This is on a 2018 Ranger 150 that I picked up a couple weeks ago. The previous owner warned me that the front right brake would sometimes lock up and he's just crack the bleeder fitting and let his kid keep on riding.
When I got it home, I noticed the pads all the way around were nearly gone, so I replaced them. In the process I noticed the caliper bracket on the steering spindle was not straight (previous owner admitted his 8yo hit a tree but he bent everything straight). I realigned it as best I could and bled the front and rear brake lines (removing the opposing master cylinder push rods in the process). In the process I rounded out one of the hex-headed pad retaining bolts, so I purchased new after-market calipers made for the 150. They were installed about a week ago, along with the pads that came with them.
Everything was clean and there was minimal drag when the wheels were turned by hand.
Today, going down a rather long (1+ mile) steep gravel back road, I kept the speed/RPM up enough to let the engine do most of the braking. Still, by the time I got to the halfway point, I kept hearing a moaning from the front end. When I stopped to check, both front tires were nearly skidding as I just barely touched the brake pedal. The rotors were smoking hot (like an idiot, I have the blister to prove it). And the buggy stopped on the decline as though I had the parking brake on. Restarting the trek, both front wheels skidded in the gravel. I was stuck. Wife came with a wrench so I could bleed pressure off of each caliper - and I was good to drive home from there with the kids.
By the time she got to me, the front had cooled enough that I could drive, but I could still feel the drag.
In any case, since both of the calipers did this, I'm wondering if it could be anything other than the master cylinder.
TL;DR
When I got it home, I noticed the pads all the way around were nearly gone, so I replaced them. In the process I noticed the caliper bracket on the steering spindle was not straight (previous owner admitted his 8yo hit a tree but he bent everything straight). I realigned it as best I could and bled the front and rear brake lines (removing the opposing master cylinder push rods in the process). In the process I rounded out one of the hex-headed pad retaining bolts, so I purchased new after-market calipers made for the 150. They were installed about a week ago, along with the pads that came with them.
Everything was clean and there was minimal drag when the wheels were turned by hand.
Today, going down a rather long (1+ mile) steep gravel back road, I kept the speed/RPM up enough to let the engine do most of the braking. Still, by the time I got to the halfway point, I kept hearing a moaning from the front end. When I stopped to check, both front tires were nearly skidding as I just barely touched the brake pedal. The rotors were smoking hot (like an idiot, I have the blister to prove it). And the buggy stopped on the decline as though I had the parking brake on. Restarting the trek, both front wheels skidded in the gravel. I was stuck. Wife came with a wrench so I could bleed pressure off of each caliper - and I was good to drive home from there with the kids.
By the time she got to me, the front had cooled enough that I could drive, but I could still feel the drag.
In any case, since both of the calipers did this, I'm wondering if it could be anything other than the master cylinder.
TL;DR
- Both front brake rotors locked up rendering movement impossible after a long down-hill run.
- Calipers and pads are new (replaced a week ago)
- Brake system was bled (full master cylinder reservoir was pushed through all calipers).
- Original right caliper had history of locking up (according to previous owner)
- After brakes cooled, forward movement was possible (but with drag until bleeder valves were cycled).
- Caliper bracket alignment appeared correct on both sides (right side required adjustment after wreck).
