Author Topic: Bad virbation (Read 7526 times)

dianne · « **on:** March 06, 2014, 10:20:00 AM »

I have bad vibration over 30 miles an hour right now. I don't think it's the harmonic balancer (if it even has one) or anything like that. At 55 somewhat ok and speed limits here are 70, when I hit 60 to 65 I feel like the that pilot in Star Wars who shakes and blows up afterwards LOL

This was Dave's brownie and he said the driveshaft has been replaced with a Windstar or some aluminium driveshaft and was balanced. I can't get a hold of Dave right now. My mechanic, when I explained what was going on without explaining that new driveshaft replacement, thinks it might be the u-joints.

Could it be as simple as that or the actual driveshaft? Should I bring it to a place that does driveshafts or just replace the ujoints?

Any advise would be awesome!

rramjet · « **Reply #1 on:** March 06, 2014, 12:20:47 PM »

Could be u-joints or the operating angle of the u-joints or too much run out in the drive shaft. The u-joints need to operate in the same plane with respect to each other within about 3 degrees. This shouldn't be a problem unless something has been done to the rear end or transmission to change the pinion angle with respect the the output end of the transmission.

I did have a similar situation on another car I have that had a shortened drive shaft. Who ever shortened the drive shaft did not get things straight and there was a too much run out, (wobble), causing vibrations at about 55 mph. Didn't notice a problem until I lowered the rear end gear ratio which put the vibrations in a noticeable speed range.

I would start by checking u-joints especially if the problem just started and is not associated with any other drive train changes you have made.

dianne · « **Reply #2 on:** March 06, 2014, 04:05:00 PM »

NICE PINTO!!!!!!

I don't think the driveshaft was shortened and I haven't driven the car over 40 probably before this. Took it on the highway and it was brutal. I've made no changes to the drivetrain, but there has always been a vibration with the car.

I guess we'll start with the u-joints...

Pinto5.0 · « **Reply #3 on:** March 06, 2014, 06:37:23 PM »

Aerostar driveshaft is a bolt in. It's not the issue unless it was damaged. It could be a u-joint, tire, wheel bearing, etc. The 1st thing I would check is tires for a broken belt.

dianne · « **Reply #4 on:** March 06, 2014, 06:50:53 PM »

The tires were new when I got it. Another thing that I noticed when driving around 35 I have vibration and then when I step off the gas it stops. I'm thinking that one is the pulley, I can replace that easily. At 50 and over I'm white knuckling this car and if I step off the gas it's still bad. I'm thinking that the wheel bearings could be it. This is the first time I've driven it over 40 or 50.

Rob3865 · « **Reply #5 on:** March 06, 2014, 06:53:23 PM »

In general there are two types of vibration in vehicles. High frequency like a heard of pissed off bumble bees such as drive shaft, u joints or axle bearings and low frequency, like an out of balance, out of round tire, bent wheel or axle shaft. You need to determine which frequency you have and that will help zero in on it. Most of the time tire, wheel and axle problems (low frequency) will show up as a vibration through the seats, floor and steering wheel, if on the front. Generally, axle bearings, u joints or drive shaft imbalance or damage will show up as a "buzz" at a much higher frequency. Hope that helps.

Pinto5.0 · « **Reply #6 on:** March 06, 2014, 06:56:18 PM »

I've had new tires break a belt. It's easy to spot. I'd check suspension bushings too while you're at it.

dianne · « **Reply #7 on:** March 06, 2014, 07:17:45 PM »

Well, my mechanic is going to look at it this week. It's probably those things your mentioned and I will mention them to him also

Wittsend · « **Reply #8 on:** March 06, 2014, 08:20:07 PM »

If you are stepping off the gas and the vibration stops it is very doubtful it is your tires or their balance.

A driveshaft problem should not cause the tires, and thus the steering wheel to shake (though it may pick up vibrations through the car structure). A driveshaft issue would cause the whole car to resonate. If you have a means to safely get under the car you can check for bad U-Joints. They should not slide side to side or appear to rock in their cups. Who knows, the nuts on the U-Bolts might just be loose.

To test the driveshaft attach a piece of chalk to a board. While holding the board firm to the underside of the car have someone rotate a rear tire and slowly move the board towards the driveshaft. The chalk mark will show if the shaft is bent. Check the U-Joints first because they can cause the same problem. If the problem wasn't there before, you haven't high centered the car on a large rock, or accidentally put a floor jack under the driveshaft and then lifted it - your driveshaft itself is probably ok.

My guess it that the U-Bolts at the rear are loose or one of (maybe both) U-Joints are bad.

dianne · « **Reply #9 on:** March 06, 2014, 08:28:23 PM »

Quote from: Wittsend on March 06, 2014, 08:20:07 PM

If you are stepping off the gas and the vibration stops it is very doubtful it is your tires or their balance.

