Wobble when accelerating

Tonyx · Post by **Tonyx** » 06 Mar 2013, 08:10

My 2001 XC70 wobbles under hard acceleration and is worse with harder accel. Some info:
* front suspension is essentially new(new struts, strut mount, ball joint, sway links, control arm, tie rods)
* recently had wheel alignment
* front engine mount replaced(one by pass side front wheel)
* top engine mount(ties into cross bar) and lower transmission torque mount are new within 6 months
* no wobble during decel

I can almost count the frequency of wobble 2 - 3 hz. Doesn't seem to change with engine rpm or car speed.

What to look for next?

Rocky · Post by **Rocky** » 08 Mar 2013, 15:01

Torque steer.

Tonyx · Post by **Tonyx** » 12 Mar 2013, 07:49

I doubt it. The wobble surfaced recently, wasn't there before.

Post by **chrism** » 12 Mar 2013, 10:43

A bad CV joint will cause a low frequency shake under acceleration. Mine did. The shaking subsides when the throttle is let up.

Tonyx · Post by **Tonyx** » 12 Mar 2013, 14:15

I heard that before. Is there a way to test for bad CV joint without disassembly?

Tonyx · Post by **Tonyx** » 14 Mar 2013, 19:22

Calling Jimmy. I could use your expertise on this one..,

deanmohideen · Post by **deanmohideen** » 17 Mar 2013, 04:24

Hi

I have come across a few of this problems on xc70. The support bearing of right front drive shaft is exposed to intense heat from the turbo. The heat dries up the bearing leaving a fair amount of up and down movement. If you can move the shaft up and down by hand on your vehicle you then have to get a exchange drive shaft or you may be able to get a bearing to replace the faulty one.

Good luck

Dean

Tonyx · Post by **Tonyx** » 17 Mar 2013, 08:31

Super. Thanks for that info, Dean. I'll try to move it by hand.

Tonyx · Post by **Tonyx** » 30 Mar 2013, 05:07

It took a long time to get under the car, winter temperatures, but the middle bearing checked out ok - no movement with good shake. What I did see was the inner cv boot had spewed grease, both driver and passenger side. I saw a line of grease rooster tail emanating from the inner cv location.

I did not see an obvious tear in the boots, it's almost like the grease was squeezed out. Ironically the wobble is not noticeable now. There is no clicking. It's like too much grease was there causing issue and now its out, its working normally. What are your thoughts on this?

Tonyx · Post by **Tonyx** » 21 Apr 2013, 11:23

Update:
Replaced both passenger and driver side half shafts in front. As said earlier both shafts spewed grease from inner cv joint. I felt slight slack spanning the inner cv's. No slack felt on the outer cv's nor the middle bearing on the pass side shaft.

Some lessons learned:
1 replace wheel bearings at the same time - really reduced the background white noise which I didn't noticed until it was eliminated. If installing new bearing assembly, knock out the old unit and thoroughly wire brush the area to facilitate installing the new unit.
2 be sure the harmonic balancer is on the new driver side half shaft. Some remanufactured parts did not included the balancer which I promptly rejected.
3 be sure the half shaft is in neutral position, level, before wedging it out of transmission case. If screw driver or pry bar doesn't work don't hesitate to use broad cold chisel to wedge it out. Pass side came out without hesitation
4 loosen the two strut to knuckle bolts and remove only the top bolt. Keeping the bottom bolt in allow you to rotate the knuckle enough to remove the half shaft without messing with control arm. You do need to undo stabilizer bar links, the tie rod and the brake calipers from the knuckle.

Tools needed:
18 & 19mm wrenches for tie rod and stabilizer link ball joints
12mm socket for pass side half shaft middle bearing bracket and underbody shield
14mm socket for half shaft retention bolt
15mm socket for brake caliper bolts
17mm socket for wheel bearing mount bolts
19mm socket for wheel lug bolts
21mm socket for strut bolts
Hammer and cold chisel for wedging out driver side half shaft

As its fresh in my mind feel free to ask any questions. I can honestly say it can be done in 30 minutes per side.