Brake fluid light and bleeding the brakes.

[sefner]

I've had an intermittent brake fluid warning light since I bought this bike(84' Royal) last summer. Pads are new all around and the both reservoirs were/are full. Brakes seemed to operate fine.

 

I decided to bleed the brakes thinking that might help. I'm new to bleeding the brakes on motorcycles, but I have done this on cars as a kid. I bought a mightyvac to help with the process. Not sure if I'm bleeding the system right due to my inexperience. I bled from the metering valve, then the left front, then the rear. Then I bled the right front. The mightyvac seemed to always pull air bubbles... I started using the mightyvac just get everything primed and then finished off by pumping the pedal, holding it down, opening the bleeder valve and re-tightening. I continued this sequence as often as needed to make sure there were no air bubbles.

 

Brakes seem to work fine, but the warning light is now on all the time... I then removed the rear reservoir lid(this sucks) to check that the rubber boot and float were OK. There was some black sludge in the bottom of the reservoir so I drained and cleaned the inside. I pumped lots of Dot 3 to flush everything. Put it all back together and the warning light is still on. I also noticed that my pads seem to touch the rotors even when I am not applying the pedal. The wheels do turn, but with some resistance. Is this normal? I'm open for some suggestions. Thanks. Vince

[Venturous Randy]

This is probably not brake fluid level related. You may need to check the connections and clean them that go from the reservoirs. You also may need to look at the pin terminals in the CMS in the middle of you dash.

I suspect if you are loosening the bleeder valve, putting a hose on it and them pulling a vacuum, you are probably pulling some air in around the threads of the valve.

RandyA

[bobcat]

I had a similiar problem on my 86..wound up the float in the brake resevoir on the rt handlebar was stuck..I took the lid off the resevoir and tapped the float, it rose to the top and the red warning light went out...

 

All fixes should be that easy....

BTW: Are you sure BOTH resevoirs are full? ( Had to ask)

Edited April 5, 2009 by bobcat

[Squidley]

If you have black sludge in the reservior the system needs to be completely cleaned. I know you didn't want to hear that, but there is a return oriface in the rear master cylinder that can get clogged and lock the rear brake up. You do also know that the 1st gen has a linked brake system, the rear petal controls the rear caliper and the left front one. Make sure that you have the system properly bled, there is a bleeder up by the top of the stering head on the right side for bleeding the front.

[bongobobny]

Yah, my guess is a stuck float as well, especially if you are seeing sludge in the resovoir. That being the case I DEFINATELY recommend rebuilding components. The only alternative for brakes on a motorcycle is to find something soft to hit...

[GeorgeS]

First thing to do is Replace ALL of the Fluid.

 

Pump a lot of fluid thru all 3 Calipers. Use Valvoline " Synthectic " fluid.

 

Just doing that might clear up the problem. If not, then most likley you are looking

at rebuilding the Master Cylinders, and the Calipers.

 

I assume your talking about an 84 ? If so, and System has never been rebuilt, then

most likley you need a complet brake system rebuild. ( Age, not miles, is the factor )

Edited April 5, 2009 by GeorgeS

[sefner]

Thank you for your suggestions. My brakes seem to be working fine. Just the darn warning light...

 

I think my bleeding procedure was correct for an 84' linked brake system. The dot3 I found in the system before flushing was on the darker side, so I used nearly 2 large bottles of dot3 to flush and fill. I wasn't getting any sludge while bleeding, but the little found in the bottom of the rear reservoir I cleaned using q-tips. The floats move freely in both reservoirs. How does the rubber boot under the lid work? It seems to be in good condition on both.

 

A complete break overhaul isn't something I'm sure I can tackle yet. Sounds like fun though. Not!