A driveshaft problem should not cause the tires, and thus the steering wheel to shake (though it may pick up vibrations through the car structure). A driveshaft issue would cause the whole car to resonate. If you have a means to safely get under the car you can check for bad U-Joints. They should not slide side to side or appear to rock in their cups. Who knows, the nuts on the U-Bolts might just be loose.

To test the driveshaft attach a piece of chalk to a board. While holding the board firm to the underside of the car have someone rotate a rear tire and slowly move the board towards the driveshaft. The chalk mark will show if the shaft is bent. Check the U-Joints first because they can cause the same problem. If the problem wasn't there before, you haven't high centered the car on a large rock, or accidentally put a floor jack under the driveshaft and then lifted it - your driveshaft itself is probably ok.

My guess it that the U-Bolts at the rear are loose or one of (maybe both) U-Joints are bad.

Thanks! Dave said that he had the driveshaft checked for balance before he put it in the car. So I'm guessing it must be the u-joints... Thanks!!!

amc49 · « **Reply #10 on:** March 07, 2014, 03:49:24 AM »

You can chunk a driveshaft weight to do it or simply spit out a u-joint clip. Put clip (find one) back in after pushing cup back tight and done.

Wouldn't hurt to jack car up to spin wheels, any tire problems generally show pretty quick in rotation.

You people will love this one. I haven't balanced tires on the last 3 cars now, I use the tires with no balance at all. It requires the wheels to be known fairly true, they must be known to be pretty close to neutral before you start doing it. Meaning no really big weights used to balance them. Newer tires now rarely need lots of weight from off neutral. The tire WILL wear wonky but I drive FWD cars and rotate all older fronts to the rear, the new ones going on front only. I buy only pairs, never all 4 at once. FWD cars will ALWAYS wear tires out of round on the back because no heavy rear end there any longer, they begin to rise off the ground in oscillation and the oddball wear starts. Balancing does nothing for that issue except to ever so slightly slow it down. Doing that I still get like 95% of the wear tire is rated for. Here in Texas the tire will then heatcrack before I can wear it out and that's what forces replacement of most of them if not outright damage from all the crap construction workers let fall out of trucks to tear up tires. You can tell the no balance but only as a almost imperceptible roughness that is easy to overlook. It does not generally show until like 70+ and my cue to slow down. I've seen one tire in the last 16 or so bought that needed later to be balanced, that one tire was wonky and showed up instantly and easy to find it. Went back to no balance after it was burned out. I quit rotation as well, the back wearing wonky just makes you put oddball backs on the front doing so. FWD cars drive impeccably with really good tires on front, the backs can be garbage. The way I do it requires little upkeep and runs forever. That's on FWD ONLY though. Still, it saves lots of money.

I haven't aligned a car in 35 years either, do it all myself but enough thread jacking....... ..............

dianne · « **Reply #11 on:** March 07, 2014, 08:26:44 PM »

U-joints was the issue he said. He'll replace them on Wednesday! :-D

Thanks guys!!!

Pinto5.0 · « **Reply #12 on:** March 08, 2014, 03:25:10 PM »

Quote from: dianne on March 07, 2014, 08:26:44 PM

U-joints was the issue he said. He'll replace them on Wednesday! :-D

Thanks guys!!!

That's good to hear. Hopefully that's the end of it.

74 PintoWagon · « **Reply #13 on:** March 08, 2014, 06:06:42 PM »

Glad to hear it's an easy fix.

dianne · « **Reply #14 on:** March 08, 2014, 06:21:22 PM »

Yeah, me too LOL

jeremysdad · « **Reply #15 on:** March 12, 2014, 03:24:41 PM »

A little late, being Wednesday (Hope they got it fixed for you with the U-joint replacement!), but when my Dad was teaching me 'the ropes' oh so long ago, he summed vibrations up like this:

U-joint/driveline issues, you feel though the seat. (Rear wheel drive vehicles)
Front suspension/tire issues, you feel in the steering wheel.
Brake issues, you feel in the brake pedal.
Clutch issues, you feel in the clutch pedal. (Different with newer hydraulic clutches???)

They're good guidelines, but not perfect. I have added my own edits over the years. Before diving into replacing U-joints/driveline parts, I'll rotate tires to see if the vibration moves (I have found that rear tire problems come through the seat, as well, so rotating tires lets me see if the vibration comes through the steering wheel).

But, I'm cheap. I like to do free things before buying parts or laying on my back in the driveway.

lol

dianne · « **Reply #16 on:** March 12, 2014, 04:13:38 PM »

The u-joints are bad in mine, so needed replacing. But the car is going now anyway...

jeremysdad · « **Reply #17 on:** March 12, 2014, 04:21:05 PM »

I was hoping it was done, and you would be reporting back with great results!!!

Good luck!

dianne · « **Reply #18 on:** March 12, 2014, 04:25:59 PM »

Thanks. You know I love the car and if I had shorter legs I would be fine with it. But with the Maverick and Galaxie and Mustang King Cobra II (which seems to fit me better), the Pinto is going

It's such a cute little car!

dianne · « **Reply #19 on:** March 19, 2014, 05:30:31 PM »

I'm keeping the car. The problem is that driveshaft and it's not long enough so when you're driving it's causing the vibration.

