Out of storage spring 2022/No front brake and solution

[ssevy]

Upstate NY has been very reluctant about closing the door on winter and letting the warmer days return, but following a sunny hike with my wife around the Saratoga Battlefield today, I got that urge to get the bikes out.
The tiger cranked about 5 seconds before starting right up and running smoothly, but the front brake lever moved all the way to the grip, and pumping it did nothing to improve it.
I am going to go diagnose it now, and I'll post whatever I find. For you folks guessing or betting: no, there was no fluid on the floor of the storage unit, and yes, fluid is visible through the master cylinder sight glass. My money is on the rubber seal on the plunger.
If you have read my cross-country trip report from last spring, you may find it as ironic as I that my rear brake was the working brake and the front brake was the dud

[ssevy]

I opened each front bleeder and pumped the lever, and got nice clean fluid with no bubbles.
Still no lever when I closed them back up.
Going to pursue it tomorrow.


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[Nick Calne]

Good luck with it. Maybe start with a full replacement of fluid by volume. It is cheap and braking is kinda useful

[ssevy]

I bled the system and replaced the fluid with new Amsoil Dot 4. Last season I had put in new Motul brake fluid before my cross country trip, as it had great temperature ratings and reviews. Expensive stuff!
Anyways, the Amsoil fluid restored the brakes back to top form, and I think I will just stick with it from now on, as I never had any issues with it in the past.
I'm not sure if the Motul fluid didn't like the cold storage season, or if it was worn out after the cross country trip, as I had no issues prior to putting the bike up for the winter?
The Motul fluid I took out looked clean and perfect, with no signs of water or air bubbles, so I guess it is a good reminder that changing out the brake fluid every season is a good practice, and one which I do every spring regardless.
I modified the thread title to help someone in the future who may be searching for this same issue.

[Nick Calne]

Good news! Maybe pencil in a caliper overhaul for next spring. I did mine a year or so ago and realised I hadn't done it for many years.

[ssevy]

Hi Nick
They were all rebuilt last spring prior to my trip.


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[Sin_Tiger]

Master cylinder seals 

[ssevy]

I wrapped a velcro strap around the lever and left it for a week or better. If the seal was bad, I am assuming I should have found the lever bottomed out from fluid bypassing and leaking out the piston shaft, which I did not. After being left like this, any air must have worked its way to the top, as the lever is now very firm and solid. I never would have believed that changing perfectly clean looking fluid could have resolved this, but it did, and I am back to my usual Amsoil and no more super expensive Motul.

[Lee337]

Generally do the same thing when I do any work on the front brake, pull the lever & tie it back for 12 hours. Always feels much firmer. Done it with the Tiger & Trophy as well as the 'Spares n repair' tiger I had.

Wouldn't have believed it until I tried it myself.

[Sin_Tiger]

I've seen them hold OK when the pressure forces the seal tight but be poor until you build pressure. Perhaps changing the fluid was enough to flush something out, glad it worked though.

9 times out of 10 I've found the tiny vent hole in the bore to be blocked, it blocks easily and can get forgotten about.

[Beernard]

Hi All,
Bleeding brakes is a bleeding issue (as in bleeding obvious, bleeding coitwrecker, etc). Forgive me, Friday night, long weekend. I have resurrected some hydraulic front brake issues (including Tiger, Trophy, CB 750). It has not always worked, otherwise I would retire on the sales! Rats. On all my hydraulic front brake and clutch setups, I have arrived with this:
- Do the usual (fluid, pump it up until you can feel it, be disappointed, go nuts for a while, drink more piss, go to bed because the missus can't bear your frustration). When I wake up and check the missus is still somewhere on the precinct, I do this:
- unbolt the master cylinder
- think about how bubbles rise with gravity
- hold the cylinder in one hand and rotate it to the point you think the air may rise into the cylinder and be expunged (be very creative here)
- press the lever (again be very creative here. Turn it, wriggle it , talk to the shaman, put it down and have a beer) My experience is that those little bubbles that cause the problem seem to move a little bit slow. Press the lever many times
- do this for a while
- bolt the cylinder back on
- is it better?
- if not, write me a nasty letter @Brakephopia.com
Just trying to help here. I do this with all mine. Saved some, no effect on others.
PS I once drilled out the entry into the master cylinder (because it looked small and may have been an air trap). Gave me a useable brake on my CB750.
Bern (in good faith)

[Sin_Tiger]

Are you sure the beer bubbles haven't migrated 

[Beernard]

Thanks Sin. Now there's a thought. Beer instead of brake fluid. You know, we had a TV show over here called Bush Mechanics. They swore by washing machine liquid when in a spot, so maybe anything's possible. All the best.

[Madruss]

After replacing the seals & oil in the forks, then re installing the whole front end, some months before, I hadn't touched the brakes till yesterday.
The lever went straight to the bar, so I did a 3 stroke bleed of the lever on each caliper before I attempted remove it. Lever pressure was regained 60%, so a complete fluid flush/bleed improved pressure markedly.
Historically brakes & fluid- I went to the Northern Territory Australia working in 1977 leaving my daily ride 1973 Candy jade Honda CB500/4 in the garage at home.
Some months later on a phone call home Dad informed me he couldn't move the bike as the front brake was "locked"
A bleed of the caliper solved that. A girl I met up north had a mini which had the same issue.
So the moral of story, "change your brake fluid regularly"