Clunking in dash area at low speed

[erics667]

Hey guys/gals,
I've been going nuts for some time with a shimmying and clunking sound in the engine bay area while driving straight at low speeds in 2wd, just down the road kinda stuff. Like right behind the firewall area and I can feel it in the brake pedal. I've tightened down all I could think of. I've tried it all to no avail. Any ideas for something not so obvious? 1974 302 C4 with new rubber all around. Thanks!!!

 

[billh1289]

Is this at low speed while driving straight or turning? In 2WD or 4wd?

 

[erics667]

2wd on pavement going straight. My final fix was tightening the hood bolts. Thought that was it....but no

 

[Rangerbj]

Is the down shift (kickdown) bar loose or too close to firewall

 

[73azbronco]

the emergency blinker relay?

 

[SteveL]

Motor mount?

 

[DirtDonk]

And while you're at it, describe the semi too.

Do you have a body lift? If so check for clearance in and a floor shifters.
Have you looked under the hood at the rear corner of the driver side cylinder head? If anything has shifted or been modified it's possible that the cylinder head is touching the body.

 

[Pa PITT]

DO you think it's in the motor compartment or I thought you started with it under the dash.
When I worked at Chrysler the shop foreman took me on lots of drive to listen for Bumps & knocks.
.... One would drive & other would listen . HE'S Say put it in neutral . & we'd let it roll a while . Under load off load . Clutch in & out. Foot touching each pedal every so slightly.
Even tying a string to road & pulling on them . Tying string to groups of wiring cables .
... Good luck.
..... It's not on your front disk brakes pads is it.
... I had a small clunk that drove me crazy for about 6 months.
I'd be idling through the pasture at maybe 15 mph. Hunting. & Clunk clunk clunk.
Touch the brake pedal & it'd go away.
. Finally someone told me my Anti Rattle clip were on backwards.. IT WAS THE LITTLE CLIPS THAT GOES ON THE Brake pads I had them on the wrong end of the brake pads .
............ Now that was nice to find.
But I heard that noise while driving through a drive thru at the bank . In line at the back or stopping to get a coke at the D'Q..& HUNTING .
a small noise drive me crazy.

 

[Rustytruck]

check the heater box and mounts and may the fan mounting too. there is supposed to be pade between the unit and firewall. anyone been doing work in there?

 

[erics667]

Thanks for all the suggestions, I appreciate it. My brother helped me figure out that my hood moves side to side. Hinges have *just* enough play that they can move. New hinges require welding so in the interim I've just shimmed with a small piece of rubber that falls out when I open the hood. Not worth welding in new hinges IMO. Thanks!

 

[Rustytruck]

hood moving side to side shouldn't happen there are wedge shape pads on the side of the fenders to wedge and support the hood.

 

[EPB72]

hood moving side to side shouldn't happen there are wedge shape pads on the side of the fenders to wedge and support the hood.

https://shop.broncograveyard.com/Rubber-Bumpers/products/1683/

As Rustytruck said you can find them here..../\/\/\ 5th part down...

 

[jckkys]

What I think Pa Pitt suggested is an orderly trouble shooting process that finds the source of the clunking sound. Shimmy isn't a sound and is likely a suspension/tire issue. Hearing is only somewhat directional and getting your ears under the dash should help in locating the source. You may be able to see something move when the clunking is heard, while you're down there.
As Rangerbj said the kick down rod can hit the firewall, but it would be worse when bouncing down a rough road, than when driving straight at low speeds. Carter AFB/AVS carbs move the kick down rod outboard closer to the firewall. Ford and Holley carbs are what the rod was designed to work with. So if you have Carter/Edelbrock carb, take a look at the kick down rod.