Front End Noise

[Mothy]

I have been getting a creak/clunk noise from the front end of my 911SC for some time and its driving me nuts. Not loud but persistent and distracting. Bit like a cable slapping against the bulkhead.

It seems to be coming from about halfway down from dash to floor near where the stearing rack is located. I've pulled everything out thats loose, lubed the sway bar bushes and the main bushes. I''ve searched for anything that might hit something else - even done some temporary rubber packing round the brake lines in that area to see if that was the issue - but to no avail.

It's not consistent in its timing - not always over bumps but more like a torsion thing - which made me think more swaybar or torsion bar related.

Already replaced the ball joints and the tie rod ends - wasn't them (but they needed doing anyway).

The funny thing is that it is more consistent with the rythym you might have if there was something loose in the fuel tank, floating around and occasionaly hiting the sides.

However I might be onto something - when I was working under the hood on the weekend I just hapened to lean on the gas tank and it made a noise similar to what I have been chasing. Sure enough, the tank moves very slightly and would do when driving as the body flexes.

There seems to be a seal or rubber strip under the mounting edge of the tank but it looks old and perished - is the tank ruber mounted or is it mean to be bolted/clamped down solid?

I hope I'm onto something at last. Anyone had a similar trouble?

Tim

[74threeliter]

I am experiencing similar trouble and notice there are 3 brackets with allen head bolts holding the gas tank down. Seen under the hood. Are these the only items holding the gas tank down? Has anyone else experienced this squeaking noise coming from a moving gas tank? Could this be a sign of suffering torsional rigidity or is a weld job in my future?

[JFairman]

If you have bilstien struts it could be a worn bent roll pin that secures the end of the shock rod inside the bottom of the strut.

If thats it usually the clunk can be fixed by removing the roll pin, rotating it 180degrees and reinserting it.

[tazzieman]

My guess is torsion bar bushings.
Time to check condition of T bar and look for evidence of T bar cap rubbing on crossmember.
If so either replace control arm bushings($ or $$$) or if this year's budget stretched - the cheap and cheerful weld fix.

[74threeliter]

Ok, i need to divulge more background information. And ask:
Does anyone know how much hardware holds down the gas tank?
Is it relatively an easy job to remove the gas tank?


JFairman -
Bilsteins = yes
Bent roll pin = no
180 degrees? are you suggesting to reinsert the threaded pin for ball joint adjustment (911-341-119-06-M260) specifically shaped to only enter from one direction through a different direction?

tazzieman -
torsion bar bushings = brand new p/b
crossmember = alluminum good condition


Gas tank moves when placing hand over it and pressing and makes the squeaking noise i experience when turning or driving over speed bumps.

[E Sully]

The tank is just held down by a few metal clips and allen bolts. Easy to remove and replace the seal. Hardest part is draining the gas out.

[74threeliter]

hanks E Sully,

I went ahead and re-tightened the 3 allen head bolts. It seems the tank shifted due to two of them being loose and i was able to rock the gas tank left and right replicating the squeak noise. Now the tank is tightened down and no more squeak. One of the brackets was no longer pressing and holding down the tank. This bracket was the one next to the battery.