Soft brakes after bleed

[AVI8_636]

Last season while going through tech at the track, a few guys agreed that my brakes needed bleeding since they were pretty soft, but still safe for the time being. I just took the 636 out of storage last week and bled the brakes and replaced the fluid. It was my first time bleeding brakes, but I followed a step by step guide and thought it went well, however my brakes are even softer than they were before. I took the bike for a test ride and when pulling the front brake, it's soft and the brakes gradually bite rather than immediately being effective. Anyone have any idea why this would be? I didn't see any bubbles while bleeding (I used a clear hose, and finished the bleeding when clean fluid started coming out).

[CBR929RE]

air in there somewhere. keep bleeding.

[stoinkythepig]

If you are bleeding by squeezing the lever, the problem is likely that the flow is too slow to drag air bubbles down to the bleed valve. The bubbles will rise back up toward the the brake line, in between lever squeezes, and never come out. Try pulling the calipers off the forks and lift them in the air when you bleed. Put a piece of 1/4 plywood between the pads to keep them from filling the gap left by the rotors. You'll clearly need help for this.

I know some people hate them, but I have had great success for 20+ years with a mity-vac vacuum bleeder. I put teflon tape on the bleeder threads to keep air from leaking in and reducing the effectiveness of the vacuum pump.

[Stromper]

Yes any helper will help a lot

Squeeze slowly while you work the nipple

Hose smoz

Also bleed your banjos too capture fluid in a rag if on bike rinse quickly and thoroughly

If your friendless then take a bleeder to a good parts store

Use it to mach it with an auto bleeder nipple about $9 plus on the copious use of tfe tape for sealing
The auto bleeder has a check valve so you can't suck air back in

[Aprilia Pilot]

Take a look at how the line comes off the master cylinder. If its "uphill" there could be air trapped at that point. i often take the master off and orient it the other way so air will travel up to the reservoir and tap it while moving the lever.

[G21forme]

I zip tie a couple beer cans to my front with 1/4" tubes to my front stand and bleed until clear, has always worked for me but I have Superbike lines so it may be different I think we have the same bike and it's always worked for me.

Sent from my SCH-I535 using Tapatalk

[AVI8_636]

If you are bleeding by squeezing the lever, the problem is likely that the flow is too slow to drag air bubbles down to the bleed valve. The bubbles will rise back up toward the the brake line, in between lever squeezes, and never come out. Try pulling the calipers off the forks and lift them in the air when you bleed. Put a piece of 1/4 plywood between the pads to keep them from filling the gap left by the rotors. You'll clearly need help for this.

I know some people hate them, but I have had great success for 20+ years with a mity-vac vacuum bleeder. I put teflon tape on the bleeder threads to keep air from leaking in and reducing the effectiveness of the vacuum pump.

When you say slow flow, will the bubbles ever come out? Or does it just take a very long time and a lot of lever squeezing? I don't have a vac pump but I've definitely read a lot about the mity-vacs.

Take a look at how the line comes off the master cylinder. If its "uphill" there could be air trapped at that point. i often take the master off and orient it the other way so air will travel up to the reservoir and tap it while moving the lever.

Thanks for the tip, I'll go take a look and see if mine is setup that way.

I zip tie a couple beer cans to my front with 1/4" tubes to my front stand and bleed until clear, has always worked for me but I have Superbike lines so it may be different I think we have the same bike and it's always worked for me.

Sent from my SCH-I535 using Tapatalk

Might have to try that trick with the zip ties.

[stoinkythepig]

When you say slow flow, will the bubbles ever come out? Or does it just take a very long time and a lot of lever squeezing? I don't have a vac pump but I've definitely read a lot about the mity-vacs.

I don't think you can squeeze, wrench on bleeder and ensure the reservoir does not run dry fast enough by yourself, so the air bubbles never flow down to the calipers.

[Paul_E_D]

Easiest way to get air out is to back bleed. Get a syringe at CVS, fill it with fluid and press the plunger till all air is out of the hose (just like a doctor, LOL) and then PUSH fluid from the caliper to the master res. Then a couple of squeeze bleeds and you will have awesome brakes.

