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Old August 28th, 2015, 05:05 PM   #1
gogoKawi
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No Front Brake Pressure

After racing last weekend and almost running off the track because of brake fade, I decided to change my fluid and brake line. I still had the rubber line. Went with Galfer since that what I purchased for my old 250. Put it on with no problem. Fluid went in with no problem. Bled brakes, with the only issue being that the lever goes all the way back to the grip. Bled the brake at least 4 times with the same result. I used the way outlined in the manual and a vacuum kit to no avail. Very frustrated since I've changed lines successfully at least 3 times.

I haven't tried the zip tie on the lever overnight yet. But I would think that there would be more pressure in the line.

Any help you can give would be appreciated.
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Old August 28th, 2015, 05:54 PM   #2
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Banjo bolt snug?
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Old August 28th, 2015, 06:15 PM   #3
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Sounds like maybe your caliper,

Quote:
For those of you whom are scratching their heads, here you go,*


Front Caliper Service (also rear as well)

Many folks have posted here with a Varity of front brake problems.

*Many of which are attributable to the lack of proper maintenance.

*Here’s how you can always have a brake like when your bike was new.

A short list of the problems and the causes.

Soft lever or lever goes to the bar.

The usual cause is the pistons are pushed too far back into the caliper by a flexing a warped, coned, disc.

*Using up too much piston travel before the disc is pinched.

Juddering in sync with wheel rotation.

The disc is worn, and its thickness varies. *This causes the caliper to “sink” into the thin part and when the thick part comes around, it gets wedged into a smaller space causing a tightening of the brake. Then the tight spot passes through and it like the brake is released. Then repeat, repeat.

Cupped, coned, or warped disc.

Unfortunately this is a common problem with EX’s the cause is the disc is stretched in the center due to being rigidly bolted to the wheel. *The huge force of braking is transmitted to the wheel through the webbed center of the disc which gets stretched and becomes larger than the space it occupies in the center of the disc. This causes the center to push to the side trying to find room for itself.

*Resulting is a cone shaped disc.

Soft lever 2

The caliper has pistons only on one side, so as the pads wear the caliper must shift sideways apply even pressure on both sides of the disc.

*To allow this the caliper floats on two pins. *If these pins get dry (no grease) dirty or bent. The caliper won’t center itself and bends the disc to wherever it is.

This take up lever travel and when released pushes the pistons further back than necessary.

*If not fixed will eventually destroy the disc (warp it).


Ok how to prevent all of the above.

When new pad time comes around, resist the temptation to just pop in new one and go.

*Every time you must do these things.

Remove caliper disassemble and clean it.

Clean and re grease the sliding pins.

Polish the caliper pistons to remove dirt. If you just push the pistons back into the caliper leaks will result. Or binding.

Tools required:
12 mm socket
8mm open end wrench
3” or bigger C clamp
a supply of new bake fluid.
wire brush and or steel wool.

Remove the caliper from the fork leg but leave the brake line on.

Remove the old pads and the mounting frame (the sliding pins)

Remove the cover from the Master Cylinder on the Handel bar.

Attach the C clamp to one of the pistons but don’t squeeze it. *Pump the lever on the bar slowly to push out the other piston almost all the way. *Put the C clamp on that piston and push out the other one.

Remove both pistons by hand.

Remove all the rubber part from the caliper, the seals are in the grooves in the caliper and dull pointed thingy will get them out easy.

Disconnect the caliper from the brake line.

Soak all the rubber parts in new clean brake fluid * ONLY!!!!! * Rub them with you fingers till as clean as new.

The caliper can be cleaned with a wire brush or even a Moto tool for the internal grooves, NOW’s the time to paint it if you wish.

Polish the pistons till they are smooth and shinny. They are chrome plated. If any of the plating is chipped or damaged below the dust cap groove. *Replace it.

The master cylinder is the subject of another write up and we’ll assume it in good working order here.

If you suspect your disc is bad, your bets bet is to replace it with an after market one fro EBC or Galpher.

*Don’t remove the disc unless you intend to replace it. *It will assume a new shape if it is * stressed and will not be flat again. You can try to check its condition by placing a straight edge across the face of the pad swept area looking for any distortion.

Re assembly

Take the nice clean rubber seals and install them into the caliper then the Dust covers.
Wet all the rubber with new clean brake fluid and partially fill the caliper with new fluid.

Push the pistons though the dust seals and into the caliper body until the dust covers snap into the grooves.

Fill the MC with new fluid and pump the lever while holding the Line above the MC till clean fluid flows.

Connect the line to the caliper while holding it above the MC.

Pump the lever with the bleeder valve open till fluid flow from the bleeder.

*Hold the caliper so that the bleeder is the highest point.

Close the bleeder and pump more fluid into the caliper but don’t push the pistons all the way out.

Then squeeze the pistons all the way back in and install the new pads.

Re grease the slider pins and assemble the dust seals and re mount the caliper on the forks but leave the bolts loose.

Now clamp the caliper to the disc with the brake lever.

