Loss of braking in rain

[davidon]

Brakes work great in dry weather but if I hit a rain storm (just did) Brakes seem to drastically loose efficiency, can freely move lever about an inch before i get any resistance. Then there is only about 1/2 inch left until it hits the bars. Can't figure out why so drastic a change. Seems like it does not matter if fluid is new or not. Any other possible cause? Then after weather dries out (this happened last time) brakes go back to working fine.

 

[VMAX1260]

never heard of that before lol. braking system is a closed system . weather shouldnt effect it. you should check if your system has any air inside by bleeding it, also check that everything is bolt to place and you have no leaks.in a dry wheather empty slowly a bottle of water first in the brake master cylinder to see what happens. then go to the callipers and do the same thing to see if you can locate the begining of the problem

 

[Fire-medic]

What pads are you using? Gentle braking all the time will glaze your pads. Try removing the pads and roughing them w/some sandpaper. Do the same w/the rotors, see if that helps in the wet. Or move to CA, they don't get rain:biglaugh:

I would bleed the entire system/fully-change the fluid w/it from a new can, not one that's open already. Do you have aftermarket levers?

 

[davidon]

What pads are you using? Gentle braking all the time will glaze your pads. Try removing the pads and roughing them w/some sandpaper. Do the same w/the rotors, see if that helps in the wet. Or move to CA, they don't get rain:biglaugh:

I would bleed the entire system/fully-change the fluid w/it from a new can, not one that's open already. Do you have aftermarket levers?

I don't think it is pads. i have changed fluid from new bottles maybe i just have to do it more often than once a year. Yes aftermarket levers, lines, calipers

 

[MaxMidnight]

Changing the fluid won't make any difference as Mr VMax1260 suggests.

Given that the dry braking is OK then I'll assume that the calliper pistons are free.

Think about what the difference is between dry and wet braking...water.
The only place that the water will effect is the disc/ pad interface therefore this is the area that need to be considered.

Assuming that the discs are within the wear limit and are not badly grooved then the only other variable will be the disc pads.

Curious to know why you don't think they are the issue?

 

[PATMAX]

88? Are these solid discs then. I think drilled or wavys rotors will fix your problem if so.

 

[95spfldmax]

Changing the fluid won't make any difference as Mr VMax1260 suggests.

Given that the dry braking is OK then I'll assume that the calliper pistons are free.

Think about what the difference is between dry and wet braking...water.
The only place that the water will effect is the disc/ pad interface therefore this is the area that need to be considered.

Assuming that the discs are within the wear limit and are not badly grooved then the only other variable will be the disc pads.

Curious to know why you don't think they are the issue?

+1
Definitely a strange problem.....

 

[Hellboy]

I agree with Patmax. If they are the older solid disc then the braking effect when wet wouldn't be as good when wet. Maybe when it's dry they are gripping better with less input and then when wet you are just have to pull much harder to get the same response. I would/did Upgrade to ventilated disc.

 

[VMAX1260]

I agree with Patmax. If they are the older solid disc then the braking effect when wet wouldn't be as good when wet. Maybe when it's dry they are gripping better with less input and then when wet you are just have to pull much harder to get the same response. I would/did Upgrade to ventilated disc.

it hasnt to do with gripping. of course when wet it will be difference with gripping. he is talking about the distance of the brake lever. it almost stops to the handle bar.

 

[jfeagins]

Brakes work great in dry weather but if I hit a rain storm (just did) Brakes seem to drastically loose efficiency, can freely move lever about an inch before i get any resistance. Then there is only about 1/2 inch left until it hits the bars. Can't figure out why so drastic a change. Seems like it does not matter if fluid is new or not. Any other possible cause? Then after weather dries out (this happened last time) brakes go back to working fine.

How about this: check the condition of the rubber end seal of the master cylinder on the handlebar. Maybe water is getting into the end of where the spring is supposed to return, and interfering with spring travel differently when wet than when dry???????:confused2:

As cheap as the master rebuild kits are, I'd be getting one, and tearing that master apart to look for any signs of a problem.

 

[alorio1]

88? Are these solid discs then. I think drilled or wavys rotors will fix your problem if so.

+1 My 85 has always had brake fade when I ride in the rain, you also changed the brake levers to shorter I assume which changes the travel of the plunger of the master cylinder I would think.

 

[[email protected]]

Pretty sure he doesn't have the OEM calipers and rotors anymore :biglaugh:

Wish I had a good answer for you on this. I can't think of any good reason why the brake lever would go to the handlebar when its raining. Doesn't really seem to make any sense :confused2: I can understand reduced braking ability in the rain but the lever shouldn't gain a bunch of freeplay.

 

[davidon]

ISR drilled rotors..like George said it is the lever travel that is the problem not the effectiveness of the braking itself. I would have to think it might be the MC but again why is it fine in dry weather? Maybe I will ask ISR about this.

 

[MaxMidnight]

Is it about lever movement...or about how much it needs to be pulled in to get sufficient retardation?

Due to the loss of braking efficiency in the wet you will need to apply more force to the lever which would suggest that it will need to be pulled in further.

 

[VMAX1260]

Is it about lever movement...or about how much it needs to be pulled in to get sufficient retardation?

Due to the loss of braking efficiency in the wet you will need to apply more force to the lever which would suggest that it will need to be pulled in further.

as he said is the distance the lever makes that gets very close to the handlebar when wet. the braking power will be the same with no strugling with your hand with more power so you can apply the brakes. But it gets dangerous if the lever reaches the handle bar. Isr are one of the best m/c . I cannot understand what is the problem. Please throw some water when dry to the m/c to locate if the problem is the callipers or the m/c

Is it about lever movement...or about how much it needs to be pulled in to get sufficient retardation?

Due to the loss of braking efficiency in the wet you will need to apply more force to the lever which would suggest that it will need to be pulled in further.

 

[jfeagins]

...or about how much it needs to be pulled in to get sufficient retardation?......

:rofl_200:I gotta admit - I think my level of retardation stays about the same whether I'm braking in the sunshine, or under heavy rain conditions. :biglaugh:

 

[VMAX1260]

did you sort it out ?

 

[thor_eyerdhal]

Are your rotors made of cast iron?