please help : car vibrates heavily

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moparjon

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hi , i just picked up a 74 valiant with 225 /6 automatic . i need help trying to diagnose a severe vibration problem . i am not sure if its steering suspension , brakes or transmission or other . as i have never experienced this problem before .

what happens is at first the car drives fine and smooth . then , after awhile it suddenly starts to vibrate heavily , like an earthquake . feels like its the front , but could be trans . it usually happens when i slightly decelerate or lightly press on brake pedal . but continues until i either mash the brakes hard , or pull over and park for a few minutes . and sometimes vibrates just on its own .

so far i have only greased the front end . and looked at the front brakes , everything looked ok and the drums came off just fine . though it does pull a little to one side when braking . i will adjust that , but have'nt yet . also , when i tried to back up yesterday . it did not move in reverse right away . i had to gas it a little then it finally broke free and backed up . felt like sometime was holding it up .

just wondering if anybody has had this happen to them before .

i thought maybe the wheels are out of balance and or the drum might be warped , but i don't know if that would be a constant vibration are intermittent one . or be strong enough to shake the whole car violently .

talking to a few people locally , they suggested , worn tie rods and another person said definitely the transmission . like the engine is fighting the trans or something .

anyway , any thoughts or ideas would be greatly appreciated . thanks

p.s. i will be posting this in steering , brakes , and transmission , so if you see it there to , its the same post .
 
I would strongly recommend not driving this car! The problem could be almost anything and it could cost you your life if you keep on driving it this way. If you can't diagnose difficult mechanical problems, then you should not trust your life to fixing it yourself. Please take it to a professional shop my friend.
 
68gtxman said:
I would strongly recommend not driving this car! The problem could be almost anything and it could cost you your life if you keep on driving it this way. If you can't diagnose difficult mechanical problems, then you should not trust your life to fixing it yourself. Please take it to a professional shop my friend.
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X2 it's time to climb under there for a thorough inspection of the suspension components and bushings, wheel bearings, engine/ trans mounts, or could even be separated belts in a tire. You have to start a process of elimination.
 
Because you describe the brake pedal having an effect, this is most likely wheels / tires / balance OR improperly fitting wheels or nuts which are not allowing the wheels to fit "centered" and or tight ................OR a front end problem IE something out of line, loose, or broken............OR brake problems in some cases


First "start" to try to eliminate. Use a qualified friend if possible. "Two heads." Stay sober while doing this. Remove all wheels and examine carefully for such things as interferance between center hole and rear axle center, or front hubs. If alloy wheels with shouldered nuts take care that the shoulders are not too long. In other words look CAREFULLY at the wheels, studs, nuts, and the way they mount

Jack up the rear safely, run the car in different gears. Feel for vibration. You need to support it under the rear axle. Listen, feel, and look

Do a careful test drive. Have a friend watch 'drive by' and look for wobble

IF POSSIBLE find at least a pair of additional mounted / balanced tires to try for test drives. Switch them front / rear. ROTATE the tires up on a jack, feel for loose, look for wobble.

READ the service manual. Go through the front end, looking for looseness. To check ball joints, you need to jack under the lower arms. This is also best done with two people

This can be caused by an "additive" problem, that is, one front tire (example) out of balance, coupled with worn front end parts that allow slop and movement.
 
Sounds like your describing front end "death wobble" Need to thoroughly inspect the front end !
 
I had a similar problem with my '73 when I got it, found SEVERELY worn idler arm, tie rod ends, and upper control arm bushings on passenger side. Replaced all and have not had the same issue. Symptoms were front of car shaking intermittently at any speed, pulling while breaking, and clunk/clanking sound from front end while breaking, going over bumps, or accelerating. Again, like 68gtxman said, this is very dangerous, and if you are not experienced in this type of work or diagnosis, trailer the car to a shop who is.
 
you might want to check for rusted up wheel cylinders that don't return or brakes adjusted too tight and dragging shoes .take a temp gun and shoot all the wheels and see if one is hotter then the outhers
 
GeorgeH said:
X2 it's time to climb under there for a thorough inspection of the suspension components and bushings, wheel bearings, engine/ trans mounts, or could even be separated belts in a tire. You have to start a process of elimination.
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wheel bearings seam fine , but both engine mounts and trans mount are bad . i am going to start there . since they need to be done anyway . thank you . i didn't even consider them . there is lots of play in all of them .
 
moparjon said:
wheel bearings seam fine , but both engine mounts and trans mount are bad . i am going to start there . since they need to be done anyway . thank you . i didn't even consider them . there is lots of play in all of them .
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Don't stop there though.
 
GeorgeH said:
Don't stop there though.
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i changed trans mount and i am waiting for engine mounts to arrive. in the meantime i want to start checking the front end . i know how to check ball joints , but how do you check for wear in other components like tie-rods ? idler arm ? bushings ? etc . the service manual only has how to replace them , not how to check them for wear .
 
moparjon said:
i changed trans mount and i am waiting for engine mounts to arrive. in the meantime i want to start checking the front end . i know how to check ball joints , but how do you check for wear in other components like tie-rods ? idler arm ? bushings ? etc . the service manual only has how to replace them , not how to check them for wear .
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Easiest way is jack the car up and support it safely. Have someone wobble the steering wheel and lay under the car and watch the joints. Wiggle them by hand or with a bar. If they are really bad it will be obvious. How old are the tires? Have you checked the U-Joints?
 
not sure about the tires age . the look good with plenty of tread , but may have been sitting awhile . could have a flat spot . i did check the u-joints by hand . there was no movement at all .
 
Prob just worn out suspension. does not take much play. MT
 
To tell the age of tires is fairly easy. On the sidewall you will see DOT with a few numbers following it and then what looks like a plate cast into the rubber with 4 numbers in it. Example if you see 4013, this means the tire was made the 40th week of 2013. 0914 would mean the 9th week of 2014. If it is three digits this means it was made before 2000! Junk it!
 
Check for a broken K member around the lower control arm bushings.
I had an old dart that would give the "death wobble" over 60 mph with no warning.
Also you described hitting the brakes make it happen, something is moving throwing the car out of alignment.
 
Front end is shot. Do the entire front end. And service that trans. Oil,filter and band adjustments.
 
Upper control arms on these cars are notorious for the upper ball joint threads to rot,making the ball joint separating from the control arm....something to check.JMO
 
Sounds like one of the front brakes are sticking, heating up the drum and causing it to overheat and grab! As soon as it happens again, pull over and check the drums/disc in the front, they can get so hot they'll glow red!!! I've had it happen on a number of cars!!!
 
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