Results 1 to 10 of 10
  1. #1
    CB750 Member fg1972's Avatar
    Join Date
    May 2019
    Location
    Australia
    Posts
    11

    Brake master cylinder, rebuild or replace?

    Hello again,
    My front was a bit blocked up with crud but managed to get it free with compressed air up the line and working enough to allow me to remove all the pistons from the calipers. Now that Iíve fully dismantled the master cylinder, I could easily clean it up in a sand blaster then buy a new rebuild kit and new reservoir as mine is a translucent white plastic one that has deteriorated somewhat. The cost of the rebuild kit and reservoir is about triple the cost of buying a new aftermarket complete front brake unit. What are peopleís thoughts on those aftermarket units from China? My rear also doesnít work so Iíll be probably looking at a similar challenge when I get to that.

  2. #2
    CB750 Enthusiast NicksHonda's Avatar
    Join Date
    Apr 2018
    Location
    Sacramento, CA
    Posts
    45
    I wouldn't sand blast it. I imagine you won't get ALL the sand out, but maybe.
    I went with an aftermarket master cylinder. So far so good. I know, it's not original, but mine isn't going to be in any concourse, nor will it be a collector as it isn't now.
    Havin' Fun in Sacramento!

    2006 BMW R1200RT
    1979 Honda CB750L

  3. #3
    CB750 Addict pidjones's Avatar
    Join Date
    Sep 2018
    Location
    East TN
    Posts
    275
    I've used Chinabay MCs, and found that they must be disassembled, cleaned thoroughly, and reassembled properly with brake fluid lubing the assembly. Don't be surprised at the stuff that comes out when you clean.
    "Love 'em all.... Let GOD sort 'em out!"

  4. #4
    CB750 Member mitchi's Avatar
    Join Date
    Feb 2014
    Location
    Georgia
    Posts
    20
    My thoughts zactly................!!!

    I'm intending on ordering after market MC in a bit, cause both of my fours front brakes are locking up.

    I've rebuilt the calipers, but no the MCs.
    "If it ain't raining, I'm riding"

  5. #5
    CB750 Member mroussetos's Avatar
    Join Date
    May 2018
    Location
    Toronto, Ontario
    Posts
    15
    Was it hard to rebuild the calipers? What tools do i need? Thanks
    Save lives. Shoulder check!

  6. #6
    CB750 Member Bloody Mary's Avatar
    Join Date
    Nov 2019
    Location
    Western PA
    Posts
    28
    I rebuilt calipers on my '81 Custom...hardest thing was getting the pistons out. A breeze after that.

  7. #7
    CB750 Member Never2Old's Avatar
    Join Date
    Jun 2020
    Location
    Connecticut
    Posts
    6
    How did you get the piston out? Mine is frozen pretty good, been sitting for many years.I'm soaking it in PB Blaster, not sure what else to do. If I get my master cylinder rebuilt I'll try using the brake itself to move the piston.

    DC

  8. #8
    CB750 Guru amc49's Avatar
    Join Date
    Sep 2015
    Location
    Fort Worth TX.
    Posts
    3,006
    Rig a grease gun fitting to caliper and use the gun to remove the piston. Will remove ones the M/C won't touch.

    Have a care about it, at 5000 psi the grease gun will remove fingers if you get them in the wrong place at the wrong time.

  9. #9
    CB750 Addict Medyo Bastos's Avatar
    Join Date
    Oct 2012
    Location
    Mid South
    Posts
    191
    Quote Originally Posted by amc49 View Post
    Rig a grease gun fitting to caliper and use the gun to remove the piston. Will remove ones the M/C won't touch.

    Have a care about it, at 5000 psi the grease gun will remove fingers if you get them in the wrong place at the wrong time.
    Ditto, you can even scoop the grease back into a can and reuse!


    Sent from my iPhone using Tapatalk

  10. #10
    CB750 Member Bloody Mary's Avatar
    Join Date
    Nov 2019
    Location
    Western PA
    Posts
    28
    The '81 had two calipers. One came out by using my small tire inflator forcing air into the fitting. Wouldn't work on the other one. Used a larger compressor the same way...blew it right out easily.

Similar Threads

  1. Wanted - 77-78 Cb750 front brake master cylinder assembly
    By 77CB750 in forum Classifieds
    Replies: 3
    Last Post: 08-25-2017, 06:17 AM
  2. Replacement Brake Lever - Nissin master cylinder
    By ethanf in forum The CB750 Garage
    Replies: 3
    Last Post: 12-10-2015, 02:08 PM
  3. 1973 CB750 disk brake master cylinder
    By pdcarpen in forum The CB750 Garage
    Replies: 0
    Last Post: 11-27-2013, 11:31 AM
  4. 71 K1 master cylinder rebuild
    By Vicman in forum The CB750 Garage
    Replies: 16
    Last Post: 10-07-2013, 08:44 PM
  5. master cylinder rebuild
    By Clint in forum The CB750 Garage
    Replies: 1
    Last Post: 01-12-2013, 10:06 PM

Posting Permissions

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