Vibrations an Shaking in standstill on brake..

[Tim's68 Newport]

Hi guys, im new here
My name is Tim and i come from germany,hanover exactly.
I own a mopar since april this year and i had a great summer so far!
It is a 68' newport with the standard 383 2bbl,290hp and a 727 automat.
Atm my car is sleeping in my warm garage and wait for spring!
On my last trip i notice very strong vibrations,mostly on the co drivers side door.
The whole car is shaking,but there it is the most.
It only happen when in "D" and stay on the brake and waiting for traffic light for example.
No shaking when i accelarete or cruisin, just when braking for the last 20-10mph until i stop.

Any thoughts on this?

 

[Davea Lux]

Hi guys, im new here
My name is Tim and i come from germany,hanover exactly.
I own a mopar since april this year and i had a great summer so far!
It is a 68' newport with the standard 383 2bbl,290hp and a 727 automat.
Atm my car is sleeping in my warm garage and wait for spring!
On my last trip i notice very strong vibrations,mostly on the co drivers side door.
The whole car is shaking,but there it is the most.
It only happen when in "D" and stay on the brake and waiting for traffic light for example.
No shaking when i accelarete or cruisin, just when braking for the last 20-10mph until i stop.

Any thoughts on this?

If the engine runs smoothly on acceleration and highway speeds, it sounds like the idle adjustment on the carburetor is probably not properly adjusted (too lean) or there is a piece of dirt clogging one of the idle circuits. You can try moving the idle screws out 1/2 turn to see if the idle improves, and report back. Are you noting any black smoke coming out of the tail pipe(s) at idle?

Dave

 

[Tim's68 Newport]

If the engine runs smoothly on acceleration and highway speeds, it sounds like the idle adjustment on the carburetor is probably not properly adjusted (too lean) or there is a piece of dirt clogging one of the idle circuits. You can try moving the idle screws out 1/2 turn to see if the idle improves, and report back. Are you noting any black smoke coming out of the tail pipe(s) at idle?

Dave

I was more on the motor mount and suspension side,but good to hear your opinion.
Makes absolutely sense,because i really have to change the carb and rebuild it.
It is leaking and well...when im holding speed at 60mph it is like somebody is pulling the bumper in the rear..hard to explain.. at first i change the carb !

 

[Knebel]

Bisschen vibrieren hat noch niemandem geschadet lol. I wod wod, idle mixture or idle speed too low?

 

[Tim's68 Newport]

Ne,ne... it feels like a 1/4 mile car with 2000hp right before the start...
The whole car is shaking and you think the co drivers door fall off

 

[Knebel]

I wod wod,

What the hell did my phone autocorrect to come up with THAT????

Anyways, if its that bad, maybe motor mounts loose or something? Or it is some sort of 2000PS drag engine but I'm sure you would feel that while cruising.

 

[Tim's68 Newport]

What the hell did my phone autocorrect to come up with THAT????

Anyways, if its that bad, maybe motor mounts loose or something? Or it is some sort of 2000PS drag engine but I'm sure you would feel that while cruising.

I will take a picture of the motor mounts.
But i think they look good.
I hope it is the carb.

 

[Big_John]

It is leaking and well...when im holding speed at 60mph it is like somebody is pulling the bumper in the rear..hard to explain..

Lean surge... If this just started, you probably have a vacuum leak. Since you are experiencing a "vibration" (I assume you mean rough idle) with the brakes on, I'd be suspicious of a leak at the power brake booster.

 

[Tim's68 Newport]

No it doesnt feel like a rough idle....i report back when i have changed the carburetor.

 

[Big_John]

No it doesnt feel like a rough idle....i report back when i have changed the carburetor.

Then I'm not understanding.

when im holding speed at 60mph it is like somebody is pulling the bumper in the rear.

I think you have two different issues here... Please, correct me if I'm wrong, but you are talking about the car "surging" at 60 MPH. That's probably a lean condition and most likely caused by a vacuum leak or some sort of carb problem.

just when braking for the last 20-10mph until i stop.

This is some issue with the brakes or possibly the drive shaft or rear end.

It only happen when in "D" and stay on the brake and waiting for traffic light for example.

This is the statement that is confusing... Does it vibrate when the car is not moving?

 

[Tim's68 Newport]

Yes when the car is not moving.
Just when the engine work with low rpm "against" the brake. Without pushing the brake in "P and N" everything is fine.
The surging,you know what i mean, is another issue and definetly carb related.

 

[Knebel]

can you make a video and upload to youtube?

 

[Tim's68 Newport]

I will do when the new carb is not working.