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I have been chasing a driveline vibration for a week that has me batty. It was very slight, barely noticeable originally, but I'm so anal. Found the center bearing carrier badly torn. Changed it and the vibration got much worse--only on takeoff at about 5 mph. I pulled the shaft, found the front joint binding in one direction and the rear one a little rough. Middle joint was perfect, smooth and solid. I hate doing U-joints so I took it to a shop. They swapped in the joints and found the shaft out of balance. All back together tonight as the wind is howling, but absolutely nothing has changed. Obviously something about the height of the center of the shaft changed when I changed the support. Bushings out back are in more than good shape. What could I have missed? No leaks at the back of the trans--it's dry and the mount isn't squished. I did the tail shaft bushing some time ago and there is zero slop. Wish I could shim the center bearing! Suggestions bricksters?
Thanks.
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Hi David,
Sorry, I cannot bring any experience to this. But I can scan:
(TP 30442/2 11/84)
--
Art Benstein near Baltimore
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Hi Art, good to hear from you. Yes, that's the one I have and have found posted elsewhere on the site. While I admire the creativity of whomever did the little diagram with keyboard figures, the other is a bit...clearer.
I have to say, I can drop a driveshaft now in about four minutes flat. I'm going to write to the networks and see if we can do a new reality series based on driveshaft removal time trials. This one has been in and out of the car about twenty times now.
Our Bertone donated it's shaft for a test. Even with a very very slightly sloppy center joint, the car ran perfectly with the Bertone's shaft in place. The curious thing here is that after only one short run with the other, recently re-balanced-for-the-third-time shaft, the front and rear joints were binding. This must be either damage to one of the yokes, or both, or the clips and/or tolerances on the cups for the joints are off. I'm going to start from scratch and have my shop install new joints. I don't usually do them myself, but I had an afternoon free--or not so free it seems.
Stay tuned for the exciting conclusion....
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Hello David.
i onec had a problem simular to this. i also tried all kinds of stuff with no luck.
my solution was a complete JY driveshaft swap that solved the problem.
remind me to never mess with the U-joints again, EVER.
good luck
Mike
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This has been the most trying 240 project in recent memory. Not that my memory is that good any more. Second drive shaft was the key. I borrowed one from another car!
Back from its fourth trip to the balance shop, the '80's drive shaft is back in place with all new u-joints. PO told me he'd just changed them a month earlier. A page out of Conan Doyle for certain. When all else has been eliminated, whatever is left, no matter how unlikely...etc etc. In all honesty, they certainly did look fresh and clean. Lesson learned: When your gut tells you one thing, and the PO tells you another, trust your gut. And Mike, you got that right. Two things I simply stopped messing with about two years ago: AC and u-joints. They both always seem to turn into black holes for time and effort. The machine shop charged me 8 bucks per joint to install them. How can I beat that? (Except with a pile of damaged sockets, my bench vise and a sledge--the DIY u-joint method.)
Thanks to all for the input over the last several days. I contribute as much information as I can as often as possible to the board. Great to know so many others do the same. And thanks to our Bertone that so valiantly loaned its drive shaft to the cause. Wow. When am I going to get around to putting that back?
DS
P.S. Anybody looking for a set of torque rods shortened 5mm????
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David,
Had a similar problem a few weeks ago: vibration I thought was from the driveshaft. The problem turned out to be a bad front pinion shaft bearing in the differential. The fixes I did (replacement carrier bearing, new tailshaft bushing) worsened the problem. Trop the rear driveshaft at the differnetial flange and see if there is any radial play in the pinion shaft. If you can get both rear wheels off the ground, rotate the flange to see if there are any "rough spots."
Good luck.
Glen
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If you can get both wheels off the ground with jackstands under the axel try starting the engine and runing up to 5 mph. Maybe apply some brake to simulate load. If you can reproduce the problem in the shop maybe someone can observe the vibration from outside the car and spot the problem.
