Replaced lines and rebuilt calipers, still spongy

[pnedac]

Hi gang,


I am at a loss on this 80 GS750E. I rebuilt the calipers completely, replaced all the brake lines with SS, bled until there was no air bubbles, but they are still stupid spongy up front. The back brake finally come around when I replaced the line, and is now working about 90%(vast improvement).

The only part left that has not been replaced is the master. It is the original. What would a master rebuild kit do? I am just curious about whether I should go that route or just replace the whole master cylinder with a new one.

Any ideas?

Any help is greatly appreciated.

Pnedac

[Agemax]

put a new seal kit in the M/C. if it is original then it will be old and tired, and probably wont be able to provide the pressure needed to cope with the rest of the rebuilt system.

many kits are available but most members here will tell you to use genuine Suzuki kits only.
i, however have had success with the cheaper aftermarket kits. the choice is yours.

[LarryJ]

vacuum bleed well, with a mitey mite type pump too.

[pnedac]

Good looking out guys thank you. I will look into the rebuild kit.

Cheers

[eil]

Yes, ditto on the Suzuki OEM kit. It's typically called a piston and cup set on the fiche.

If you have a mitey mite style pump, it makes bleeding so much easier. But I was able to vacuum bleed quite successfully with a large $1 disposable medical syringe: http://www.thegsresources.com/_forum...d.php?t=205846