The big bang...theory?

Cam · 02-05-2010, 01:23 PM

I've posted this in my build thread as well, but i know my car doesn't really appeal to everyone so posting here for a better chance of a reply...

I've had a mysterious banging in my car for some time, after a looong and expensive search (replacing other parts) I've found the issue..

I am by no means a suspension expert, so I'd like some input on what would cause the upper control arm to do this?? I'd go and buy another and swap it over, but clearly there's a bigger issue??

Thanks in advance..

KR1STO · 02-05-2010, 01:28 PM

jeesus...
how low is your car cam...?
what are the bushes like..?
how are your shocks..?

5.0 ED · 02-05-2010, 01:30 PM

So its been bashing against the diff, i'd be checking all the bushs, sounds like the diff was be binding up to a rather weird angle to do that.

Too low? Are bump stops still in? i doubt it, but maybe your getting a little too much suspension travel.

**aussiblue** · 02-05-2010, 01:32 PM

Cut springs?

Cam · 02-05-2010, 01:32 PM

Not overly low, SL in the rear, my 18's are just Level with the guards..
Bushes are a little cracked (will go get pics..)
Shocks are about 10 000k's old (although, that thought has crossed my mind)

5.0 ED · 02-05-2010, 01:32 PM

arms haven't been put on wrong sides? ie left on right, right on left somehow?

burnz · 02-05-2010, 01:33 PM

on the top of the diff centre are two torque rods they would be worn out. (bushes)
that would cause the diff to twist and bind on the trailing arms.

Cam · 02-05-2010, 01:41 PM

Quote:

Originally Posted by 5.0whiteaughia

So its been bashing against the diff, i'd be checking all the bushs, sounds like the diff was be binding up to a rather weird angle to do that.

Too low? Are bump stops still in? i doubt it, but maybe your getting a little too much suspension travel.

Nah she's not low at all

Quote:

Originally Posted by aussiblue

Cut springs?

Hell no..

Quote:

Originally Posted by 5.0whiteaughia

arms haven't been put on wrong sides? ie left on right, right on left somehow?

I'd guess no, problem has gotten worse over the space of about 5 000km, but possible i spose, my old mechanic did turn out a lil dodgy.. (installed thermostat upside down...)

Quote:

Originally Posted by burnz

on the top of the diff centre are two torque rods they would be worn out. (bushes)
that would cause the diff to twist and bind on the trailing arms.

Makes sense... off to have a look...

Thanks for the help so far guys!

POELWYK · 02-05-2010, 01:43 PM

hmm my car's dif bashes something under there to the only thing i could see what the rales had some marks on them

Cam · 02-05-2010, 01:55 PM

Quote:

Originally Posted by burnz

on the top of the diff centre are two torque rods they would be worn out. (bushes)
that would cause the diff to twist and bind on the trailing arms.

You'd be referring to:

I must say all the bushes look ok with the exception of my sway bar bushes on that side, but I suppose that's not really reflective of how well they are working...

burnz · 02-05-2010, 02:23 PM

no the rods ontop of the diff.

The Monty · 02-05-2010, 02:44 PM

Theres no rods on top of the diff?

Cam · 02-05-2010, 02:49 PM

Thats what I thought, I have nfi what all this suspension stuff is called...

All I can see is the sway bar above the diff? (this is non IRS by the way...)

**Peuty** · 02-05-2010, 02:59 PM

Hmm not good mate. That would certainly explain the banging though.

I'd be checking all bushes, up on a hoist if possible.

burnz · 02-05-2010, 03:03 PM

Quote:

Originally Posted by The Monty

Theres no rods on top of the diff?

so fords dont use strut rods??
so how do you stop it from twisting?? when accelerating/brakeing.

Cam · 02-05-2010, 03:07 PM

Quote:

Originally Posted by Peuty

Hmm not good mate. That would certainly explain the banging though.

I'd be checking all bushes, up on a hoist if possible.

It Certainly does Dan...

Looking at all the bushes (car is on stands) they all look ok, but then I really cant see inside the control arm bushes. The sway bar bushes are cracked on that side, but everything else looks good.

Josh (The Monty) and I were chatting on msn, he's recommended a trip to the wreckers and buy a new upper / lower control arm and associated bushes. I'm not convinced it'll fix the problem, but looking at the rear end it doesn't really appear to be overly complicated, so I guess it'd possibly fix it.. Thoughts?

Obviously new stuff would be better, but funds are tight after just spending masses of money getting everything else on the car sorted..

Cam · 02-05-2010, 03:09 PM

Couple of pics burnz..

burnz · 02-05-2010, 03:12 PM

yep has both, their mounted above each other.

**aussiblue** · 02-05-2010, 03:14 PM

Quote:

so fords dont use strut rods??
so how do you stop it from twisting?? when accelerating/brakeing

Watts linkages as shown. Also see http://en.wikipedia.org/wiki/Watt's_linkage for how they work.

Cam · 02-05-2010, 03:23 PM

Ok, so all that makes sense.. In all reality it'd be either:
Replace upper control arm, and associated bushes (upper and lower)
Possible collapsed shock (still have to replace the control arm anyway..)

Other then that, I cant see any other causes?

The Monty · 02-05-2010, 03:33 PM

Too much sliding, lol. Might be a bit from the torque and the live rear. Makes it twist a bit, it might be making it twist too much.

mik · 02-05-2010, 03:44 PM

looks like too much suspension travel? incorrect shockers?

**aussiblue** · 02-05-2010, 03:45 PM

Quote:

--------------------------------------------------------------------------------
arms haven't been put on wrong sides? ie left on right, right on left somehow

or back to front and upside down - did that mechanic do any work on the rear diff or suspension?

Cam · 02-05-2010, 04:16 PM

Shocks are definitely the right ones, plus, the otherside is perfect.

It could be that it is back to front / upside down, he put in new springs in the rear...

I think I am going to take it to someone, I need it done right the first time..

**Peuty** · 02-05-2010, 04:22 PM

Fulcrum at Yeerongpilly

http://www.fulcrumsuspensions.com.au...n-centres.html

Cam · 02-05-2010, 05:04 PM

You used them before mate?

SLO AU XR8 had recommended City Suspension.. I need somewhere who isn't gonna charge out their backside for the work..

SLO AU XR8 · 02-05-2010, 10:52 PM

Cam, Fulcrum are expensive but good. City Suspension is cheaper, and deal with alot of Fulcrum gear. Call City Suspension and talk to Greg or Tim, the phone number is 3808 3266.

**Peuty** · 02-05-2010, 11:00 PM

Yeah all of the track cars at my ex job had the work done by Fulcrum...very professional, know what they are doing and prices were good.

Alby1 · 02-05-2010, 11:00 PM

This may be useless info, but i had same problem when i had upper control arms replaced in my el xr8 by pedders. Turns out they have a remanufactured upper control arm that has a slight bend in it, problem solved. And they fixed it for free so still happy.
Have the uppers been replaced before?

Al

ratter · 02-05-2010, 11:12 PM

do you have bump stops still fitted?