I just recently finished overhauling the braking system on my CRX Si. I installed new Axxis Ultimates, Carbotech OE rotors in front, adjusted the rear drums, and flushed the system with Valvoline synthetic fluid.

While my braking is certainly improved, I still feel it could be better. I think I expected more out of this setup. The stopping power is more than adequate for normal driving, but under hard braking it seems like it could be better. The pedal is firm but modulation under hard braking is less than fantastic. The pads only have about 150 miles on them (they were bed in properly), could they still improve?

Is there anything else I can do to improve braking without changing calipers?

 

switching to new braided brake lines will make response better. you could also bump up the mastercylinder from an integra, but that only changes the brake force/pedal force ratio. i dont think this is really any benefit, but ppl sem to like any change they make as an improvement....

 

The benefit of a larger master cylinder swap is brake feel. The basic principle behind this is really simple -- your brain can detect changes in pressure exerted by your foot much better than it can detect displacement of the foot. So given that a larger master cylinder moves more fluid with a given pedal displacement, when you step on the brakes, the pedal moves less before the pressure builds and you start modulating based on pressure much more so than displacement. The result is better brake feel.

S/S lines contribute too by preventing the brake lines from bulging under pressure, and thereby increasing pedal displacement.

 

I can change the feel of the brakes greatly by making sure the system is bled thoroughly. Before spending lots of money, spend a few bucks on brake fluid and bleed again.

Also, are you locking up the tires?

Andy - who wonders if Damon thinks he looks like Brad Pitt but really looks like Ed Norton...

 

Were these the only changes or did you rebuild the calipers and/or replace the drums or anything else? I am a litle thrown by the firm but poor modulation comment. Is the brake pedal firm and hitting right at the top of the stroke or firm when you engage it but further down than you'd expect? Is the modulation issue an issue of lock-up or not releasing or becoming more grabby the longer you hold the pedal at the same point? If you didn't replace/machine the drums, was there a noticable lip on the drum (leading edge that is the determination of how much you can - while off - adjust the shoes)? If the rotors are brand new, I'd think they need to be cut in before the pad material is making good solid contact (you say pads have 150 miles so I am not sure if this means that the rotors just went around the block). I am not sure if your pads will "improve" over time, that's not something I am accustomed to (but for a good few hard stops they will need to mate w/ the rotors from my experience).

Hope this isn't too simplistic - just trying to help.

 

I cannot lock up my Azenis (haven't tried to absolutely mash the pedal through the floor, but it's not possible even with hard pressure). The system was obviously bled at the time the system was flushed.

The calipers were not rebuilt, the drums didn't have a lip on the inside. Is there any way to inspect the health of the caliper? The pads and rotors were installed at the same time. I think my modulation problems are mostly due to my expectation of more bite as I press harder and not really receiving it past a certain pressure.

BTW, I don't look like either, just a fan of the movie.


[Modified by tylerdurden, 5:47 AM 1/22/2003]

 

what was your bedding procedure?

 

5 miles of normal driving, then 4 stops from 40-10, let brakes cool for 10 min, then 4 stops from 50-10 with hard pedal pressure, let brakes cool, park car w/o parking brake on (I know that doesn't matter in my case but I did it anyway). The braking performance came up considerably between the first 10 miles on the new rotors/pads and once I had about 35-40 miles on them. Adjusting the rears also made a noticeable difference. I wish I could drive a CRX with a similar setup so I can see if I should expect more from my setup or if this is as good as it gets.

 

I think you didnt get them hot enough to bed them in...

 

that'd be my guess too... get em good and hot and then they'll give you the braking you're looking for

 

get them hot enough to where they stink and start to smoke, then drive around for 5-10 min w/o using the brakes so they cool.

 

what do you suggest for getting them hot enough? driving in a parking lot doing 50-0 stops?

tyler- did you take the calipers apart clean the pins and re-lube them? i did that when i did my brakes and noticed a big difference. the car had also been sitting for a while too.

 

See if you can find a Master Cylinder Brace for your car.

That made a huge difference in braking feel on my Type R.

 

Does anyone know if they came out with a MC brace for EK chassis?

 

Do a series of 30-10, 40-10, 60-10 stops (dont stop the car, you'll heat soak the rotors) until you can really smell the pads stinking.

 

I'm thinking perhaps you should have left out the "let brakes cool for 10 minutes" part. I wonder, like others mentioned, if you got them hot enough for bedding.

Axxis does not include bedding instructions in their boxes (yet, Hawk does). Generally when someone asks, I tell them 4-5 easy stops from 30 mph, 4-5 not so easy stops from 50 mph, and then 1-2 moderately hard stops from 60+. this should get the hot enough to green fade, but not hot enough to glaze. I did this exact same procedure on my SE-R and my moms Jeep, both with Ultimates and the results are stellar.

Hmmm....you sure about the name on that


[Modified by MaddMatt, 5:28 PM 1/22/2003]

 

So you're telling me I have to go heat up the brakes? Well, if I have to. But I won't enjoy it.



BTW, I did clean the calipers with brake cleaner and relubed the pins with antizeize, but I didn't disassemble the caliper or anything. I'll see about re-bedding them. Thanks for all the input, guys!

 

bedding in carbotech pads was alot of fun last year - they really stink! (the odor that is)

 

Is there a way I can tell I'm smelling pads and not fluid (fluid can boil and cause an odor, yes?)?

 

Nah none that I've ever smelled (boiling happens in the caliper afaik - its more a matter of gassing water molecules and making the hydraulic fluid more compressible - but get someone who really knows to explain that stuff). The smell will be akin to driving by a smelting plant (if you are familiar), a metalic smell.

 

you will feel when fluid is boiling and smell when pads are cooking

on most new pads they willl smoke when first broke in, but if not they will definently smell

 

My Ultimates billowed clouds of smoke out of the fender wells during bed-in They should get hot enough that they're stinking, smoking, and well... your car won't have very much braking power. It's good to do it on a very unpopulated, straight road at night if possible so you minimize the chances of upsetting the local constabulary, other vehicles, and any other reasons for needing brakes when you don't have them.

 

FWIW, I was with a friend this past weekend while he bedded in his Viper's new StopTech rotors... twelve braking periods from 65 to 5-10, one after another, no break in between. The pads were incredibly hot and smelly. I was ill afterward. Bedding brakes is scary but it does work. Try it again, a bit harder.
-Adam

 

I didn't figure they needed to be worked THAT hard, but I guess I'll give it a try and hope it leads to an improvement. How long should I allow for the brakes to cool after bedding them in?

 

[QUOTE]BTW, I did clean the calipers with brake cleaner and relubed the pins with antizeize, but I didn't disassemble the caliper or anything. QUOTE]

don't use antiseize on the pins. over time (not that long) it causes them to stick. Use dielectric silicone grease.