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Author Topic: How to make front brake on my YZ feel firm???  (Read 7221 times)

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Offline Braap257

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How to make front brake on my YZ feel firm???
« on: August 13, 2010, 07:49:15 AM »
Okay so last night after i finally got that old oil drain plug out i decided to check on the brakes. The rear is solid. The front however feels quite spongey and the fluid is old. so i changed the fluid and rebled the brakes with my brother the problem is they dont seem to get firm like i want them.... and every time he fills the reservoir there is a bubble on the 1st squeeze of the lever. What does that mean???  I guess what I'm really asking is how to get the front brake nice and firm???

Offline G-MONEY

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Re: How to make front brake on my YZ feel firm???
« Reply #1 on: August 13, 2010, 08:32:52 AM »
Sounds like your master cylinder needs to be rebuilt aswell as the caliper. A factory shop manual will show you how to do this. You are only replacing seals and cleaning out old gummy fluid. Remember to polish the pucks in the caliper unless they are teflon then leave them alone.
"Everthing's the same just slightly different"

Offline Coop

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Re: How to make front brake on my YZ feel firm???
« Reply #2 on: August 13, 2010, 09:04:56 AM »
First things first. Be 100% positive you bled them thoroughly and got all the air out. Then check the screw on the lever and be sure it is adjusted so it's pushing the plunger in far enough.
- Mike - Don't take life so seriously, nobody gets out alive.

Offline eprovenzano

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Re: How to make front brake on my YZ feel firm???
« Reply #3 on: August 13, 2010, 12:48:17 PM »
Is it possible to back bleed them?  On my KTM, I have a hydraulic clutch.  When I changed the fluid, I cracked open the bleeder, then with a syringe and a small piece of tubing from the local farm and feed store, I pushed fluid back through the system. 

Just a thought.
Eric Provenzano
2019 KTM 300 XCW TPI
2000 KTM 300 EXC (Son's)
2001 KTM 380 EXC
Sold 1991 KDX 200... fun play bike
Sold 1999 KX250
Sold 1999 YZ125 (son's)
Sold 2001 Yamaha TTL 125 (son's 1st bike)
Sold but never forgotten 1974 Honda Elsinore CR250M
Sold 1974 Honda Elsinore CR125

Offline ford832

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Re: How to make front brake on my YZ feel firm???
« Reply #4 on: August 13, 2010, 05:38:50 PM »
Unbolt your caliper and take out your slide pins and pads.Clean the anchor where the pads slide and put a little grease there as well.Clean your pins a put some grease on them as well(silicone type brake grease).A slightly binding slide will give you a spongy brake.A slightly bent rotor will as well but the brake firmness will increase with your second pump when sitting still if that's the case.
Once its done and all put back together,put your thumbs against the caliper while grabbing the anchor with your fingers and push hard so your caliper piston goes all the way in(I do this after every ride as well front and rear-especially if I've been upside down)This will force the fluid back up in to your master cylinder along with any air.That little bubble you see is normal.If you see many-it's not and it's rebuild time.Normal bleed procedure is to pump your lever and while holding it in,crack your bleeder until the lever goes to the bar then tighten the bleeder.repeat.Bike systems typically trap air when disassembled.Tapping the joints and leaving it sit overnight then rebleeding helps.
The first time you push the piston back with your thumbs,take the cover off so the fluid will overflow then repump the lever while refilling.
When you do it after a ride with the covers on,the rear will push back much easier and farther than the front due to the extra space in the reservoir.
I'd rather a full bottle in front of me than a full frontal lobotomy.

Offline Braap257

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Re: How to make front brake on my YZ feel firm???
« Reply #5 on: August 13, 2010, 07:13:41 PM »
So when bleeding you should pump the lever then while pressed crack the bleeder screw open and let the lever hit the bars? Idk how long you are supposed to keep the bleeder cracked open, how hard the lever should be pressed.. ect..

Offline ford832

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Re: How to make front brake on my YZ feel firm???
« Reply #6 on: August 14, 2010, 05:23:59 AM »
Yep,pump it a couple times then hold it firmly and open the bleeder until the lever hits the bar then while holding it there,tighten the bleeder and repeat.As soon as you open the bleeder the lever will hit the bar so you just end up holding it a second or so.
I'd rather a full bottle in front of me than a full frontal lobotomy.

