Front Brake Problem

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First I hope this is the proper place to post this to... (if not Mod/Admin please move thread to correct forum)


There is a very small pull distance needed to fully engage my front brakes (it's a pretty hard pull right off the bat not like it starts soft then get's harder as you pull in more).
I put the bike on the center stand and spun the wheel. You can audibly hear the pads lightly rubbing against the disc and see that there isn't free travel of the wheel.

My question to the community is why would this be happening? (I've been looking for a while online and can't find anything)

Any help appreciated :)


Other info...

2000 Honda ST1100

The front pads have plenty of life left

Fluid levels are good and there doesn't appear to be air in the system
 

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Joe
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It's normal for them to rub a little on the center stand. When was the last time the brakes were bled? Might be good to do to eliminate air in the system.
 
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jpolloni
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I don't know but I'm getting some DOT 4 fluid this evening... The brakes just don't feel "right"
& By bleed what do you mean? Completely change the fluid out that's currently in the system?
 

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Joe
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I don't know but I'm getting some DOT 4 fluid this evening... The brakes just don't feel "right"
& By bleed what do you mean? Completely change the fluid out that's currently in the system?
Yes sir, typical brake fluid service. Also check to see if the pistons look ok, they'll be dirty but just look for any surface damage or pitting, a q-tip works well to rub the surface for a quick look. Next tire change get a closer look and clean with brake fluid NOT brake cleaner.
 
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Yes sir, typical brake fluid service. Also check to see if the pistons look ok, they'll be dirty but just look for any surface damage or pitting, a q-tip works well to rub the surface for a quick look. Next tire change get a closer look and clean with brake fluid NOT brake cleaner.
Honda front brakes IMO are notoriusly very responsive, specially front braking of their motocross bikes. Aside from that, I would first bleed the system before total dis-assembly of caliper pistons, etc. Just keep fluid level in master cyl. during this process. The lever assembly also has a five position lever locating cam adjustment, but you likely already knew that;).
 

ST1100Y

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You can audibly hear the pads lightly rubbing against the disc and see that there isn't free travel of the wheel.
Some slight rubbing is normal, but what do you mean by "no free travel" of the wheel?
If the wheel comes to a sudden stop after been spun by hand, I've to assume seized calliper pistons, thus a brake overhaul might be in order.
I'd first check if the reservoir is not filled over the max; check view glass if air bubble is visible, if not remove lid and syphon excessive liquid (level on max line only with pistons fully retracted on both callipers; never overfill...)
Then see if its possible to push the calliper pistons in smoothly (fingers on the rotor, thumbs on the calliper case), normally the force of your thumbs should be sufficient to push the pistons fully in with moderate force applied.
If its very hard/the pistons won't bulge at all (like if you have to jerk your knee against the case to get them moving), a brake overhaul is required...
 
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Sounds normal to me, as far as having no "free play" at the brake lever. The front wheel should spin fairly easy when the wheel is off the ground, but there will also be a slight drag.

Bleeding & flushing is a good idea - should be done every year or two , but it will not add "free play"to the brake lever. If anything, would reduce it.

If you have air in the system, that would give you more "free play" . If you want to do a quick removal of air ( I doubt you have air in the system, however ) , take the plate off the master cylinder and crack open the bleeder fitting ( one at a time ) and let gravity drain some fluid. Sometimes that will release any small bubble of air that is trapped.

If you are going to flush & bleed the system ( replace the fluid ), reverse bleeding ( forcing fluid from the caliper back up into the master cylinder ) is the easiest, quickest, and least frustrating way to do the job, by using a syringe and a piece of rubber tubing. Invert the syringe and expell all air before starting to reverse bleed. You can start by opening the bleeder fitting and filling the master cylinder with new brake fluid and let it run out of the fitting, but then follow up by reverse bleeding to purge all the air out of the system. Clean out the master cylinder of any crunge first.

To repeat, I don't think you have a problem. But the fluid should be drained & flushed every couple of years.
 
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moddy

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I too have the same symptom of maybe a quarter to half a spin before the wheel comes to a stop, and found this thread to see what someone else did. I have a 91, and rebuilt both front calipers with new seals 6 months ago. I also was able to pry the brake pad toward the piston to compress both sides and squeezed the brake level to re seat the pads and still have the same slight compression to the rotor without squeezing the brake. I will bleed, with new dot 4 on hand, and report back soon.
 

moddy

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I took the master cylinder cover off, and noticed the fluid was about a 1/4 of an inch lower than the max line. It wasn't so low that I believe air was introduced to the system, but it reminded me of the wind blowing my bike over since the caliper rebuild 6 months ago. I wonder if while it was laying over, brake fluid came out of the line and air got into that way? It's raining at the present, and need to see if I can bleed the potential air out of the line, and that's why the pads won't come a little farther from the rotor. The wheel turns about a full revolution now, but still comes to a stop sooner than I think it should. More later..
 
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jpolloni
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I think I found the problem!

I replaced all the rubbers on the front brakes and obviously got new fluid into the system...
When I first drained the loop fluid had coagulated into a thick globby gel and was sitting in the bottom of the reservoir (wish I had taken a picture).
The same crap was also in the calipers. I'm going to try and get it out for a ride to verify everything's in working order but I'm pretty sure everything is good now.

:D


Here's a picture of the Caliper (Piston in & piston out)
 

ST1100Y

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Here's a picture of the Caliper (Piston in & piston out)
YIKES!!! :scared2:
That's some nasty crud in there...
I hope you flushed that all out really good...

Methinks fully cleaned, with new rings and new brake fluid you will not recognise the brakes anymore... ;-)
 

moddy

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I remember this stuff in the caliper and master cylinder. In the last couple of weeks I did not make time to change the fluid to see if it would relieve pressure. After about 3 days when I rode it a short distance, there wasn't the caliper drag I'd been experiencing, that was good. I believe it is my 25 year old brake lines that need to go. So, the right thing to do would be to replace my lines first.
 
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moddy

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I have replaced my lines and what a difference. When riding 2up recently, I mentioned the braking I was doing, coming up to a light, was done with one finger. It took more than that when my brake lines used to flex a lot more. Replaced the clutch line and rebuilt the clutch master cylinder.
I will also admit to cleaning the white grit from behind the caliper seals. The piston drag, when releasing the brakes, did not allow for the pistons to retreat. Having only replaced the seals 1 year ago, it was either a bad seal and short lived anyway, or riding through the winter would seem to be a guaranteed front caliper overhaul. Hopefully I picked better seals this time.
You know what else my two year old front brake pads did? They corroded between the pads and metal plate to the point one half of one side crumbled off!
 
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