Re: E30 - '86 325E - ABS Question

[alex.fadeev@xxxxxxxxxxx]

"Scott Ruffner" <jpr9c@domain.elided> wrote:
> I've got an ABS "problem" - the ABS seems to be working just fine,

OK.

> although I believe it is coming on when it shouldn't. 

When?

> The brake pedal feels "crunchy" or "brittle" like it's vibrating
> at a high frequency, which I am guessing is what it feels like 
> when the ABS activates.

Yep.

> I don't particularly mind having ABS but I don't use it, 

Got brakes?

> and am likely to lighten up the pressure on the pedal if I get 
> into a skid/slide situation. I guess I just don't want to learn 
> a new style of driving, so I've never tried to slide with it 
> activated. 

It's simple: press until the ABS starts massaging your foot, than press 
_harder_. 
Contrary to popular believe, ABS is not a binary input device. The harder 
you press the brake pedal with ABS pumping, the more aggressively does it 
work. 
If you easy the pressure on the brake pedal or just continue to brake as 
hard as you did before the ABS kicked in, you will wind up with longer 
stopping distances than you would have had before ABS kicked in.

> In any case - can someone confirm this is what I'm feeling? 
> I do believe I can hear a motor activating. If indeed it is 
> just the ABS activating, then any thoughts as to the problem
> of false triggers would be appreciated.

Based on your description, it sounds like ABS is working as it should.
What leads you to believe the ABS is activating prematurely?

> I notice this most when the car is cold, and I'm making a low-speed 
> turn while braking. 

Cold car => cold tires, cold brake pads and cold rotors => potentially 
lower coefficient of friction. Between crappy tires and pads, all my E30 
cars used to drop into ABS mode long before an E36 would.
When was the last time you bled/rebuild your brakes? If one of the pistons 
is sticking, it could trigger premature ABS activation.

> I'm hoping someone else has experienced a case of "the right 
> front sensor always fails prematurely on these cars," and can 
> give me a shortcut. 

Sorry, I can't think of any 'known' E30 ABS issues.

> Yes, I could just disconnect the ABS, as I've noted others have
> done, but I'd rather keep everything working on this car rather
> than start the inevitable slippery slope.

Good idea. 
Doubly so since ABS is a really good thing in the vast majority of the 
situations. The only time it extends your stopping distance is when 
braking over loose turf (tires can't dig in).

alex

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