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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: Chipmunk Breath on November 07, 2025, 03:49:19 AM

Title: Front brake spungy
Post by: Chipmunk Breath on November 07, 2025, 03:49:19 AM
Hey all— my '84 1100 has a spongy front break lever pull. I replaced the master cylinder with new, bled both sides free of any bubbles however the pull just won't totally firm up. The lever pulls nearly to the grip. Brake pads have almost new thickness. I have not done anything with the calipers at this point. When I pull the lever though I do hear a mechanical sound coming from both of them. What am I missing?
Title: Re: Front brake spungy
Post by: Motofun on November 07, 2025, 06:26:11 AM
Is the replacement master an OEM or aftermarket?  Different cylinder diameters will affect the required stroke length.  Are the brake lines still the original squishy rubber lines?
Title: Re: Front brake spungy
Post by: red on November 07, 2025, 11:15:06 AM
Chip,
These days, you can get banjo bleeder bolts, which install at the top of the hydraulic lines, next to the master cylinders. Banjo bleeder bolts cost about US$ 25.00 each at the right MC shops, and twice that at the wrong shops.  That new bleeder makes a real difference in hydraulic line bleeding. Use all new hydraulic washers, any time you disconnect hydraulic lines.
You can remove the last air from the line(s) if you tie the hand lever(s) tightly back to the handgrip overnight.
Title: Re: Front brake spungy
Post by: Pat Conlon on November 07, 2025, 11:55:47 AM
Still have those 42 year old rubber brake lines?
Title: Re: Front brake spungy
Post by: Sparky84 on November 07, 2025, 03:49:53 PM
As suggested, tie that lever back and it seems there is still air in there somewhere.

More bleeding, more and more.
Jiggle that lever, don't pull it all the way it but just giving it multiple jiggles (and you are only just moving it a touch).
Perseverance is the key Chip  :good:

You are using new fluid ?