twohoos

One man's insane is another's routine I guess. Remember you can't even try this until you have enough braking power to fully engage ABS, so the car is already at point where it's safe for street driving. (As robrob's page observes, some people "suffer a spongy brake pedal for years" - presumably those years involve some actual mileage.) And given the circumstances --this being the most technical subforum of a sports car owners' site-- I don't think it's insane to infer that the OP, and future similarly-afflicted readers of this thread, can responsibly identify a safe time & place for a single hard ABS stop.

That said, I think we can all agree: bring on the wood brake video!

B serious

Its insane to assume I was referring so much of my post towards you. Perhaps it is you who thinks your method is insane.

#deepthoughts

B serious

Most spongy pedals come from lack of maintainence.

Nobody checks if their pads are seized in the bracket or if the pin sliders slide.

Sometimes, pads are rusty or ill fitting. Sometimes caliper brackets are rusty and swollen. I've had to file down the pad ears on a lot of aftermarket pads so that they're not jammed solid into the bracket. Also had to do it due to rust.

Air doesn't magically appear in a brake system. Why is the air in the lines? If you never opened the system up in the first place...or if you have already bled the system thoroughly, then start with something other than bleeding the brakes 800 more times with increasingly expensive boutique brake fluids made from the urine of a unicorn.

Pads being overly compressible and/or backing plates that are too thin or flexible will cause a spongy pedal too.

twohoos

LOL mind=blown

shind3

LOL, glad you guys liked my idea.

Here's an addendum to my earlier post. Maybe drive the car a bit to get above 10mph or whatever it takes to get the ABS self-test to complete after engine start. Then with the engine running, park it, put the rear on jackstands, remove rear calipers, and stick a piece of wood between them. Then put it in gear and get the rear wheels rolling. Then press the brake pedal. The car might think the front wheels are locked and it'll pulse the front ABS circuits. Maybe? lol. Though, I don't see how this is any different than doing a 'line lock brake stand burnout'. There must be some logic that prevents ABS actuation if it sees the vehicle never actually got above a certain speed.

limenuke

I won't have any seized items or a cracked hose since I also recently installed a stoptech st40 BBK.

I ended up accidentally getting air into my MC after bleeding the BMC. How did you do such a stupid thing, you may ask. Well, I had a funnel for my brake reservoir while I was bleeding my brakes. I did not realize the funnel was pointing directly into the exit port of the reservoir, and partially sealing it off from the rest of the reservoir fluid. So even though the fluid was topped up, the fluid in the funnel ran out and I heard the dread empty-beverage-straw sucking sound during one of my pedal strokes.

I will re-bleed the BMC tonight thru the front left ABS fitting, jack up the car again, and bleed the front left caliper and hope my brake feel returns.


I have to emphasize that there are a few brake rumours which I simply do not believe. Spongy feel due to "compressible brake pads" seems quite unlikely. I have driven the cheapest pads on my old honda civic and have never had a spongy feel from those pads. I think that spongy pedal from compressible pads is a myth. Another myth is that brake fluid can be compressible. Liquids are essentially non-compressible. You either have air in your lines or you have a leak. You do not have a compressible liquid.

B serious

I haven't heard any myth that brake fluid is compressible.

Organic pads sometimes compress a little more. Some pads have thin backing plates.

In your case, probably do the ABS bleed first.

Have you bed the pads in yet?

hirev

replace master cyl. it has a leak?

B serious

Yes, if the pedal was pushed to the floor during the bleeding/pad seating process, there is a small chance the master cylinder internal seal is damaged.

You're not supposed to full-stroke the pedal.

DanielB

A simple way to activate ABS would be to wait for some rain ... but only if you know the rest of the brake system is in good order.

Obviously may not be an option depending on where you live ...