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Thanks to all for so much input. This chilly morning's work has not produced much more than additional confusion. With the car on jack stands and running, I would swear I can see vibration in the back half of the shaft. However tubing is never straight. That's what balancing is about. Certainly I can see nothing shaking, even with a little handbrake applied. I did try stuffing some rubber hose into the center donut. This changes the vibe a little or moves it up and down the mph scale one or two mph, no more. The shaft seems to want to move right in the tunnel. Carrier seems pushed slightly toward the passenger side, but I think this is pretty common. I have tried tweaking the support bridge using its slotted holes. Moving it right seems to help a little, but if I do that and leave the hoses in, not only do I get my takeoff vibe, but I can get a steady state rumble at 2000 rpm in first to boot! Pulled the back half of the shaft and rotated 180 degrees just for good measure. No change at all. I have the shaft out again. Amazingly, though they were fine when it went back in, both the front and back u-joints are now tight in one direction. Knocking flanges about changed nothing. I have removed the front joint, which is new. Can't see anything wrong, but I notice that the clips are mix and match--uh oh. That can't be right.
DS
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Thanks Glen. I'll do that. Rear end is quiet, so I haven't given a huge amount of thought to the diff, but that's a good "next".
DS
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Noise/vibration pathways can be tricky. When mine went, I was convinced the problem was the front u-joint on the front driveshaft. While trying to diagnose the problem, I worked my way from the front to the rear. By the time I found it, I needed a new axle :-(
I know it's easier said than done, but hang in there. Every sympton on these cars has a problem source, and every problem source has a solution. Glen
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Hi Glen. You are absolutely right of course. It simply takes patience. At this point, having run beautifully and vibration free with the Bertone's shaft in place, at least the "self doubt" part is over with. Felt like the drive shaft from the beginning and blast if that's not it after all. Loathing--that may take a little longer to subside. This story would fascinate Conan Doyle. When all else has been eliminated, whatever is left, no matter how unlikely...etc etc. New u-joints, but obviously not installed correctly--or some such thing. Of course I still have to get the shaft back with the new u-joints and install it, so I should not count my chickens quite yet.
DS
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If the problem were balance or yoke alignment, I would expect the vibration to occur when accelerating or coasting. If in the suspension is the vibration affected by lightly applying the brakes or just hand brake? Could anyone see a wheel hopping as you drive past them? I agree that at 5 mph nothing is spinning fast enough to cause a vibration at the frequency you are experiencing. Is it possible the engine has developed a rough spot in the rpm range right at 5 mph. Try reving the engine in neutral and in gear with the brakes on.
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Thanks much. The vibration does indeed occur only on acceleration. Right now, with latest balancing, it seems to be right around 8 mph, but the early speedo tends to bounce a little so hard to pinpoint. At any rate, definitely off idle and definitely below 10 mph. Never on de-cel and not in reverse either. I have to do a visual for wheel hop--need my other half to finish her coffee first for that! No rough spot in the engine. There is a little resonance in park at around 1500, but it doesn't coincide with the rev range when it vibrates on the roll. Nothing like the judder if I rev in gear--were you thinking torque converter or flex plate? Never does it unless the car is driving. Nothing from the brakes, which are all new including rotors.
DS
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I know that you have stated that the two shafts are in phase. What is important is the understanding of "phase". Firstly it doesn't simply mean that the u-joint crosses are parallel. It means that the yokes are symmetrical. In others words if the u-joint bores on the trans flange are horizontal, then the slip sleeve yoke must also be horizontal, or the geometry will produce a pronounced vibration. You can see this on the rear shaft - both yokes will be parallel. The same is true for the front, but you have four choices when assembling, and only two will be correct.
Balance is only a factor at high rpm, and is not engine load sensitive.
Even new u-joints can be tight if not installed correctly, and many shops don't install them correctly and fail to relieve the compression across the yokes properly.
You might also try stressing the center support left and right to preload the rubber a bit. A brisk take-off and a low speed judder will show the steady bearing to be "too centered" and putting it to one side can help.
At the end of the day, Volvo screwed up the driveline badly in these cars by using two shafts in order to gain ground clearance. It's a common fault with 120's through to 740's.
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Thanks Rhys. I have indeed spent quite a bit of time pondering the conflicting input on alignment of the yokes. Even Bentley has two diagrams that don't agree. Based on this post (http://www.brickboard.com/RWD/index.htm?id=833258&show_all=1)it is my understanding that when the yoke on the transmission flange is horizontal, both the yokes on the front of the front shaft and immediately behind the male splined section should be aligned and, thus, vertical. This leaves the yoke on the differential input vertical. If I understand you correctly, that's not right. I need to have the trans flange yoke, the slip sleeve yoke and the diff flange yoke all horizontal (or vertical). Yes? At one point in this exercise I took the time to drop the rear of the shaft and try it in all four positions--to no effect. The latest news is from late today. Having eliminated the tires from the equation, I removed the shaft and convinced my shop to take one more look. This car came with a new center bearing already in place but the carrier torn. The bearing is clearly new. They found that the female splined section was bent. Once straightened, they found that the rear shaft did indeed need some weight. I trust they have it balanced "in phase". However it was for naught. With the shaft back in, the results are exactly the same. However I do have to look in the morning and see what the yokes look like. It was quite late by the time I finished up. I'm considering pulling the shaft out of my '83 and bolting it in to see if I can eliminate something!
