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Jan Shim
21st December 2000, 10:00
Hello All ,

I have this annoying rattly noise coming from the steering since Subaru
fixed my gearbox two weeks back. The noise wasnt there before so I'm pretty
sure it's something they did, and I'm hoping someone has experienced this
before and have a clue what I'm on about. The noise is like a faint rattle
and I can feel the tingling sensation through the steering wheel.

The gearbox was opened to replace a stuffed centre diff bearing and the
number of of items that had to be removed are: drive shafts, exhaust ,
turbo heatshield among many items. The weird part is the noise isnt
consistent and appears to rear its ugly head once things get hot. This is
to say if I floor the car when everything is nice and cool, the
noise/tingling sensation/steering vibration doesnt happen but after it's
hot, it's there all the time on every throttle opening even at 0.5 bar.

Another example is when you slow down at an approaching junction, turn the
steering left and step on the gas, as soon as there's boost, I immediately
hear the noise and felt the slight vbration from the steering wheel. I
cannot imagine what it might be .. i have checked the entire steering rod
and nothing is touching it plus the steering also vibrate in sync with the
clutch judder .. it's as if the noise is coming from underneath ... no
obvious signs of tear or wear on the steering joints ...

Jan

NITO
21st December 2000, 16:05
Hi Jan,

Mine has exactly the same thing. If I turn left and boot it it's very bad, at other times I can feel it even if accelerating gently in first gear. It feels as though the steering rack is shuddering and it's as you say small tingling through the steering wheel. I showed this to my local dealer who think it may take ages to find what it is until it gets worse! Their first impressions is that it could be driveshaft related. I have also heard a theory that it could be wheel bearing related as apparently Subaru used the wrong type of grease in cars manufactured at a certain time (98)that both your car and mine fall into!

It's really pissing me off now and has got worse since I had a lower brace fitted. Previous to this it was only with the steering turned left and pulling out of junctions but since fitting the lower H bar it also happens in a straight line when accelerating even on light boost.

If you find the solution beforehand then let me know, I'll do the same. I'm aiming to have it looked at in January sometime!

Regards
Nito

carlos_hiraoka
21st December 2000, 16:24
Nito, what you have stated about Subaru using the wrong grease is CORRECT, here in Peru the SUBARU recalled all the Impreza Turbo's and the Legacy's 2.5 to change this wheel bearing grease, as the other one seemed to be of very poor quality....

carlos_hiraoka
21st December 2000, 16:25
BTW.....recalled the 1998 ones....

Jan Shim
21st December 2000, 22:13
A fellow member on the Oz eGroups list told me he had the same "buzzing" noise with his steering and was later diagnosed to be air trapped in the power steering fluid as a result of low fluid level. His car is also a '98 and occurred on a turn and when going over speed humps.

On mine, when shooting a straight line, it appears intermittent. Since changing the PS fluid isnt costly, I'll have a go at it only this time I wont use any of the dealer crap they put in there. Since PS fluids are Dexron II, same as Automatic Transmission Fluid, I'll put in fully synthetic Mobil 1 ATF. I'll let you guys know how it goes by end of today.

Pete Croney
22nd December 2000, 10:01
Hi Jan

There a few of things that you should check...

First, as you correctly say the driveshafts and downpipe need to be moved when the gearbox is removed.

I suspect that the noise is actually coming from the downpipe. Are you certain that a new gasket was fitted on the back of the turbo. If not, gas leaking here can sound like a pinking sound.

Check the lower suspension joints. The driveshafts stay in the hub, but these lower joints are split to move the shafts away from the gearbox. They are held in place by cotter pins.

Provided the driveshafts were moved in this manner, the CV joints should be fine. I have seen cars that have had the driveshafts levered off the stub axles, instead of splitting the hubs. This causes damage to the lip on the CV that protects the oil seal.

The power steering fluid is not touched in the clutch job, but it is well worth replacing it with Dexron III. Castrol make a good one and this has cured PS problems in lots of cars, including my own RA which spends lots of time at high revs.

Jan Shim
22nd December 2000, 12:43
Thanks to everyone for your comments. The problem was traced to a vibrating heatshield on the turbo pipe that connects to the headers. The heatshield is of a cylindrical design held securely to the turbo pipe by a few weld spots. Over time, they deteriorate with engine heat and break off. This has happened to a number of WRX and STi here.

While the heatshield is now free to move about, it helps to now that the heatshield incorporate a "butterfly" wing with a thread on each side. The turbo heatshield bolts to these. Since the lower half of the turbo heatshield has been removed, the loose heatshield has in fact been vibrating and rotating till one of the wings touched the steering shaft coupling .. go have a look under the car and you'll see just how close the turbo pipe is to the steering shaft.

The most obvious thing to do with this problem would be to have the heatshield removed and have it welded back on OR I could fit a ZeroSports "venturi" pipe in its place OR fit an aftermarket exhaust manifold that incorporates a turbo pipe .. so many options, so little cash. Nah, I had the mechanic fold the wings away as far as possible from the steering so now PROBLEM SOLVED. No more odd rattly noises on acceleration or turning.

Nitto, perhaps this is exactly what you're expericing ? You need the car on a hoist to be able to easily see this. Look for the steering coupling and you should see the turbo pipe near it.

Peter, how do you completely get rid of the old power steering fluid ? There isnt a drain hose if I recall correctly. The last time Subaru worked on my power steering pump leak, they had the fluid sucked out of the reservoir.

NITO
22nd December 2000, 13:15
Interesting Jan,

I've had the turbo up-pipe replaced with an hks one without heatshields as it came with the GT turbine kit. I'll have a look though and see if there is anything that could be touching this though!

Nito