May have found my bus...but it has a rear end vibration

[Sleddgracer]

Originally Posted by o1marc

What does lubrication on a stationary bearing do? I'm not saying you didn't need bearings replaced. I'm just saying the excuse they used of it sitting too long was just ludicrous. Do an internet search and see if you can find any other story to verify this. If you think about and use common sense when picturing it, it just don't make sense.

I'm not about to argue with the experts that were on the scene - just because some or most are dead and gone does not make my telling of the incident inaccurate - that motor home was fresh from the manufacturer, I'm guessing Detroit or Michigan, drove to Oregon while driving the owner nuts with the vibration - he swapped the whole rear member, brake backing plates and all for a used assembly that didn't vibrate - I swapped bearings in the new assembly and it didn't vibrate either - the guy in the store knew more about bearings, even recognizing them by sight, than the people that made them, in my estimation, and he agreed with the idea that I've repeated here

[Tango]

I'm with the "never heard of it crowd" but then, there's probably a lot I've never heard of.


Personally, I'd be more inclined to check the things I DO know to occur when any vehicle sits for an extended period.


1. Tires flatten even on soft ground and it doesn't take very long. On concrete it can happen in a couple of weeks.



2. Rust bumps inside bearings. Unless they are fully packed and overflowing with waterproof grease...they can and will form rust bumps inside any bearing that can often be felt once they are finally spun up. They can be anywhere...wheels, driveline, can even occur inside an engine. Sometimes will mostly go away with use but best to replace.


3. And one for the books...mud dauber nests. Heard of a vibrating driveline on restomod that had spent a few years in a shed. Turned out there was a big remnant of a mud dauber nest on the outside of the driveline E-brake no one noticed until they got on the road. First couple of looks missed it and most of it actually stayed attached after driving a hundred or so test ride miles.


Quite a testament to the little buggers engineering.


Once chipped off, all was well.

[Sleddgracer]

Originally Posted by Tango

I'm with the "never heard of it crowd" but then, there's probably a lot I've never heard of.


Personally, I'd be more inclined to check the things I DO know to occur when any vehicle sits for an extended period.


1. Tires flatten even on soft ground and it doesn't take very long. On concrete it can happen in a couple of weeks.



2. Rust bumps inside bearings. Unless they are fully packed and overflowing with waterproof grease...they can and will form rust bumps inside any bearing that can often be felt once they are finally spun up. They can be anywhere...wheels, driveline, can even occur inside an engine. Sometimes will mostly go away with use but best to replace.


3. And one for the books...mud dauber nests. Heard of a vibrating driveline on restomod that had spent a few years in a shed. Turned out there was a big remnant of a mud dauber nest on the outside of the driveline E-brake no one noticed until they got on the road. First couple of looks missed it and most of it actually stayed attached after driving a hundred or so test ride miles.


Quite a testament to the little buggers engineering.


Once chipped off, all was well.

experienced mud on the back of a wheel - rear end seal being ruined by driving through long grass, various other stuff - all easily explainable - do you think it possible that the tiny rust spots wore off on the 1600 mile drive and left a small indentation in the bearings?

[Tango]

Pit and bumps of rust will pretty much go away with a little driving. But the actual oxidized metal particles will remain inside and accelerate wear. And any pits in the race will certainly impact the bearing function. How badly just depends on how bad/deep the pitting. Worst part is that it's next to impossible to diagnose without pulling the bearing. And once it's out...hey...ya might as well throw a new one in. Oh...and look into the truly "waterPROOF" grease and a proper grease packing tool. Doing it right makes a really big difference.

[jimburke77502]

Alliens did it!! Oh wait, they don't exist...... Had it happen on a 95 P30 step van. Right along with the axle seals. Flat spot actually was causing the dif lube to leak out and get all over the brakes. Ended up doing bearings, seals and a complete brake job. There's a gremlin for every single car, truck, and bus part out there.

