyle.rj133]

I think the wire is for the brake light on the gauge cluster

 

[gotblazers]

I checked the reservoir again, is it full enough?:

That is def. a bit low for my taste and dirty as shet. A brake fluid flush and bleed would be a good thing to do. it would also be a good experience for you. Brake fluid should be swapped every 5 years but is rarely done.

I didn't find any leaks. Here are some pics, let me know if you see anything out of order:

That looks like a potential leak to me. Its hard to say without being there.


Adjustment for the Drum brakes?

Im pretty sure that is an access hole to reach the Star wheel. Turning it in a direction will make the drums sit closer or farther to the drum. Your goal when you are adjusting the rear drums if you use the proper starwheel method is just a slight drag. Excessive drag will bring down mpgs and wear out pads sooner. No drag will give you a soft pedal. Its also helpful when you are unable to remove the drum. A trick my dad taught me for adjusting rear drum brakes is to put it in reverse up to 10mph or so and slam on the brakes. Do the same thing forward. We repeat between 3-6 times and its always worked on our shet. Im not sure if theirs any real scientific basis to that though .

Something to remember about brake systems is that they are hydraulic and even a pinhole leak can affect it in a big way. It could be in the hardlines going along the frame rails albeit very unlikely. you could have leaking wheel cylinders in your rear drum brakes a very common issue in drum brakes on anything older than 10 years. Soft lines and connection points are also good places to look. Sometimes the master cylinder will fail internally and it wont leak anywhere within the hydraulic circuit.

Judging by
1.your low fluid level
2.The fact that you have to pump the brakes to build pressure

Im going to guess that you have a leak somewhere. Im guessing we are talking about the truck in your avatar and presuming theirs no ABS components to worry about here?

I'd reccommend getting it up on jackstands at least in the rear and pulling off those rear drums to check the wheel cylinders as well as pad thickness and the drums if you have the proper equipment. If you dont have the facility's to jack it up remove the drums you can take it to a goodyear and ask for a brake inspection for free. Our corporate owned stores do technically offer those services free of charge (in order to sell you shet so expect lots of annoying upsellings).

 

[70jimmy]

Yep that is too low for my liking also.

Another place that is often overlooked is the grommet for the vacuum line on the booster. Make sure it isn't cracked and leaking when brake pressure is applied.

 

[DEMON44]

Old rubber lines can swell, during application as well. And become porous.

Sent from my Desire HD using Tapatalk

 

[scotto0609]

I would be leary of that master cylinder,it has visible corrosion with nasty brake fluid.I believe I would start there!

 

[4xcrazy]

Ditto on the res, first thing that came to mind when you said it went to the floor just out of the blue, sounds like it just died on ya, had it happen to a few in the past, sucks.

 

[sweetk30]

that fluid is NASTY AS HELL

time for full system flush and if me i wouldnt not trust that master as all that junk just eat's and shreads the guts in the master and you loose performance. new/reman master easy and cheep.

also great time to remove that tee fitting for the brake controler and remove it from the system.

 

[ryoken]

by far the most abused and ignored fluid in a vehicle..... that sh*t's not even translucent, looks like choco milk...

level is WAY low.. I would start by verifying no leaks.... wheel cylinders are the usual culprit with drum brakes, no signs of that tho.... once you have no leaks... FLUSH THAT FLUID!

 

[4X4HIGH]

After seeing that fluid if it were me I would be replacing the master cylinder, both front calipers, and both rear wheel cylinders and then fresh fluid and bleed the system properly. That's just me but I don't mess around with the brake system or steering systems on vehicles, they're too important to overlook them even the slightest.

 

[bp71k5]

Sounds like a bad master cylinder to me, although one of the rear brake pics looks like something was leaking at one time. Not recent though.

Don't worry, replacing the master cylinder is not difficult and isn't all that expensive, it's bleeding them that sucks.


-Brian

 

[tRustyK5]

After seeing that fluid if it were me I would be replacing the master cylinder, both front calipers, and both rear wheel cylinders and then fresh fluid and bleed the system properly. That's just me but I don't mess around with the brake system or steering systems on vehicles, they're too important to overlook them even the slightest.

This...

The fluid level isn't low enough to cause a pedal to the floor incident, and there are no visible leaks in your pics. That leaves the culprit as the master cylinder bypassing internally.

Swapping a MC is actually pretty easy, the most important part is bench bleeding it first. they're not even terribly expensive. Calipers up front are cheap, and also easy to change. Most important part of that job is ensuring you use new copper washers where the brake lines attach.

Rear wheel cylinders are probably the cheapest part of the job, however replacing them requires tearing down the drum brakes. Not hard (do one side at a time!) but honestly if you're gonna go through the work you may as well get new shoes, springs, adjuster and have the drums turned if they're scored at all.

Your brake fluid condition is a really good barometer of overall brake system condition, and your brake fluid is brutal looking...

 

[cameronsaddress]

Thanks everyone,
I just finished up installing a new master cylinder and flushing /bleeding the lines. I got all of the dark crap fluid out of the system. The new ms came with a bench bleeding kit and it was fairly simple.

Wow, what a difference. I drove it around a bit and the pedal does not need to go as far as it use to in order to stop the truck. I think this nailed it!

Thanks for all of the support!

Cam

 

[ashman]

gratz man!

 

[Greg72]

Check the vacuum line that runs to the brake booster too.

The line should run directly to vacuum port on the manifold, and the hose MUST be vacuum hose, not fuel hose or some other generic type...otherwise, the hose will collapse under vacuum and you'll get NO vacuum assist to the booster.

Based on how much ghetto stuff the previous owner did to your truck, I wouldn't be surprised if that hose was wrong too. A collapsed hose will still allow your brakes to work, but with a proper hose you should end up tasting the windshield under hard braking.