Page 1 of 2 12 LastLast
Results 1 to 15 of 17

Thread: AW11 Spongey brakes after new MC and multiple bleeds

  1. #1
    Original Trendsetter Chief Engine Builder Harreh's Avatar
    Join Date
    Jul 2008
    Location
    NSW
    Posts
    3,234

    Default AW11 Spongey brakes after new MC and multiple bleeds

    I've upgraded to the hilux master cylinder in my AW11 as I couldnt get the original unit new, vito and I have done multiple bleeds on the system but it is still feeling very spongey. Front calipers have been rebuilt, MC has been bled using the procedure in the BGB and we've gone through over a litre of fluid. There are no leaks anywhere in the system.

    The brakes also arent firming up with pumps either. So it doesnt appear there is air in the line

    Any idea why this would occur??

    AW11 Turbo build

    1UZ Soarer Turbo build
    Imitation is the most sincere form of flattery

  2. #2
    dont work in my backyard Domestic Engineer pandaah's Avatar
    Join Date
    Aug 2009
    Location
    WA
    Posts
    648

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    how far are you letting the pedal travel when the bleeder is cracked, if you let the pedal go all the way to the floor youve probly let the piston go to the back of the master cylinder and hit abit of crusty shit and its fucked the seal..

    im assuming the master cylinder is second hand?.. cos it sounds like thats where your problem lies

  3. #3
    Original Trendsetter Chief Engine Builder Harreh's Avatar
    Join Date
    Jul 2008
    Location
    NSW
    Posts
    3,234

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    Nope, the master cylinder is brand spanking new

    AW11 Turbo build

    1UZ Soarer Turbo build
    Imitation is the most sincere form of flattery

  4. #4
    dont work in my backyard Domestic Engineer pandaah's Avatar
    Join Date
    Aug 2009
    Location
    WA
    Posts
    648

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    hm pritty strange.. and you say theres definetly no leaks?.. have you tried cracking all the bleeders, letting them drip for 10mins and locking them up?.. thats how i usually bleed brakes on my own..

    have you upgraded anything else?, disc brakes front and rear?

  5. #5
    Original Trendsetter Chief Engine Builder Harreh's Avatar
    Join Date
    Jul 2008
    Location
    NSW
    Posts
    3,234

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    I've had a mate here help me bleed, nothing else upgraded, all 4 wheels are discs from factory, definately no leaks, checked it multiple times.

    Just drove it again after another full bleed and rebleed of master. It still feels odd, theres an entire range of nothingness in the pedal followed by good braking. No amount of pumping fixes it though

    AW11 Turbo build

    1UZ Soarer Turbo build
    Imitation is the most sincere form of flattery

  6. #6
    dont work in my backyard Domestic Engineer pandaah's Avatar
    Join Date
    Aug 2009
    Location
    WA
    Posts
    648

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    Ahh i see, so really its not spongy its like the piston in the master cylinder needs to be pushed in further for it to operate properly, you could try getting under the pedal and adjusting the rod so its longer so when you first initially push on the brake pedal it actives the booster/mc earlier

    otherwise maybe the pin the the aw11 booster isnt as long as the hilux booster you got the mc from

  7. #7
    Original Trendsetter Chief Engine Builder Harreh's Avatar
    Join Date
    Jul 2008
    Location
    NSW
    Posts
    3,234

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    Cheers mate, that was I thinking, the pedal freeplay however is within BGB spec. I think I might give it a go anyway.

    You're thinking along the same lines a me and Vito though

    AW11 Turbo build

    1UZ Soarer Turbo build
    Imitation is the most sincere form of flattery

  8. #8
    dont work in my backyard Domestic Engineer pandaah's Avatar
    Join Date
    Aug 2009
    Location
    WA
    Posts
    648

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    Maybe jus try give it abit more length as a little length will be multiplied by the pivot in the pedal

    worse case scenario you can get your booster rebuilt and they can change over the pins, hope thats helps let us all know how you go

  9. #9
    Original Trendsetter Chief Engine Builder Harreh's Avatar
    Join Date
    Jul 2008
    Location
    NSW
    Posts
    3,234

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    Cheers mate, going to my mechanic tomorrow who's doing my suspension setup, I'll get him to take a look

    AW11 Turbo build

    1UZ Soarer Turbo build
    Imitation is the most sincere form of flattery

  10. #10
    Original Trendsetter Chief Engine Builder Harreh's Avatar
    Join Date
    Jul 2008
    Location
    NSW
    Posts
    3,234

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    Winding out the adjuster has made a considerable difference, however its still a bit odd, it was also pretty much already at the end of its adjustment. Going to my mechanic tomorrow, plus braided lines and new rear pads soon so lets see what kinda difference it makes then.

    Thanks Pandaah
    Last edited by Harreh; 29-08-2010 at 11:19 PM.

    AW11 Turbo build

    1UZ Soarer Turbo build
    Imitation is the most sincere form of flattery

  11. #11
    Junior Member Too Much Toyota
    Join Date
    Sep 2005
    Location
    Qld
    Posts
    5,590

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    just a thought - did you assemble the MC? could be that the spring in the centre section is not right or something else is backwards/munted.

    Also - suggest you get mate to slowly push on pedal while you closely look at each wheel cyl seeing how the calipers tighten up. Might identify whether they're all closing up at the same rate (which would help identify possible MC or piping issues. Careful observation of brake lines at same time will help in diagnosis.
    ------------------------------
    ST185 road barge / MZ11 forest barge / RA65 garage barge

  12. #12
    Blasphemist Chief Engine Builder Bananaman's Avatar
    Join Date
    Dec 2005
    Location
    VIC
    Posts
    3,026

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    Repeat bleeding process with one man bleeding kit instead of vito ?

    I've only ever experienced what you describe with faulty MC's, so would be nice to think that isn't the case here. Is hilux MC into AW11 a done thing? Ask someone who's done it if they had to do anything tricky?
    KE20 CA18DET / RN25 12R / IS200 1G / NA MX5 B6

  13. #13
    Junior Member Too Much Toyota
    Join Date
    Sep 2005
    Location
    Qld
    Posts
    5,590

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    a drum-brake MC may not have (or have different) reverse-flow restrictors - they stop the slave pistons from retracting too far as the brake pads wear down. I vaguely recall a discussion about this in the context of rebuilding MA61 MCs.
    ------------------------------
    ST185 road barge / MZ11 forest barge / RA65 garage barge

  14. #14
    Toymods Events Secretary Too Much Toyota trdee's Avatar
    Join Date
    Jul 2007
    Location
    NSW
    Posts
    10,243

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    do the hiluxes have drum brake rears?

    yeah it was very weird. it didnt feel like there was air in it, more that the master cylinder wasnt actuating till you pushed the pedal about halfway down.

    bardin; it's fairly common for those who do brake upgrades on the adub to also upgrade the master cylinder to the hilux unit
    1988 AW11 9A-GTE - Turbo Missile | 2004 Elise K20A - N/A Screamer | 1984 MA61 1JZ-GTE - 80s cruiser
    Quote Originally Posted by Rex_Kelway View Post
    .....and the within first laps everything that made the AW11 great hit Rex as if the 'Gods of driving fun' had all Jizzed on his face.....
    Quote Originally Posted by JustenGT8 View Post
    Mono blocs mate....as close to yours as a Ferrari is to a Fiesta

  15. #15
    dont work in my backyard Domestic Engineer pandaah's Avatar
    Join Date
    Aug 2009
    Location
    WA
    Posts
    648

    Default Re: AW11 Spongey brakes after new MC and multiple bleeds

    yes.. most hiluxs ive seen have drum brake rear ends..

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •