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need help...front brake

  • Thread starter Thread starter boathead
  • Start date Start date
B

boathead

Guest
i was just beginning to bleed the front brake....squeezed the lever, opened the bleed valve..

some fluid came out of the bleed valve, so i am thinking all is great. closed the bleed valve, and then released the lever...and it was lax. nothing. i can move the lever freely back and forth, it is simply swinging in the wind.

i took off the banjo fitting, and no fluid is getting through.

what to do? please steer me in the direction i need to go. the fluid that is in the resevoir was black. i am sure it was not changed in the longest time. is it possible that something lodged in the bottom when the initial bleed pump occurred?
 
Your best bet is to remove the MC, take it apart and clean it. There are a couple of very small passage in the MC that if clogged will not allow fluid to return.
Black fluid in the reservoir is old and saturated with moisture, you don't want that in your brake system. Rebuild kits are available that will include the piston, spring and seals. Once you put everything back together flush out the lines with some fresh fluid.

Does your bike have dual calipers? The manual has a bleed procedure for this type of setup.
 
It looks to me as if the master cylinder piston has seized or jammed in the bore of the MC. Maybe being pushed in to an area where it has not been before when you were bleeding the brakes. If the fluid in the MC was that black then you need to disassemble the MC anyway and give it a good cleanout.
 
i have a clymer manual. yes, dual caliper.

and now the stupid questions....

does the brake lever push on the master cylinder?

and when i take everything off, what should i clean it with? brake cleaner? or any solvent?

and yes, i suppose it feels like something got jammed in there.

also, there are some wires attached at the bottom of the brake lever. what are they?

you guys are the best. what a wonderful resource.
 
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The brake lever pushes the piston into the MC bore. Your best bet is to clean everything with clean brake fluid. When you get it apart make sure that the MC bore is rust free and does not have deep scratches. I think the manual should have some measurement specs (tolerances) for the bore and piston. Hopefully your piston is not jammed in the bore. The hardest part is getting the snap ring off the MC, you either need long nose snap ring pliers or a scribe to work it out of its bore. Rebuild kits are available from OEM parts suppliers.
 
tentatively, i think i fixed it with your help. i pulled out the piston with needle nose pliers, and it sprung back into position. cleaned what i could, reattached the lever, and put the assembly back on the bike. put in brake fluid, and continued the bleeding process with success. there is good pressure at the lever, and the piston is moving freely.

as i type, taking the mc apart is beyond my abilities. i will ask a friend to come over and take a look at it, but at least i can move the darn thing now.

this afternoon's project will be trying to get the brake light switch back on. as i was taking it off, a little piece fell out before i could see where it went. i might be screaming for help later on. plus, i saw on ebay a replacement switch kit, and it shows a little spring...i have no spring, or if i did, the spring sprung....only god knows where.

thanks for the help fellas.
 
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tentatively, i think i fixed it with your help. i pulled out the piston with needle nose pliers, and it sprung back into position. as i type, taking the mc apart is beyond my abilities. i will ask a friend to come over and take a look at it, but at least i can move the darn thing now.

this afternoon's project will be trying to get the brake light switch back on. as i was taking it off, a little piece fell out before i could see where it went. i might be screaming for help later on. plus, i saw on ebay a replacement switch kit, and it shows a little spring...i have no spring, or if i did, the spring sprung....only god knows where.

thanks for the help fellas.

The brake light switch assembly is still avalible from Suzuki....you can get it from bikebandit or flatoutmotorcycles or even your local dealer...
It doesn't cost much, I just got one myself.
 
i might have to buy one, but i think i have a working one. mine was working just fine until i pulled it apart! i'll know this afternoon.

bikebandit's schematic identifies as "contact holder" as the little piece that i didn't see where it came from. i have the piece, just don't know what the heck to do with it.
 
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Concerning your master cylinder, be sure you clean out the very small hole in the bottom that equalizes the pressure from the lines to the reservoir when the handle is not being pushed. Very easy to miss, can have serious problems if it's missed.

Cleaning anthing that uses brake fluid, like the inside of the master cylinder or the calipers, should only be done with clean brake fluid. Solvents, including brake cleaner, can mess things up.

You may not have to buy parts for your brake switch. Your clutch 'safety' switch is the same thing. You can move parts from the clutch side to the brake side, then go into the headlight housing and bypass the wires going to the clutch switch. The good side of that is that you will no longer have to hold the clutch to use the electric starter. The bad side of that is that, if the bike is in gear when you push the starter button, the bike will move, so make sure it's in neutral or you have the clutch pulled.