[EastCoastCB]

Originally Posted by jimburke77502

Alliens did it!! Oh wait, they don't exist...... Had it happen on a 95 P30 step van. Right along with the axle seals. Flat spot actually was causing the dif lube to leak out and get all over the brakes. Ended up doing bearings, seals and a complete brake job. There's a gremlin for every single car, truck, and bus part out there.

Its likely that aliens exist, but its not likely we'll ever cross paths.
https://en.wikipedia.org/wiki/Fermi_paradox

[WoodenYouKnowIt]

Originally Posted by jimburke77502

Alliens did it!! .

Yes, I agree! The aliens are the culprits. They abducted the bus and then, when they brought it back to earth, they dropped it from just a little higher than they should have and thus, they bent the bearings.

I hate it when that happens.

[Seriousracer]

Bearing Brinelling Ihttps://www.google.com.au/search?q=bearing+brinelling&spell=1&sa=X&ved=2ahUK EwitpsbUvO7gAhWK14MKHd29DcAQBSgAegQICxAC&biw=320&b ih=438

Or look up understanding how components fail by Donald j.Wulpi. Page 195 yes I live in that book. He glances over a different aspect of bearings failures.

Long story short
A Diesel engine is very hard on bearings. Especially wheel bearings. New non work harden bearing /races will flat spot with continuous hammering of a Diesel engine running. Older bearings will flat spot if the bearings are stopped in the same spot

Any motor bike riders in here ?? Motorbikes Especially Harley Davidson destroy head bearings on the triple tree.to the point they can lock up.

New rear end was probably either assembled with a hammer or over tighten ( yes you can over tighten and cause brinelling. )
Pretty sure that isn’t the problem.

To the original posters question
Probably wheel balance (dyna beads?? Or static weights??) flat spotted tires ,center shaft support bearing rubber starting to go, ujoint starting to go, slip shaft starting to go
Lots of cheap possibilities. Right up to transmission out put bearing starting to go.
Could be bad engine mounts letting the engine vibration through the chassis or a drive shaft that needs rebalancing. Problem with busses and double over drives is you driveshaft speed goes way over 3000 rpm which is the industry standard for balancing drive shafts. So any wear starts a vibration. You can a freshly rebuilt driveshaft balanced to 4000 if you find the right place.
Which leads us to I forgot to mention drive shaft phasing if someone separated the drive shaft to replace a ujoint. The may have not gotten the phasing right.

Ok I will stop now.

[vintageracer]

I just spoke personally with a SKF Bearing Aerospace Bearing Engineer I know about this issue of flat spotting a bearing. A bearing and race is steel and will not flat spot sitting. Flat spotting on this bus's rear-end bearings is BS according to this 30 year bearing engineer.

A bus sitting for 2-10 years WILL NOT FLAT SPOT THE BEARINGS!

He does say if the stored bus were to experience frequent "wiggling" from some source without physically moving the bus you could possibly have an issue with the Brinell hardness wearing on the sitting bearing surface wearing due to the repeated "wiggling". It will take a LOT of "wiggling" like years of constant "wiggling"!

If the bearing loses it grease/lubrication on a part of the bearing the bearing can corrode which could present a problem in the bearing or the race. This is most likely the bearing issue if one exists at all. Incorrect installed or incorrect loaded bearings can also present a problem. A bad axle, spindle or oil seal can cause a bearing problem.

This bus in question did not flat spot the bearings from sitting. IF there is a bearing problem it occurred before the bus was parked.

The "Bearing Seller" in Oregon has a real racket going on and BSing people to death! No he does not know more than the bearing engineer's!

[Seriousracer]

Wiggling being a Diesel engine running.

A power pulse every 60 degrees on six cylinder engine
And a power pulse every 45 on a cylinder engine.
But not stored I agree unless it is in an earthquake area. Than ...