Offline Braap257

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Re: How to make front brake on my YZ feel firm???
« Reply #7 on: August 15, 2010, 07:08:41 AM »
Okay thanks Ford I will try that.

Offline Braap257

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Re: How to make front brake on my YZ feel firm???
« Reply #8 on: August 15, 2010, 08:31:11 PM »
I got them! They feel perfect. No sponginess whatsoever!!! I just bled and bled and bled and finally the lever smoothly goes back and is nice and responsive. ;)

Offline eprovenzano

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Re: How to make front brake on my YZ feel firm???
« Reply #9 on: August 17, 2010, 07:54:32 AM »
Thanks for posting the cure and results.  Glad you got her fixed....
Eric Provenzano
2019 KTM 300 XCW TPI
2000 KTM 300 EXC (Son's)
2001 KTM 380 EXC
Sold 1991 KDX 200... fun play bike
Sold 1999 KX250
Sold 1999 YZ125 (son's)
Sold 2001 Yamaha TTL 125 (son's 1st bike)
Sold but never forgotten 1974 Honda Elsinore CR250M
Sold 1974 Honda Elsinore CR125

Offline Braap257

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Re: How to make front brake on my YZ feel firm???
« Reply #10 on: August 17, 2010, 07:55:50 AM »
Thanks for posting the cure and results.  Glad you got her fixed....


 :)

Offline JETZcorp

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Re: How to make front brake on my YZ feel firm???
« Reply #11 on: August 17, 2010, 08:28:27 PM »
Call me naiive but... why do brakes even need fluid anyway?  Is it that completely impossible to make a mechanical system that uses leverage to put pressure on the disks?  Maybe I'm underestimating how much power those calipers lay down, but I've seen what kind of balls a clutch spring has and I imagine that crushing down five of those with the traditional system of levers and cables takes a lot of force, yet the traditional cable-and-lever system works quite well and is practically zero-maintenance.  So do the brakes require that much more force than a clutch, or is there another reason (Maico and KTM clutches notwithstanding)?


Is this Maico a 440 or only a 400?  Well in all the confusion, I forgot myself.
But considering this is a 1978 Magnum, the best-handling bike in the world, you have to ask yourself one question.
Do you feel lucky, punk?

Offline riffraff

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Re: How to make front brake on my YZ feel firm???
« Reply #12 on: August 17, 2010, 09:28:04 PM »
The reason is progress Jetz, not to mention hydraulics take a lot less effort for the same stopping power and/or clutch activation
aaahhhhh yes, I remember the good old days

Offline JETZcorp

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Re: How to make front brake on my YZ feel firm???
« Reply #13 on: August 17, 2010, 09:34:57 PM »
Is it really that important that you have to deal with threads like this?  Sounds like this issue would've been a real bastard in pre-internet days.  And, although it's easy to say "oh yes, add hydraulics" it seems like these smart people could come up with something simpler that provides a mechanical advantage.  Simplicity is an end in itself; who wants to keep track of thirty different little fluid changes that need to be made, the failure of which can send the bike careening into oblivion?  If there's something fundamental about disk brakes that require that much force, then I can't really complain.  But, if they're just throwing on hydraulic this's and that's for marketing purposes, so they can brag about pulling stoppies when a fly lands on the lever, I can't see myself getting behind it.

And by the way, just to make it clear, I am not arguing in favor of ye olde drum brakes here, in case someone thought I was implying that.


Is this Maico a 440 or only a 400?  Well in all the confusion, I forgot myself.
But considering this is a 1978 Magnum, the best-handling bike in the world, you have to ask yourself one question.
Do you feel lucky, punk?

Offline TMKIWI

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Re: How to make front brake on my YZ feel firm???
« Reply #14 on: August 17, 2010, 10:06:18 PM »
Hydraulic systems, jetz are one of the simplest systems going.
The Romans used hydraulic systems 1000 years ago. Using water.

Machanical systems are not practically maintenance free.
They are just a pain in the arse.
Hydraulics are not all voodoo and incense.

Have a ride on a modern euro bike with hydraulic clutch. Go for a 4 hour ride in some of the shittiest tracks you can find and i guarantee you will not want a cable clutch again.
Yes cable works fine , but once you have used hydraulic you will wonder why every bike does not have one.

If you don't fall off you are not going hard enough