Vibration 65 Riviera

Need some help trouble shooting a vibration I am experiencing in my 65 Buick Riviera 401. I just had the driveshaft completly rebuilt and when I decelerate from 53 mph I get a vibration. Also when the car is in park or nuetral at about 2000 rpm's I feel a vibration from the motor. I think I am safe to rule out the driveshaft and need some help to determine where it might be coming from. Does anyone know if you remove a torque converter does it have to be put back on the same way or does it matter. Thank you in advance for any help in this matter. Gerry

OK Gerry: It's difficult. You need to isolate the vibration by a process of elimination. You can disconnect the torque converter from the engine and run it. As far as the drive shaft, look at it as if it might still be the culprit. Like I said, isolate all components. It could even be the balancer or in the pulley system, maybe tires? You won't know until each component is for sure ruled out.. It's a pain. Diagnose each component, verify diagnosis and then repair, then verify again. Good luck, Mitch

Did you have the driveshaft balanced when it was rebuilt? Did you install a new driveshaft center support?

Yes to both.

I have no idea why it matters but did they mark the phasing of the rear yoke when they took it off of the differential and put it back the same? Everytime I've had someone work on my Riv's driveshaft they've done that.

Hi,

Just to add my 2cents......I have found that it does matter about the torque converter hook-up. Definitely mark it for re-assembly but if you changed anything---what I have done is try all three possible positions(of the torque converter) and use the one with the least amount of vibration.

Hi Again;

I also want to ask 1. Did you have the vibration when you decellerate from 53 mph before you had the driveshaft rebuilt---have you tested going 55mph then putting it in neutral to see if you stillhave the vibration as it slows through the range where it vibrates in gear----if it is not there then you have a motor/torque converter/harmonic balancer vibration issue.

Did you have this vibration before the driveshaft was rebuilt? I know that the CV Joint next to the rear end are very sensitive to vibration if not rebuilt properly.

Yes I had the vibration before I rebuilt the driveshaft and I did do the neutral test and no vibration. The Transmission was remove to have it resealed and I bet the torque converter was not mark before removal because it seems this all started after that.

Yep, chances are the 7th hole in the flex plate isn't aligned with the corresponding divit in the crank flange. You can do an archive search on that or for pictures go to www.v8buicks.com and find the "Da' Nailhead" site. There's a similar post on there that has pictures posted.

Ed

Here is an update, I rotated the torque converter and tried all three positions and still the same problem. I also removed the belts and still get the vibration in the motor at 2000 rpm's.

There are six evenly spaced bolt holes in the flex plate which will align six different ways. Only one of them is correct. The correct alignment occurs when the seventh hole, which is not symetrical with the other six is aligned with a corresponding dimple which has been drilled into the back of the crank flange.

The nailhead is externally balanced and needs the flex plate and balancer to be properly aligned on the crank to achieve an overall balance.

Ed

I would check the flex plate too, but if I am following this thread right the vibration started after the trans was removed for a reseal and the flex plate should not have been moved...., Unless they installed an engine rear main seal.

That is right they never removed the flex plate. I also installed a complete exhaust system at the same time, but I went over that numerous times and nothing is touching the frame or body.

Did you install a stock or custom system? If a custom system, did they install a cross-over or blend pipe?

Stock system with a different muffler.

Bringing this to the top to see if the issue got resolved, and what the cause was.

Drive-line vibrations can be a bear to find and fix. I chased a problem with an OT car that I changed transmission and rear gears for months. Luckily I had a great drive-line shop that helped me figure it out.

Hopefully the problem with your Riv. was fixed and the knowledge will help us all who are rebuilding our cars so as not to have the same problems.

Still having the same problem and have not figured it out yet. I am suspecting it is the exhaust because that was changed during the same time the transmission was removed and resealed. I wish I had and answer for everyone. I will figure it out because its driving me crazy and I will let everyone know.

I just read the last post to this thread and then went back and read the first post again with something in mind. In the Riview, there's been something discussed for years that's referred to as the "Riviera Rattle." It's a vibration set up by the fuel retrun line hammering against some part of the frame. I'm just curious if this could be what you're suffering from. You used the word vibration. Rattle never entered my frame of reference unitl now. You've checked everything else, you might as well give this a shot too.

Ed

I just read the last post to this thread and then went back and read the first post again with something in mind. In the Riview, there's been something discussed for years that's referred to as the "Riviera Rattle." It's a vibration set up by the fuel retrun line hammering against some part of the frame. I'm just curious if this could be what you're suffering from. You used the word vibration. Rattle never entered my frame of reference unitl now. You've checked everything else, you might as well give this a shot too.

Ed

My Rivi has had a strange rhythmic rattle for years, it's intermittent. Mostly on decel. Sometimes I dont even have to be moving and it does it. Maybe its the Riviera Rattle!

Im going to investigate tomorrow. This is a great forum!

Ed,

Where can I find a copy of that article. I would like to read it. Thanks Gerry

?????????????? (Name unknown)

I don't recall that it was an in-detail article, more likely just something that appeared in the Tech Q&A in a Riview sometime in the past.

Just take a look at the fuel return line (fuel filter to tank) and see if there are any clearance issues. Grab it, shake it, and see if it hits anything solid that could make a rattle.

Jim Cannon may be able to add to this.

