Thought this was of interest... Robert K. Kuhn CRX Owners Group President (http://www.crx.org/southcal)
1990 Honda CRXsi (http://drive.to/jiggy) ICQ # 3714283 (nickname: godzilla) ---[ Forwarded Message to follow ]--------------------------
To: [EMAIL PROTECTED] From: Citizen Kang <[EMAIL PROTECTED]> Subject: RE: [hooligan racing] Un-balanced brakes? Date: Mon, 23 Sep 2002 17:36:59 -0700 Reply-To: [EMAIL PROTECTED] In a closed hydraulic system such as your car's braking system, any restriction within the system would have to be pretty significant before it created such an "unbalanced" situation. The laws of fluid dynamics (or "hydraulics") state that the pressure at any point in the system is *identical* to the pressure at any other point in the system -- provided that there are no leaks or special proportioning valves present. This is NOT the case if the entire system is NOT sealed. For instance, if you disconnected both brake hoses from the front calipers and pushed down on the brake pedal, in a perfect world you would end up with an equal amount of fluid discharged at each wheel. Any restriction would create a noticeable imbalance. This would not be the case if the hoses were reconnected and the bleeders tightened to contain the pressure. Your friend might have installed rotors that were produced from different batches or at different factories. A slight difference in metallurgy and/or design might create a situation where one side would wear out faster than the other. If it is simply a matter of more brake dust on one side than the other, it might be a simple matter that the air ducting to the side with less dust is superior in some way compared to the other. More than likely, however, it could be a flex hose of caliper that is not allowing the pads to completely move away from the rotor surfaces when you remove your foot from the brake pedal. Fluid under pressure will force partially collapsed flex hoses open enough to move the fluid TO the calipers, but such a hose might not allow all of the fluid back OUT. Caliper pistons also rely on an o-ring with a square cross-section to retract the piston. When under pressure, the cross-section of this seal becomes parallelogram-shaped. When the pressure is relieved, the seal's "memory" tries to make the seal square again. Then there's the equal likelihood that grit has gotten between the piston and the bore of one of the calipers, increasing the friction between the two. And don't rule out a partially stuck proportioning valve either. Any of these cases will create a scenario where the pads are allowed to drag ever so slightly (sometimes even more so) on the rotors, resulting in premature wear. PS: And as for having your existing rotors checked for "warpage", you should know that much of the work involved is taking the rotors off of the car and putting them on the machine so that they can check them accurately (unless they happen to have "on-car" lathes, in which case it would be less). Regardless, they won't do this sort of thing for free. The local Midas even charges $20 Cdn to do brake checks now (which is deducted from any brake work should you decide to have the work done there). "Free checks" are simply too time consuming nowadays when the hourly shop rate is around $75 Cdn. -----Original Message----- From: Beatrice L. Reynolds [mailto:socal_crx_gurl@;hotmail.com] Sent: September 23, 2002 12:57 PM To: hooligan racing Subject: [hooligan racing] Un-balanced brakes? I've noticed that the amount of brake dust on my left front wheel always seems to be thicker than the front right wheel. I then remembered a message on a Honda mailing list a few years back where the poster had mentioned that he had made a similar discovery on his Accord and thought perhaps that one set of pads was just wearing out faster than the other side. I also recall that he had the rotors checked for thickness and found that the one side was indeed thinner than the other (still within spec) and it was significant. The pad thickness was also visibly noticeable. Basically he ended up having to replace the master cylinder because it was not "balanced". IOW, pumping more fluid to one side as opposed to the other. I don't remember if the poster mentioned anything about the car pulling to one side or the other under braking. This message was of great interest to me because it was around the time where I was looking to replace my stock rotors with Power Slots and that is what the poster had. For those of you who remember, I installed mine back in 2000 and I haven't had a problem with them. So --- Having said all that, I decided to pull the front wheels this morning and inspect the pads and rotor. The pads are within specs and the left side is a bit thinner than the right. The left side is about 5.0mm and the right side is about 7.0mm. The service limit is 3.0mm as per the service manual and I used a vernier caliper to make the measurements. Both sets seem to have been worn evenly as far as I can tell. I measured at the center as well as at both ends. I did not check the rotor thickness as I do not have the proper setup/caliper. But I am going to take it down to the local Midas and have them do a thickness check for me. Since they can not turn the rotors for me (and in theory it should not be needed as per Power Slot), they can at least check for any warpage. There is also no deep scores in the rotors. Is this something that I should be concerned with? Or would this be somewha t normal? I don't have any pulling to either side while braking. The rear is stock and I checked both sides and both sides measure pretty close to one another. Beatrice L. Reynolds ([EMAIL PROTECTED]) Jackson Supercharged NOS injected 1990 Honda CRXsi "Yes, you just got spanked by a girl..."
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