New hawk250 rear brake issue

WWRAFTER · 02-01-2018, 03:31 PM

Have a couple weeks on the bike and have had a problem with the rear brake since assembly. They haven’t held any pressure in the system even after the initial flush. On the first ride, the rear brake faded and would not stop the bike. While bleeding, it continued to push air out, even after several ounces of fluid. I suspect a leak in the slave cylinder (noticed brake fluid during assembly). What is the best way to rule out faulty seals and location. If I can figure this out I can have the part shipped out on warranty.
Thanks, Russ.

Megadan · 02-01-2018, 03:44 PM

Do you still find any wet spots on the braking system after riding? If it introduces air while simply bleeding, and it is indeed a leak, it shouldn't be too hard to locate said leak.

Otherwise, the fading out while riding can also be caused by the rear brake adjustment. This is a common issue with new bikes. If there is no free play in the pedal then it will put a tiny bit of pressure on the brakes. As you ride the brakes will rub and slowly heat up, eventually leading to brake fade.

ben2go · 02-01-2018, 10:07 PM

Bad crush washers on the banjo fittings will leak and also allow entry of air into the system. A little piece of grit in the master cylinder will also cause brake fade or loss of pressure like the system is full of air. I am experiencing that on my current bike. I need to tear it down and clean it out. I just don't have time to fool with it.

WWRAFTER · 02-01-2018, 11:01 PM

I have not noticed any brake fluid after riding, but I’m not sure I could tell, the bike has been getting pretty wet from the riding terrain. I have the brake pedal adjusted with quite a bit of travel (I’m adjusting it at the master cylinder), although it doesn’t start actuating the brakes until almost to the end of the pedal travel.

WWRAFTER · 02-01-2018, 11:07 PM

Quote:

Originally Posted by ben2go

Bad crush washers on the banjo fittings will leak and also allow entry of air into the system. A little piece of grit in the master cylinder will also cause brake fade or loss of pressure like the system is full of air. I am experiencing that on my current bike. I need to tear it down and clean it out. I just don't have time to fool with it.

Any idea where to source the crush washers? Air is definitely getting into the system, no matter how much I bleed it, I’m getting air pushing out the bleeder valve on each cycle.

ben2go · 02-02-2018, 09:35 PM

Quote:

Originally Posted by WWRAFTER

Any idea where to source the crush washers? Air is definitely getting into the system, no matter how much I bleed it, I’m getting air pushing out the bleeder valve on each cycle.

Any auto parts stores will have them. Take in your banjo bolt for the brake line to get the right size. I think they are 10mm. I prefer the copper ones but the aluminum ones work well.

I don't know what fluid you are using but I use Valvoline DOT3/4 and it works well. It seems to bleed easier than moto spec brake fluids. It could be all in my mind too.

Azhule · 02-03-2018, 02:32 AM

Mag 1 makes a really good DOT 4 brake fluid too, keep an eye on amazon to pick a case of them up for cheap

WWRAFTER · 02-03-2018, 10:04 PM

Thanks guys. Going to be a couple day soon before I can try anything else out. Thanks for the info Ben.

ben2go · 02-03-2018, 11:08 PM

Quote:

Originally Posted by WWRAFTER

Thanks guys. Going to be a couple day soon before I can try anything else out. Thanks for the info Ben.

You're welcome.

02-01-2018, 03:31 PM	#1
WWRAFTER Join Date: Jan 2018 Location: Grants Pass, OR Posts: 18	New hawk250 rear brake issue Have a couple weeks on the bike and have had a problem with the rear brake since assembly. They haven’t held any pressure in the system even after the initial flush. On the first ride, the rear brake faded and would not stop the bike. While bleeding, it continued to push air out, even after several ounces of fluid. I suspect a leak in the slave cylinder (noticed brake fluid during assembly). What is the best way to rule out faulty seals and location. If I can figure this out I can have the part shipped out on warranty. Thanks, Russ.
	0

02-01-2018, 03:44 PM	#2
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,110	Do you still find any wet spots on the braking system after riding? If it introduces air while simply bleeding, and it is indeed a leak, it shouldn't be too hard to locate said leak. Otherwise, the fading out while riding can also be caused by the rear brake adjustment. This is a common issue with new bikes. If there is no free play in the pedal then it will put a tiny bit of pressure on the brakes. As you ride the brakes will rub and slowly heat up, eventually leading to brake fade. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
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02-03-2018, 02:32 AM	#7
Azhule Join Date: Dec 2015 Location: CO Posts: 1,525	Mag 1 makes a really good DOT 4 brake fluid too, keep an eye on amazon to pick a case of them up for cheap __________________ "Think as you like... but this self proclaimed Professor is always right" - Buckshot "You never know what someone is hiding beneath their smile..." - NinjaTom - R.I.P.
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02-01-2018, 10:07 PM	#3
ben2go Join Date: Jun 2011 Posts: 1,335	Bad crush washers on the banjo fittings will leak and also allow entry of air into the system. A little piece of grit in the master cylinder will also cause brake fade or loss of pressure like the system is full of air. I am experiencing that on my current bike. I need to tear it down and clean it out. I just don't have time to fool with it.
	0

02-01-2018, 11:01 PM	#4
WWRAFTER Join Date: Jan 2018 Location: Grants Pass, OR Posts: 18	I have not noticed any brake fluid after riding, but I’m not sure I could tell, the bike has been getting pretty wet from the riding terrain. I have the brake pedal adjusted with quite a bit of travel (I’m adjusting it at the master cylinder), although it doesn’t start actuating the brakes until almost to the end of the pedal travel.
	0

02-03-2018, 10:04 PM	#8
WWRAFTER Join Date: Jan 2018 Location: Grants Pass, OR Posts: 18	Thanks guys. Going to be a couple day soon before I can try anything else out. Thanks for the info Ben.
	1