So if anyone has a 1973 wagon driveline/driveshaft I need one...

amc49 · « **Reply #20 on:** March 19, 2014, 06:35:59 PM »

Why is it too short? Has someone mismatched one there?

Jack up rear of car under AXLE so car still rests on suspension, mark present in/out location of yoke in tailhousing seal and remove rear u-joint from axle to allow you to shove driveshaft gently all the way up into housing. If you have one inch or so space difference there the shaft length is not the problem.

Pintos are known for wearing out the end bushing in trans tailhousing to let the driveshaft wobble about.

Pintosopher · « **Reply #21 on:** March 19, 2014, 08:31:47 PM »

Quote from: dianne on March 19, 2014, 05:30:31 PM

I'm keeping the car. The problem is that driveshaft and it's not long enough so when you're driving it's causing the vibration.

So if anyone has a 1973 wagon driveline/driveshaft I need one...

I had a bad Virbation once, My doctor never told me My Shaft was too Short

Seriously , Find the thread on Pinion angle of the two U joints, measure and then check the Stroke of the forward joint into the tailpiece. This is too funny LOL!

Pintosopher, innuendo is a great form of Humor, stock your barn with tons of it!

dianne · « **Reply #22 on:** March 19, 2014, 08:59:11 PM »

About an inch gets into the transmission. It's vibrating from there.

Yeah, I guess it is funny LOL

74 PintoWagon · « **Reply #23 on:** March 19, 2014, 10:15:53 PM »

Only an inch into the tranny???, that's not enough!. When measuring for a drive shaft you push the yoke all the way in then pull it back one inch, then measure center to center of the u-joints between tranny and end.

Clydesdale80 · « **Reply #24 on:** March 19, 2014, 11:47:10 PM »

I could be wrong but i feel like there is some confusion here. $:-\$

I believe she means that there is an extra 1'' that could be slid into the trans., not that it only had an inch in it to begin with. If I'm correct then I think the driveshaft length is fine and the problem likely lies elsewhere.

If I'm wrong and you mean that under normal conditions there is only an inch of the shaft inside the transmission, then that could definitely cause some problems.

Sorry if i'm just adding more confusion

74 PintoWagon · « **Reply #25 on:** March 19, 2014, 11:57:39 PM »

Well, it could be but I got the indication that "About an inch gets into the transmission" meant that's all that went in the tranny???, but maybe I understood wrong???..

Pintosopher · « **Reply #26 on:** March 20, 2014, 05:40:04 AM »

Quote from: dianne on March 19, 2014, 08:59:11 PM

About an inch gets into the transmission. It's vibrating from there.

Yeah, I guess it is funny LOL

Diane, my apologies for the off beat humor, too many hours of CBS television. If the swapped in Aerostar driveshaft is to short overall (Center to center on the U-joint Yokes) then you'll need to replace the whole unit. If the yoke that inserts into the trans tailpiece is too short, then you could replace that with a pinto unit, but then it might need a driveshaft re-balance to keep the vibes from returning. If the car has had a ride height change, (too high in back, or lowered more than stock) then the u-joints might not have a correct pinion angle relationship, and that will really cause some noise and eventual failure of the joints. As AMC49 said , the bushing the tailpiece does wear out and you can't cure that with another driveshaft.
You should have about 2- 2-1/2 inches or more into the tailpiece with the axle at ride height, less than that is asking for trouble. Just think how many 4X4 driveshafts you might have seen on the side of the road when the length issues were ignored.
Best of Luck,
Pintosopher, One bale short of a full stack

dianne · « **Reply #27 on:** March 20, 2014, 06:45:48 AM »

Quote from: Clydesdale80 on March 19, 2014, 11:47:10 PM

I could be wrong but i feel like there is some confusion here. $:-\$

I believe she means that there is an extra 1'' that could be slid into the trans., not that it only had an inch in it to begin with. If I'm correct then I think the driveshaft length is fine and the problem likely lies elsewhere.

If I'm wrong and you mean that under normal conditions there is only an inch of the shaft inside the transmission, then that could definitely cause some problems.

Sorry if i'm just adding more confusion

It's less than an inch in the tranny. So that's the issue I guess.

dianne · « **Reply #28 on:** March 20, 2014, 06:47:58 AM »

The car sagged when I got it, but I did have air shocks thrown on and leveled the car, that could have done it also I guess.

Srt · « **Reply #29 on:** March 21, 2014, 03:45:24 AM »

Quote from: pintosopher on March 19, 2014, 08:31:47 PM

I had a bad Virbation once, My doctor never told me My Shaft was too Short
Seriously , Find the thread on Pinion angle of the two U joints, measure and then check the Stroke of the forward joint into the tailpiece. This is too funny LOL!

Pintosopher, innuendo is a great form of Humor, stock your barn with tons of it!

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Author Topic: Bad virbation (Read 7526 times)