2G How to get rear brake calipers to work harder?

[LeeSD1]

Okay so ive noticed over the years on a few 2g eclipses both non turbo models and turbo models that the rear disc brake calipers dont really work that hard; meaning they dont apply alot of pressure to the rear brakes. It seems as if the front brakes do all the work when braking...Now i was thinking there might be a way to modify the proportioning valve so a little more pressure can be applied to the rear. I was just wondering if anyone has ever done anything like this before since i searched around a little and didnt find anything..Now im not sure if there is any difference with a ABS brake system. Thanks for all the help!

 

[bryanwheat]

The front is supposed to do most of the braking. It is designed this way so that you don't loose traction in the rear while braking. This is something that i wouldn't even attempt unless you are on a track and can actually test the effects of what you are doing. It could make the car very dangerous to drive, especially when it is slick out.

 

[LeeSD1]

i didnt want the back to brake harder then the front i just want the back to help out some more. the car is for a straight line 1/4 mile track and under heavy braking seems like only the front are really working. Guess i just wont worry about it.

 

[2gmitsueclipse]

I absolutely would not suggest modifying the stock proportioning valve. Wilwood makes an adjustable proportioning valve that you adjust rear bias.

 

[Pipnorcali]

Like he said willwood valve or running better brake pads in the rear works..

 

[bryanwheat]

The correct solution here would be to upgrade both with larger diameter slotted rotors, higher quality pads as well as ss brake lines and possibly a 3g master cylinder. You want to increase braking force but keep the front to rear proportion the same. If you apply much more force to the rear you will lock them up and cause the car to slide out.

 

[RamenPride]

the rear disc brake calipers dont really work that hard; meaning they dont apply alot of pressure to the rear brakes. It seems as if the front brakes do all the work when braking...

That's how they're supposed to work. The rears do a lot more "work" than you give them credit for. Try touching the rear disc after an easy drive.

 

[LeeSD1]

Ok thanks guys ill look into the wilwood valve thats more of what I was looking for ill do some upgrades to the rear

 

[96eclipse_rst]

Ok thanks guys ill look into the wilwood valve thats more of what I was looking for ill do some upgrades to the rear

Careful while your doing that man. Make sure all the brake lines are good and not leaking

 

[wolf alchemy]

Wouldn't getting slightly bigger piping for the rear breaks work as well. Just with this its really a once you do it your done. Obviously don't make it an inch bigger, but less than a centimeter. That way itl be easier to pump the fluid to the back tires compared to the front. If I were you. I'd have a math person calculate the size of tubing. Then the distance from cylinder to front and rear brakes. Then he could most likely tell you how much to go by. But the adjustable valve is the best idea.

 

[bud09]

That's how they're supposed to work. The rears do a lot more "work" than you give them credit for. Try touching the rear disc after an easy drive.

i've done some hard braking before and checked my brakes and the fronts were steamy hot and the backs were ice cold

 

[bryanwheat]

i've done some hard braking before and checked my brakes and the fronts were steamy hot and the backs were ice cold

This is because the fronts do 90+ percent of the work. Most all cars are designed like this for a reason. It is because when you brake the front of the car is pushed down applying most of the weight of the car onto the front axle. Because of this the front brakes must do most of the work. If you install an adjustable valve and start applying more force to the rear than you will lock the rear up with normal braking. If you want your car to stop better than you need to upgrade the front brakes first, than the rear. Just adding more force to the rear isn't going to help you stop faster, it will only make the car unstable.

 

[1990dsmkid]

I agree the front does most of the braking but not 90+% of it. Its more along the lines of 70-30 split from what I have seen and been told through the years. Not saying this is exact but I cant see it being 90 or more in the front. Like everyone else has said, just upgrade to wilwood, brembo, or baer. Dont mess with trying to make the rears work harder. If they were meant to then they would be produced thay way

 

[Marc Pacheco]

How to get rear calipers to work harder? Pay them more money

 

[2slow4now]

I would upgrade the brakes in a set. If your doing a brake swap from another car then I would do both front and rears off that car to keep them in proportion to each other. Like guys do with the evo brembos or the 3000gt vr4 swap.

When you brake the weight of the car shifts to the front much the same as when you launch it shifts to the rear. If you transferred more power to the front and less to the rear while it's lifting off the ground during the launch what would happen? The front would spin loosing power that could have been used for the launch. Same for more braking in the rear. When you brake and the nose dives pulling weight off the rear more braking in the rear would just lock the rear, loosing braking power.

 

[TSiAWD666]

I personally like a bit more braking in the rear than what you get with the stock bias but not a whole lot. As people pointed out these cars are very front heavy and so the front ends up doing most of your braking anyway.

A cheaper way to get a bit more rear brake bias is to go to a stronger brake pad compound in the rear. For the street this would be very hard to do because you don't have any data between pads on which has slightly more stopping power than another. For a track pad there are usually ordered friction levels available and you would just go up and up until it was too much for your liking.

Another way would be to bolt on a larger diameter rotors in the rear like using Evo 8 calipers/rotors (but these would necessitate the 3g brake master cylinder or something similar) to get some more brake torque.

 

[bud09]

i understand how brakes work, and really wouldn't mind upgrading myself. but, i have 16 inch rims so a big brake kit is out of the question. i don't need something too crazy, mainly for daily driving and occasional autocross.
i would definitely think ss brake lines would help out the most first, then new calipers.

 

[Todd TCE]

Just for the record here:

1. Changing the master cylinder won't change brake force in and of itself. A smaller bore will make more pressure and have a longer, softer feel to it, some say spongy. A larger bore will make it firmer and require you push harder as it has less pressure. But...the overall force will remain relative to your leg. You'll just push more or less to obtain the same result. Only true dual split mc pedal set ups allow you to change this as they are single axle systems. Your car now is not- it's one cylinder for all.

2. A Wilwood prop valve will not increase rear brake performance by fitting it into the rear brake system now. It will only reduce line pressure (relative to input pressure and chosen knee point) never increases it (that's your leg only).The only way such a change could help is to full remove the factory proportioning system now or "gut it" and run both rear lines to the adjustable prop valve and back out splitting it in a tee. A lot of plumbing work there but they you'd be able to dial out the amount of rear you prefer (or allow more if you wish) via the adjuster.


More rear brake (as rightly pointed out):
1. Higher Cf rear pads.
2. Larger rear rotors.
3. More rear piston area.

Other than the pads, none of that is going to be easy to do.