revhard

I read the FAQ on brake bleeding and am uncertain to when this should be done and exactly what you get out of it.

Thanks

Testut

[QUOTE]Originally posted by revhard
[B]I read the FAQ on brake bleeding and am uncertain to when this should be done and exactly what you get out of it.

I can't remember how often the S2000 manual calls for replacing the brake fluid, but I would suggest at least once every two years, more often (once per year) if you run your S2000 at track or autoX events.

The reason for replacing your brake fluid is that water and other contaminents can get into your brake system, reducing its stopping ability and affecting the longevity of the hydraulic parts (master and wheel cylinders). This is also the reason that all brake fluid bleeding/replacing instructions specify using ONLY fluid from a NEW can (i.e., once you've opened a can of brake fluid, water vapor can enter the can and be absorbed into the fluid within).

I would recommend pressure bleeding over SpeedBleeders (and I've used both). The SpeedBleeders are fine, but I notice a better pedal feel with a pressurized approach and a lot less work. Just my $.02.

Skip

JRM

It first removes any air from the lines that could cause a spongy pedal. Secondly, it is a way of replacing old fluid with new. As it becomes old it loses some of it efficiency in with standing heat produced by the braking action. Braking ability will be reduced. It's ability to act as a hydralic fluid is greatly reduced. Chemical properties break down and can cause internal corrosion.

So changing the fluid helps to maintain efficiency and over all performance of the system. When should it be done? Well, when the fluid becomes a dark amber color and has a slight burnt smell. If you track the car then you should probally do it after the event. Or about every 25K.

xviper

[QUOTE]Originally posted by Testut
I would recommend pressure bleeding over SpeedBleeders (and I've used both).

Testut

A low pressure is applied to the master cylinder, typically less than 10# (apologize to my metric friends here, but I don't have the equivalent value in my head in Newton meters ). As the pressure is being applied simply back off on the bleeder screw until fluid comes out. Close the screw when no air is visible in the fluid.

Pressure bleeding kits are available through many sources and cost anywhere from $40US to... ? Some of these kits even use a spare tire as the pressure source, although with the air pressures in some of today's spare tires, that may be excessive. I've used both SpeedBleeders and this method and much prefer this method as less air seems to remain in the system (at least with the cars I've had).

Skip

xviper

Thanks. I've not heard of this till now. The bleed kits I've seen and one that I was planning to get "sucks" the fluid out at each wheel under vacuum. It's a manually operated pump (repeatedly squeeze the trigger on the handle) that sucks the fluid into its own reservoir. What do you think of these?
ps. I don't do newton meters either. Even us Cannucks have our limits.

Triple-H

In addition to all the above info there is the factor of high speed driving schools. Brakes should be bleed/flushed before every school so when the car goes on the track the fluid is fresh, clean and at its best.

As old fluid absorbs moisture out of the environment it begins to lower the boiling point of the fluid. The fluid in the caliper is exposed to some extremely nasty heat because of the brake pads and the rotors getting hot and spreading the heat to all things attached.

In the worst case (ok I could think of worse but we will not go there now) the heat gets so high in the caliper the brake fluid actually boils, thus the boiling action adds air bubbles to the system and now the pedal will feel very soft and scary because air can be compressed.

Brake bleeding is done as a performance/safety issue for cars going to the track. On my '90 CRX-Si that would do about 3 to 5 schools per year I would pump 2 pints of fluid through the system before each event. That is more than what is needed but I have always felt a few extra bucks on fluid was worth my peace of mind.

Tanqueray

[QUOTE]Originally posted by Triple-H
[B]In addition to all the above info there is the factor of high speed driving schools. Brakes should be bleed/flushed before every school so when the car goes on the track the fluid is fresh, clean and at its best.

Triple-H

Originally posted by me
Watkins Glen is a hard braking course, the CRX-Si does not have flat out speed so I stay "fast" by braking deeper and harder than most cars, we are after all talking about only 2,000 pounds. With Hawk Blue pads rated at something well over 1,000 degrees I have actually boiled the fluid (stainless steel brand performance/racing fluid from Racer Wholesale) in the calipers. The extra fluid is nothing compared to peace of mind. Heading into Turn One at 100+mph and braking at the 200-foot marker and looking at an armco wall right in front of you, requires really good brakes. Fluid is cheap. Safety is taking whatever precautions you can to protect yourself and others out there while you are dancing with the coefficient of friction. IMHO.

Testut

[QUOTE]Originally posted by xviper
[B]Thanks.