My brake light came on, rear brakes don't work

[SoulReaver]

So my brake light came on the other day, and now my rear brakes don't work. Anyone have any idea why this could have happened? How the hell do I fix this?

[Bowtie4Life]

have you checked the rubber brake line on the axle and see if it's torn at all?

[Fastbird]

First thing I'd check is the master cylinder resevior to see if it's low. if it is, start inspecting lines because you've most likely got a leak somewhere. How exactly do you know the rear brakes aren't working?

[KissMyWhtSS]

I'd try bleeding the rear brakes to ensure you're getting pressure back there.

[SoulReaver]

have you checked the rubber brake line on the axle and see if it's torn at all?

I have not actually checked yet. The car has been in the shop and I noticed this on the way there.


First thing I'd check is the master cylinder resevior to see if it's low. if it is, start inspecting lines because you've most likely got a leak somewhere. How exactly do you know the rear brakes aren't working?

The reservoir is actually low. There is probably a leak like you think.

I think the rear brakes aren't working because I drove the car around for about 3 hours. When I got close to my house I sped up to about 40 and then stood on the brake pedal. I got out of the car immediately and touched the rear rotor. I could have made ice on that thing with water it was so cold.

The front rotors were like scorching hot.


Have you found anything out on this yet?

Not yet, car comes back to me on Wed.


I'd try bleeding the rear brakes to ensure you're getting pressure back there.

I'll try this asap.



It's also worth noting the brake pedal practically touches the floor when I brake.

[my95z28]

yeah, you have a leak. Just stick your head underneath the car and locate the steel lines running along the. Wherever the leak is will be COVERED in brake fluid for about 1.5-2ft. It shoots outta there pretty good. Just be glad that you are driving a car with a 2 part master cylinder. Older cars don't and you will lose ALL brakes when you blow a line. Remember when bleeding to go in the order of Passenger Rear, DR, PF, DF to bleed.

[95LT1Z28]

Dont know if you figured this problem out yet man. I do have a suggestion, maybe the master cylinder is low because your brakes are worn? This happened to me on my dd nissan truck.

[SoulReaver]

I haven't been able to check on anything yet guys. The body shop finished my collision damage, but while it was in there we decided to get some other paint stuff fixed up as well. It'll probably be another 3-5 days at least.

Thanks for all the help guys!!

[KissMyWhtSS]

You might try writing the brake problems off as part of the accident. :tt2:

[SoulReaver]

You might try writing the brake problems off as part of the accident. :tt2:

As much as I would like to do that, the insurance claim has already been paid for and repairs completed :(

[95LT1Z28]

Any news on your problem man?

[SoulReaver]

I got it all squared off yesterday.

I replaced:

The rear brake pads
The Master Cylinder

I also bled that bitch and all 4 calipers. The rear calipers have sliders just like the ls1 brakes, so I gave those a grease job. One of the rubber boots that protects the grease had slipped off of one of the 2 connection points, so I fixed that as well.

The brake light went right off. Well not quite. lol. I guess that light detects air in your brake system. I turned the car on and bled the brakes. Every time we opened the bleeder valve, the light would go on, but once I applied pressure to the brake, via the pedal, the light would go off.

Thanks for all the help and encouragement guys! I love this place ;D

[KissMyWhtSS]

Glad you got it figured out Randall. :)

The snow gone yet? I think were due a 100+ pic photoshoot.

[SoulReaver]

The light came back on! UGH! It's raining like a whore right now. I bought a new caliper and threw it on, hopefully that fixed it.

[KissMyWhtSS]

Both rear calipers or just the front?

[phantomzer0]

Ive been working on this all day. I had a seized up caliper on the front passenger side. I fixed that. Now, my rear brakes just barely work. They dont stop the rear wheels from moving. No clue what's up with that now.

I've bled the fucking rears about 15 times each. The pedal gets nice and firm, but when the car goes on, the pedal gets floaty and the rears just don't work well. Fuck me.

[phantomzer0]

I meant to post that as Soulreaver, woops. I'm on Russ' Computer, lol.

[SoulReaver]

Ok BIG Update!

It turns out, my passenger side caliper was locked up. Don;t ask me how. Anyhow, the fluid was pushing on the pistons, but had no where to go, so it blew the piston gasket out. It shredded the gasket/boot into 2 separate pieces.... DAYUM.

So, using some spare junk calipers, I was able to rebuild myself a nice new caliper. It works perfectly now.

Now onto problem number 2. My rear brakes didn't grab enough to stop the rear tires from moving. It turns out, the line that plugs into the master cylinder, was not tightened down fully, leaving some air to get in. FUCK. SO after about 3 hours of bleeding the rear brakes, we finally figured that one out. We bled them a few more times before the sun went down.

I have good pressure in the lines now, but I think they still need to be bled a bit more.

The front's are my next target. We bled the brakes with the car off, but I found out yesterday, the car needs to be on. WTF? The front brakes have never been bled with the car on, so that is the next project.

[RumbleZ]

The car doesn't need to be on, but does need to be started a couple times. There's a specific bleeding procedure.

Have you been bleeding the ABS modulator? There are two bleeders on it amd need to be bled in sequence.

Sounds like you've got all the hard parts taken care of at the calipers so here's a quick rundown of the Gm way of bleeding and it hasn't failed me yet.

Do not touch brake. Start car. If ABS light goes through it's normal routine of flashes and goes off, proceed. If it doesn't go off you need to get the car scanned and find out why it's on. If the light goes off after a few flashes, leave car running about 10 more seconds or so and shut the car off. Repeat this process one more time just do not touch the brake yet while doing this. This cycles the ABS motors. I skip the next step which is technically to do an ABS motor rehome with a TechII. I've never needed to do this.

For bleeding, Start with the ABS modulator. There are two bleeder valves on the front of it. Start with the one on the left side of the ABS (standing at front of car looking towards windshield) that sits about an inch rearward of it's partner. Bleeding these is no different than at the brake caliper, pump until there's no bubbles in the tube, hold and close the valve. Then bleed the other one on the ABS.

After that, move on to the calipers. They need to be bled in this order:
Right Rear, Left Rear, Right Front, Left Front. Obviously make sure to keep that master cylinder topped off at all times, I always just make a habit of pouring a little in after every two or three pumps, and definitely before moving from one bleeder to the next. Once you've been through bleeding the calipers in order, the ABS modulator needs to be bled again in the same order you did before. You don't need to go through the starting the car process again, just do the bleed. Sometimes I will add another bleeding round at the calipers in the same order as above, but usually not necessary.

If for some reason after all this the pedal does not feel solid, the ABS modulator should be cycled again (dont' touch brake, start car, let run for 10 seconds after ABS light stops flashing and goes off, like above), GM says to do that 5 times and then repeat the bleeding procedure from the beginning. I've never had to go that far though.

Hope this helps, good luck with it.

[SoulReaver]

Thanks a bunch Rumble. That is awesome stuff you have posted. I'll do it this way for sure this time around.

Also, by right rear, you are referring to passenger rear right? Furthest away from the MC, right?

[RumbleZ]

Yep, Right= passenger, Left = drivers