# Brakes (FL) Won't Bleed after Repair **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [June 21, 2015, 3:27am UTC](https://community.cartalk.com/t/brakes-fl-wont-bleed-after-repair/90343 "2015-06-21T03:27:53Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [June 22, 2015, 5:09am UTC](https://community.cartalk.com/t/brakes-fl-wont-bleed-after-repair/90343/21 "2015-06-22T05:09:22Z")
@casper I’ll ask a more specific question . . . With the old master cylinder, did you have problems bleeding the right rear? And what method did you use? ---
**Author:** ![casper](https://avatars.discourse-cdn.com/v4/letter/c/b4bc9f/32.png) [@casper](https://community.cartalk.com/u/casper)\ **Post date:** [June 22, 2015, 5:20am UTC](https://community.cartalk.com/t/brakes-fl-wont-bleed-after-repair/90343/22 "2015-06-22T05:20:38Z")
Yes… The right rear had the same symptoms as the front left. I was concentrating on the front which is why the “(FL)” is in the title. I believe the fluid flow is controlled/directed through the ABS module. ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [June 22, 2015, 5:47am UTC](https://community.cartalk.com/t/brakes-fl-wont-bleed-after-repair/90343/23 "2015-06-22T05:47:13Z")
@casper Thanks for that information Now I see what was going on ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [June 23, 2015, 4:30am UTC](https://community.cartalk.com/t/brakes-fl-wont-bleed-after-repair/90343/24 "2015-06-23T04:30:09Z")
It isn’t uncommon for an existing master cylinder to go haywire and need replacement due to a bleeding process. Think about what happens. All the time it has been in use the MC piston resided in a small portion of their available travel space inside the MC bore. Because it is locked there by the hydraulic pressure. But when you release the hydraulic pressure for a bleeding, the piston can then move freely in the bore. And when it does, it can encounter a burr in a portion of the bore it never traveled to before, which then damages the piston seal. That’s why some of the experts here recommend to use a pressure bleeder procedure rather than rely on the common DIY method of pushing on the brake pedal while tightening/untightening the bleeder screws. I 'm just a DIY and don’t have a pressure bleeder myself, so the compromise technique I use is to push on the brake pedal with my hand only so I can limit the amount of travel I allow for the brake pedal. So far this has worked for me well on my Corolla, original brake MC for over 20 years. ---
**Author:** ![AhLee\_Yong](https://avatars.discourse-cdn.com/v4/letter/a/b5a626/32.png) [@AhLee\_Yong](https://community.cartalk.com/u/AhLee_Yong)\ **Post date:** [March 31, 2018, 7:02pm UTC](https://community.cartalk.com/t/brakes-fl-wont-bleed-after-repair/90343/25 "2018-03-31T19:02:35Z")
Hi there, i know its been 3 years since this post active, i am facing the same issue with my Lancer Evo3 (righth-handed car) for FRONT LEFT caliper that wont give pressure if my keys in IGN position. if the key some what at OFF/ACC/START position, i can feel the MC piston is freely travel while i am bleeding the brakes. i notice just now while i am doing full swing pressing the pedal while my keys at ACC, still holding the pedal until i switch my keys to IGN an then i release the pedal, then i try to press it again, an i felt so hard to press, the MC pistons wont travel! by the way, i am by passing the FORNT LEFT caliper while doing this, meaning my caliper was on the floor just finished inspection (I suspected my caliper had jammed but not!), but i rather want to test the FRONT LEFT pressure line itself, so i put a transparent hose to it and dump it to the brake reservoir tank on the other end, it should press freely right? due to no restriction of fluid flowing,right? but i then found the ABS is locking/restrict the flow of the brake fluid while my keys at IGN position. if I put my key at the other position, i can press the brake pedal freely again. I disconnect the ABS harness at the ABS controller for now so that my car can be drive-able. i would do more harness inspection for my ABS system then, because i had replaced all item below; -Master Cylinder pump (OEM) -brake pistons (i have 4 piston, 2left, 2 right) -brake service kits (in my case, my service kits same with Mitsubishi pajeroV6/storm for front twinpot caliper) -brake fluid flushed (dot4) -brake bleeding all 4 FR/FL/RR/RL -ABS pump/controller -ALi Terengganu, Malaysia. [Previous page](https://community.cartalk.com/t/brakes-fl-wont-bleed-after-repair/90343.md?page=1)