.
 
You can just use a spring from a ball point pen to make a replacement. Just cut it to length, it worked for me. While your at it shine up the copper "u" and the contacts on the board with the wires then a little dieletric grease before you put it back together.
P.s. the contact strip is adjustable it will slide a little on the 2 screws so you can set when the brake light comes on.
 
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ok, sure enough, i need a bit of help.

i am trying to figure out what to do with the "contact holder" (that is what bikebandit calls it), the little piece that sits on top of the wire contraption, and i guess it is activated by the brake lever.

looking underneath the mc unit, where it all attaches, i see the brake lever, and two slots. i assume i have to situate this piece into one of the two slots????

if so, which one? towards center, or towards the right?

and is it this piece that is moved by the lever, or is it the adjustable contact pad that moves?
 
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ok, i think i figured it. but, i am thinking that the wire pad, the thing with the two wires, is worn. i got the brake light to work for maybe 2 minutes, but when i tightened everything, nothing. another hour of playing around, and only inconsistant results.

would it be reasonable to simply assume that the worn copper wires are not providing the contact i need?

or am i just being dumb?
 
The switch is adjustable, try loosening the screws up a little and sliding the switch one way or another and seeing which direction you need to move it to get the light to work properly.

Regarding your brakes, sorry to say it but you really need to do a full system tear down and replace the lines. That black crud is all over your brake system and if you don't clean it out, your brakes could lock up at any time and pitch you on the ground. The lines have a scale on the inside which is why then need to be replaced but the master and calipers can be cleaned out and the parts reused if they are in good condition.

Good luck.
 
thanks, nessism. you said what was sort of lurking in my mind, only didn't want to confront it. i guess i'll search for the lines, and i guess i'll become a pro at brake disassembly and cleaning.
 
I'd have to second what Nessim posts about doing the brake tear down.

And, really, I have no great gift for mechanics, but it really isn't difficult if you don't mind taking it slowly and going step by step.

This forum is a great resource. I found my reservoir full of black crud too, and the fluid coming out of my lines was just as dark. I'm in the middle of a break system tear down and the parts can all be found on-line.

It's not as expensive as you would think, either.
 
The hardest part of the entire job is getting the snap ring out of the MC. Once you get this out everything just falls out. Clean it up and replace the parts..your done. Caliper rebuilding is also pretty easy..the hardest part is inserting the piston in the bore. Take your time and go slow because if the piston is not square in the bore and you remove it you'll more than likely tear the seal. I used a socket and a vise to press the piston in.
 
The hardest part of the entire job is getting the snap ring out of the MC. Once you get this out everything just falls out. Clean it up and replace the parts..your done. Caliper rebuilding is also pretty easy..the hardest part is inserting the piston in the bore. Take your time and go slow because if the piston is not square in the bore and you remove it you'll more than likely tear the seal. I used a socket and a vise to press the piston in.

Piston needs to push in with finger effort or something is wrong. Agree with keeping it square though.

Biggest issue with rebuilding brake systems seems to be getting the master cylinder primed so it will pump. A brake bleeder vacuum pump really helps here. And don't forget to grease the sliding caliper pins with high temp caliper grease - available from better auto parts stores.
 
Piston needs to push in with finger effort or something is wrong

That ain't happening on my calipers unless you have fingers like a hydraulic press. With new pistons and seals there is no way I would have the strength to push the piston in until it bottoms in the bores. The MC piston can be put in with finger pressure but not the calipers.
 
That ain't happening on my calipers unless you have fingers like a hydraulic press. With new pistons and seals there is no way I would have the strength to push the piston in until it bottoms in the bores. The MC piston can be put in with finger pressure but not the calipers.

Sounds like something is wrong. Not that I'm an expert or anything, but I've done the calipers on about half a dozen bikes and I've never experienced what you are saying. Did you lube the piston and seals with brake fluid before you installed the piston?
 
The hardest part of the entire job is getting the snap ring out of the MC. Once you get this out everything just falls out. Clean it up and replace the parts..your done. Caliper rebuilding is also pretty easy..the hardest part is inserting the piston in the bore. Take your time and go slow because if the piston is not square in the bore and you remove it you'll more than likely tear the seal. I used a socket and a vise to press the piston in.

where to i start my attack? looking into the mc, i see the piston, but some sort of rubber...i don't want to say gasket...or seal...but it sort of flops around loosely as the piston is depressed.

is this where i start? and how to get that rubber out so i can at least see what i am dealing with with the snap ring?
 
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