Front disc brake issues

Tweaked the front forks a bit on my last ride with the CRF 150F, couple of light drops onto the left side. Today I changed the front tire and re-adjusted/re-aligned the front forks. I reinstalled the front wheel and axle correctly, but I just can't get the front disk brake pad from contacting the front disc. The front wheel spins fine, but there is just a slight amount of contact. The front wheel and disc seem true (the disc rotor is not bent). The front forks and axle are not bent. Any thoughts? I doubt it will cause any issues, but it just bugs me.

A slight amount of contact is fine. That's the way disc brakes are... You said it spins freely, which is good. If you spun the wheel, and it came to a stop very quickly, then you would have troubles.

A slight amount of contact is fine. That's the way disc brakes are... You said it spins freely, which is good. If you spun the wheel, and it came to a stop very quickly, then you would have troubles.

I was hoping to hear that.

The caliper is mounted on pins so the caliper can slide left to right. You need to lube the pins with a little disc brake grease so they move freely. If the pins get all dry and contaminated (corroded) then the pads may drag on one side.

The caliper is mounted on pins so the caliper can slide left to right. You need to lube the pins with a little disc brake grease so they move freely. If the pins get all dry and contaminated (corroded) then the pads may drag on one side.

I bet that is the problem. Do you have to use "disc brake" grease, or will any bearing grease like Belray waterproof grease work?

Disc pads are supposed to rub on the rotor when not being compressed or used. There is no retracting spring or anything like there is on drum brakes. Try spinning any disc brake wheel on a car when it is up on the rack and it will not spin very long because of slight pad drag on the rotor. This is perfectly normal. I would say if you have the front wheel suspended on your bike and you give it a good spin by hand, if it spins a couple of revolutions before coming to a stop, you are fine and nothing is binding. (By contrast, when I spin the front wheel on a drum brake bike, it will spin forever.)

Good luck

Disc pads are supposed to rub on the rotor when not being compressed or used. There is no retracting spring or anything like there is on drum brakes. Try spinning any disc brake wheel on a car when it is up on the rack and it will not spin very long because of slight pad drag on the rotor. This is perfectly normal. I would say if you have the front wheel suspended on your bike and you give it a good spin by hand, if it spins a couple of revolutions before coming to a stop, you are fine and nothing is binding. (By contrast, when I spin the front wheel on a drum brake bike, it will spin forever.)

Good luck

Thanks--it does spin pretty freely, so I think everything is fine. I will make sure that the caliper pins are greased/moving freely with no binding.

I bet that is the problem. Do you have to use "disc brake" grease, or will any bearing grease like Belray waterproof grease work?

The correct grease is high temperature silicon grease for car disc brakes (expensive; my last purchase was $25 for a 5oz tube), but MC brakes on trail bikes don't get that hot so IMO BelRay waterproof would be OK.

I have never used anything but disc brake grease so I don't know how well other grease's would last without getting soft and leaking out.

One tube of grease will last a lifetime.

i've always just used hightemp waterproof grease from wallyworld, cheap and works for me

Thanks everyone.

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