fl-krawler said:
Are you running 4 or 6 piston calipers? The 4 piston ones have a huge problem with caliper flex, and it only gets worst with the more pressure you add to the system. On my last buggy I had a vacuum boost brake setup and my brakes were horrible with the wilwood calipers. Wilwood told me to not exceed 1000psi on the brakes as that was all they were designed to handle. There is a pretty good thread on pirate about the wilwood/spidertrax/tubeworks brake setup and switching to hydroboost and off the shelf oem brake parts. They aren't as bling or light, but work better.
This is all true.
I have consulted Wilwood about this and they do not recommend it. Their calipers are made for 1000 psi max. Hydroboost will be at least 1500 psi., vacuum boost will be 1000+. Depending on your system, what psi it runs at, etc, possibly way more.
Taking the second MC out didn't help your situation, your fluid displacement was halved by that, probably resulting in more pedal required to accomplish the same amount of braking. If you had enough pedal travel before you took it out, I would try putting another one back in only a smaller dia. MC, maybe 3/4" or so.
Generally speaking, smaller bore = more pedal travel with higher pressure. Bigger bore = less pedal travel with lower pressure. It sounds like your girl doesn't have as much leg strength as you, so basically she's not able to generate as much line pressure. That's why I say smaller bore MC if you have enough pedal travel to accommodate it.
That and / or the calipers could be flexing, which wouldn't surprise me in the least bit. Wilwood calipers were designed to stop light little sprint cars on the street, not heavy 4x4's with 40"+ tires trying to cling to a mountain. Back in the day Dibble had major issues with dual piston Wilwood calipers flexing when he was trying to do wheel brakes on his rockwells. I think he posted a video with the rig just sitting there and you could watch the caliper flex. Here's some others you can find online:
Wilwood Caliper Flex #5 on Vimeo
Wilwood Caliper Flex 2nd Video on Vimeo
Wilwood Caliper Flex #4 on Vimeo
Doesn't sound like whatever vehicle that is is running in the vids. IE, no boost yet. Any boost is just going to make it worse.