DS
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Hi David;
As you know from looking at the rear shaft, the two u-joints in it are phased correctly because that's the way it is welded at the factory. The variation is in the yoke that has the external splines, and that yoke must match the one on the forward end of the front shaft - parallel. Some mechanics believe that the "cross" of the u-joint is all that needs aligning, when in fact it's the yoke that's important - hence only two out of four positions work.
Rhys
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Thanks Rhys. Then in fact, the diagram in the post I listed is correct as is the Bentley diagram on page 450-4. Slip yoke and the front shaft front yoke should align. Diff yoke and trans yoke will be at 90 degrees to each other. Dawn is creeping up so I slid under the car with a flashlight. This is indeed how the shaft is set up currently. I guess I could try 180 degrees about, but it's been balanced in this position. The center bearing brace can only be moved about 1/4" and that doesn't affect the carrier much, but I'll give that a shot too. A friend suggested I stuff some hose in the voids in the carrier donut!
DS
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Just to remove all doubt, I would rotate your tires to see if there is a change. Is there any chance your centre support donut is not the right part? I once ordered one for a 740 and got a 240 part - I puzzled on that one for awhile trying to figure out how to make it work. It is definitely not right that you should have to trim the rubber - if it was in wrong, I'm amazed you could get the bolts tight on the metal support housing. You're going to kick yourself if it's just tires (a shifted belt in the tire?), so I'd eliminate that possibility ASAP.
Ron
93 245
near Brantford, ON, Can
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You got that right. I've been too busy to bolt the shaft back in this morning, but I'm gettin' there. I plan on swapping on a couple of tires from my wagon and going for a drive. If the shake disappears I'm going to shoot myself. On the center support, I also considered the possibility that it's the wrong part. Maybe the larger bearing takes a different outside diameter--but that's not it. I've double checked all the parts. M-46 cars have the larger shaft but the OD of the donut is the same. If this were the donut for the larger bearing, it would be really sloppy in the center and it's not. I certainly did consider that though. No reason in the world one would have to modify the blasted thing to fit--and to have it give positive results! I considered trimming it further but my sense of propriety just won't let me. Has to be something else.
DS
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If anyone is following this post, here's the update: Several trips now to two different drive shaft shops have resulted in no changes to the shaft. Everyone agrees it is in phase and in perfect balance. Thus, with that eliminated, I have been poking around elsewhere. Engine mounts have been changed as has the trans mount. I have spent hours moving the trans crossmember down, shimming the trans mount up--both only result in the vibration getting worse. Trailing arm bushings are in great shape, must have been changed at some point. I did find that the bushings in the torque rods were "vertical", and while I know there is some disagreement about this, I removed the rods and put in a set of later rods with urethane bushings. No change. The only thing that has made any difference at all is shaving about 3/32" off the top of the center bearing carrier donut. This cut the vibration in half. Based on that, I decided to go whole hog. I took the OEM rods, cut and shortened them 5mm. The factory "short" rods are 5 and 10mm shorter than the standard rods. Since take-off vibrations are nearly always pinion angle related, and raising the center bearing a little helped a little, I figured this was the trick. Absolutely no change at all. What a stumper! What have I missed?
DS
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Just a thought. How fast would a shaft spin at 5mph? Methinks not fast enough to vibrate. I assume its an automatic and I look for a broken rear shock or mount. If a standard a bad pressure plate or tranny mount.
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Hi Jack. Gotta tell you, anybody who uses "methinks" in his post gets my thumbs up (chuckle). You are correct, shaft sure isn't turning very fast. It is an automatic. At this point I have to think it's something completely unrelated to drive shaft. Gotta be! What is your line of thinking on the shocks? That is, what might be happening? As to "mount", which mount are you referring to there? I'm at the point where I need to get my attention drawn to something unusual that might be the cause. Thanks for the input!
