spongie brake lever....air or hose swelling?

[RJ2112]

You should be able to take a straight edge and lay it on the face of the rotor, and see if there is a gap. The straight edge will only be able to check maybe 1/3 of the rotor at a time, with the wheel still on the bike. Have someone take the weight off the front wheel, and move it 1/3 of the way around and check again, until you have looked at the whole disc, on both front rotors. You may need to use a flash light shining behind the straight edge to see the gap.

If could also be a master cylinder problem.... but let's eliminate one thing at a time to be sure we have it finished.

 

[gusss]

last night I left the reservoir open, and put a zip tie to the lever...
This morning things felt better, but it's still spongie...
I also brought the calipers off and cleaned pads and discs with air and isopropilic alcohol!!!
I also tryed testing for a bent rotor, and they look 100% straight

I still feel the boing boing at the lever..

 

[gusss]

I even moved the lever and reservoir about 1cm to the left...
I have to press very hard to brake, my hand hurts already...


This past anoying already and is now a safety issue

 

[RJ2112]

I even moved the lever and reservoir about 1cm to the left...
I have to press very hard to brake, my hand hurts already...


This past anoying already and is now a safety issue

If the rotors are both straight and true.... it's probably the master cylinder. The O rings that seal the piston to the master cylinder bore are the next most likely culprit.

 

[gusss]

If the rotors are both straight and true.... it's probably the master cylinder. The O rings that seal the piston to the master cylinder bore are the next most likely culprit.

I can probably find someone to lend me another master cyclinder from another bike a susuki bandit... Do you think I should do this before trying any replacements?

 

[RJ2112]

I think that is a very good idea.

Another question has occurred to me..... what type of brake fluid did you use when you serviced the system? DOT 3, DOT 4, or DOT 5?

 

[gusss]

I think that is a very good idea.

Another question has occurred to me..... what type of brake fluid did you use when you serviced the system? DOT 3, DOT 4, or DOT 5?

dot 4......

lastly dot 5, for one day, and then came home and put dot 4 again.
so dot 4 in there as we speak.

I was checking out the manual for the master cylinder inspection...
Is it easy to inspect the O-rings ?? Is it easy to pull everything out of there without damaging something?

 

[RJ2112]

dot 4......

lastly dot 5, for one day, and then came home and put dot 4 again.
so dot 4 in there as we speak.

I was checking out the manual for the master cylinder inspection...
Is it easy to inspect the O-rings ?? Is it easy to pull everything out of there without damaging something?

This might be part of where the problem is coming from..... someone else will confirm; but the last time I checked, DOT 5 is a different chemical composition from DOT 3 and 4. They are not compatible, and will decompose.

When you went back to DOT4 from the one day of DOT5..... did you flush everything out completely?

As far as inspecting the O rings, it's tough to tell if anything is wrong with them..... remove and replace. You want to shine a light into the master cylinder bore to inspect for corrosion or pitting, or any sort of rough surface. The size of debris that can defeat the O ring is incredibly small.... a grain of sand is plenty big enough.

 

[gusss]

This might be part of where the problem is coming from..... someone else will confirm; but the last time I checked, DOT 5 is a different chemical composition from DOT 3 and 4. They are not compatible, and will decompose.

When you went back to DOT4 from the one day of DOT5..... did you flush everything out completely?

As far as inspecting the O rings, it's tough to tell if anything is wrong with them..... remove and replace. You want to shine a light into the master cylinder bore to inspect for corrosion or pitting, or any sort of rough surface. The size of debris that can defeat the O ring is incredibly small.... a grain of sand is plenty big enough.

sorry for the confusion ... It was dot 5.1
thanks

 

[TownsendsFJR1300]

You don't want to mix DOT 4 with DOT 5.

I would buy/borrow a Mity Vac brake bleeder and try that first. If air is trapping in the "T", un-bolt it so you can manueauver it into different positions when bleeding and get any possible bubbles out of that section... I have found also when bleeding to move the lever in and out (doing nothing else) and you will sometimes see air bubbles come out of the hole in the bottom of the master cyclinder(especially if you got the entire system dry).

If you have any inclination towards braided SS lines, now is the time to put them on as most have two single lines that run directly up to the master cylinder. It is considerably easier to bleed those.

My FZ with HEL SS lines are hard when pulling 3/4 of an inch in (outter edge of the brake lever), solid at 1".... The brakes work considerably better with these lines.....

 

[gusss]

You don't want to mix DOT 4 with DOT 5.

