rear disc brakes ?

lbanner

lbanner

New member
I'm working on installing rear disc's on my HP Fiesta. I need suggestions on mounting position. My question is where to mount the caliper in front of the hub (leading) or behind the hub (trailing)? I was told if mounted in front would it cause the rear of the car to unload. Any thoughts would be much appreciated
 
If you're mounting the caliper to the same part of the spindle assy, I can't see caliper position changing anything on suspension geometry since the forces act on the same plane.
the big issue I see is getting the bleeder screws in the proper position to get air out of the calipers.
 
Matt is 100% right and has all of the bases covered including the sometimes forgotten bleeding issue. Regardless of where the caliper is mounted on the spindle, it yields a moment (aka torque) about the spindle centerline. It is no more complicated than that.
 
Jay Lutz":e6rh6e96 said:
including the sometimes forgotten bleeding issue.
Click to expand...

Been building my own brake brackets for my cars for 10 years and have made that mistake a few times. Wilwood also makes a point to mention this in their tech documentation on their calipers and say you might even want to unbolt the caliper, hold it vertical, and stuff a block of wood or something in there to take up the disc space. then bleed that way.
 
Many of the aftermarket calipers such as Wilwood have threaded fittings on top and bottom, so you can put the bleeders where you want and plugs in the other holes. Some other thoughts to consider: Access while working on them; suspension movement; fitment of cooling ducts if you should need them later- usually air to the front half of the rotor is easier to do, so the calipers would be to the rear; debris shedding- If the rotor enters the caliper going down, it can trap and hold rocks, dirt, rubber shards, etc on the top of the caliper. If the rotor enters going up, gravity will help fight this problem as some debris will just fall off...
Jay Lutz is a brake engineer. He is right about the brake forces- as long as they are fed back into the axle/spindle/upright, the result is the same.
 
EX Brake Engineer. For the last 15 years, according to my bride, all I do is drink coffee and talk on the phone all day. Beats a real job I guess.
 
Just to stir the pot a little.

F1 teams mount the caliper at the bottom, presumably for a lower CG.

-Kyle
 
Moving an ounce in an F1 car makes a difference. Then there are people like me who can't tell the handling differences in a 5psi change in tire pressure or a full/empty tank of gas.
For most of us, moving a 5lb caliper down a few inches isn't going to matter.

Mount it where it fits and makes things easy to service. the advantages of CG change are in the noise on your car...
 
I've got pictures somewhere of the rear disc set-up on my LPHP Fiesta (now sold), including some pics of the brackets. PM me your email and I'll get them off to you.

Rick
 
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