Ps that also could have been damage from when the chassis was shipped they can get trucked in for hundreds or thousands of miles. They will stack the engines axle on rearend s.
Picture is of coachman in middlberry Indiana. Hundreds of chassis

[Booyah45828]

Ok, maybe with skf bearings. Nobody mentioned skf bearings though. Ask your friend what happens if the bearing doesn't have a hardened race or rollers. Maybe cheap/overseas bearings were used and that's what happened.

Doesn't matter if they were damaged due to brinnelling or rust. The bearings were damaged, which caused the vibration, and were subsequently replaced.

I think this bearing horse has been beat to death.

[Seriousracer]

Not really
Not yet. It’s just getting fun
I would like to the” aero space engineer. “.
But seriously the way they are shipped it could have destroyed the wheel bearings. Note wheel bearings.
I am going through Elkhart/ middleberry the next couple of days and I will try and get pictures of how they are shipped.

But I believe I posted a fiat and informative response to the original posters question

[Sleddgracer]

Originally Posted by Tango

I'm with the "never heard of it crowd" but then, there's probably a lot I've never heard of.


Personally, I'd be more inclined to check the things I DO know to occur when any vehicle sits for an extended period.


1. Tires flatten even on soft ground and it doesn't take very long. On concrete it can happen in a couple of weeks.



2. Rust bumps inside bearings. Unless they are fully packed and overflowing with waterproof grease...they can and will form rust bumps inside any bearing that can often be felt once they are finally spun up. They can be anywhere...wheels, driveline, can even occur inside an engine. Sometimes will mostly go away with use but best to replace.


3. And one for the books...mud dauber nests. Heard of a vibrating driveline on restomod that had spent a few years in a shed. Turned out there was a big remnant of a mud dauber nest on the outside of the driveline E-brake no one noticed until they got on the road. First couple of looks missed it and most of it actually stayed attached after driving a hundred or so test ride miles.


Quite a testament to the little buggers engineering.


Once chipped off, all was well.

Originally Posted by vintageracer

I just spoke personally with a SKF Bearing Aerospace Bearing Engineer I know about this issue of flat spotting a bearing. A bearing and race is steel and will not flat spot sitting. Flat spotting on this bus's rear-end bearings is BS according to this 30 year bearing engineer.

A bus sitting for 2-10 years WILL NOT FLAT SPOT THE BEARINGS!

He does say if the stored bus were to experience frequent "wiggling" from some source without physically moving the bus you could possibly have an issue with the Brinell hardness wearing on the sitting bearing surface wearing due to the repeated "wiggling". It will take a LOT of "wiggling" like years of constant "wiggling"!

If the bearing loses it grease/lubrication on a part of the bearing the bearing can corrode which could present a problem in the bearing or the race. This is most likely the bearing issue if one exists at all. Incorrect installed or incorrect loaded bearings can also present a problem. A bad axle, spindle or oil seal can cause a bearing problem.

This bus in question did not flat spot the bearings from sitting. IF there is a bearing problem it occurred before the bus was parked.

The "Bearing Seller" in Oregon has a real racket going on and BSing people to death! No he does not know more than the bearing engineer's!

- your opinion - nice job of knocking on someone you have never met or witnessed his skills - I was there, watched what went on in his store and he was no sham - I personally felt the catch in the bearings as I turned them by hand - the owner of the motor home was being driven crazy by the vibration and traded the new rear end for a used one that fixed the problem - what caused the 'catch', I can't swear to it, perhaps a combination of water sitting in the low part of the races? - maybe the motor home was parked next to a busy railroad that caused a jiggle? - I don't know that either - maybe the new bearings had been improperly lubricated, but I find that hard to believe - what I do know is that the bearings in a rear end of a motor home that had sat for 2 years, then traveled an estimated 1600 miles +/- were damaged, had a noticeable catch in them as they were turned by hand and new bearings ended the vibration

[semipro]

I've heard of bearing failure from vibration while parked. In the past bearing failures on some imported cars were attributed to vibration on the ships that transport them over.