I would buy/borrow a Mity Vac brake bleeder and try that first. If air is trapping in the "T", un-bolt it so you can manueauver it into different positions when bleeding and get any possible bubbles out of that section... I have found also when bleeding to move the lever in and out (doing nothing else) and you will sometimes see air bubbles come out of the hole in the bottom of the master cyclinder(especially if you got the entire system dry).

If you have any inclination towards braided SS lines, now is the time to put them on as most have two single lines that run directly up to the master cylinder. It is considerably easier to bleed those.

My FZ with HEL SS lines are hard when pulling 3/4 of an inch in (outter edge of the brake lever), solid at 1".... The brakes work considerably better with these lines.....

I will go with braided lines, just after I fix my problem...

I have already un-bolt the T and the caliper, in order to eliminat the U on top of the fender...I did this for 15 minutes, but I'll be doing this again but instead I'll leave it over night!!!

Thanks

 

[RJ2112]

Gusss,

I have to ask, when you removed the 5.1 and replaced it with DOT 4, did you thoroughly flush all of the 5.1 out of the calipers, lines and master cylinder?

The seals and gaskets are what will deteriorate.... this used to be a big deal with old English sports cars, too. The brake fluid used in England was not the same as most of the rest of the world.

The second question: what are the characteristics of the spongey lever?
1) Does it always have resistance, and you can overcome that to squeeze the lever towards the bar? (that would be the flex of the rubber lines, and will be 'cured' with SS lines.)
2) What happens when you rapidly 'pump' the lever? Does the lever gain resistance, and become firm, farther and farther from the grip? (that would indicate air trapped in the line.... you can compress the air by pumping the lever) We're talking about pumping the lever 3 or 4 times per second, until it's stiff.
3) If the lever works 'normally' SOME of the time, and then loses pressure occasionally, it's not either of those things. (I believe this is the scenario we are trying to solve, right?)

 

[gusss]

I left all night the caliper hanging....
This morning, nothing improved!

I did flush all the 5.1 out even with the pistons in to make sure everything was replaced.

1) it always have resistance, but a resistance from the begining of the pull, it's a boing boing resistance, and not a stiff lock and then a resistance .... As in other disc brake bikes.
2) When pumping lever nothing happens, just boing boing boing.
3) it is not loosing pressure, I just have a spongie lever a predictible one...
And if I want to make a stoppie I probalbly have to use 4 fingers (that hard)!

 

[Rumpole of the Bailey]

Our bikes are designed to travel fast and consequently, we have the best brakes around. My manual says to have the brake callipers serviced by Yamaha every 2 years. Ok, I can change pads and change fluid. I have rebuilt callipers on my car but when it comes to my bike that sometimes does 180kph, Yamaha are doing the brakes.
The back brake won't save you.

Youyr issue is in the front callipers and the little stainless steel cylinders and pistons that have o rings that work so my brakes feel hard, not spongy.
This isn't rocket science.
Head to Yamaha, and I would take the bike there on a trailer, it isn't roadworthy.

ps, riding in the rain, on roads with grit (roadworks) etc can cause small amounts of silt to enter your callipers and damage the brakes.

Your barakes are faulty.
Cheers,
Rumpole

 

[TownsendsFJR1300]

If he pulled all 4 pistons from each caliber to clean them out, he was looking at the seals and dust seals (and thus can replace them himself). And yes, they do recommend seal and line replacement every two years. Yamaha includes a packet of brake grease (pink) for the pistons/seals for re-assembly as well.

I agree, there is a problem, either air in the system or the master cylinder is failing/failed. I wouldn't ride it either with it the way it is currently.

Being there's little to no pressure, I'd pull the front brake master cylinder and make sure its clean and the o-rings look ok and not flattened. Blow out the passages too.

As stated earlier, I'd invest in a Mity Vac and bleed them with that. It would be considerably easier and cheaper than a trip to the shop..

The aftermarket, SS dual lines are also easier to bleed.

 

[RJ2112]

I left all night the caliper hanging....
This morning, nothing improved!

I did flush all the 5.1 out even with the pistons in to make sure everything was replaced.

1) it always have resistance, but a resistance from the begining of the pull, it's a boing boing resistance, and not a stiff lock and then a resistance .... As in other disc brake bikes.
2) When pumping lever nothing happens, just boing boing boing.
3) it is not loosing pressure, I just have a spongie lever a predictible one...
And if I want to make a stoppie I probalbly have to use 4 fingers (that hard)!

The fact that you can indeed lock the front hard enough to do a stoppie even in this condition probably means your system still has a seal.... what position do you have the lever adjuster at on the brake lever?

The little chrome wheel with the 1 2 3 or 4 on it.... which setting do you have it on?

