Brumby Vibration issues

AndrewT · Post by **AndrewT** » Sun May 18, 2014 11:33 am

Check the tailshaft uni joints too while you're under there

taza · Post by **taza** » Wed Sep 17, 2014 10:12 pm

Vibration ia still there. Car is still RWD. I have a 500km trip to do Sat and want it sorted. I don't think I can live with that vibration for 5.5hours!

So far ive changed;
RH rear CV shaft (tonight)
All 3 rear diff support mount bushes
engine mounts
Gearbox mounts
Tailshaft uni joints
All 4x rims and tyres, plus balancing and wheel alignment
exhaust hanger bushes/rubbers
Check wheel bearings and replaced both front

I'm now going to get Outter Control CV spevialist to ckme out tomorrow and rebuild the shaft I pulled out of the brumby tonight... then swap that with the old one in the rear.
The LH rear CV shaft is completely original, boots and all. I feel this may be the culprit!
if the grease is all hard and funny colored like the wheel bearings it may have done the same in the CV joints causing the joints to heat up and **** out...

Smokey · Post by **Smokey** » Fri Sep 19, 2014 9:15 am

What does the tail shaft center bearing look like? Mine rattles/flogs about when car is heavily loaded and engine us under load in 4wd. Imagine it would be way worse in rwd.

taza · Post by **taza** » Fri Sep 19, 2014 9:43 am

It's a single piece, doesn't have a centre bearing?? Ive done both front and rear uni joints in it.
I've now replace both rear CV shaftd at $400 trade price and still no joy!

Smokey · Post by **Smokey** » Fri Sep 19, 2014 10:23 am

taza wrote:It's a single piece, doesn't have a centre bearing??...

IC, showing how little I know about MY specifics.
Hard when these issues crop up, on the up side car will be sweet when you solve it, with all the replaced parts. Hard on the wallet though.

Proton mouse · Post by **Proton mouse** » Fri Sep 19, 2014 12:50 pm

You have changed tail shaft uni's but have you had the tail shaft balanced?
Might have dropped the balance weights or could even have a slight dent or bend along the length of it, if it has
had a whack while 4wd-ing? Maybe even years before you got it, only surfacing now you've gone rwd only
(and hence putting it under load full time)
John

Subydoug · Post by **Subydoug** » Fri Sep 19, 2014 1:15 pm

Taza, all my vibration issues went away when I took off the 14" speedies I had and went to some 13" Subaru rims. I would wind the suspension up/down until your cv angles are neutral. Did you check the steering rack for play?

Regards

Doug

coxy · Post by **coxy** » Fri Sep 19, 2014 9:48 pm

Borrow a tail shaft, even though you replaced the Uni's I guarantee that will be the problem, what you are experiencing I would bet comes from the front uni joint on the tail shaft.
Do not forget when converted to RWD the tail shaft now does ALL the Work unlike previously when it was either along for the ride bludging or sharing the work load 50/50 in 4WD

BBoypebs · Post by **BBoypebs** » Sun Sep 21, 2014 12:33 pm

Put it simple. The rear suspension and drive line are designed or constructed to handle RWD. I had the same issue when I did it to my brumby. You can try to construct a much stiffer differential mounting system and a two piece tail shaft. But my recommendation is to convert to AWD for ultimate better handling and smoothness.

taza · Post by **taza** » Sun Sep 21, 2014 2:38 pm

I borrowed a tailshaft today off Subarino... I'll try that.

BBoyPebs, when I first did it there was no vibration for a month or so... I juat want it sorted for the time being. The Brum is getting a 04 wrx conversion and driveline installed in 6months or so.
just for now its a real PITA!

Thanks guys. I'll see how I go. when it stops raining I'll install the spare tailshaft.
lile most of you have said it probably has a dent or a weight has come off..

Post by **Bantum** » Sun Sep 21, 2014 2:46 pm

Just re-read this :

taza wrote: ... Its fairly stock but has been converted to RWD ...

I missed that little nugget the first time, so would say 'Well there's your problem right there' ...

Worth repeating that the AWD drive system in the Brumby was not designed to run full time 100% through rear end ...

taza wrote: ... Any ideas ? ...

Return it back to stock - Or if you do want to keep running it in RWD permanently, you'll have to 'beef' up the drive & suspension system to handle it - like previous posters have mentioned.

Cheers, Bantum ...

taza · Post by **taza** » Sun Sep 21, 2014 3:17 pm

Bantum wrote: Worth repeating that the AWD drive system in the Brumby was not designed to run full time 100% through rear end ... ..

In the same way my Forester wasn't designed to run a 07 outback Awd gearbox with L-Series low range, 6 speed sti front diff, 5 speed dccd centre diff and dual cone syncro for first to make it a beast offroad.

it'll get what it needs when I go Awd and ej but for now it can stay RWD.

taza · Post by **taza** » Sun Sep 21, 2014 7:17 pm

Got sick of it raining so went outside and changed the tailshaft on the front lawn in the rain....

The verdict is there is still the same vibration that makes every panel and window rattle when you load it up in 4th gear under 70km/hr... Seems slightly worse than the other tail shaft.. the front and rear uni joints had a little play in them however.

At 100-130km/hr the vibration is almost gone, however this could be due to the uni's. I can now see out the mirrors and not hear every pannle rattling away.

I'm thinking i've hit a curb and a weight has come off or something along those lines.
I can live with the vibration that is there as I'll be going EJ and AWD 6months to a years time.

taza · Post by **taza** » Sat Dec 20, 2014 10:33 pm

For future reference my problem turned out to be a dented tailshaft. Having swapped that out with another I have no issues. One bonus is now I've replaced so many driveline components and bushes it does drives great!

The AUSubaru.com.au Forums

Brumby Vibration issues

Not stock ...