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Hey everyone I started to see my red brake and PDAS light illuminated for maybe 20 to 45 seconds when starting the car for the first time after sitting. Consulting some of the wise here suggest it points to a failing bomb that leaks pressure overnite. My brakes and hydraulics are perfect in operation and I never see any lights after the initial charge up. I am curious to hear from anyone with similar symptoms whether you live and let live or whether it was a sign of Coming Failure. Bomb is bout $250 and somewhat annoying to replace on a system i just hammer bled so im not dying to do it just cuz.
The system was fully flushed and hammer bled after my motor project a few months back. This symptom was not instant it showed up maybe a few months later
The pump run time seems to be getting longer, I'm going to think about doing this sooner rather than later. Porsche DE has a decent price on the bomb - anyone seen it cheaper? https://www.delawareporscheparts.com...g2LWdhcw%3D%3D
I'm not seeing a factory procedure for replacing the accumulator. Am I missing something or did you simply follow the procedure to depressurize the system and then remove, replace?
Yes, I moved the pressure port from the old bomb to the new one. I think it's 14mm?
I depressurized the bomb according to the bleed instructions, made sure that the pressure pump was unplugged, and removed and replaced.
I had the whole ABS hydraulic unit out at the time which made the job that much more fun.
Cool that sounds like a plan. I'm confident around the hydro lines but the 80psi pre-charge business is a bit of black magic to me. Am I trying to be careful when I remove those little yellow plugs in any way or is this simply a remove and replace operation with attendant bleeding afterwards?
As described. I followed the procedure in the factory manual to bleed. My notes that aren't covered in the manual:
Remove the pressure test fitting first (14mm hex) as it makes removing line below easier
Remove remaining lines with bomb bolted in place
Remove bomb and bracket with 3 locknuts (10mm hex). if you wanna go nuts (yes, pun, deal with it) buy new elliptical locknuts but I re use these for non-engine/suspension things like said bracket.
Clean pressure test fitting (quick ultrasonic bath for me), don't install on new bomb yet like I did, then had to remove it to reinstall lines duh.
Swap bracket over to new bomb
My new bomb's bleeder was HEAVILY painted so much that a 9mm would not fit even after a light filing. I had to remove the bleed screw and file it clean on the bench.
Get the hydro lines aligned and snugged then reinstall three locknuts
Snug her all up and install the pressure test port.
Bleed bomb and solenoid per factory procedure. I did not bleed post solenoid aka PDAS bleed as per factory lit, no need to if lines not disturbed post solenoid.
If not obvious (I had to remind myself) this circuit is totally isolated from actual brake circuit so not need to bleed calipers if you don't need to - mine are fresh.
I was pleased to start the car this morning and not hear the pump run at all. That is a big difference from the red warning light and long pump run time I was getting every morning.
is it normal for the pump to get loud as it completes its run? This makes some sense as it is fighting against extremely high pressure but my pump sounds very mellow for the first 80% of it run time and then quite noisy like an oilless pancake compressor for the last few seconds
The procedure is in the factory manual beginning section 47-1. If you search here you will find links to PDF versions of the manuals
06-28-2020, 10:49 AM
Bomb replacement / brake and pdas red lights