 

There seems to be wires that run from each reservoir. Do these connect at the reservoir, can I just pull them to clean the connectors? Also, would I just need to reheat the solder joints on the circuit board behind the dash panel to make sure none have cracked loose? Thanks for your help. - Vince

[Rocket]

There seems to be wires that run from each reservoir. Do these connect at the reservoir, can I just pull them to clean the connectors? Also, would I just need to reheat the solder joints on the circuit board behind the dash panel to make sure none have cracked loose? Thanks for your help. - Vince

 

To check the rear sending unit operation. Follow the wire up the right frame tube, disconnect the wires & put in a jumper on the main harness side. power up the bike for the CMS to cycle through & see if the indicator stays off. You can do a similar test for the front sending unit (connection behind the headlight). This should narrow down the cause, of the warning light, if both reserviours are full. If these bypasses do not affect the warning light operation, then the CMS is probably at fault.

[Ivan]

The problem with the Mighty Vac system of bleeding brakes is that Mighty Vacs pull bubbles from some other dimension, kinda like the Zero Point Module on Stargate Atlantis. The point is that you will never get a perfect bleed with the Mighty Vac. They are GREAT for moving lots of fluid fast or up hill though. But you must ALWAYS finish with the standard procedure of open-stomp-close-relax. to get all the bubbles out.

[sefner]

The problem with the Mighty Vac system of bleeding brakes is that Mighty Vacs pull bubbles from some other dimension, kinda like the Zero Point Module on Stargate Atlantis. The point is that you will never get a perfect bleed with the Mighty Vac. They are GREAT for moving lots of fluid fast or up hill though. But you must ALWAYS finish with the standard procedure of open-stomp-close-relax. to get all the bubbles out.

 

I finally learned that after 1 bottle of dot3 and a phone call to my master mechanic (my Dad). :-)

 

I did try using a jumper on either reservoir to isolate which system is causing the warning light to ruin my weekend. Still no luck. This little light of mine still shines no matter what. I took the bike for a test drive because the light did go out after I cleaned the connections and re-joined them. I thought that was it, a loose connection. Rode for a short while and the warning light came back on... Brakes are fine, but I'm losing more hair. :-)

[Condor]

I finally learned that after 1 bottle of dot3 and a phone call to my master mechanic (my Dad). :-)

 

I did try using a jumper on either reservoir to isolate which system is causing the warning light to ruin my weekend. Still no luck. This little light of mine still shines no matter what. I took the bike for a test drive because the light did go out after I cleaned the connections and re-joined them. I thought that was it, a loose connection. Rode for a short while and the warning light came back on... Brakes are fine, but I'm losing more hair. :-)

 

The rear reserve has a pleated type baffle/gasket. When the baffle is extended out all the way it will push the sensor float down and give a false fluid level reading. Happened to me on the '83. Since removing the reserve top is a PITA, I used a wire hook thru the fill hole to get a couple of the pleats compressed and the red light disappeared. Not perfect but effective.

Edited April 6, 2009 by Condor

[sefner]

The rear reserve has a pleated type baffle/gasket. When the baffle is extended out all the way it will push the sensor float down and give a false fluid level reading. Happened to me on the '83. Since removing the reserve top is a PITA, I used a wire hook thru the file hole to get a couple of the pleats compressed and the red light disappeared. Not perfect but effective.

Thanks Condor. I read your previous posts about that, but I guess I didn't quite understand until now. Lightbulb moment I guess. I just looked at baffle to see if was shaped right, no holes, etc. I'll try the "hook" trick to see if it's causing my problems.

[Condor]

Thanks Condor. I read your previous posts about that, but I guess I didn't quite understand until now. Lightbulb moment I guess. I just looked at baffle to see if was shaped right, no holes, etc. I'll try the "hook" trick to see if it's causing my problems.

 

If you already have the baffle out where you can inspect it, then my last, and the previous post are mootas they were about doing the 'adjustment' with the reserve still installed. Just make sure the pleats are folded. Sorry about the double post. I didn't mean to repeat myself....old age I guess...

[sefner]

I meant I had read previous posts in another thread(s) where someone had a similar issue with the warning light. No senility involved with that one. :-)

 

Yeah, I had the lid off to check it out. It seemed just fine. It may have gotten messed up reinstalling the lid though. Very tight quarters in there... I'll check to see it's interfering with the float though.