Abs?

[Chruby99]

So the snow hit the donner pass. I drove thru the chain up checkpoint and did not have to chain up... Nice. Conditions were icy and the car handled great. However, upon a break check to test conditions at @ 60 mph all the wheels locked up and nearly spun out. What is the deal with this abs. I felt no abs pump just an all wheel lock up. No ABS dummie light.

[Chruby99]

And is the vicious coupling in the transfer case this tight to cause an all wheel lock up. I have had this same thing happen on dry pavement. All wheels lock up and the car usually does not want to go strait. Of course on dry pavement I am usually going way faster than I should and laying into them hard. But on snow. My wife drives this. I have always loved abs for winter driving but all wheel lock ups frequently end up as spin outs in the winter weather

[nando]

I don't think the VC can cause all 4 wheels to lock up. it doesn't work like that.

something could be wrong with your brakes. are both of your clutch switches working? is the ABS dummy light bulb still there? it could have been on and the PO removed it instead of fixing the problem. basically a full test of the ABS system is required, but that could be tough as there's scant documentation and the dealers are going to be of no help.

also, do you have snow tires on the car? the ABS system is designed to work on ice, but it only works well if you have snow tires. with regular tires, you won't be able to stop, at all.

[Chruby99]

Have to pull the instrment cluster

I will have to pull the cluster and check the bulbs. Replace some while it is out.
The tires are all season Pirelli P6 205/50 16 pretty wide for a car this size. Not Snow tires

Makes sense for them to loose traction on the snow

I will check the bulbs on the dummy lights If that looks good I will find a spot mabee on the side of the road. Brake hard with one side of the car on paved road and the other side on the gravel. I will see If I can lock up on the gravel side to activate the abs..

Are the abs systems on these similar to other cars where a pump engages anda pulsing can be felt on the brake pedal

[Chruby99]

I thought this may be caused by the transfer case. I have tried pulling the parking brake on my other 4x4 in the snow and it caused an all wheel lock up
Not a good Idea at speed.

[Chruby99]

Clutch Switches?

This is an auto.

Does this apply to me

[nando]

no, not in that case - but it still could be caused by ABS.

an ix with a good VC should lock up all 4 on a slick sufrace if you pull the ebrake. as you know, not a good idea. :)

on dry pavement, having the ebrake on will cause all sorts of wierd drivetrain gyrations. also not good..

yes, you should feel the ABS pulsing through the pedal.

stock ix tires were 205/55-15, so a 205/50-16 is not wide at all.

[Chruby99]

I will look into it thanks for your input

[AndrewBird]

If all 4 wheels locked at the same time, the ABS won't kick in as it doesn't notice a difference in wheel speed. It would be like if you weren't moving with the brakes on. The ABS will only engage if it senses a wheel moving slower then the rest.

In other words, you have to have some grip for it to work.

My suggestion is don't drive 60 in the snow. Just because you have AWD does not make you invincible.

[nando]

Not true on the ix. It has an accelerometer.

[AndrewBird]

Oh really? Interfesting. Learn something new everyday.

[Chruby99]

Looks like the parking brake bulb and the abs bulb are dead on the dummy warning lights. Looks like I will have to start inspecting the abs system. Wheel sensors, accelerometer, and abs module. Anything else I need to check out.

[nando]

what year is the car? early models also have an ABS relay, later ones do not.

[Chruby99]

2/89

[Chruby99]

It is out of your neck of the woods Nando. Purchased and serviced until the mid 90's at Bellevue BMW