Brake pedal problem, can anyone help?

Isn't about 2" from the top approximately max brake pressure that will stop the car? If you hit that wall and get a bleed off pedal sinking with engine on or off that would imply a leaking master. What you want when driving is a firm solid pedal that hit a point solid and the car stops directly or goes into ABS pedal pulsing mode both with plenty of pedal travel left unused.

 

Did you bleed with ignition on (abs on)?

 

Check the relays on the opposite side of the car from the abs. On a left hand drive they are under the front hood on the passenger side. You have to unscrew and lift the carpet.

 

I don't think I am understanding your description. However, what you describe is sort of like a bad brake line. The lines are rubber and old. Breakdown internally can cause weird symptoms like the wall with no braking or reduced braking effect and failure of brakes to release. The newest 348 is 22 years old! I would replace brake lines of this age as routine maintenance. Girodisc in Washington used to make Stainless braided lines you can check with them. They are not hard to make or source by fitting.

 

Unfortunately we no longer offer brake lines but I don't think that's your issue. It sounds like the ABS is acting up and cycling a valve that closes off the input to the outlet. I've never seen this on one of my 348's but we have a 456 that did something very similar when we were bleeding and cycling the pump with a Leanardo, it would lock the left rear caliper and the pedal would go hard, it was very strange and only after cycling the pump a few times did we get it to stop acting up. Being that the pump is Bosch we were able to blame this one on the Germans for a change

I would keep cycling the ABS pump and see if anything changes. Other than having the lines pinched, a blockage in the lines or something in the master cylinder that won't allow travel there isn't much else it could be.

Best of luck, keep us posted.

 

For whatever it's worth, Goodridge, the well respected maker of SS braided brake and clutch lines, makes two different sets of brake lines for the 348, and offers them in a rainbow of colors. I just ordered a black set with stainless fittings from Demon Tweeks. Seems like they were under $125 shipped. As mentioned above, considering the age of 348s at this point, a new set of high quality lines seems like cheap insurance. They typically improve pedal feel as well, so win/win.

 

Ahh shoot, well I'm glad you got it sorted regardless! Guess I need to poke around in here more often, it's tough to keep up with you guys sometimes!

 

I'm having to same issue. What was the final fix?

 

Jackie and Jill just posted that the fix was a stuck valve.