I have a 1984 firebird and when i go over 75 the dash vibrates very badly. Does anyone know what is the best thing to do?

 

front end alignment if not aligned.. and subframe connecters

 

Strut tower brace will also help.

 

i know this is a stupid question but when you put in subframe conectors do you need to put two in or one? i am not sure how they are installed because the tech article is not working. If you put two in when you buy them do they come in two or one? Thanks

 

Other possible causes include unbalanced driveshaft, improperly balanced or bent wheel(s), and bad shock(s). Subframe connectors and strut tower braces, while something you should install, will only mask the real problem. Your car shouldn't vibrate until a much higher speed. My '86 has been over 120 with no vibration, in fact it gets smoother the faster I go.

 

from what i know,, subframe connecters come only in pairs. you can get the bolt in ones, or the weld in ones. im personaly gonna buy the bolt in ones cause i dont have access to a welder. i get vibrations in my 84 TA too,, but not till bout 75-85mph.. i know im in bad need of a front end alignment, and front tires... take your car to a tire place and ask them to look the front end over, this should come free of charge (at least it is here).. if you have something broken, then they will tell you what it is. if nothing is broken or bent, then they will align it if needed. i know this does WONDERS for dash and steering wheel vibration. the sub frame connecters will get rid of the other vibrations, like the rattles you hear when you go over bumps in the road. hope this helps...keep us updated!

 

Get the ones you weld in. You can have any muffler shop weld them for less than $50. The bolt holes on the bolton type connectors end up with elonggated holes over time.

 

yeah i was wondering about that on the holes......you wont have to remove them for anyother mods are you??

 

Sweeeet. Thanks a lot for all of your help guys. I will try some of the things recommended. Hope they work. I am sure they will though. Thanks. I also heard the weld in subframe connectors were better. Does the t-56 transmission come in the newer f-bodies? Is it easily tranfered to a 84. I am ordering a crate motor in place of my 2.5l 4banger I dont think the current tranny will be able to handle the power.

 

The T-56 isn't a direct bolt in, but is pretty easy to accomplish. Go to the transmission board and search or post there. All the help you need. You should do the same on the motor swap board as well.

 

To go along with what was said, all those things mentioned before will help...

One of the reasons your dash vibrates so badly is probalby because the construction is 95% plastic. There is a strip of steel sheetmetal, that stretches across the dash (about knee height) and then there is a single strip of sheetmetal that screws to your firewall. Everything else is plastic.

I have considered re-inforcing the metal strip that stretches across, and then run more sheetmetal up to the firewall, that would keep the vibrations down on the dash. Unfortunately I have not for the following reason: I am afraid that if I attach it wrong it might cause a crack. So I leave it alone.

Hope that helps

John

 

I had a lot of rattles that were really easy to fix, give this a try.
Most of the rattles that were coming from the dash were loose parts, specifically the defrost ducts and the speaker mounts. Subframe connectors will help with most of the rattles but these still rattled after I got them. Just spend an hour looking for loose parts, the worst parts were where the defrost ducts join together on either side. I just took some soft foam from an old camping matress and put it in there so the dash pad presses down on the loose parts. Mine is completely silent now.