I believe it says on the bar reservoir DOT 3 or DOT 4 is acceptable, I'd use the heavier stuff personally. Before you go draining and refilling your system though, I'd check these things first which are easier to check than swapping your fluid and could easily be your problem. (and air does not spontaneously enter a line and air would actually be more likely to cause soft brakes, not sticking ones.) Unless you boiled the fluid, but this seems unlikely So on with diagnosis.

1. Does the caliper slide smoothly on the slider bolts that mount it (where the rubber grommets are) stickyness here is a great way to get a consistent pressure and squeak. Pull your wheel off and shift the caliper back and forth on the sliders, if it doesn't move freely (should be slow but smooth moving), pull the bolts, clean them up shiny with WD40 or other solvent lubricant, dry off and apply a quality caliper grease. If they are pitted from rust, replace of course.

2. Is your rotor either rusty outside the brake pad area, or is it worn in such that there is a bit of a cup at the very edge of the pad where it transitions to not worn down? Sometimes you'll get a squeak from a bit of abrasion at the corner of the pad from either rust or normal rotor wear. if so you CAN clean up the edge of the cup on the rotor with just a wire wheel, or grind a tiny bit off the corner of your pads , but it's really time for a new rotor.

3. Are your front pads OEM and do they have a self cleaning slot and have you tried cleaning them with brake cleaner? Dirty pads squeak too (but wouldn't explain resistance.)

Number one is my top pick for your symptoms. If not and there is definitely resistance, I'd guess that maybe you need to rebuild or replace your caliper. Seems awfully early in mileage for that but since you replaced the cover, maybe some contaminant got in there in the form of humidity or moisture somehow and you didn't realize it, it only takes a tiny bit to create rust spots and sticking. Could also have gotten a little nick in one of the piston boots and gone through a creek. However, based on you saying that there is resistance, something is sticking and sticking means either the sliders for the caliper, or the pistons on the caliper (or the master cylinder itself) because they are the only 'moving' parts that can stick and create pressure after you release the brake lever. Good luck sorting it out

 

We are supposed to grease the speedometer pick up? LOL Whoops.

 

I agree with jacksonriding7, don't mess with the brake fluid until you've done the other checks. Bleeding the front brake can be a real pain.

Ride on
Brewster

 

I think you only have to do that if your bike get's dirty from time to time
j/k... please dont delete me

 

MIght be time to rebuild the front caliper. If your not careful, over time you can get dirt inbetween the piston and the "o" ring. This will casue the effect you are talking about. Only makes it worse when putting new pads on and pushing the calipers back in to allow room for the new pads. Might just try taking the caliper off and cleaning it really well with some brake cleaner.

 

I agree on the application of brake fluid around the piston o-ring area in some cases. Over many years of owning MTB hydraulic brakes and motorcycles, every once in awhile you get a sticky caliper operation that nothing fixes...rebleeding, resetting pad position, etc. In most of those cases, an application of a small amount of brake fluid into the circumference of the piston at the o-ring/piston bore interface will free up a sticky piston. I accomplish this with the caliper unbolted and being held by hand. Get a brake puck or other appropriately sized object to keep the pistons from popping out of their bore(s)...some obviously only have one live piston. After brushing away any grit and dirt from the piston circumference with a fine toothbrush, I take a squeeze bottle containing brake fluid and squeeze fresh brake fluid around the piston bore opening...very sparingly on the brake fluid as it doesn't take much to do the job. I then work the brake lever very carefully to push the piston out a bit...not too much...and then push the piston back in. I do this several times, and in most every case, that sticky piston loosens up and functions properly...and it usually works for a very long time. Wipe off all excess brake fluid before reinstalling the pads. It's been a rare case when this didn't work for me. When this didn't work, there was usually a more serious problem in the caliper or master cylinder.

 

Awesome advice here guys. I have some work to do tonight when I get home. I will pick up some brake fluid as well, just in case and also for the cleaning TNC is describing. As I think about this, I did get new shoes on my wheels so maybe when I remounted the tire something changed. Thanks again guys and I will give an update once I have made some more attempts at solving the problem.

 

Sometimes rubber lines can collapse internally. I've been told it pinches itself off and will hold a bit of pressure in the line, not enough to stop the master cylinder from pumping but enough to hang up the brakes. It happened to my sisters car with the flex line. Could be a bad rubber line from the factory?

 

While changing over to my summer wheels I checked my speedo gear (plastic) cause my speedo was bouncing a bit. It was worn really bad in the center and the valleys of the gear were packed with what was once the gear teeth. Needless to say a bit of grease will do you good. I had to get a new gear.

 

Okay, so I took the claiper apart. Cleaned around the pistons very well and applied some teflon lubricant around the pistons and worked them back and forth. The one thing I did notice while doing this is that if I pulled on the brake lever the pistons would see saw a bit but the piston closest to the inside of the brake pad (side without the bolt) would continue to rise and never would return to position. It just kept creeping up and up. And didn't want to see how far it would go because I was afraid it would lift itself right out of the assembly. Either way, I cleaned it all very well. Put a little teflon lubricant on the slide bolts and reassembled. And low and behold, same problem. I had better clearance at first but as I applied the brakes they slowly got worse and wheel got more resistance from the brake. This seems like a bad thing, like new caliper time or something.

How should the pistons act when braking? So I know what to look for when functioning properly. I think maybe I will clean the slide bolts a little more with more lubricant but I don't think that will solve my problem this time. Is it possible to have the system too full of brake fluid, mind you I haven't added any so I am not sure how that would have happened? Unless the aforementioned scenario of an internal tubing failure is responsible I guess. Anymore ideas? Thanks for the help up to now.