I am having a slight problem with my '85 500SE euro's braking.. After 15 mins of driving, and applying the brakes coming to a stop, the brake pedal goes to the floor and the ABS light comes on. I have a squishy pedal as if there is no brakes unless you pump it.. After you shut the car off and restart after 5 mins.. Everything is fine.. and then another 15 mins.. pedal goes to the floor and ABS light comes on.. I have checked everything twice thoroughly: pads, calipers, shims, checked Vacuum connection at the booster and installed a new hard line with one-way check valve, and re-bled the brakes twice..

My question is..

1. Where is the ABS ECU located? I would like to try unplugging it and checking the brakes
2. Does this have anything to do with the MC?
3. Is this a vacuum situation? The car does have AMG high-lift cams in it aswell as major internal work..


Thanks,
Chris

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"Why operate within the law when you can operate above it?"

MB roster
'85 500SE euro Ratrod
'92 500E's x2 / '94 E500 stored
'91 560SEC w/43K stored
'92 Cabby 16V OE 2.1 AutoX car
JDM RHD cars now.

ABS computer is in the middle between the two firewalls.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

I'm not familiar with your model. but check the OVP and its fuse. I had ABS/ASR lights come on, and I cleaned the wheel sensors and checked pads and wear sensors. No change. Then I checked the OVP, fuse was good. Still, I swapped the OVP with a known good one and voila, the lights went off and all is well. However, I did not have soft pedal issues, only limp home issues.

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87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)

Starting with the easy stuff, I'd check the caliper pins on which the caliper floats. Make sure they're tight, mine is 22 ft-lbs, not sure about yours.

If you're sure the rotors are not warped and the pads are in good shape, check the pins for tightness! Sounds like the pistons are getting pushed back along with the calipers after a short drive and the first pump brings them back against the rotors.

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1990 300E
124.030
chassis 103.983