TT250 Removed front axel now brakes bind
 

I was removing my front axle to install a digital speed sensor, got the wrong one, so I went to put the original mechanical one back on. I can't get it to seat all the way against the hub, the seal on the sensor is about a 1/4" off the hub when aligned (1/2“ when misaligned) . I'm not sure if the bearing moved or what but for the life of me I can't torque my axle without the brake rotor binding on the back / inside brake pad (opposite pad to pistons). It still drags a little even before I torque the axle. I have made sure that I aligned the speed sensor to the hub, it's like the bearing moved when I pulled the axle or something. I believe the bearing is what's stopping the sensor from sealing against the hub. I tried gentle hammering on the speed sensor to push the bearing until it seats but the bearing doesn't budge, which makes me second guess myself. The axle has always came out easy so I doubt the bearing would move. I looked at the CSC tutorial and couldn't find any clues to what I could have screwed up. The forks stayed on the bike, and all I removed was the axle, speed sensor, wheel & spacer but now I can't make them fit back together.

Anyone know what might be going on and how I can fix it?

the sensor has a tab that has to go in a certain spot

Yes I am aware that the sensor has to be aligned in the hub, two tabs and then positioned properly against the fork, another tab to prevent it from spinning.

My issue is that no matter what I try the sensor won't seat properly against the hub leaving a small gap around where it I assume is supposed to seal against the hub. If I push on a side where either tab is it will touch the seal but never both sides at once. The sensor has a rubber seal and its filled with 'clean' grease, not full of dirt. I've tried removing and reinstalling the axle at least 6 or 7 times and the results are always the same.

I had a similar thing happen a couple of weekends ago changing the brake pads on my daughter's UTV. I go to assemble everything back up and the outer brake pad was jamb up so tight against the rotor I couldn't turn it. Like you I removed it multiple times and couldn't figure out why it wouldn't go all the way back on. I ended using a deep socket and tapped the bearing to make sure it was all the way in. Put it all back together and everything was good. :hmm: How the inner bearing moved in the first place I have no clue. It's pretty snug in there.

The hub appears to be two bearing on either side of a spacer. Both bearings are tight against the spacer. I tried using a socket and hitting it with a 3lbs mallot but it won't budge at all. The axle came out easy, I was able to spin it out half way and pull out the rest just by hand.

Are there specs on where the bearings should be in the hub? Or does anyone know if the bearing is tight against the seal on the spacer side? Mine has a small gap, not sure if you can tell from the picture.

I have a different Bashan wheel. But I took some pictures of the bearings for reference... did you compare the two speed sensors for depth? maybe the digital one pushed the wheel bearings in and that's whey the center of your wheel has shifted... just a thought.

The digital sensor was for a Halk and doesn't fit on a TT250. Once I got the mechanical sensor off my TT250 and seen it I immediately noticed the differences in the parts, so I never bothered to try installing the obviously wrong part.

My bearings appear to be too close to the speed sensor and not pushed in far enough rather then pushed in too far. Perhaps when I pulled the axle out the bearings came with the axle for a little bit, I really don't know, none of this makes any sense. Unfortunately now the bearings won't budge and I don't have the proper tools to move them or the knowledge of how far they need to be moved...

Are the spacers the same size? Beveled on one end?

Just a single spacer that is the same on both sides

That is just strange. :hmm: And It's not like you have 20 pieces that you have to put in a certain order either. Spacer on rotor side and sensor on the other and slide bolt through. I wish I lived close by just to look at it myself. Hope you figure it out.

Just thought of something. Is you brake calipers moving freely? Pins may just be getting stuck and could need lubrication.

Are the tabs on the sensor both exactly the same size? They look like it the picture but maybe they are slightly different. Have you tried rotating the sensor see if it aligns better?

Another thought, maybe the problem is the sensor. Did the output gear go in too far and push the input out slightly causing the gap? Or did it fall in as I don't see a tab or pin on the output side. I would open the sensor and check that everything is aligned.

Is there a burr?
 

On Andy's pic, is there a Burr on the right side indent?? could some miles cause heyholing and prevent this non seating?

gh

First, the breaks have single sided pistons and the stationary side is what's binding. Brakes & rotor look fine, no strange wear. The tabs may be slightly different sizes but both are much smaller then the slots. No burs, I cleaned the old grease off and nothing is preventing it from seating properly except the bearing. I have a bottle jack but nothing to use as a frame to press against. On Friday I'll find a shop that has a press that I can use to push the bearings in further.

The caliper floats on a stationary mount. The caliper should move freely on the pins the caliper is mounted on.