C4 brakes

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kriknomis
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C4 brakes

Post by kriknomis » Sun Apr 01, 2018 10:39 am

Hi all,
I have a 2003 c4. Absolutely fantastic car that I have had for around 7 years now. My only issue is the brakes. They have never been what I would call confidence inspiring. I have had a Boxster (1999) in the past and the brakes on that were spot on. My car has Psm and I’m sure I have read somewhere that you need to bleed them with the car plugged in to the correct software to modulate them during the procedure. I am about to bleed them so would like to know if I am wasting my time. Has anybody any advice before I proceed.
TIA
Simon

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gnat
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Re: C4 brakes

Post by gnat » Sun Apr 01, 2018 5:08 pm

Can't speak as an expert, but as a 01 C4 owner I can tell you two things.

1) Braking is a key part that makes a Porsche and the 996 C4 is no exception. Getting ready to start year #18 with it and it's stopping ability can still surprise me.

2) These are (comparatively) simple machines that don't have computers tied into every little thing like more modern cars. Again, not an expert, but it would surprise me if a computer was required for the procedure.

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Sneaky Pete
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Re: C4 brakes

Post by Sneaky Pete » Mon Apr 02, 2018 5:48 am

As a previous '99 C4 owner that was tracked alot I always bled my brakes myself. Per the shop work manual the ABS pump needs to be bled / flushed with the piwis after all brakes are bled. A Durametric can do the same thing. That said I never did the last step because my brakes were always good. Are you doing the brake bleed or is a shop doing it?
Pete

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b3freak
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Re: C4 brakes

Post by b3freak » Mon Apr 02, 2018 7:57 am

kriknomis wrote:
Sun Apr 01, 2018 10:39 am
Hi all,
I have a 2003 c4. Absolutely fantastic car that I have had for around 7 years now. My only issue is the brakes. They have never been what I would call confidence inspiring. I have had a Boxster (1999) in the past and the brakes on that were spot on. My car has Psm and I’m sure I have read somewhere that you need to bleed them with the car plugged in to the correct software to modulate them during the procedure. I am about to bleed them so would like to know if I am wasting my time. Has anybody any advice before I proceed.
TIA
Simon
Hey Simon,

Can't go wrong with bleeding the brake lines properly, but since you've had the car 7 years now, have you changed out the pads and rotors?
2002 Porsche 996 Carrera - bare bones basic, but still a blast to drive! Heck, I don't even have PSM on it. Ha!

Tyler H
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Re: C4 brakes

Post by Tyler H » Sat May 19, 2018 9:08 am

Don't forget to bleed the clutch too...there could be some air trapped up there. Bleed the outside of the calipers first, then the inside. Start at the RR, then LR, RF, LF.

Since you have PSM, you might need Durametric to help bleed them, but I would try to do it manually first anyway.

If you're in the mood to throw parts at it, get some braided SS brake lines -- your stock rubber lines could have failed internally. If you do replace lines, here's a helpful trick: Scoot the seat back, take a 3' broom handle or similar, put it against the brake pedal and then move the seat forward to keep your pedal depressed about half way. This blocks the ports in your master cylinder, so you can take your time changing the lines -- the fluid will not siphon down from the MC.

The brakes should be firm and effective in these cars. I've still never tested my ABS on the street, despite trying. We'll see what happens on track.

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