confusingboat

I installed a set of AMS stainless brake lines on my 2015 MR this past Saturday (pleasantly surprised that they didn't replace the front hardlines), and I now have to "preload" the brakes by lightly depressing/releasing the pedal once about 10-20% before reapplying the brakes in order to get the rock hard response.

The res. is at the max line cold with RBF600 and I've bled the whole system twice the old fashioned two man way using the proper order as described in another thread (rear passenger, front driver, rear driver, front passenger, outside bleeders first).

My car sits overnight with its nose up on an inclined driveway (possibly helps the air bubbles work their way up and out?), and it's been getting a little better each day, so my question is this: should I just wait to see if the problem resolves itself completely or should I bite the bullet and rebleed the whole system again with my newly-acquired Motive Power Bleeder? Both times the car was bled with the engine off, if that matters.

hoobastnk90

Well if there mushy then there is still air in the system. How much fluid did you use when you changed out the lines?

Tantrum X

iTrader: (12)

If you bleed the brakes in the order you wrote, there is your problem. It suppose to be rear driver, front pass, rear pass, front driver.

blockade35

iTrader: (8)

Sounds like air to me. Did you do anything else to the car when you changed the fluid? I spent most of a weekend chasing a mushy pedal once which turned out to be a bent titanium shim that I had put in.

Og Neon

iTrader: (1)

I would recommend bleeding them again. I track my car year around and bleed my brakes almost monthly and the order you mention as well as tantrum (which is the same as yours just a different order) I have never followed. I do it more old fashion. I start with the caliper furthest away from the master cylinder, Rear Passenger, Rear Drivers, Front Passengers, Front driver. I also start with the inside bleed nipple then do the outside bleed nipple. I say give that a try with a 2nd person pumping the brakes.

Some tips, make sure you closing the nipple good when the pedal operator is pumping it back up. I have slacked on that and sucked air back in. Also watch your fluid level, i have let that slip too before and had to start all over. Lastly, make sure they are really pushing on that brake pedal hard. If they are too soft with it I have gotten some mushy feel as well because they are not putting enough force on the fluid to push the air to the bleed nipple. Let me know how that works. Like i said i bleed regularly and have never had an issue yet.

hoobastnk90

And one last thing make sure you tightened the new SS brake lines as there could be a leak causing your mushy pedal feel.

confusingboat

This was the cause of my 2nd bleeding session lol after I found the one leak I got pissed and tightened every connection again.

So far I've used a little over 1L of fluid on the swap, and I still have an extra 2L.

After receiving a bunch of different information on the proper bleeding order from different sources, I used this bleeding order, because someone said it was the same on the VIII, IX and X: http://www.joe250.com/cars/evo8/brak...ebleeding.html

I was on my way out to my parents' to bleed them again on Tuesday (they have a much larger garage and a large, flat driveway), then, when I was in the car wash with nothing better to do I held the pedal down to the floor for a good while whilst giving the engine a minor rev. Upon leaving the wash the play was gone (dafuq?) and they've been fine ever since.

I didn't end up bleeding them that night because I was still annoyed with jacking the car up and removing the wheels twelve thousand times the previous weekend.

I'll continue spot checking for leaks and monitoring the fluid level and report back if anything comes up.

Thanks for all the suggestions, and we'll see how these bad boys perform at Proving Grounds.

confusingboat

UPDATE:

After driving the brakes hard for a couple weeks, they firmed up real good, and performed flawlessly in autox.

The fluid level dropped slightly, but there are still no leaks. Seems like there was some air that worked its way out of the system and into the res.

So to anyone else experiencing this issue, fear not: it is (probably) only temporary