DS
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I saw M46 [manual trans] mentioned in a post but not by you. So, if it is a manual, there is a "flex joint" made of rubber. As I recall it is just behind the tranny and has about 4-5 bolts for the differential. About $80 part give or take. They get old and the rubber wears out. Had the vibration problem that appeared out of nowwhere in an '87 244 M47 and that fixed it.
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Thanks Oscar. This is an 80 with a BW55 automatic. No rubber flex disc!
DS
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Sometimes the pirate speak helps cut to the chase. Your vibration could be some form of torque pull chatter. I had a both a broken rear spring and shock on my '65 mustang ..... senior parties in the sand dunes ArrrgggHHHH ! Got a wicked vibration on takeoff with the left rear wheel almost hopping. In your case firming up the supports would probably amplify the movement at a weak point further away, say at the point where a shock mounts. You might eliminate a vibrating exhaust from the equation also ... by wedging block between the pipe and frame. avast me hearty!
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Aye, tis a bothersome affair. Thanks Jack. I'm investigating all sorts of things at this point. I wonder if the diff is at fault! Wheel hop, hmmm. I've learned that the Cooper Trendsetter tires are from 2000 (once I finally found the DOT code). This car belonged to an octogenarian who rarely drove. I wonder if I've got a terminal flat spot. The rear end shows no sign of sag at all, still got that jaunty sedan rake to it. Springs are stiff. I'll take a look at the shock mounts, but the car is very quiet as far as ride...no clunks, groans or creaks. I'll take a look though. I guess the first thing I'll do is bolt on another set of tires and see what that does.
DS
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TB bushings!!!!! lol
My vibration lightened up some when I removed my towbar, spare tire and jack, and other assorted junk from my trunk.
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TB bushings??? The rear weight thing is all about pinion height. Wish I could say that was the trick, but there's nada in the trunk now, and ride height doesn't seem to be the issue. Still, I'm tempted to prop up the back somehow and see what happens. Thanks Justin!
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Yeah, the rear geometry gets tired after all those years, especially if you or the PO towed with it, such is my case.
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I have been doing the same thing for the past 4 months lol
Started with the carrier bearing and assembly. Then tailshaft bushing and oil seal, trans mount, both engine mounts, first u-joint, removed the drive shaft and made sure the yokes were aligned correctly...
Even though the u-joints seem fine when you move them off the car, they are under very different strain on the car, especially upon take off when the rear squats. I will be doing the middle and last u-joints together, and if that doesn't clear it up, I am going to move my attention to the rear suspension. Trailing arm bushings and tracking bar (panhard bar) bushings. There has to be light at the end of this tunnel :-)
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I have to say, the yoke alignment thing is one of the items that always leaves me doubtful. Diagrams in Bentley and Haynes are contradictory and I'm never sure I've got them aligned properly. Gotta check that again for the third time. Ran out of light tonight.
DS
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I assume you change the bearing or know it is good. I didn't see the year car or miles on car. A torn rubber means the bearing could have spun or the rubber had a rough life against the elements.
The support rubber goes back in with the spring down. It should be fairly stout and seated properly. The rubber may not seat perfectly all the way around. Just needs to be firm and centered. How firm are all three mounts for the engine & trans. The passenger and rear ones go first for oil reasons.
I'm curious why they or how they check the balance of the drive shaft. Most shops do not have the equipment to bother with that. They just mark everthing before removal.
If you or they change the support bearing they had to separate the two shafts. It may be one spline off. Look carefully at the short end relationship. One spline or 180 out could have happened. Did the splines get a splash of fresh grease?
That's all I can think of from what you gave.
Phil
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Yep, bearing and the carrier. Rear mount is in great shape and the fronts are dry and "square", no oil damage, no leaks. Car doesn't even have 100k on it. Of course the mounts can be incredibly deceiving. I just don't understand why the vibes got so much worse after changing the carrier. The shop I took the shaft to has the correct dynamic balancer. They added a quarter-sized weight to the front of the shaft which is pretty substantial. This shaft has some barely visible alignment arrows on it, but it also has some yellow paint. Thus I'm assuming that one or both halves might be used from a yard at some point. Maybe that's why the imbalance. I did separate the halves to do the bearing, got them back where they go. Looks like the shop did too. Yolks sure feel a bunch smoother front and back! I'll have to take the whole thing down again in the morning and see what I can see. Can't shake the feeling that something is out of alignment with the new carrier. Weird. It's very tempting to put the old donut back in and see what happens. The new one seemed very tight into the tunnel. Almost like it was too large. Hmmm.
Thanks Phil.
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