Stiff pedal

[qksubi]

Ok I've researching a way to get a good bleed subaru says to bleed in this order rf,lr,lf,rr but doesnt mention ABS and Stoptech says this!?
http://www.stoptech.com/tech_info/wp_bleeding_abs.shtml
Scott, Dean whats the deal what do you guys think?

[sperry]

I believe Subaru's have a Bosch ABS system. Finding a nice easy way to trigger the ABS to cycle would be a nice thing.

Some people were going to look into it as part of the open-source ECU software they were working on, but I'm not sure the ECU actually talks to the ABS controller at all. I'll bet we need some other tool... either the dealer diagnostic computer, or a cheaper version that only cycles the ABS.

[MPREZIV]

I'm pretty sure that you need the dealer specific diag. tool to work the ABS. I've got my own personal OBD scanner, and it won't even pull ABS codes, let alone let you cycle the motor. I know there's more expensive scanners in the aftermarket out there that will let you pull ABS codes and diag, but I've never seen one that will let you actually cycle the motor...

It seems like it'll take someone specifically making a scanner that will let you do this, or finding some other way to cycle the motor. I do know that if you jump the ABS relay in the right direction, you can get the motor to run. I could look more into it if you guys like. (?)



I think the "go jam on the brakes really f*ing hard" looks like the most fun way to do it though!

[Dean]

ABS controller is a seperte controller on the Audi, but you connect to it just like the ECU, and issue commands, etc.

IMHO opinion, if you do a base flush, and then change fluid before each event, the fluid in the ABS controller should be pretty good because it cycles good stuff into the controller when you ABS at the last event. It is unlikely that "bad fluid" makes it all the way from the brakes to the controller and gets in during an event.

[cody]

Dean, does that apply for AutoX too? Best to flush before the event and not after?

[Dean]

For auto cross, you are unlikely to get your brakes hot enought to really worry about it with good fluid. Maybe a couple times per season would do.

Before and after is best, before is better if you only do one.

[Speedtoy]

Depending what fluid you use..always flush AFTER race events. Before doesnt solve anything, except make more fluid sales for someone...

RBF600 from Motul, good stuff. But it -has- to be consistently flushed..race or not. Its extremely hygroscopic, and needs to be on a steady path from the master cylinder to the bleed nipple. Especially once abused.

You'd be suprised how fast black, burnt fluid can circulate to the master cylinder from your calipers.

The Motul5.1 can sit in your system for long term use..American style. Fill and ferget.


RBF600 isnt required for autox..you wont get that hot.

[sperry]

Originally Posted by Speedtoy

Depending what fluid you use..always flush AFTER race events. Before doesnt solve anything, except make more fluid sales for someone...

RBF600 from Motul, good stuff. But it -has- to be consistently flushed..race or not. Its extremely hygroscopic, and needs to be on a steady path from the master cylinder to the bleed nipple. Especially once abused.

You'd be suprised how fast black, burnt fluid can circulate to the master cylinder from your calipers.

The Motul5.1 can sit in your system for long term use..American style. Fill and ferget.


RBF600 isnt required for autox..you wont get that hot.

So your suggesting that people flush after an event, then drive around on the street for a month drawing water into the system and then race on a soft pedal w/ wet fluid?

I'm going to keep flushing before my events, so I have a nice firm pedal and fresh fluid when I'm out on track hauling the car down from 120. I don't really mind the soft pedal on the street w/ burnt fluid after the event, since I'm not pushing the car taking it to and from the meets.

[Speedtoy]

I dont..and my source doesnt..consider a month long-term use. If you intend to use RBF600 for 1 or 2 events a year, then you should flush before an event, but most people Ive run into dont use $15/bottle fluid for 1 or 2 events a year when they wont be seeing that much energy in the system.

But..youre welcome to flush a few oz before an event, just that a # of weeks isnt an issue....no worries.

The thing bout the old fluid burnt after an event, is the larger volume of fluid (a bottle) required to clear it all out once it migrates up to your MC. Even with an ABS pump in there, you can get the gummy stuff up that far in just a few weeks to a month..at least on my Z06 I can start seeing brown fluid up there that fast. If the fluid degrades that far up in the system, you have no choice but to perform full flushes as a matter of routine maintenance if you dont pull a few oz's after race days.

Someday on the RX7 I'll actually install the recirc system so I wont boil fluid in that car anymore.

[MikeK]

Originally Posted by Speedtoy

Depending what fluid you use..always flush AFTER race events. Before doesnt solve anything, except make more fluid sales for someone...

I completely disagree with this.

[tysonK]

Originally Posted by MikeK

I completely disagree with this.

Maybe he mean weeks after the event but right before the next event.

You might actually agree with him depending on what he means.

[Speedtoy]

Originally Posted by MikeK

I completely disagree with this.

And thats fine. Its your choice to contaminate your entire braking system with burnt, compromised, brake fluid.

The fluid in the system does freely circulate.

Of course this all assumes that youre developing enough heat to compromise it that much.

[MikeK]

Let me rephrase. I don't disagree that you should flush after an event, I just think that it's important to flush before. At least it has been my experience that the only way my brakes will survive a whole track weekend is to have fresh brake fluid immediately before the event.

[Speedtoy]

And I wont call you wrong for doing it...

If you ever happen to come to a Norcal NASA event, lets test your theory. We have a brake fluid vaporizer in tech that will test the current boiling point of fluid. We'll see what its good for..it would be cool to find out.

In my rx7, ive found the fluid to drop 50d in boiling temp in a single weekend, tested at the end. Ive never tested before a race...after a month sitting. But I dont drive it either for that month.

[khail19]

I think it mostly depends on whether the car is a daily driver or not. If it is, I think before an event would be better, or before and after if feasible.