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Replacing Caliper Question

It could be that the m/c piston needs rebuilding...seals are worn/damaged so no compression of fluid, or corrosion has eaten away metal in crucial area. Either way, I would try flushing the entire system, noting the condition of the fluid. If clean and just clear...and silicone based DOT 5 is just old (should be purple). If DOT 3 or DOT 4 it should be pale honey clear...if brown or black, it has contamination from old seal "slough off", corrosion/oxidation deposits and water. Depending on how long it has been in low lying areas, it can cause local corrosion and metal galling. You may have to do the rebuilding of the calipers as well...perhaps even replacing the hoses and such...are all the rubber parts in there original?
 
NEWHD74FAN said:
It could be that the m/c piston needs rebuilding...seals are worn/damaged so no compression of fluid, or corrosion has eaten away metal in crucial area. Either way, I would try flushing the entire system, noting the condition of the fluid. If clean and just clear...and silicone based DOT 5 is just old (should be purple). If DOT 3 or DOT 4 it should be pale honey clear...if brown or black, it has contamination from old seal "slough off", corrosion/oxidation deposits and water. Depending on how long it has been in low lying areas, it can cause local corrosion and metal galling. You may have to do the rebuilding of the calipers as well...perhaps even replacing the hoses and such...are all the rubber parts in there original?
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All of the parts in the caliper are new, as the caliper was sent out for chroming, and all new parts put in after that. Everything is DOT 5. I didn't have any issues with the M/C prior to placing the new caliper on. I just simply drained all of the fluid, replaced the caliper, refilled the fluid, and am at this point now. Thanks again for the diagnosis though.
 
Hard to know how far to go with troubleshooting with knowledge the bike is a 2002...is a long time for the braking components. Most can easily forget that there are neoprene/rubber seals and hoses deteriorate with age, but internally.
 
cmvsm said:
That's where I actually have my problem then, as the lever goes all the way to the handgrip. There is no resistance that I can feel. The fluid seems to remain in the master cylinder and not freely travel through the line to the caliper. Not sure why that is, as it was doing fine before I changed the caliper out. The caliper is new, so there shouldn't be any issues there.

Any suggestions on how to get the fluid moving through the line so I can begin building pressure? Thanks.
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I have had the same problem as the shape of my bars even with the wheel turned to the left puts the banjo bolt at the highest point and the air in the brake line will stop there
the brake fluid cant get in because of the air when pulling the brake leaver the air just compresses
get a large syringe put a bit of flexible see through pipe on it fill with brake fluid fit on to caliper bleeder ensure master cylinder is empty and the top cover is lossley fitted depress plunger on the syringe forces brake fluid from the bottom and pushes the air out the top when you feel resistance on the plunger then the brake fluid has got to the piston in the master cylinder further effort will cause the brake fluid to squirt out of the small hole in the master cylinder so stop there and bleed as normal
difficult front brake done in 10 mins

Brian
 
nice tip Brian. Does sound like there's some air in that line. You definitely need some type of lever pressure when you depress the lever, to get the line pressurized and have the line pressure assist with pushing any air pockets up and out towards the master cylinder. So gotta get that addressed first. If you can't get any lever pressure working, those speed-bleeders are not going to work for you until you get some level of pressure built up in your brake line.

I'd either try what Brain suggested or if you have a mity-vac, use that. Mity-vac's are mighty handy to have in your toolbox. You can also try cracking that banjo bolt and see if you can get that air pocket to escape by cracking the bolt. Pump the lever - hold lever depressed and gently crack the banjo bolt, tighten banjo bolt back and release lever pressure. Same process as when normally bleeding a brake line at the bleeder valve. Do that a few times and see if you can get some pressure into your line. Cover your work area good as you don't want any brake fluid to get onto your tank, fenders, etc when you do that.
 
