[RWilson]

Hey everyone,

I put on a lift kit this weekend and while I was at it I threw on some new SS lines and new Akebono ceramic brake pads. While bleeding the brakes with my wife helping, I keep getting lots of air bubbles on the rear brakes. Keep trying to bleed and the air isn't going down. What could be wrong? Am I loosening the bleeder too much? Is the master cylinder bad?

When we bleed the front brakes, I could no air. Pedal is still extremely mushy and truck takes awhile to stop! Please help diagnose

 

[Bosnian Discovery]

Replacing brake lines introduces a lot of air into the system. Often it does take a while to bleed out.

Did you bleed the ABS pump? There are 6 hard lines on the pump itself and each needs to be bled individually. Lots of space for air to hide in the pump.

Are you following the correct bleeding sequence? Rave specs FR, FL, RR, RL, but most guys tend to do RR, RL, FR, FL. Either works, as long as you follow one or the other.

Are you actually bleeding correctly? The pedal needs to be pumped and fully depressed before opening the bleeder and needs to remain fully depressed until you tighten things up. Make sure your wife understands the process and that she actually has the leg strength to maintain the pressure. She might be backing off too soon.

Are you keeping the reservoir topped up? Letting the fluid level drop too low can cause air to be sucked back into the system.

Don't worry - it's not your master cylinder. Even if it did fail it wouldn't introduce air into the system. I just rebuilt mine at 112K miles and it looked brand new internally.

Keep working at it. Just last month I did the SS lines/Akebono pads upgrade and I've never had my brakes feel better. Well worth it.

 

[RWilson]

Thank you for the reply! A couple followups if you don't mind...

1 - I did not touch the ABS pump at all, only the 4 bleeders on each caliper. We bled the lines according to the RAVE (FR, FL, RR, RL). How would I go about bleeding the ABS, and will I have to bleed at the calipers again afterwards?

2- The method we did was to pump the brakes 2-3 times, hold on the last time and press as far as we could... open the bleeder valve (pedal would move a few more inches to the floor)... close the bleeder valve... allow the pedal to return back up. My wife definitely wasn't able to push the pedal all the way to the floor without me opening the bleeder valve. If that is required, I'll have to redo the bleeding process.

 

[Bosnian Discovery]

No problem - happy to help.

1. This is a repost from another thread and it's what I did:

"Dear god, don't you guys listen to us LR techs, the easiest way to bleed any modulator is to bleed it at the modulator. Not the brakes. just fill the reservoir then have an assistant pump the brakes five times and hold. open the first line on top then open all five of the lines and then tighten up and pump five more times then open them again. this time starting with the second one on the top and then open all five lines, then pump five more times, open the third one, pump five times and then the fourth one on top and the all five and fill it back up. that will get the air out without using testbook. In fact this way works for any modulator on any vehicle except for older P38 and RRC."

I followed with a caliper bleed to make sure the system was good.

2. It sounds like you did it right. There's NO way to get the pedal to the floor with the bleeders closed, but just make sure that you're not backing off on the pedal pressure until the bleeder valve is fully closed after releasing pressure. Only a 1/4 turn should be enough to crack the bleeder and prevent any air seeping past the threads.