Front brakes intermittently getting harder.

[leosantanalg]

For the past 2 weeks my front brake has been hardening all of sudden. It loses all the free play before it brakes or it will brake just by touching the lever. I have to adjust the levers to get a little travel before brake engages and then while riding, all of sudden it comes back and I end with extra travel of the lever and have to re adjust again. This been happening over and over! any thoughts???

 

[leosantanalg]

13 minutes ago, oni nou said:

Brake fluid is expanding because it is getting hot causing lack of freeplay......check your adjustment of the lever has enough freeplay as per manual check that the master cylinder is not overfilled...check your pads are releasing properly and not dragging against the disc[lightly dragging is normal..I mean causing the wheel not to spin easily] when the lever is released.

This has just been on here in a post by zippy ...it turned out that his front wheel bearings were binding causing heat that dissipated in the disc to pass to the fluid through the pads and calliper pistons.

Funny you said that because yesterday was 90º and when I pulled the bike out of the shed the front wheel was literally stuck. and there was no free play at all! I had to adjust the lever to give some free play and while I was riding, the second time I went to use the brake, it was gone! I almost had to squeeze my fingers to make it brake, calling for another adjustment. How can I prevent it form getting hot? Is it possible, I might have air in the line?  Interesting about the front wheel bearing, but since mine was stiff even before ridding I doubt it would be my case, correct? 

Thanks again

Edited July 19, 2017 by leosantanalg
changes

[jonnyc21]

6 hours ago, leosantanalg said:

Funny you said that because yesterday was 90º and when I pulled the bike out of the shed the front wheel was literally stuck. and there was no free play at all! I had to adjust the lever to give some free play and while I was riding, the second time I went to use the brake, it was gone! I almost had to squeeze my fingers to make it brake, calling for another adjustment. How can I prevent it form getting hot? Is it possible, I might have air in the line?  Interesting about the front wheel bearing, but since mine was stiff even before ridding I doubt it would be my case, correct? 

Thanks again

That sounds like moisture in the system, I had a car that was doing something like this and it was water in the lines.  I had seen some strange issues like this when air in the lines as well, however not quite as random as your describing.  

I would first flush/clean everything out double checking no air or water in the system and then if you continue to get the issues let us know how that works. 

[lineaway]

Bent rotor, loose front axle, air in the system.

[eagle8]

I'm thinking it could be a combination of things like lineway has suggested ?

[thats_a_five]

Here is the link to the thread started by Zippy.  It has some pretty good information about what can be causing these issues. 

 

[leosantanalg]

21 hours ago, jonnyc21 said:

That sounds like moisture in the system, I had a car that was doing something like this and it was water in the lines.  I had seen some strange issues like this when air in the lines as well, however not quite as random as your describing.  

I would first flush/clean everything out double checking no air or water in the system and then if you continue to get the issues let us know how that works. 

How to double check for air or water in the line?? just bleeding and replacing oil,basically?

 

[jonnyc21]

If you really want to know for sure use a chemical test strip or test meter to know how much.  

The easy is what I would say is differential diagnosis. Flush with new and if you find a lot of air that's likely it, if just discoloration and the issue goes away post flush it was likely contamination (water or other) reducing the boiling point.  

If it isn't fixed then you might have a problem with the caliper or master in some way.

Edited July 20, 2017 by jonnyc21

[jmutiger]

I'd say you have too much fluid and nowhere for it to expand to as it heats up.  And potentially a master cylinder that is being restricted so fluidly can't back flow to the resivoir properly. 

Fluid gets hot as it is used and expands when hot.. So it has to be able to go somewhere.  It's a sealed system. 

 

 

[still trying]

I have had similar issues over the years;

Dirt causing the caliper pistons not releasing, fluid heats up break drags, break stays on, doom.

Adjusting the master cylinder piston so it didn't return back past the tank port, break gets hot fluid expands, break stays on, doom

water in the fluid, as things get hot it boils and puts the break on for you, doom (caused by sitting in storage too long)

air in system spongy break, minor doom.

And as mentioned above, warped disc, wheel bearings, loose axle etc,etc.

Good luck fixing this and let us know what you find

Frequently clean the caliper and pistons (exposed bit), then push the pistons back in and pump out, with the tank cap off, Don't let the level get too low..

Change the fluid at least twice a year

Keep plenty of material on the pad. This keeps the pistons further in the cylinder giving them better support, reducing wear, and the chance that if worn they bind and lock, damaging the cylinder.