92 300d 2.5

had a slippery drive this morning, and i have an abs question.

if my abs dashlight is NOT coming on, that's good, right? i was wondering if it's supposed to come on every time abs is engaged...

my wheels feel like they are locking up when i am stopping, but i also get some sort of vibration. i really can't tell if the abs is working or not. how does one test for this? i'm pretty sure my wifde doesn't want to stand in teh parking light as i drive and brake around her...


david

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newfane, vt
84 300td 223k modified greasel conversion (sold)
92 300d 2.5 185k with frybrid kit

Hi DAvid, nice greasy roads eh? I believe the ABS light would not come on during normal use. to test fing a parkig ,ot and do some testing. press the brake pedal hard....if you can feel the vibe/pulsing and can steer your ABS is working as designed. Personally I'm not a big fan of ABS, That could change If I need it and it allows me to steer around something I would have hit tho....This stuff is supposed to change to rain

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Rob M
Norwich, VT USA
1980 240D Euro delivery 4 speed manual silver/blue
~160K miles

The ABS light comes on when their is a fault in the system. When the light comes on the ABS will not engage and you have regular brakes.


To test the ABS slam on your brakes, if they lock up it isn't working. You should hear and feel it pumping away though if its working.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

well, i feel it, and hear it, but still slide as if my wheels are locked up. i suppose it could have been so greasy this morning that i still slid with teh abs on. i can't imagine if it hadn't been working...

rob, did your kids have school this morning? my drive was awful...

david

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newfane, vt
84 300td 223k modified greasel conversion (sold)
92 300d 2.5 185k with frybrid kit

another way to test the ABS is to put the rears up on jackstands, start the car and put it in drive. When you get to a certain speed, hit the brakes. Since the front wheels are not spinning, the ABS computer thinks they are skidding, and pulses the front brakes (which you should feel through the brake pedal).

be careful though to ensure that the car is SECURELY jacked up - ensure that the jackstands are secure, and that the front wheels are properly chocked so they do not move. And also be careful to minimize your movement inside the car while performing this test.

i personally test my ABS whenever I get the chance, i.e., on snowy/icy desolate roads (where the brakes and tires are subjected to less stress and wear, compared with dry roads). I believe in getting in tune with my car's reactions under such situations so I can predict what it will do then. For example, one of the motivations of ABS is to regain some degree of steering control so you can steer yourself out of trouble (or choose the least expensive target!). Having said this, one must also be familiar with the car's reactions in dry conditions on summer tires.

under such conditions, one will discover that the amount of steering control is diminished from what can normally be expected. This means that in a panic stop in slippery conditions (with the ABS pulsing away), one can only feed a certain amount of steering angle, beyond which steering is ineffective. But the AMOUNT of steering that one knows is available can prove to be invaluable if put to good use. This can only be learned through experimentation.

School was a go....Morning commute for me was s-l-o-w......

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Rob M
Norwich, VT USA
1980 240D Euro delivery 4 speed manual silver/blue
~160K miles

slow for me too. i had two moments of the slow slide into oncoming traffic. luckily, there was no traffic at the time. hate the 10 mph slide...
have you ever heard of getting your tires studded after driving for awhile? i opted not to stud, but was wondering if i could do it now. seems like some studs sure would help.

david

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newfane, vt
84 300td 223k modified greasel conversion (sold)
92 300d 2.5 185k with frybrid kit

Usually if the ABS light flickers on it is either low voltage, or dirty sensor(s).

Drive slowly down an icy, clear road and slam on the brakes. As the brakes pulse, cock the wheel left and right. If you can still control the car, you have experienced the reason why ABS came to be and verified the system is OK. Merc's 4-wheel ABS is able to pump the brakes up to 30 times per second.

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1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)

i think mine must be working. i either wasn't slamming hte brakes (would that make it worse?) or it was too icy. i tried it on the way home, and i could steer and stop reasonably well.

david

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newfane, vt
84 300td 223k modified greasel conversion (sold)
92 300d 2.5 185k with frybrid kit