Look at the space between the fork lugs and the caliper, clamp and release a few times as you tighten the bolts by hand. It one lug touches much before the other the odds are you mounting bracket is bent. You can straighten it.

*After you get it the best you can. Some shim washers made from alum can stock can be fitted to the loose side.*

** *What we are doing here is trying to minimize the bedd in time and gets the best pad life.


Ok with everything tight you should be through, Notice we don’t need to bleed the brakes, but if you screwed up in any of the above steps, you might do that here.

Be careful to Bedd in the new pads gently.

*Too much pressure too soon will burn the pad material as only a small area will be gripping at first. You also won’t have full braking power till the pads are fully familiar with the disc
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Old August 28th, 2015, 07:26 PM   #4
gogoKawi
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Quote:
Originally Posted by Alex View Post
Banjo bolt snug?
Quote:
Originally Posted by Ghostt View Post
Sounds like maybe your caliper,
I'm just going to disassemble everything. Banjos were tight. And the pistons moved pretty easily and evenly. Very strange that all was good prior to the brake line swap. I may just install the old brake line to see what happens. If it works, then it's time to call Galfer.
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Old August 28th, 2015, 07:44 PM   #5
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you double checked the MC banjo too right?

my brake pressure is perfect but I've run into caliper issues myself that I'll be finally fixing after the race on sunday (it works, it's just not ideal and you barely brake on lightning afaik)

my issue may actually be jumping into new pads too quickly rather than easing them in, my natural braking style could be hurting more than it's helping as you pointed out at the last VIR N round
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Old August 31st, 2015, 05:29 PM   #6
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Took apart the caliper and it was clean as a whistle. I just regreased the right slide since it was a little dry. The pistons moved smoothly and had no tarnish. I took off the stainless line, reconnected the stock line, and flushed it twice. Now the brake pressure is where it was before, which wasn't great but better than with the stainless line. With the Galfer, the pads grabbed at the grip. With the stock line, it grabs at a little more than half pull, which is awful BTW. But, I can work with it.

Thinking back, both of the 250s I had had horrible braking pressure. I got around it by using aftermarket levers and extending the out as far as possible.

I'm going to order a caliper rebuild kit and a master cylinder rebuild kit. Hopefully they will fix whatever the issue is. I would love to just change MC, but my race org doesn't allow it, yet...

Last futzed with by gogoKawi; August 31st, 2015 at 07:28 PM.
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Old August 31st, 2015, 05:31 PM   #7
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MOTM - Mar '14
I want them to, it's a simple switch and I firmly believe that it is the biggest thing holding back our brakes from feeling like they should
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Old August 31st, 2015, 08:01 PM   #8
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Quote:
Originally Posted by gogoKawi View Post
Took apart the caliper and it was clean as a whistle. I just regreased the right slide since it was a little dry. The pistons moved smoothly and had no tarnish. I took off the stainless line, reconnected the stock line, and flushed it twice. Now the brake pressure is where it was before, which wasn't great but better than with the stainless line. With the Galfer, the pads grabbed at the grip. With the stock line, it grabs at a little more than half pull, which is awful BTW. But, I can work with it.

Thinking back, both of the 250s I had had horrible braking pressure. I got around it by using aftermarket levers and extending the out as far as possible.

I'm going to order a caliper rebuild kit and a master cylinder rebuild kit. Hopefully they will fix whatever the issue is. I would love to just change MC, but my race org doesn't allow it, yet...
Another option is changing out the MC with one from a zx600c early models. It has a bigger piston, and bolts right up to the Ninjette.
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Old August 31st, 2015, 09:08 PM   #9
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Quote:
Originally Posted by Ghostt View Post
Another option is changing out the MC with one from a zx600c early models. It has a bigger piston, and bolts right up to the Ninjette.
not legal with our race org rules
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Old August 31st, 2015, 10:31 PM   #10
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not legal with our race org rules
Really?, its very hard to tell them apart, as the difference is a slightly bigger bore on the MC piston.





I remember reading about it somewhere, but can't seem to find it, anybody??

Note: I forgot this isn't a PreGen, so just forget what I've been posting LOL I really need need to pay attention where I'm at.
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Old October 10th, 2015, 01:05 AM   #11
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i have the same problem
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Old October 10th, 2015, 01:19 AM   #12
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i have the same problem
Have you serviced your calipers? See my write-up above
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Old October 10th, 2015, 01:44 AM   #13
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The reason is the stainless brake line, since it is not that easy to bleed.
In most cases those lines keep the air bubbles inside and often it will help to bleed the brake in the opposite direction, from the caliper back to the mc. A big syringe from the hospital with a hose on it will help.
Also what should be done is to tap (is this the right word?) the stainless line with a lightweight screwdriver to loosen the bubbles and make them go out.
Another thing which helps in most cases is to push the pistons in the caliper full way back, maybe then tighten it to not come out while bleeding.
Stainless brake lines are good but not so easy to bleed.
And if you would spend some money then here is the best solution http://www.stahlbus-us.com/index.php...-bleeder-valve
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