'99 V70 Understear ?

Check very carefully the viscous coupling / transfer box is healthy- it sounds to me like the coupling is shot (i.e. locked solid) and too much power is being sent rearwards..

Tim..

I had the same annoyance with my 2WD V70 (98 T5). I put up with it for

6 years, before I finally fixed it last year. Before you try this, make sure another car acts the same way, but what I did was put a rear sway bar on that was from a sedan. The original wagon rear bar was 17 mm, the sedan one, 21.5. I was worried that maybe this was going too far, but to my taste the car was just perfect. Even in the snow, or on gravel roads, the car seems perfectly balanced. I kick myself for waiting 6 years.

The only trick for you is that Volvo doesn't list the bars by diameter. You need to read the chassis code of the plate by the battery. On my V70 the chassis code is 5F2PEVS, the 'V' refers to the rear sway bar. On the S70, the rear bar is coded 'N'. You'll have to find an AWD S70, compare bar size to yours, and hopefully it's bigger. Or you can try a set of bars from ipd. I didn't want to use an ipd bar because they've had problems with their rear bars breaking on the 2WD cars. The rear bar is a different (normal) design on the AWD cars, so there shouldn't be a problem.

Also, the XC is jacked up a bit and has tall tires, so it's never going to be great.

Is there an EASY way to test the Viscous coupling ? Or is that a shop thing ?

Start with analyzing your technique regarding entry into the corner. Understeer occurs when the slip angle of the tire contact patch is exceeded and the tires just begin the sweet growly squeal sound that lets you know the tires are working. The transistion from quiet tire noise to the working sound should be smooth and gradual beginning just after turn in at the entry of a corner to a constant pitch through the apex and to the exit. Adjust your apex to see where the optimum entry point should be for your chassis. Remember that a later apex will allow a smoother transition into traffic, while an earlier apex will allow higher exit speed and use more road. Anticipate. Although smooth is key and exit speed is the name of the game you have to be constantly aware of how much stick the car has. As soon as the tire pitch begins to rise be prepared to correct the steering in anticipation of loss of rear wheel grip. The tendency to overcorrect decreases with practice but is almost always the result, so be prepared to correct in the opposite direction to save the car from a spin. You will likely need to repeat the correction two or three times to successfuly execute the save. If when driving into a corner an abrupt lift on the throttle causes violent trailing throttle oversteer then the chassis is horribly balanced and will need extensive sorting to put it right.

Once this is achieved start adjusting tire pressures until the maximum speed can be attained through the same radius turn with reliable precision. Find an empty parking lot at a factory where you can drive in circles of various diameters and spin without running into things. At this point adjusting the sway bars is in order. Stiffening the front, going to a larger diameter bar, and going to a stiffer rear bar will keep the car flatter through a turn. Although too stiff a rear bar will induce understeer. This puts more load on the outside front tire on turn in so that in a street car it's prudent to raise the tire pressure enough to keep the tire on the rim while turning. Since street tires don't develop all that much grip anyway a pressure somewhere in the mid to high 40's psi should be adequate.

Sorry for the rant. Driving techniques need to be learned and practiced. Bravery is no substitute for skill at high speed.

Bob

Jack up the front of the car and place it on stands, *just clear of the ground*.

*VERY* carefully engage top gear or Drive if auto and gently apply a very small amount power, handbrake off.

If the front wheels spin and the car stays still the Viscous is ok.- tho there will be some bind.

If the front wheels dont turn and it tries to push off the stands, the viscous is shot.- i.e. locked solid.

Tim..

I would go into the same corner harder and harder until the tires screemed...

And they I would listen to see how hard they screemed. I learned that I liked it when the scremed a bit, but if they were screeming a lot it was not a good thing because they could let go at any time.

I also learned that different tires behave, well, differently. The Dunlop AS 4000's screemed LOTS, and were very predictable. The next set of tires I got I never found they edge of because they were to sharp... They stuck like rain raicing tires in the straights, but barely screemed at all before loosing it... GREAT drag tires, lousy street or rally tires.

My Volvo 850 doen't have the musscle to be pushed the way I like to drive, which is a good thing, but it is extreemly neutral in driving.

The '99 V70 is fun, not as much fun as my old eclispe, but it weighs twice as much and has half the HP. Needless to say the first time I went into a corner expecting 850 results and I was half a lane from where I was supposed to be, plowing ahead, I got off the gas, and was quickly re-united with the line I desired. I have been "pushing" to find that edge ever since...

Bob S.

"Robert Dietz

And of course, for multiple reasons, practising this should not be done on public roads, but you should know where the limits are - both yours and your car's.

One other point: A stiffer rear sway bar will induce oversteer or reduce understeer. Increasing roll stiffness at one end of the car increases the amount of the force that counteracts the car's lean at that end. This allows the tires at the other end to remain more evenly loaded (i.e. less weight on the outside tire), giving that opposite end more grip.

Turned out to be a broken component.

turning (slowly) the other day my Left front Axel folded back. Apparently a bolt holding the axel to the strut snapped and had been doing strange things.

Glad it didn't happen at speed....