Full Brake System Replacement and Bleed Process

[FarFire70]

Long post - looking for advice on the planned approach at the bottom of this post.


My project has been on hold for a few weeks but I'm hoping this weekend to get after it again. Next up is a full replacement of the brake system (along with frame exterior painting).

Front: New VANCO 16" Kit

Rear: New Centric Calipers & Rotors w/ BMB Pads

Hard Lines: New SS from Classic Tubes

Soft Lines: Raybestos (extended front lines)

Keeping original Master because it hasn't shown any issues to date. (Welcome feedback on that, 155k miles on the original)

I've done a lot on the Jeep (and other cars) but full brake system is not one of them (new caliper or soft line, yes - but not a full end-to-end (essentially) replacement). Spent a lot of time researching here on the forum and the broader internet and compiled the below plan. The below is an aggregation of helpful advice from folks like @mrblaine, @Chris, and so many others.

Hoping to get after starting this piece of the project this weekend. That will start with pulling the old lines, getting the axles back under the Jeep, and then I can get after the bleeding parts of the below. In the interim, I want to put out the planned checklist to see any feedback on my plan to get this brake system back on Jeep and bleed correctly. Welcome any feedback.

For reference, starting point as of today is the Jeep with a board between the driver seat and brake pedal to keep fluid in the master before the system was opened (thanks @mrblaine again). All soft lines and calipers are already removed. Old hard brake lines are still on the Jeep and have been open for 3+ months. Next step is to remove the old hard lines and paint frame, then start the below.

If there's interest, I'll take the below, feedback, and a bunch of pics and create a How-To after I complete this part of the project. Let me know.

—-

New Parts Install & Bench Bleed Master

1. Install Hard Lines
   • Except from Proportioning Valve to Master Cylinder
2. Install Calipers, Rotors, & Pads
   • Be sure bleeding screws are on top
3. Install Soft Lines
4. Remove Brake Pedal pressure holder (piece of wood pressed against seat and pedal before when system was originally opened)
5. Bench Bleed Master Cylinder
   1. Using bench bleeding kit (Dorman 14151), put little sheet metal screws in the holes where the hoses attach to seal the plugs
   2. Remove hard lines from Master Cylinder
   3. Install sealed plugs into Master Cylinder
   4. Remove Master Cylinder from Jeep
   5. Mount in bench vice
   6. Remove old brake fluid from Master Cylinder reservoir with turkey baster and fill with fresh fluid
   7. Loosen the Rear plug(closest to the plunger), push in the plunger, hold, tighten plug
      • Don't use a sharp tool to push master cylinder (no Philips screwdriver)
   8. Repeat Step 7 until fluid has filled the bore
   9. Loosen the Front plug (furthest to the plunger), push in the plunger, hold, tighten plug
   10. Repeat Step 9 until fluid has filled the bore
   11. Stroke the push rod until it only goes in 1/8" or so (The master is fully bench bled, the plunger will move in roughly 1/8" or so)
6. Reinstall Master Cylinder in Jeep
7. Remove sealed plugs from Master Cylinder
8. Connect hard lines lines from Proportioning Valve to Master Cylinder
   • Expect brake fluid to seep from Master Cylinder. This keeps air from entering Master Cylinder

Gravity Bleed

1. Attach Gravity Bleed Kit (OEMTOOLS 25036) clear line to Right RearCaliper bleeding screw.
   • Mount the magnetic container above the level of the Master Cylinder reservoir
   • Tubing size note: 3/16" I/D and 1/4" I/D will cover most vehicles
2. Open Right Rearbleeder valve
   • Use a 6-point box end wrench on valve
3. Monitor Master Cylinder reservoir fluid Level - DO NOT let it run dry
4. Once fluid appears in gravity bleed clear line, close the bleeder valve
5. Repeat steps 1-4 for Left Rear caliper
6. Repeat Steps 1-4 for Front Right caliper
7. Repeat Steps 1-4 for Front Left caliper

Bleeding Brakes

1. Ask Wife to help in driver seat
2. Start at Right Rear Caliper
3. Attach clear line to bleeder valve. Put it leading to a collection bottle but doesn't necessarily need to be submerged.
4. Open bleeder valve
5. Tell Wife to push pedal to the floor hard and fast
   • Watch for air bubbles leaving caliper
6. Close bleeder valve
7. Tell Wife to let pedal up
8. Repeat steps 3-6 until no air bubble remain
   • If it needs more than 5-7 bleeds per corner, stop and find the problem because flushing more fluid down the drain isn't going to fix the problem.
   • Monitor Master Cylinder reservoir fluid Level - DO NOT let it run dry
9. Repeat steps 3-8 for Left Rear caliper
10. Repeat Steps 3-8 for Front Right caliper
11. Repeat Steps 3-8 for Front Left caliper
12. Let the system sit for 4+ hours (overnight is better), then repeat steps 1-11

 

[rustygastank]

Nice I’ve been thinking of doing this because all my lines are looking a little ruff. I really want to replace the lines that are attached to my axles

 

[RobertJ]

I like to reverse pressure bleed a new system, and if the peddle is a little spongy after that I'll gravity bleed to finish it off. Works every time.

 

[MarkH]

Can you confirm the instructions for Gravity Bleed?

• Mount the magnetic container above the level of the Master Cylinder reservoir

Shouldn't this be below for gravity bleed to work?