Air in my brake lines?

jaredthomas27 · November 30, 2011

Hey guys, I did a rear drum brake change a few weekends ago in my 08 1500. Ever since, my brake petal has felt very week. I can easily bottom out the petal and that makes me nervous knowing I am going to be doing some towing in the near future. I thought that maybe I did not manually adjust my rear brakes enough after I put them on so I went back and readjusted them to where the rotor had some friction with the brake pads. I thoroughly cleaned the rotors and the brake parts when I changed the brakes. Also I checked the front brakes and they are still in good shape, I bought the truck used and im guessing they were recently replaced. Could I have allowed air to somehow enter the system while doing this? I never opened the brake system so I wouldn't think so but it sure doesn't feel right. Any thoughts? Thanks guys!

00Silverado4x4 · November 30, 2011

First make your fluid level is good. Then could try a couple of back ups & sharp braking. That'll further adjust your rear shoes. If that don't work then inspect all brake lines for leaks. If none than I'd proceed with full brake bleed.

jaredthomas27 · November 30, 2011

First make your fluid level is good. Then could try a couple of back ups & sharp braking. That'll further adjust your rear shoes. If that don't work then inspect all brake lines for leaks. If none than I'd proceed with full brake bleed.

Yeah I did the backing up and braking. Never seemed to help. I suppose ill check the lines next for leaks where air could get in. Thanks!

ifshinxs · November 30, 2011

I'm not sure if I'm reading your post right...Did you change your brakes out from Drum to Disc?

jaredthomas27 · November 30, 2011

I'm not sure if I'm reading your post right...Did you change your brakes out from Drum to Disc?

Sorry, my words were kind of confusing as I used the wrong words a few times (rotors=drums, pads=shoes, etc) so no I didnt not go from drums to discs. I just replaced the brake shoes in the drum.

=v8-only= · November 30, 2011

yes you have to bleed the system even though you didnt open it up.

pm26 · November 30, 2011

Make sure you installed the parts correctly. The rear wheel cylinders have small push rods on the ends that need to be properly engaged in the brake shoes to force them against the drum when hydraulic pressure is applied by pushing on the brake pedal. If parts have been installed correctly, then you have air in the brake system. Did you change out the wheel cylinders? Just changing the brake shoes without disconnecting the hydraulic system woudl not introduce the air into the system.

yes you have to bleed the system even though you didnt open it up.

No, you don't.

jaredthomas27 · November 30, 2011

Make sure you installed the parts correctly. The rear wheel cylinders have small push rods on the ends that need to be properly engaged in the brake shoes to force them against the drum when hydraulic pressure is applied by pushing on the brake pedal. If parts have been installed correctly, then you have air in the brake system. Did you change out the wheel cylinders? Just changing the brake shoes without disconnecting the hydraulic system woudl not introduce the air into the system.

yes you have to bleed the system even though you didnt open it up.

No, you don't.

No I did not change the cylinders and I rechecked to make sure the shoes were sitting properly on them and they were. I also went ahead and checked my brake lines and they look brand new and without leaks. The owner before me must have had new ones put on, they still had the barcode tags on them and they were all painted nice with black without rust. So what do you think, should I just bleed the system and go from there? I did notice that the master cylinder was not filled all the way but it is still in between the min and max line. Thanks for all the help so far, much appreciated!

pm26 · November 30, 2011

Definitely bleed the brakes, starting with the right rear wheel cylinder, left cylinder, right front caliper, and left front caliper, in that order.

jaredthomas27 · November 30, 2011

I dont know if this means anything but if I pump the brakes while getting ready to stop it stiffens the pedal. But it only does it for that stop, I have to do it again for the next stop.

00Silverado4x4 · December 1, 2011

I dont know if this means anything but if I pump the brakes while getting ready to stop it stiffens the pedal. But it only does it for that stop, I have to do it again for the next stop.

Definitely bleed out your brakes as pm26 said. One way or the other you've got air.

jaredthomas27 · December 1, 2011

I dont know if this means anything but if I pump the brakes while getting ready to stop it stiffens the pedal. But it only does it for that stop, I have to do it again for the next stop.

Definitely bleed out your brakes as pm26 said. One way or the other you've got air.

Alright will do that. The last vehicle I bled the brakes did not have antilocks on it. Is there a different procedure or anything I need to look for when bleeding with my new pickup?

newdude · December 2, 2011

Make sure you installed the parts correctly. The rear wheel cylinders have small push rods on the ends that need to be properly engaged in the brake shoes to force them against the drum when hydraulic pressure is applied by pushing on the brake pedal. If parts have been installed correctly, then you have air in the brake system. Did you change out the wheel cylinders? Just changing the brake shoes without disconnecting the hydraulic system woudl not introduce the air into the system.

yes you have to bleed the system even though you didnt open it up.

No, you don't.

No I did not change the cylinders and I rechecked to make sure the shoes were sitting properly on them and they were. I also went ahead and checked my brake lines and they look brand new and without leaks. The owner before me must have had new ones put on, they still had the barcode tags on them and they were all painted nice with black without rust. So what do you think, should I just bleed the system and go from there? I did notice that the master cylinder was not filled all the way but it is still in between the min and max line. Thanks for all the help so far, much appreciated!

OEM brake lines are black from the factory so those most likely are original lines. I believe they are nylon coated, hence the black apperance.

00Silverado4x4 · December 2, 2011

I didn't bleed my truck's brakes any differently than on non ABS vehicles & they work just fine.

ifshinxs · December 2, 2011

Now that I understand what your doing...

On drum brakes assuming you have the shoes installed correctly..Once you put the drums back on you'll need to adjust the shoes to fit firmly (but still able to turn) against the drums by spinning the star adjuster through the backing plate. If not you'll have excessive travel in the wheel cylinders.. This may be why you have to pump the brakes to get a firm pedal each time you stop.

If you didn't open a bleeder valve you "shouldn't" have air system but in your case it might be a good Idea just to make sure your lines are clear from any air once your rear brakes have been adjusted..Can't hurt!