I personally dont like most of the 1 man bleeding systems as most seem to allow a little air back into the system as the bleeder seals at the cone on the base of the bleeder once loosened off the threads of the bleeder can allow air to be drawn into the calliper
so i apply pressure to the brake leaver open the bleeder close the bleeder and release the brake leaver then the only draw into the system is from the master cylinder

But first you need to get the brake fluid into the system

Brian
 
Everyone has their own favourite way to do this stuff. When the system has been completely open and there is no fluid in it, this is what I do:

  • Attach a clear tube to the bleeder (not speed bleeder) and put that in a clear glass jar.
  • Fill the master with clean new DOT 5.
  • Put a bungie cord on the brake lever holding it open
  • Open the bleeder valve
  • Let it gravity feed until the master is almost empty, and refill master
  • When the master is almost empty again, close the bleeder
  • Using a large syringe, inject clean brake fluid (no air) into the clear hose until the master is "full"
  • Close the bleeder and disconnect the clear tubing
  • Leave the brake lever tied open over night so that any remaining air bubbles can migrate up to the master
  • In the morning, pump the brakes until the pistons are pressing hard against the pads (and therefore the rotors)
  • Top up the master as required
Done on the front.

Rear you have to do the old fashion way. Pump it up and then bleed it into a jar with brake fluid covering the end of the tubing. Have the jar and tubing ABOVE the bleeder valve. Keep pumping and refilling the rear master until there are no more bubbles coming out of the tubing.

TQ
 
TQuentin1 said:
Everyone has their own favourite way to do this stuff. When the system has been completely open and there is no fluid in it, this is what I do:

  • Attach a clear tube to the bleeder (not speed bleeder) and put that in a clear glass jar.
  • Fill the master with clean new DOT 5.
  • Put a bungie cord on the brake lever holding it open
  • Open the bleeder valve
  • Let it gravity feed until the master is almost empty, and refill master
  • When the master is almost empty again, close the bleeder
  • Using a large syringe, inject clean brake fluid (no air) into the clear hose until the master is "full"
  • Close the bleeder and disconnect the clear tubing
  • Leave the brake lever tied open over night so that any remaining air bubbles can migrate up to the master
  • In the morning, pump the brakes until the pistons are pressing hard against the pads (and therefore the rotors)
  • Top up the master as required
Done on the front.

Rear you have to do the old fashion way. Pump it up and then bleed it into a jar with brake fluid covering the end of the tubing. Have the jar and tubing ABOVE the bleeder valve. Keep pumping and refilling the rear master until there are no more bubbles coming out of the tubing.

TQ
Click to expand...

Shaking the hoses will help burp the air bubbles, try it:s
 
Ok, thought I'd give an update. Thanks again for everyone who gave advice...much appreciated.

First option was the syringe. Can't tell you how hard it is to actually find one big enough. Anyhow, went to inject the brake fluid in and the syringe exploded. Not good, so on to option 2.

I bought a bleeding kit for $25 at Harbor Freight. Same one that someone recommended on the forum! Hooked it up and worked like a champ. Pulled the fluid right through the entire system in no time. The lever now goes roughly half way back and is firm at the end. Ideally, how far should the lever be pulling back, and should I be looking for spongyness at the end of the pull?

Now my other question. Just an odd observation. I was rolling my bike back and forth to ensure that the pads were stopping the bike in both directions, which they were. Feels similar to what it was before replacing the caliper. However, when rolling the bike forward, hitting the brakes, the forks seem to dive a little more than they were before, and then they stick right where they are. So I roll the bike backwards, hit the brakes, and the forks come up and stick right where they are.

Maybe I just didn't notice before, but seemed a bit odd as before I don't believe that the forks moved at all during the roll back and forth exercise before. Am I just dillusional or is there something to it?
 
cmvsm said:
Ok, thought I'd give an update. Thanks again for everyone who gave advice...much appreciated.

First option was the syringe. Can't tell you how hard it is to actually find one big enough. Anyhow, went to inject the brake fluid in and the syringe exploded. Not good, so on to option 2.

I bought a bleeding kit for $25 at Harbor Freight. Same one that someone recommended on the forum! Hooked it up and worked like a champ. Pulled the fluid right through the entire system in no time. The lever now goes roughly half way back and is firm at the end. Ideally, how far should the lever be pulling back, and should I be looking for spongyness at the end of the pull?

Now my other question. Just an odd observation. I was rolling my bike back and forth to ensure that the pads were stopping the bike in both directions, which they were. Feels similar to what it was before replacing the caliper. However, when rolling the bike forward, hitting the brakes, the forks seem to dive a little more than they were before, and then they stick right where they are. So I roll the bike backwards, hit the brakes, and the forks come up and stick right where they are.

Maybe I just didn't notice before, but seemed a bit odd as before I don't believe that the forks moved at all during the roll back and forth exercise before. Am I just dillusional or is there something to it?
Click to expand...
I think you got it, now go for a ride and make sure they work good:s
 
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