Forums    General Discussions    Gear Vendors
Page 1 2 3 
Go to...
Start A New Topic
Search
Notify
Tools
Reply To This Topic
  
Gear Vendors
 Login now/Join our community
 
"Host" of Barthmobile.com
Supporting Member of Barthmobile.com 1/19
Picture of Bill N.Y.
posted Hide Post
quote:
Originally posted by bill N.Y.:
I wish there was more that we could tell you. I don't believe that your going to figure this out on your own.
(loud drum noise: BUMM,BUMM,BUMMM) Maybe I was wrong. (I've looked, the world did not come to an end) There is more that I can tell you. You'll have to get dirty if you want to do this. I don't suspect you will do it, but to cover all the bases...
quote:
Originally posted by bill h:
Another consideration is that big brake drum on the end back there. It now has a longer moment arm, so any imbalance or off-center...
If you want to check the brake drum for balance and/or just the G/V then remove the U-joint at the transmission and put the vehicle in drive. Step on the throttle slowly until speedometer reads the max speed you would ever travel in a Barth. Take it easy as there is no real resistance so it will get up to speed very quickly. Try out your G/V in different speeds and note what it's doing.

Common sense says you've got to be carefull. Also this same principle applies to how your going to use the G/V while doing this. If you don't know what I mean by this then don't attempt it!

Because your parking brake is attached to the back of the transmission there will be no parking brake. Make sure your on a flat surface when doing any part of this and that ALL OF YOUR WHEELS ARE CHOCKED FRONT AND REAR. I know this sounds like overkill (it is) but I would hate to get a knock on my door with a "notice to appear" because the two wheel chocks on one wheel came out and it rolled away on you.

After you have done your testing to see if the drum and or G/V is causing your problem place transmission in NEUTRAL, wait till the speedo stops or slows down to just about nothing and then turn off the vehicle. DO NOT place it in park until the engine has been turned off for several seconds and the speedo is NOT MOVING as you'll destroy the parking pawl inside of the transmission.
quote:
Originally posted by humbojb:
Was I right to state the unsupported length as the length between the tranny support and the first carrier support bearing?
The driveshaft is measured from the center of U-joint to center of U-joint. You are measuring "unsupported length"? You need to measure "the Driveshaft" from "yoke to yoke".

If you want to see if the long driveshaft is out of balance then do this same thing by taking the U-joint apart after the carrier bearing and then test again.

Hope this extra stuff helps you out.


˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„

Regis Widebody1990 Barth Regis Widebody
8908 0128 40RDS-C1
L-10 Cummins
Allison MT647 Transmission
Spartan Chassis
Regal Conversion1991 Medical Lab Conversion
9102 3709 33S-12
Ford 460 MPFI
C6 Transmission
Oshkosh Chassis



Quick Link: Members Only Link To Send Me A Private Message
 
Posts: 5924 | Location: Newburgh, New York | Member Since: 05-10-2003Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 2/16
Captain Doom
Picture of Rusty
posted Hide Post
quote:
If you want to see if the long driveshaft is out of balance then do this same thing by taking the U-joint apart after the carrier bearing and then test again.


I'd not recommend that procedure, because if the shaft is out-of-true or out-of-balance, it can start to whipsaw, and there's no quick way to slow it down...


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields
 
Posts: 7734 | Location: Brooker, FL, USA | Member Since: 09-08-2005Reply With QuoteReport This Post
"Host" of Barthmobile.com
Supporting Member of Barthmobile.com 1/19
Picture of Bill N.Y.
posted Hide Post
Wouldn't it "whipsaw" with the U-joint and rest of the driveshaft hooked up too? The only difference is he's not doing this on the road under a load condition turning the rear end. He's just checking to see if the driveshaft or G/V is what's out of balance or making the harmonic noise etc...

The carrier bearing would hold up the driveshaft just the same. The driveshaft will still turn at the same RPM. The only difference would be if the coach is moving or staying still.

There would be no load factor to cause a gear noise problem. Just trying to see if the driveshaft is a contributing factor.

I could have also told him to take the axle's out (cap off axle ends) and try that too. I just figured the only thing that's changed was the G/V and the first driveshaft. Trying to find what's causing this by taking things out and adding them back into the picture etc...


˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„

Regis Widebody1990 Barth Regis Widebody
8908 0128 40RDS-C1
L-10 Cummins
Allison MT647 Transmission
Spartan Chassis
Regal Conversion1991 Medical Lab Conversion
9102 3709 33S-12
Ford 460 MPFI
C6 Transmission
Oshkosh Chassis



Quick Link: Members Only Link To Send Me A Private Message
 
Posts: 5924 | Location: Newburgh, New York | Member Since: 05-10-2003Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 2/16
Captain Doom
Picture of Rusty
posted Hide Post
I misunderstood which U-joint you suggested unhooking - I thought you meant the foremost one, at the drive end of the GV box...

In any event, if the drive shaft is to be tested by disconnecting any other U-joint, I suggest it be a two-person operation, where there's an observer to watch the driveshaft for erratic behavior.

Depending where the intermediate bearing is, there may be little chance of whipsaw.

It's my totally-off-base opinion that the GV whine is normal (if not appreciated), because I think that an out-of-true/balance driveshaft would have been previously noticed. Unless the installer used a torch to cut the shaft, or cut of a counterweight, the driveshaft should be OK.

But then I don't worry about that, because the driveshaft on the Breakaway is about 12".