If you feel resistance right from the start of the lever 'pull', but it doesn't change when you rapidly cycle the lever.... it doesn't sound to me like you have air in the line. If the lever travel does not change when you get the brakes hot (brake fade will make the lever get closer and closer to the grip).... you probably don't have air in the lines.

When I grabbed the brake lever (standing still) and squeezed with all my might, I could feel resistance almost as soon as I started squeezing... and I could force the lever 2/3 to 3/4 of the way to the grip. This was with the little chrome wheel set on 3 or 4 as I recall.

The predictable 'squeeze' I think you are describing, sounds to me like the brake lines expanding. (boing boing)

The stainless steel (or any other jacket material) stiffens the hoses so they cannot expand anywhere near as much. Squeeze with all your might, and that lever isn't going to go more than 1/10 back from where you meet resistance. FJR is right..... this will be a much easier set up to bleed, and has much more consistent 'feel'.

I think it would be wise to ask the shop to inspect your brakes for you, so they can tell you first hand what is wrong.

 

[gusss]

The fact that you can indeed lock the front hard enough to do a stoppie even in this condition probably means your system still has a seal.... what position do you have the lever adjuster at on the brake lever?

The little chrome wheel with the 1 2 3 or 4 on it.... which setting do you have it on?

If you feel resistance right from the start of the lever 'pull', but it doesn't change when you rapidly cycle the lever.... it doesn't sound to me like you have air in the line. If the lever travel does not change when you get the brakes hot (brake fade will make the lever get closer and closer to the grip).... you probably don't have air in the lines.

When I grabbed the brake lever (standing still) and squeezed with all my might, I could feel resistance almost as soon as I started squeezing... and I could force the lever 2/3 to 3/4 of the way to the grip. This was with the little chrome wheel set on 3 or 4 as I recall.

The predictable 'squeeze' I think you are describing, sounds to me like the brake lines expanding. (boing boing)

The stainless steel (or any other jacket material) stiffens the hoses so they cannot expand anywhere near as much. Squeeze with all your might, and that lever isn't going to go more than 1/10 back from where you meet resistance. FJR is right..... this will be a much easier set up to bleed, and has much more consistent 'feel'.

I think it would be wise to ask the shop to inspect your brakes for you, so they can tell you first hand what is wrong.

I used to use the lever at position 5 (I have short fingers)
Now I have to use it at 4, and if I pull it with all my might, since I don't have a resistance, since the lever is spongie from the begining...I can pull it all the way to the grip, even if I put it in position 1
I wish I had a some kind of stiff! But instead I just get some kind of feel (like air).

I'll try with another master cylinder......
I'll post as soon as possible...

here is the pic of the right caliper hanging, in order to eliminate de U, and making bubbles go up if any....overnight.... no good.... no air.....

 

[gusss]

I used to use the lever at position 5 (I have short fingers)
Now I have to use it at 4, and if I pull it with all my might, since I don't have a resistance, since the lever is spongie from the begining...I can pull it all the way to the grip, even if I put it in position 1
I wish I had a some kind of stiff! But instead I just get some kind of feel (like air).

I'll try with another master cylinder......
I'll post as soon as possible...

here is the pic of the right caliper hanging, in order to eliminate de U, and making bubbles go up if any....overnight.... no good.... no air.....

I think I'm getting you confused...because of my english...
I never have that resistance or stiff lever, as in other bikes.
When I pull the lever, it feels just like the one on a cable brake bike...or just like a bicycle's front or rear brake....
When you pull the lever on your fz6, the lever stops at a certain point and you probably feel that if you keep on pulling you'll probably break the lever...
I just have a spongie feel froom the begining of pulling, and I never get that stiff, lock, stop at a certain point....
It seems like air, but I have bled my brakes probably 5 or 6 times already..
I have done this on cars and other motorcycles as well....This is not my first time.....
I'll try to disaseble my master cylinder to see what's up with the O.rings....
just going nuts here!!!

 

[gusss]

Here is a little video of my lever

[ame=http://www.youtube.com/watch?v=D8HcrRPIYdk]YouTube - MOV07163.MPG[/ame]

 

[RJ2112]

Gusss, You're right, written language is very easy to confuse.

I appreciate the video. That helped a lot. You don't have any effective braking from the master cylinder. Definitely bad.

Even grabbing the lever with all your fingers and squeezing with all your might, you should not be able to get the lever to the grip.

You probably have a compromised seal in the master cylinder.... if the problem was at the calipers, you would see a puddle of brake fluid there.

It's possible that there is a piece of grit or sand creating a gap that the brake fluid can flow through. Take the MC apart, clean everything, inspect the seals for any rough edges. Inspect the bore the master cylinder piston rides in for any pits or scratches.