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front brakes lockup while riding

WarriorPrincess said:
I am not saying I know this, but brake fluid is hyd fluid becasue hyd fluid cannot be compressed. It has not oxygen. Maybe the other oils might expand but not buy much. Again I could be worng, but just a thought.

Your thoughts on this has been very good. I believe you are correct. Just wondering.
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Im not sure either but I have heard of fluid heating and expanding. I think thats one of the reason people upgrade the hose to steel braided brake lines and bling of course..lol
 
Steel braided lines are for better feel and pressure. They don't flex like OEM rubber.

1) If the levers do not allow the piston in the MC to return all the way to it's designed return position it will not uncover the port that allows for free flow to the reservior and relaxation of the caliper and system.
2) If there is excessive water in the system it will turn to steam and create pressure in the system. The hydraulic fluid will expand a little bit but nothing like the water turning to steam. All brake systems have a little water. Condensation from the reservior, which is open to the atmosphere, is inevitable. That said it can be mitigated by use of high quality fluid and regular bleeding from the bottom of the system where the water collects since it's heavier than the brake fluid. When was the last time you bled the brakes from the caliper?
3) As stated here a full resevior could do this. People call this "hydro-locking" and it's aptly named. A hydraulic lockup of the system that is designed to operate with an air cushion or open to atmoshere and has no vent or room for air compression.

My bet is number 1 and 2. Let us know how it goes and be safe while you troubleshoot!
 
Enchanter I think you are right about the lever. I took the bike out for a ride again but only rode it in town not on the freeway just incase. As I rode I started slowly applying break to see if the lever start to harden. The first 5min the lever had some slack before it grabs which I think it should be. Then it started to get harder and harder but not hard enough to lock the the wheel. I turned around and headed back home ok without the breaks locking up. So i will take the lever out to see if I installed wrong. I'm thinking that little push rod didnt seat properly on the lever.
 
JimE said:
Steel braided lines are for better feel and pressure. They don't flex like OEM rubber.

1) If the levers do not allow the piston in the MC to return all the way to it's designed return position it will not uncover the port that allows for free flow to the reservior and relaxation of the caliper and system.
2) If there is excessive water in the system it will turn to steam and create pressure in the system. The hydraulic fluid will expand a little bit but nothing like the water turning to steam. All brake systems have a little water. Condensation from the reservior, which is open to the atmosphere, is inevitable. That said it can be mitigated by use of high quality fluid and regular bleeding from the bottom of the system where the water collects since it's heavier than the brake fluid. When was the last time you bled the brakes from the caliper?
3) As stated here a full resevior could do this. People call this "hydro-locking" and it's aptly named. A hydraulic lockup of the system that is designed to operate with an air cushion or open to atmoshere and has no vent or room for air compression.

My bet is number 1 and 2. Let us know how it goes and be safe while you troubleshoot!
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Thanks Jim
I think you are right about 1 and maybe 2. I only had the bike few weeks so I havent fully bleed the breaks yet. I only bleed the master because I install a new resevior. Tomorrow I will reinstall my lever again making sure the push rod is seated correctly also I will put fresh fluid and bleed system.
 
If the push rod isn't seated then the distance will be greater thereby depressing the MC piston further and never letting it return to design resting position and uncovering the system relief port. Carefully measure both stock and aftermarket distances between pivot point and MC piston contact point. Use a caliper and make a jig if you need to. They need to be the same or very close. That and a good brake flush never hurt anybody. Brake fluid is much less expensive than crashing in my experience!

Post up what you find so we can all learn. Good to know when playing with aftermarket bits.
 
2slow said:
Im not sure either but I have heard of fluid heating and expanding. I think thats one of the reason people upgrade the hose to steel braided brake lines and bling of course..lol
Click to expand...

The fluid will expand a little bit with heat, that's why overfill builds pressure--no room for expansion. That's why it was good after you relieved the pressure, and it might have released enough fluid to drop down to normal level.

Brake fluid absorbs moisture. Moisture will boil when it gets hotter, especially DOT 3 (keep it out of your bike). Boil = compressible vapor = loss of pressure.

Steel braid hose contains the same inner teflon line that rubber hose does, but the steel braid casing flexes less than rubber casing, so it provides a firmer feel with less applied pressure needed to provide the same amount of hydraulic pressure to the caliper. Has nothing really to do with heat transfer.
 
Ok I took lever apart and reinstalled it. I made sure the pushrod was seated correctly in the hole on the lever. when putting back screw I can feel the rod being push in a little but still had little free play when gripping. I rode around the block a few times with the breaks slightly pess to build up heat. After about 3 times around the block it started locking up again. So I took the lever apart again but this time shave off the rod making it just short enough so that when I put back it doesn't push the rod in when I screw tight. Again I took it around the block a lot and NO lockup! I was doing rolling stoppies one after another rode it a few more times around the block with breaks slightly press and no sign to the lever getting hard.
So for the guys that bet $50 for over fill. You guys owe Enchanter!!..:laughing
 
Did you use the new pushrod that came with the lever? it should have come with one that is shorter than stock. although you just shaved (I assume the stock one) it and solved the problem.
I've seen this before on a GSXR, same exact thing happened. swapped for the new pushrod and all better.
 
Mortifer said:
Did you use the new pushrod that came with the lever? it should have come with one that is shorter than stock. although you just shaved (I assume the stock one) it and solved the problem.
I've seen this before on a GSXR, same exact thing happened. swapped for the new pushrod and all better.
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I bought it off someone. It look new and never installed. The Previous owner didn't mention anything about replacing the rod and I didn't know about it. I tried to search online for Manuel no luck I even search YouTube lol
 
put the old lever on and see if the problem goes away.
 
Now replace the brake fluid. You've cooked it pretty thoroughly.
 
afm199 said:
Now replace the brake fluid. You've cooked it pretty thoroughly.
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Good point. It would be smart to do so given the relative cost and importance of the brakes!
 
afm199 said:
Now replace the brake fluid. You've cooked it pretty thoroughly.
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Thats the fisrt think I did this morning. I went out to go buy new fluid. I'm gonna bleed the whole system

Thanks
 
Enchanter said:
Good point. It would be smart to do so given the relative cost and importance of the brakes!
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Especially since he doesn't know what fluid he put in there.
 
2slow said:
What I didnt say I dont know I said I dont remember. Go back and read my post
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I read your post. If you don't remember what kind of brake fluid you poured into your reservoir, you don't know what fluid is in there, right?
 
Nice work....never heard of this before, but hell, I'm glad I read this.

Oh, I think that OP meant he referred to his "Manual" for brake fluid type, unless he has a good friend named Manuel that is a great mechanic...which is totally possible...:twofinger:twofinger

thx for the info tho...
 
What the hell, do the back brakes too. You allready have the gear out and dirty.
 
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