Hydraulic E-Brake Install

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john keefe
Level 7
Level 7
Posts: 1060
Joined: Sat Sep 02, 2006 1:13 pm
Location: Campbell, CA

Hydraulic E-Brake Install

Post by john keefe »

After 2 years I finally got around to doing a couple things for the XR. After debating it for a while, I decided on going with an hydraulic e-brake rather than mechanical (TBird), mostly because I've got 4-piston Wilwood calipers on the rears (in combo w/ Sierra Cosworth front rotors). Didn't want to give that combo up. The TBird rears are a lot simpler, but quite a lot heavier, and I really couldn't come up with a good option to make a light mechanical brake the would be wide enough for the rotor. Thought about doing a rotor attached to the diff flange, a la Land Rovers, but that would require cutting into the rear/trunk floor to get a big enough rotor. Maybe wrapping a lever-clamp around the DS that clinches it with old tire tread. Maybe if this doesn't work as well as I expect... in another few years.

Design/install was complicated because I wanted to route the lines up to an existing rear/front brake bias, and wrap it all up in the stock center floor console pieces to clean it all up and look stock/nice. I think trying to figure out how to cut and re-attach all the plastic pieces so they could be easily removed without disturbing any of the brake components took probably as much time as doing the actual hard-component install.
Wilwood MC Bracket
Wilwood MC Bracket
KIMG0295-1.jpg (22.88 KiB) Viewed 1429 times
1/16" steel plate
Installed, w/ Lines
Installed, w/ Lines
KIMG0297-1.jpg (44.41 KiB) Viewed 1429 times

Buttoned up, still have a little room in tray
Buttoned up, still have a little room in tray
KIMG0301-1.jpg (39.28 KiB) Viewed 1429 times
MC is 0.70" diam., which I figured would be enough surface area to move sufficient volume for the (total) 4 rear pistons. It does a good job for parking, but doesn't work great for a real "emergency" brake unless you're going pretty slow. You can't get enough movement pulling upwards on the stock handbrake lever to really lock up the rears. Probably good enough for sliding in rally, but I can see why those guys go with a long handbrake angled upward so you can pull back really hard (at the loss of "ratcheting" to lock in place). Kinda' disappointed that it leaves very little handbrake movement. Only getting about 2 teeth upward on the handbrake mech., and only using about 1/2 the available throw of the cylinder rod; 0.65" or 0.60" dia. would probably be better, moving less volume per stroke, giving more overall range and more clamping force.

Haven't used one before, so kind of surprised the first couple times that I had take the foot off the brake before I could apply the handbrake while parking. Usually, I have my foot still on the brakes while applying the e-brake, especially on hills, but once the pistons are locked up, there's no movement left to move fluid with the e-brake. Gotta' get used to it. At least it tells me I got all the air bubbles out when bleeding the whole system...

All in all, happy I was able to keep the big calipers out back, but not super-impressed. Solves the problem of not having a parking brake at least, so that's a plus.
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