Front suspension knock
 

Hello,

I replaced both inner and outer tie rods, lower ball joints and sway bar end links. I still have suspension knock in small road undulations - like ripples on the surface. Nothing in larger pot holes or bumps... just repeated small imperfections.

I disconnected one of the end links (took it off) - the knock is still there. The sway bar bushes look suspicious, but with one end lik off....

Feathering the brakes doesn't help - I've had loose calipers before, giving similar sounds.

Is there a known issue with the strut mounts? What's the typical reason for a rack rebuild? Leaks? Mine doesn't leak, the inner tie rods and boots were straight forward to replace w/o pulling the whole rack.

The lower control arm bushings seem ok visually and a crow bar will not reveal anything obvious.....

The sound is like a very loose wheel bearing - but I can not find anything just by yanking the wheels..... feathering the brakes should quiten this too.

Ahy ideas would be greatly appreciated :confused:

Kind regards,

Tapani

Re: Front suspension knock
 

All three of our SVXi developed "popping" sound in front over washboard surfaces. Thought it was front strut mount bearings, replaced entire assemblies in two cars...Testing the removed components out of car later determined it was actually the strut/shock/damper itself.

Re: Front suspension knock
 

it sounds like the struts may be bad. when the valving gets weak then quick and repeated bumps tend to make a knocking noise because the strut is no longer attempting to stabilize the vibration of the spring and just bouncing up and down in the tube. hard to tell for sure without the use of a chassis ear but your struts are probably old enough to replace anyway.

Re: Front suspension knock
 

What is the typical cost for parts and the typical hours of labor to replace the front struts?

I have had a similar nagging noise on my car. It went away last year, just before Reading. The magic happened when the car was up on a lift for a good amount of time for a wheel bearing replacement. One alternative I have read about, but have been unable to verify on my car, is that the sway bar could shift over to one side and get stuck there by the bushings. The implication is that the bar is not sliding freely inside the bushing. Then they supposedly bang against the bushing bracket, I guess. I suppose one could replace the bushings first with poly ones. If that doesn't solve it, I would tend to trust the people that say the struts are bad.

Let us know what you try and how it works out. I don't plan to do anything on my car until spring at the earliest.

Re: Front suspension knock
 

My 96 makes the same noises usually when it's cold which makes me think it's struts.I replaced all sway bar bushings when I got the car so I don't think that's the problem.Just kind makes a thump, nothing that sounds dangerous.It's hard to describe a noise:lol:

Re: Front suspension knock
 

It's actually one of the easiest things you can do. Just gotta have a little bit of brute force in case some of the bolts are being stubborn.

Re: Front suspension knock
 

I second this. You should also take it for an alignment very soon after. 2 breaker bars will help a great deal.

Re: Front suspension knock
 

Which parts NEED to be changed (other than the strut itself) and which parts is it suggested to change? My car's metal and rubber parts seem to be in quite good condition overall.

On a related topic, is the dust cover (part number 20322) supposed to sit at the to of the strut or near the bottom? It looks like part 20321 is supposed to hold it "up" near the mount. Mine isn't doing that. It sits near the bottom of the strut.

Re: Front suspension knock
 

I didn't look at any diagrams but I'm guessing you're talking about the dust cover boot type thing that sits inside the strut and the bumpstop? I don't know what they did when new, but the dust covers have to be omitted when assembling the coilovers, so they are not really "necessary" at all. (Not to say they don't have a useful function.) I found mine to be sitting down at the bottom, not up at the top.

I would replace the bumpstops. I don't know how much OEM ones cost, but groundcontrol sells some for $12 ea (http://www.ground-control-store.com/...tion.php/II=10 3rd one from left). If you have the cash, then changing out the front strut mounts might be nice, since by now the bearing may have developed a bit of play, but I certainly wouldn't call it necessary.

Re: Front suspension knock
 

Thanks everyone,

The struts have only 15.000 miles on them - OEM parts. They were replaced by the provious owner.

And the sound is there only on "wahsboard" surfaces..... mainly on icy roads. Sounds just like a brake caliper with worn pins - I've had this on a Ford Mondeo.

I will try and remove the other sway bar end link just eliminate all related.

On the Finnish Subaru Club forum there's discussion on same type of noise on the latest Outbacks - the factory raplaces the whole steering rack assembly - a known problem inside.

Any thoughts on the SVX rack? Why do people rebuild them?

Both my inner tie rods were worn and had play, also the lower ball joints were shot so the world of sounds has changed - but this what's left is irritating :-).

Kind regards,

Tapani

Re: Front suspension knock
 

Maybe it's play in the steering rack bushings? There are some thin bushings between the steering rack brackets and the rack itself.

Re: Front suspension knock
 

Ok thanks,

I will check them out. I had to loosen the passenger side bracket to get the boot over the rack..... I rechecked the bolts for tightness already but didn't really think of the bushing.

I need to get on a different type of lift so that the weight is on the wheels. Mine lifts from under the car.

Tapani

Re: Front suspension knock
 

That is the only thing I can think of that wasn't already mentioned.

I don't want to overcomplicate this thread, but I have a similar issue with something rattling/jiggling on "washerboard" type surfaces. It got much more noticeable after switching to coilovers. Very nearly every suspension component has been changed or determined to be ok. The strut top mounts are changed to pillow ball camber/caster plates, control arm bushings are solid polyurethane, struts are brand new konis. Inner tie rods and those rack bushings are the only things I haven't checked on. I do occasionally have an odd groaning noise when braking so it's possible it's brake related. I also think it's plenty likely that it's just something that's a consequence of my having picked such stiff/non-compliant components. The spring perches are metal on metal, no rubber between them, so I guess it could just be that too... I'll just deal with it until I get it on a lift to check out the steering rack bushings/inner tie rods.

Re: Front suspension knock
 

:)

Have you tried feathering the brakes ? There's another "known problem" with the gen 3 outback (like mine) - the pin to its hole tolerances are out even in new parts..... they are too loose. This sound goes away if you touch the brake pedal. My Outback doesn't have this, thoug, for some reason.

Maybe I will pull the pins and put in some heavy grease, copper paste or something just to try to eliminate this too.... though on the SVX the sound does not go away with the brakes applied.

Oh well,

Tapani

Re: Front suspension knock
 

Braking doesn't really seem to change anything.