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07 CRF250X weak front brake stopping power but not spongy

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2007 CRF250x. After riding for 15 miles front brakes stopping power weakens big time. Not spongy. Work great for first few miles (10 or so) then react like wet or oiled when braking but with normal lever feel...hard with no sponginess. When stopped I can pull in brake lever with full strength and wheel will turn but with resistance. Checked rotor, not at all hot. Replaced pads with Galfer Organic and still have the problem. Any ideas or same experiences? Bad caliper????? I'm stumped!

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One possibility is the fluid needs to be changed, brake fluid absioorbs moisture over time...water boils easier with brake use and will cause brake fade. After the brakes cool feel will return to normal.

When you replaced the pads was the piston in the caliper easy to push back in, did the pads slide freely on the pins and did the caliper float?

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jakeblues, when I changed the pads the piston did push back in easily and slid smoothly. One thing I might not have clarified in my post is when I'm riding and the problems begins to happen I have normal lever feel, meaning hard with no sponginess. When decending a steep hill I can pull back on the lever with all my strength and the bike slows but front wheel won't lock up or skid. Tomorrow I can go out and the brake will be fine for the first 10 or so miles before the problem starts again.

I'll change the fluid out tomorrow. Thanks again.

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It does not sound like air in the line, since it does not have a spongy feel. But these bike's brakes are hard to get all the air out

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Are your fork seals leaking?

Sounds like you have oil on your brakes. Or they were leaking and contaminated your brakes.

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Or if you got something like Armor all or tire shine on them,, that would also do it.

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According to the OP brake feel starts off normal then fades later, oil on the pads would make them weak all the time...

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2007 CRF250x. After riding for 15 miles front brakes stopping power weakens big time. Not spongy. Work great for first few miles (10 or so) then react like wet or oiled when braking but with normal lever feel...hard with no sponginess. When stopped I can pull in brake lever with full strength and wheel will turn but with resistance. Checked rotor, not at all hot. Replaced pads with Galfer Organic and still have the problem. Any ideas or same experiences? Bad caliper????? I'm stumped!

Once they get weak, do they stay that way forever, or are they good again the next day?

If they stay that way, the pads are getting glazed or contaminated. Disk may need to be resurfaced - a piece of glass and sandpaper will do the job. It could also be the fork oil theory mentioned earlier. If they get better after sitting for a while, then it is somehow heat-related. It is possible that a piston is getting hung-up after expanding too.

JayC

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What are you washing and detailing your bike with? Are you spraying tire shine on your tires? I've had to deal with that a few times after detailing my bike for pics when I was selling it:bonk:

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Once they get weak, do they stay that way forever, or are they good again the next day?

If they stay that way, the pads are getting glazed or contaminated. Disk may need to be resurfaced - a piece of glass and sandpaper will do the job. It could also be the fork oil theory mentioned earlier. If they get better after sitting for a while, then it is somehow heat-related. It is possible that a piston is getting hung-up after expanding too.

JayC

See below :

jakeblues, when I changed the pads the piston did push back in easily and slid smoothly. One thing I might not have clarified in my post is when I'm riding and the problems begins to happen I have normal lever feel, meaning hard with no sponginess. When decending a steep hill I can pull back on the lever with all my strength and the bike slows but front wheel won't lock up or skid. Tomorrow I can go out and the brake will be fine for the first 10 or so miles before the problem starts again.

I'll change the fluid out tomorrow. Thanks again.

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trail tip, works on most bikes, push your knee into the caliper until it's opened as far as it goes

then pump the lever a few times till it's stiff again, and try your brakes now

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I was riding with 4dazed the day his brake problem once again reared its ugly head. I really don't think the system needs to be bled, but I think he may need a new front rotor, or at least do some "re texturing" as I think they may be glazed. Does anyone out there have an X with a relatively new front rotor who's thickness can be measured with digital calipers? I can then measure Dan's and compare the results..

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I was riding with 4dazed the day his brake problem once again reared its ugly head. I really don't think the system needs to be bled, but I think he may need a new front rotor, or at least do some "re texturing" as I think they may be glazed. Does anyone out there have an X with a relatively new front rotor who's thickness can be measured with digital calipers? I can then measure Dan's and compare the results..

The min thickness is stamped on the Rotor if it is a stock rotor and most aftermarket.

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fork seals aren't leaking and no tire dressing used. Like jakeblues said, brakes feel and react normal for first 10 or so miles then start to lose power but still with normal lever feel. I can pull back on lever with full strength and only get about 30-50% stopping power and there is absolutely no sponginess or change to lever feel.

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Once they get weak, do they stay that way forever, or are they good again the next day?

JayC

I just went out and checked the bike. I haven't ridden since the problem on Monday. I rolled the bike on my driveway and pulled the brake lever with full strength and the braking power is about 30-50% of normal. So, this is new since it has not recovered from the problem like it did the last time. I looked close and saw no signs of any fluid leaking onto the pads. Then I tried your trail tip. I used my knee to apply pressure to the caliper. After that I had to pump the lever 17 times before the brakes worked again and there is noticibly more stopping power now. Does this tell us the caliper may be bad?

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trail tip, works on most bikes, push your knee into the caliper until it's opened as far as it goes

then pump the lever a few times till it's stiff again, and try your brakes now

Sorry MegaDeth, I quoted someone else for your trail tip. Anyway, I tried it and it improved the braking power. See my previous quote.

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I just went out and checked the bike. I haven't ridden since the problem on Monday. I rolled the bike on my driveway and pulled the brake lever with full strength and the braking power is about 30-50% of normal. So, this is new since it has not recovered from the problem like it did the last time. I looked close and saw no signs of any fluid leaking onto the pads. Then I tried your trail tip. I used my knee to apply pressure to the caliper. After that I had to pump the lever 17 times before the brakes worked again and there is noticibly more stopping power now. Does this tell us the caliper may be bad?

Not my hint (good hint too) - that generally tells you that you had air in the line or caliper. The 17 pumps tells you that your MC is bad and/or you are low on fluid.

I'd take off the reservoir cap and check the fluid level. Then, I'd pump the calipers tight (add fluid if you need to) - probably pull the tire and maybe pads too - to get as much fluid into the caliper as I could. Then I'd put the cap back on and let it sit overnight. The next day, I'd take the reservoir cap off again and push the caliper plungers as far in as they'd go. Put everything back together and re-set the pads, adding fluid if you need to. Should be good to go then, unless your MC seal is shot.

JayC

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