So I was visiting a friend in Northern California who lives 20 miles down a narrow, twisty, up-and-down dirt road. I wasn’t going particularly fast as I have 200lbs of gear on board. My technique when approaching tight turns, especially downhill ones, is to just touch the front brake, then drag the rear as I get deeper into the corner.
This worked fine for a while, but then the rear brake lost pressure – just nothing there. I could pump it and get something back, but it’s obviously not right. What was worse was that the front brake, while still sort-of working, would pulse as if the ABS was cutting in and out, but with about a second between pulses. A second can feel like a loooonnggg time when you are approaching a corner with a steep drop-off on the other side.
I stopped and both front and rear discs were blue, but the rear was hotter than the front. I let things cool down for 5 minutes and then continued gingerly, and had no further problems.
When the front brake started pulsing I considered stopping and disabling the ABS. But it occurred to me that the problem is not with the ABS, or not JUST the ABS – it must have something to do with the linked brakes? Presumably I had boiled the fluid in the rear? And then when I squeezed the front it would have to build pressure throughout the entire system before the front brakes would work. At that point there was some interaction with the ABS to cause the pulsing.
Does that sound like a fair assessment? And what’s the solution – bleed the brakes and put higher-spec fluid in it? Which one?
I’m a bit annoyed – in this case I was able to work around the problem, but I’m not going to be impressed if I get this problem on some much more difficult roads I may encounter on this trip – Copper Canyon is one that comes to mind… will be there in a month or so.
On the return trip I tried a different technique - slow on the approach to the corner (so, not much braking), and fast on the exit. Even with a full load, TCS2 makes it easy to hang the rear out so I can pretend I'm an expert rider
Trevor
This worked fine for a while, but then the rear brake lost pressure – just nothing there. I could pump it and get something back, but it’s obviously not right. What was worse was that the front brake, while still sort-of working, would pulse as if the ABS was cutting in and out, but with about a second between pulses. A second can feel like a loooonnggg time when you are approaching a corner with a steep drop-off on the other side.
I stopped and both front and rear discs were blue, but the rear was hotter than the front. I let things cool down for 5 minutes and then continued gingerly, and had no further problems.
When the front brake started pulsing I considered stopping and disabling the ABS. But it occurred to me that the problem is not with the ABS, or not JUST the ABS – it must have something to do with the linked brakes? Presumably I had boiled the fluid in the rear? And then when I squeezed the front it would have to build pressure throughout the entire system before the front brakes would work. At that point there was some interaction with the ABS to cause the pulsing.
Does that sound like a fair assessment? And what’s the solution – bleed the brakes and put higher-spec fluid in it? Which one?
I’m a bit annoyed – in this case I was able to work around the problem, but I’m not going to be impressed if I get this problem on some much more difficult roads I may encounter on this trip – Copper Canyon is one that comes to mind… will be there in a month or so.
On the return trip I tried a different technique - slow on the approach to the corner (so, not much braking), and fast on the exit. Even with a full load, TCS2 makes it easy to hang the rear out so I can pretend I'm an expert rider
Trevor