need help diagnosing drivetrain problem on 90q20v

Kneale Brownson knotnook at traverse.com
Sat Aug 11 13:52:15 EDT 2001


I thought you had to have wheels on the ground to activate the Torsen, but 
maybe I misunderstood.  Regardless, the original problem sounded to me like 
a brake caliper not releasing.  If you had to manually release the E-brake 
lever (as opposed to a frozen E-brake cable), there's internal corrosion 
past the seal surrounding the E-Brake lever shaft where it enters the 
caliper body.  I found in two rear calipers I've disassembled with 
corrosion in that area that the piston and cylinder also had spots of 
corrosion that kept the piston from releasing even when the E-Brake 
assembly was free.  There's no direct relationship other than the general 
condition of the caliper, as far as I know,  but you might want to extract 
the piston from the cylinder and inspect it and the cylinder for spots of 
rust that would limit piston travel.

At 11:08 AM 08/11/2001 -0500, Dan Simoes wrote:

>20vers, I know it's not an SUV, but maybe you can help :)
>
>I'm a little baffled on this one and figured I'd check before ripping
>things apart.
>
>The patient is a 1990 90q20v.  Symptom: when making a tight right turn,
>you could clearly notice the left rear tire dragging/scrubbing.  I
>thought perhaps the rear diff had locked, and asked a shop to check it,
>no problem found.  I chalked it up to a wheel bearing and parked the car
>as I was trying to repair the driver's seat.
>
>A couple of weeks later, my father had a car accident and needed to
>borrow mine, so I threw the seat back in and let him have the car.  He
>called me to report that the ebrake was not releasing and he could feel
>the car dragging.  I checked it and manually freed the caliper on the
>left rear side.  He brought the car back again in a day or so and said
>it was still dragging.  I drove it and confirmed this.
>
>I put the car up on blocks, removed all 4 wheels, and was hoping to see
>3 wheels spinning.  Instead, I see the fronts spinning and nothing
>happening in the rear, nothing in the prop shaft either.  WTF?  Bad rear
>diff?  Bad carrier bearing in the shaft?  With the car running and in
>gear, I can "help" the prop shaft and see both rear halfshafts turning,
>so I know the diff is not seized.
>
>Now that I'm up here typing this, I'm wondering if the Torsen center
>diff is not sending power to the rear because there is no traction.  I'm
>not positive about this though.  Assuming the rear is OK, that brings me
>back to either a bearing or caliper in the rear left.
>
>Another weird thing - the rear diff never worked although the switch
>lights up when you press it.  Well, right now the ABS off light is on
>and the green LED indicates the rear diff is locked.
>
>I'd like to get this sorted out as I'm thinking about selling the car
>anyway.  As you may have read, we picked up a used Volvo 850 for my wife
>and I'm driving her 99 Jetta TDI which I can't seem to sell due to the
>unique color (that's OK though, 49mpg suits me just fine right now in
>this economic climate).  Consider this an offer to sell the 90q, email
>me for details.
>
>Thanks for any suggestions.
>
>| Dan |




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