[reks95]

I've seen people recommend zip tying the brake lever overnight to let whatever bubbles are left rise to the reservoir.

[Uncle Snake]

Easiest way to get air out is to back bleed. Get a syringe at CVS, fill it with fluid and press the plunger till all air is out of the hose (just like a doctor, LOL) and then PUSH fluid from the caliper to the master res. Then a couple of squeeze bleeds and you will have awesome brakes.

This

I've seen people recommend zip tying the brake lever overnight to let whatever bubbles are left rise to the reservoir.

This will improve a good handle but not make a poor handle good.


.

[Kurlon]

I don't think you can squeeze, wrench on bleeder and ensure the reservoir does not run dry fast enough by yourself, so the air bubbles never flow down to the calipers.

I use a tube on the bleeder, arched up so while I'm bleeding there is a column of fluid over the bleeder. Once that is established I leave the bleeder open and pump away while watching the resi. The column of fluid ensures that I don't back-suck air between pumps.

[AVI8_636]

I use a tube on the bleeder, arched up so while I'm bleeding there is a column of fluid over the bleeder. Once that is established I leave the bleeder open and pump away while watching the resi. The column of fluid ensures that I don't back-suck air between pumps.

I thought you weren't suppose to leave the bleeder open while pumping even if you have fluid in the tube? Wouldn't that just cancel out since the fluid will get sucked back in when releasing the lever?

[Kurlon]

You get a small bit of reversion, but nothing matching how much you just pushed out. You can drain a resi pretty quick this way.

[SVRACER01]

pull the calipers and pump up the brakes a little (not too much to cause the pucks to come out). take the cap off the resivoir and then press the pucks back in. if theres any trapped air in the calipers that should get it out.
you could also try the old zip tie the brake lever to the bar and leave it over night. the pressure from the fluid should make the air work its way to the top.
you could also need a master cyl rebuild

[jasnmar]

http://www.speedbleeder.com

Makes bleeding much more doable for a person with only 2 hands.

[SVRACER01]

http://www.speedbleeder.com

Makes bleeding much more doable for a person with only 2 hands.

dude, this is 2014...who still has only 2 hands?
what else you got? a nextel?

[Viper897]

I 2nd the speed bleeders, makes it easy to pump and not get air in the system. Also orienting the mc so air rises to it is key as said previously.

[AVI8_636]

So I bled them again last night, and did have some bubbles coming out. I took it for a quick ride and they're better, but still not what they should be. I think I might go the speed bleeder route.

[nhbubba]

I've been having problems bleeding my V-Strom as well. No matter what I seem to do, I wind up with soft brakes.

I tried the mity-vac. Pumped half a bottle of fluid through and still had nothing but bubbles. Had not tried Dave's teflon tape trick though. (And I should.)
Gravity bleed. Nope.
Traditional bleed. Better, but still not great.

I finally broke down and bought speed bleeders. Installing them is on my todo list.

[Paul_E_D]

BACK BLEED. You will be rock hard. LOL

[nhbubba]

I'm still not clear on how that doesn't add air to the system. Are you using a very large syringe?

[nhbubba]

Hmmm... Youtoob has our back:

[keeena]

I've tried speed bleeders and never liked them, I think its easier and simpler w/o them.

Yes, you use a large syringe. Get a few of them, helps to have an extra to pull fluid from the res.

Pumping the brake lever between bleeds, pushing the slave cylinders in and tapping the calipers are all good for helping jog stuck air bubbles.

[Petorius]

You can get big farm syringes from Tractor Supply Co.

If you let the lines or even just the reservoir go dry, you can get a stubborn bubble in the MC in front of the piston. Then when you squeeze the lever, the bubble compresses in the cylinder instead of getting pushed down the lines. If you dont want to back bleed or use a mityvac, you can try bleeding the MC by cracking the MC banjo the same way you would open the bleed nipple on the caliper. I never do this because I am anal about using fresh crush washers and I have had good luck with the mityvac, but its worth a shot.

Also on the topic of speed bleeders- I dont understand why folks hate these so much. Don't try to install them with dry lines, but they are great for routine bleeding. I agree that the standard process is very easy as well, but for the truly lazy you cant beat the speed bleeders.