Doug,
I don't think that it is either rotor because you can never get the lever to be a "full" pull. That is the brake will never pump up, just stays at the same amount of pull. Anything else? Thanks, Bob

 

Well...... sounds like you have covered about everthing I would........

Do the calipers slide feely on their pins? If one was hanging up, it may cause the piston to be shoved back in when the brake was releasd.

Doug

 

I have a Sporty 2001, which has the same issue. I changed the front brake line due to a handle bar change out. I bled it with gravity, a vacuum pump, "tickling" etc. It comes back from the rest position to within 1" approx of the grip before it becomes firm. Definetly travel, but I never paid that much attention to the action prior to changing the line. No air bubbles visible bleeding. One note, I never see "squirts" in the master cylinder when the lever is moved, is this normal? It worked fine before the line was changed or at least nothing that made me think there was an issue. Seems a lot of bikes are suffering from this malady.

 

Just curious here, everybody with this brake issue weigh in here....

How many with the soft front brake are running DOT 5 brake fluid?

Anyone using DOT 4?

 

I posted earlier, but I'm running the DOT 5 silicone per the manual. Not really crazy about it, as I've never had trouble with the other fluids when changed every two years.

 

I put a post at the top of this forum, weigh in there what you use for brake fluid.

 

I ran across this on the Bel-Ray site, which might confirm what we're all talking about.

Brake Fluids: DOT 4, DOT 5.1, and DOT 5 Silicone
Q: Sir Tech,
My bike’s brakes are currently filled with DOT 4. Is it true that I will get better performance if I switch to Bel-Ray Silicone DOT 5 Brake Fluid?

A: No, Years ago, many road race teams used DOT 5 silicone brake fluid to get higher boiling points than the DOT 3 & 4 brake fluids of that era. DOT 5 silicone is not hygroscopic, meaning it won’t absorb water from the air, so it retains its high boiling point over time. On the other hand DOT 3, 4 and 5.1 brake fluids are glycol based and do absorb water from the air, which then lowers the boiling point. That is why you will see wet and dry boiling points, with the dry boiling points always being higher. Glycol based brake fluids may start out with a fairly high dry boiling point but as they absorb moisture the boiling point decreases. So every time your brakes get really hot and then cool, condensation occurs and moisture is absorbed. That is why it is important to replace your brake fluid regularly. It may seem obvious that DOT 5 silicone is the best choice, but not so. Today most road race teams use DOT 4 or DOT 5.1 glycol based brake fluids because the dry and wet boiling points today are very high and in some cases higher than DOT 5 silicone. The number one reason not to use DOT 5 silicone is a slightly mushy lever or pedal feeling as compared to glycol based brake fluids. This is the nature of the product. Street riders may not feel the difference, but the race teams prefer the precise feeling of glycol. The only motorcycles that I know of rolling off the production line with DOT 5 silicone are Harley-Davidson® and other American made motorcycles; and that is mainly where we sell our Bel-Ray Silicone DOT 5 Brake Fluid. I recommend you stay with the DOT 4 fluid for performance, not to mention the enormous job it is to switch your system over from glycol to silicone. If that job is not done properly, you run the risk of coagulation if remnants of DOT 4 are mixed with DOT 5 silicone. I hope that’s not too much for you at once. Maybe you should read half, take a play break, then read the rest.

 

There are a lot of things that can cause a long pedal or lever before actuation. Just like in a car it often is not one thing, but a collection of very small things that that add up.

Get the front wheel off the ground, and spin it a few times. Then stop it by hand or let it come to a stop. Now everything is in the exact position it is when you ride. Take a close look at the pads and rotor. There should be very little space between them. The pads should look like they are resting on the calipers.

Now, while carefully watching the pads, slowly move the hand lever. Take carefull note of exactly when the pads start to move. They should start to move almost immediatly. If they do, the problem is not with hydraulic system. If not, now you have to start at the top and work your way down. Fixing all the little things that create slack between your fingers and the rotor. Off the top of my head, here's some things to check.

- Does the contact patch of the lever actually rest on the MC plunger? If not, add a little JB weld to build it up, and then file to fit.

- Does the plunger pop out too far? If so, then it won't build pressure until the plunger is back where it's supposed to be. Rebuild the MC.

- Does the plunger get stuck in the bore, and not return all the way? Rebuild the MC.

- Is there a gap at rest between the caliper piston and the pad? If so, glue the pad to the piston with some Permatex Disc Brake Anti-Squeal.

- Are you using a rubber brake line? They can get weak and develop an aneurysm.


As for brake fluid, the differance in feel between 4 and 5 is very subtle. If you have a very sensative racing brake system and you really know your bike, you might be able to feel the differance near threshold. Otherwise, it's just not enough to matter. So don't focus on the fluid type, it's distracting you from the real problem.

 

All good suggestions and I will check those out. The brake system was just fine until I changed out the front brake line (longer one) and had forgotten to install the 5/32" spacer between the lever and master cylinder body. I still don't see any turbulence in the reservoir when the handle is worked, so is this indictative of a problem that started by changing the line?

I posted the brake fluid information as I thought it might be pertinent, as I'm not that familar with silicone fluid.

 

I have the same problem with my 2003 electra glide. It has been recommended to me by HD to replace the MC and change to dot 4 instead og dot 5. Im not sure that is going to work. Im not sure what to do.