Subaru Outback Forums banner

Knocking Sound - Tie Road, Axle, Or????

2113 4
I've had this knocking sound coming from the front driver's side of the vehicle.

I hear it when I go over bumps, or hit rough road. It is NOT specific to when the vehicle is turning.

I did my front brakes last night and noticed that the CV boot in that location is torn.

So my questions:

1) How mechanically talented must you be to change CV boots? Otherwise, what is a rough low-normal-high cost for CV boot at a mechanic?

2) Do you change both front CV boots at the same time, typically?

3) Is it likely that the knocking sound is coming from the axle/CV area?

1 - 5 of 5 Posts

· Registered
06 OBW 2.5, 05 Forester, had 03 H6 OBW
5,968 Posts
Assuming it's not a bad ball joint or tie-rod end (those are pretty easy to check)
Knocking sound over bumps is often a sway-bar end link that is loose or broken, and sometimes can be from a loose/bad top-hat bearing at the top of the strut.

· Registered
OBW H6 VDC, Tribeca, XT6
12,391 Posts
Has that axle ever been replaced before?

CV axle needs repaired anyway and will get worse - so repair that first and maybe you'll get lucky and it's the cause of the noise too. An exposed joint certainly isn't good and doubtful we can rule it out as a possibility.

You want to retain an OEM axle as they last hte life of the vehicle and aftermarkets do not. I don't even know how many failed aftermarket axles i've seen - it's a lot. Explode, click, vibrate, you name it - i've seen it all and I've never even worked in a shop, makes me wonder how shops can even put up with that terrible quality.

A mechanic will install an aftermarket axle. $175 - $300 Auto Parts Market you can get a used OEM Subaru axle for $15 - $35 to either install yourself, reboot yourself, or hand to a mechanic to reboot so you have an OEM axle that will last the life of the vehicle.

But in general - OEM CV axles don't usually (very rarely) knock when you go over bumps.
If they're aftermarket axles - the sky is the limits as to how they can fail.
Maybe if you recently bought the car and it was previously clicking like mad or driven in sand...maybe it could, but very unlikely.

As to the sound - good job narrowing down the location, the common causes would be:
check end links
sway bar bushings
ball joint and tie rod
strut related

control arm bushing related - the control arm bushings in those 2005's are prone to cracking, usually they all have some and that's okay - but if they were bad enough I suspect you'd notice something.

A mechanic will not reboot that axle. Most will want to replace every axle with an aftermarket just because it's easier. And if it has symptoms - like an undiagnosed noise in the same vicinity they definitely won't want to reboot it.

It's actually really easy to reboot an axle - with a few notes:

1. 1 out of 50 times (i'm making it up) the axle nut can be a savage. I've seen 3 or more broken 1/2" sockets/breaker bars, bent 3/4" gear, and 1,000 ft-lb air guns not get them off. This is unlikely, for illustration i said 1 out of 50 times - but just know to try that nut first thing and if you can't get it - be prepared to just stop the job or have heavy artillery ready.

sometimes the axle can also be hard to remove from the knuckle, but not normally. Here again - you can just remove the axle nut and tap it to see if it easily moves/slides into the knuckle.

2. It's insanely messy. Just do it over an old box or pizza box and wrap it all up and throw it away.

Other than that it's easy - remove one nut, one bolt, one pin, loosen another bolt and you've got the axle out.

remove axle nut, mark the top strut mount bolt head to retain alignment, remove it, loosen lower strut mount bolt, knock out pin and off comes the axle.

· Registered
2005 OBXT Ltd Obsidian Black 5MT
1,084 Posts
I just rebooted my driver's side inner boot on Wednesday. Took me about 2 hours.

I used the Beck Arnley boot kit. But the metal band clamps aren't that good.

Instead of removing the strut bolts, I just disconnected the lower control arm from the body, but left the ball joint connected and swung it out of the way. It helped that I had just replaced the arms last month so all the bolts were fresh.

· Registered
2006 Outback 2.5i Auto
428 Posts
The knocking sound up front that I fixed recently was the sway-bar to body bushes, which had worn enough that there was a couple of mm of play in them. That was a very cheap and easy fix, so worth checking out.
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.