Ed

Old thread, I know. But I'm curious to know if the problem (vibration/rattle) was ever solved…ttt

David

The problem has not been solved and still haviong the problem. I think it is the exhaust and have to get it on a lift to check it properly. Gerry

My 65 rivi had a vibration between 30 and 55 mph when I first bought it Back in 04. It turned out to be the rear axel bearings .the ones that are closest to the wheels. Both sides were shot out. Replaced them and the vibration is gone.

arnulfo

Where do you feel the vibration? Steering wheel? feet? under the seat? Have you checked the balance on the wheels? Does it vibe while braking?? You could have a wheel bearing thats slightly worn, the brakes would 'center' the drum and you wont feel the vibration anymore.

There is this article by Tom Mooney on the ROA web site: http://rivowners.org/members-only/Tech/enginevibration.html.

What about body mounts? What are their condition?

Have you done a thorough compression and leak down test on the engine?

Bernie

It only happens on decelaration from 50-55 mph.

Oh. It doesn't do it in neutral around 2000 RPM as well? Maybe it's not a cracked piston.

My odd little vibration was hard to find, too. But it got easier to identify:

When the problem is that elusive one needs to look elsewhere.

Bernie

I still stand by wheel bearing or wheel weight. The speed of the tire is the only thing that is consistent at speed and under acceleration the load on the bearing/wheel will hide the vibration, once you are coasting/decelerating you have relieved all load so the unbalance will be easier to feel

Hello Everyone

Correct me if I am wronghere, before you had work done on your drive shaft there was no viabration? If so it must be in the drive shaft/drive line. I would suggest that you have a look at how each universal joint was fitted and secured into the yokes. In the "old days" we used external circlips to locate and secure the universal joint caps into the yokes and they worked well. Then came along modern technology where they would inject a silicone bead into a small hole in the yoke and this would lock the caps in place and centralise them. The mistake that people make here is that they try and drill out the silicone bead and it creates all sorts of problems. When you fit new universal joints you need to buy them with inside circlips as there is no grooves for the older types. It is only this way that you can properly locate and centralise the universal joint and this will go along way to avoiding any viabrations. I would suggest that you may have one joint which is misaligned and the shop has tried to balance the shaft to over come it and have not been successful.

I am originally from New Zealand and spent many years battling universal joints with a bench vice, hammer and sockets for sleeves. We used to balance the shaft with Jubilee hose clips and these worked. I still show my students how to do this, however nowdays, most cities have a "driveline shop" or a truck repair shop who have the tools and equipment which can do this work in a fraction of the time it used to take and can sell you a universal joint for half the price that they cost at a parts shop. Thanks and good luck with the repair.

John

Chris's idea is worth checking.

But for all of our benefit, can you please recap in a table the chronological order for us when you had the vibration on deceleration and if you had it sitting still in neutral with the engine RPM up, then list everything that was done or tested and then what, if anything changed on the vibration.

I have read this thread 3 times now and I am lost on when it does and does not vibrate.

Does the car have A/C???

Thank you to everyone for all the responses.

The car starts vibrating on decelaration between 50-55 mph and in park at around 2000 rpm's. The car does not have A/C. The vibration started after the installation of a complete exhaust system and after the transmission was removed and resealed. These were done within days of each other so I am uncertain and cant pinpoint if it started after the exhaust or transmission. The vibration can be felt throughout the whole car (if that makes any sense)

- had the driveshaft rebuilt- still vibrates and did so prior to the rebuild.

- rotated the torque converter and checked all positions. Vibration did not change and also ran vehicle with torque converter unbolted from flywheel. No change in vibration.

-removed belts and ran motor and still no change.

- checked exhaust and no pipes were touching the body but I need to get it on a lift to do a better inspection.

In Park, the driveshaft and anything but the engine and transmission are ruled out. Did they replace the rear transmission mount when they installed it? There are only a few components within the transmission that rotate while in park. Since you had no engine work done and the flexplate was not removed I would rule out anything but engine mounts. Is it a New converter or did they reinstall the old one?? Did they replace the clutch plates or just replace a few seals? If they only replaced a few seals its possible that the converter is out of balance with the input shaft of the trans. Another thing to look at would be the vacuum modulator and its line. You could have the smallest of vacuum leaks.

The first step in troubleshooting the source of a vibration is to determine if the vibration exists at rest or under power while moving. In the first post it was stated the engine vibrates while at rest. Why would we ignore that and start guessing at driveline, tire, rear diff, etc...problems when we have confirmed a vibration exists in the rotating assembly at rest?

In spite of being under the impression the flexplate was not touched when the trans was removed, inspect it to be sure.

Many years ago I had a turbo 400 resealed on my driver GS and it was immediately apparent there was an engine balance problem when I started the car. The owner of the shop swore the flexplate was never touched by the tech..."why would he?" I agreed, but insisted he inspect it to be sure before I left the premises. We put the car on a lift and with the aid of an inspection mirror it was determined the flexplate had mysteriously changed positions on the crank. It was obvious from the tech`s behavior he lacked experience and had lied to the owner while under questioning.

My experience is that when the flexplate is installed improperly the vibration is severe enough to shake your molars loose. But I guess it depends on the exact position of the flexplate as to how severe the vibration becomes. Inspect the flexplate and get at the source of the engine vibration first. It is possible you have multiple issues but the engine problem is the easiest and first to be tackled. It should be smooth while taking it up and down thru the RPM range. If not, that vibration can transfer into other components of the driveline and car and become a very expensive and time consuming exercise in frustration....and you`ll inevitably end up back at the engine. Good luck!

Tom Mooney

^^^^^

What he said.

Hello Gerry

I would agree with what Tom has said and it points to a cracked or wrongly positioned flexplate. However have you had a look at your harmonic balancer?

Take care

John

My vibration was very similar to what you described……. an old-timer at Midas knew exactly what the problem was…...new rear axle bearings solved the problem. Drew