2008 Forester NA. Iintermittant wheel or driveline vibration, seems to be up front.

I've previously replaced front wheel bearings/seals. Swapped axles around. One new axle at some point. 
Seems to heat up randomly on highway and start grinding faintly, increasing, until speed changes.

It used to alarm me. Now I just slow down and find a speed where the noise remains constant, not getting louder or changing.

After stopping it seems to cool down and reset.

Every few days it happens.

I think I know why it happens on this year and model and not on my 1999 ForesterNA.

 

 

Edited February 5, 20197 yr by uniberp1

U-joint in the front of the driveline.

1 hour ago, FerGloyale said:

U-joint in the front of the driveline.

Driveshaft?

does it change if you touch the brakes? with turning L or R ?

ever happen at slow enough speed someone could pace the car and listen for the location better?

can you feel the vibration? seat-of-the-pants? steering wheel?

you might point an infrared thermometer at each corner after a highway run.

3 hours ago, 1 Lucky Texan said:

does it change if you touch the brakes? with turning L or R ?

ever happen at slow enough speed someone could pace the car and listen for the location better?

can you feel the vibration? seat-of-the-pants? steering wheel?

you might point an infrared thermometer at each corner after a highway run.

When it happens, it gets harsher when I touch the brakes, which indicates a wheel bearing.
When it resets, no change when braking.
Harshness is just in increase in audible throughout the car. Maybe the steering wheel.

Here's what I suspect. This car has 16" wide flat-profile tires. (Yokohama Avid Ascend)The additional leverage put on the wheel bearing due to the large effective offset increases the pressure on the bearing and heat distorts it. The 99 has taller narrow 15 tires.

I've had 3 wheel bearing replacements in this car. Granted one might have been cheap, but the other 2 were an NTN and the SKF hub kit. 140k miles. 

Maybe pothole Michigan has something to do with it. 

Eventually I will get tired of dealing with it, even intermittantly, and replace one of the bearings. I run it on stands and listen to identify the weaker bearing. 
 

kinda wondering if you have a sticking caliper. Light use of brakes could make it sound worse, heavy use could 'reset' it/free-up/shift  the caliper?

 

but, seems like you have experienced this before so......

Yep, my immediate thought is sticking brake. They can do all kinds of weird things.

 

I occasionally check brake temperatures to make sure they're even. The best test is drive on the freeway for some time (30 minutes+), and then coast to a stop on the exit ramp using the brakes as little as possible. Then I get out, walk around, and feel the heat off the brake rotors (use caution, if they're working correctly, the rotors should just be warm, but if you've got something sticking, it'll be HOT, you'll feel the heat radiating well outside the wheel). Rule of thumb, is they should be about the same temperature side-to-side (fronts likely warmer than rears).

Either way, I'd have those apart, and carefully inspect every moving part. I'd push the fluid out of the calipers to make sure there is fresh fluid in them and they move well, I'd clean and grease the slides, make sure the pads move smoothly in the mounts, etc. Grease everything with a high-quality grease (I use the purple bottle permatex ceramic brake grease).

+1 on the driveshaft.

Is the shaking getting worse? It happened to me in my 99 ob, (automatic trans) and it would be only when the awd kicked in. Also intermittent!

I found the problem easily, I stopped and put the 2wd fuse in and it went away. Unfortunately your forester is too new to disable the awd in that manner. 

Slide under and have a look, my front u joint was incredibly rusty. Fortunately the driveshaft is a two piece, so if you are the type to get dirty in junkyards, or are good at CL, this is a $30-50 one hour fix.

Alternatively, go to a driveshaft place and they can install a front u joint with a grease fitting like Subaru should have done...

Good luck man! Let us know the results when done wrenching!

Edited February 6, 20197 yr by sparkyboy