I'd suggest you have someone drive along side the bus and watch the wheels when the vibration occurs. In many cases you'll see a tire that's out of round or balance jumping around. In many cases, loss of balance, wasp nests, whatever will cause a vibration that is more pronounced at a specific speed. For whatever reason this speed is about 60 MPH on light vehicles. I'm not sure if that translates over to a bus though.

Edit: to support @Sleddgracer I have seen solid rock that distorted with pressure and time - but lots of both. Also, the earth has a natural vibration so I can see how sitting stationary on a parking area with a heavy load might damage bearings.

[Gdog 5651]

Back in1979 or 1980 I went to work for a new startup truck rental company "Jartran Truck Rental" as part of their fleet they had bought a CRP Load of Dodge MB300 Hi-Cube vans that had been sitting on assembly and storage lots for up to four years but were brand new, as we put them in service we got vibration complaints from renters and differential failures galore all the failures seem to come from vans stored at one location.Chrysler who had the warranty responsibility had us shut down the affected units and replace the wheel and differential bearings as this one assembly plant storage lot was next to the train terminals and the constant vibration caused the sitting vans to develop flat spots on the rollers I don't know about the oem supplier but the replacement parts were SKF. Gene

[Sleddgracer]

Originally Posted by Gdog 5651

Back in1979 or 1980 I went to work for a new startup truck rental company "Jartran Truck Rental" as part of their fleet they had bought a CRP Load of Dodge MB300 Hi-Cube vans that had been sitting on assembly and storage lots for up to four years but were brand new, as we put them in service we got vibration complaints from renters and differential failures galore all the failures seem to come from vans stored at one location.Chrysler who had the warranty responsibility had us shut down the affected units and replace the wheel and differential bearings as this one assembly plant storage lot was next to the train terminals and the constant vibration caused the sitting vans to develop flat spots on the rollers I don't know about the oem supplier but the replacement parts were SKF. Gene

I wonder if there was a connection to your experience with my experience - the time frame could possibly fit - my troubles happened mid/late 80s - the rear end was for a heavy duty one ton

[vintageracer]

Originally Posted by Seriousracer

But not stored I agree unless it is in an earthquake area.

Funny you say earthquake.

The engineer said maybe if you had repeated earthquakes in the area over a long period of time on that stationary bus.

[o1marc]

Originally Posted by Gdog 5651

Back in1979 or 1980 I went to work for a new startup truck rental company "Jartran Truck Rental" as part of their fleet they had bought a CRP Load of Dodge MB300 Hi-Cube vans that had been sitting on assembly and storage lots for up to four years but were brand new, as we put them in service we got vibration complaints from renters and differential failures galore all the failures seem to come from vans stored at one location.Chrysler who had the warranty responsibility had us shut down the affected units and replace the wheel and differential bearings as this one assembly plant storage lot was next to the train terminals and the constant vibration caused the sitting vans to develop flat spots on the rollers I don't know about the oem supplier but the replacement parts were SKF. Gene

JARTRAN was an offshoot of RYDER tuck rental. JAR standing for the owners name, James A. Ryder. He got bad advice when opening JARTRAN and went bankrupt 5 years after opening.

[Mekanic]

My F700 only gets 1 trip per year. 31-36 days per year. And it’s usually about 3500 miles.

I bought it in 2011. It did not go in 2014.
Other than that it has went every year.

No bearing problems yet.

[DWJoyce]

Bearings are tough and don't go flat from sitting. Grease within the bearings might settle at the bottom of the race. That's not a problem, the grease will redistribute itself over a short time of use.



You're assuming the seller is correct about the cause of the vibration. More than likely it's from wear and tear throughout the life of the bus. Be ready to replace parts... Speed dependent vibrations can often be traced to worn gears and bearings.


"Flattened" tires are common when a vehicle sits for long periods of time and will be noticeable at all speeds.


Good Luck