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields
 
Posts: 7734 | Location: Brooker, FL, USA | Member Since: 09-08-2005Reply With QuoteReport This Post
The Old Man and No Barth
posted Hide Post
Humbojb -You've gone from a new small noise when you installed the G/V 2 1/2 months ago, to a time bomb of potential disaster, on the basis of disastrous mental images conjured by a bunch of real and/or presumtive mechanics who haven't put their hands on the machine, & have looked at only your verbal description.

Point #1 - If everything from the engine to the handbrake drum is bolted together, you don't have 82" of unsupported weight. You have a rigid length of machinery supported by the engine & tranny mounts, plus a 60" drive shaft, half of whose weight is supported by the intermediate support bearing.

Point #2 - Your 60" long front drive shaft runs with little angularity because it's bolted to the back of the engine/tranny/G/V combination in nearly a straight line to the first support bearing after the machinery. It has U-joints to compensate for less-than-perfect alignment, & chassis flexing. If the shaft is made of adequate material it isn't going to twist or whip.

IMHO you're better off with the G/V & one 60" drive shaft in this circumstance, than you were with 2 short drive shafts & another pillow-block bearing to bridge the same distance. When you lost the extra drive shaft, you also lost several mechanical components that wear out & break down.

If all you have is the new whine, & there's no severe vibration, no evidence of worn U-joints, etc.. I'd say enjoy your new-found economy, quiet, & hill-climbing efficiency.

Cars have been my toys for 62 years. It took me at least 30 years to learn this lesson: IF IT AIN'T BROKE, DON'T FIX IT!!!
 
Posts: 1421 | Location: Upper Left Corner | Member Since: 10-28-2002Reply With QuoteReport This Post
"Host" of Barthmobile.com
Supporting Member of Barthmobile.com 1/19
Picture of Bill N.Y.
posted Hide Post
quote:
Originally posted by humbojb:
From the first u-joint to the first support bearing is 60"... The back of the front drive shaft sticks out beyond the first support bearing about 6".
This sounds like your driveshaft is 66 inches long. Doesn't sound too long now.
quote:
Originally posted by Bill N.Y.:
If it is something of a light nature and you have been called a "nit pick" before (I've been called that and worse) then maybe it's not as bad as you think it is. You are the judge as to what is slight so this is purely subjective.

I would still check out the driveshaft for "out of timing" and to see if there is any signs of a weight that came off. Look carefully and remember that if this turns into a vibration you should get it checked out more indepth. Try the trident tuning fork as this may only be a slight harmonic noise.
I have reread this post many times and this is sounding more and more like what Ed is describing.
quote:
Originally posted by MWrench:
If the drive line were the cause, be it, out of balance, "U" joints clock wrong, "U" joints defective, support bearing(s) defective, bent, deflection angle wrong, the typical symptoms would be a vibration or rumble thru out the coach and very well could be at only certain speeds, but usually get worse as RPM (speed) goes higher.

If the "whine" you are describing is of a high frequency then it is gear noise that is getting into the chassis. Whether it is the rear carrier or the GV unit hard to say with out further testing or analysis. However, because the noise wasn't there before the GV unit was installed I would think it is in fact coming from the GV unit. They do make some noise and the fact that it is only in O/D would tend to confirm that is the source of the noise.

Why is it getting into the chassis?

If the GV unit were attached directly to the transmission, the added weight might be enough to compress the rear transmission mount to the point where it is not longer able to isolate related noises. Maybe the mount wasn't replaced and it is old, hard and brittle which would contribute to noise being transferred to the chassis.

As far as noise being at a certain speed, very common, gears have a natural resonance and when the speed of the gear teeth make and brake contact with each other approach the natural resonance frequency the whine will sharply increase. The gear set is being excited with a frequency near or at its natural resonance and will continue as long as those conditions exist.

I don't think you have a serious problem (other then the drive shaft being to long) Getting rid of the whine might be difficult to do. As mentioned I would check the mounting system and the isolators first.

With my SOB, I added a ton of noise proofing and when finished it was very quiet but then I heard all kinds of noises I never heard before. I also had a whine but at and around 55 MPH, it was there before the noise proofing but seemed SOOO much louder after. Went to heavier gear lube in the diff and that would reduce it but would not eliminate it.
You could tell if it is the Gear Vendor by performing these checks.

  • If you want to check the brake drum for balance and/or just the G/V then remove the U-joint at the transmission and put the vehicle in drive.
  • Step on the throttle slowly until speedometer reads the max speed you would ever travel in a Barth. Take it easy as there is no real resistance so it will get up to speed very quickly.
  • Try out your G/V in different speeds and note what it's doing.

    Now if you wanted to check out the driveshaft reinstall at this time only up to the first carrier bearing and remove that U-joint. This will allow you to check the whole set up with the new driveshaft attached.
    quote:
    Originally posted by MWrench:
    Humbojb -You've gone from a new small noise when you installed the G/V 2 1/2 months ago, to a time bomb of potential disaster, on the basis of disastrous mental images conjured by a bunch of real and/or presumptive mechanics who haven't put their hands on the machine, & have looked at only your verbal description.
    You probably have nothing wrong with the driveshaft or G/V. Have you been called a nit-pick? I'm not trying to torque you off here but how bad is this really? I would think with the lower engine noise you would now hear other noises. I would love to get my hands on this for a test drive but know this is not going to happen.

    I would do the testing myself as described above and then also disconnect the trans mount and install a piece of support under it to isolate the weight noise transfer of the cross frame support. There are a lot more testing that a real repair shop could do and as stated earlier...You need professional help that no amount of typing is going to give you. You really need someone who you trust to give you the facts only after looking at it. This isn't something someones going to fix for you over the phone or by responding to an email.

    There's a warranty with the G/V so have them look at it again. See what they recommend. Have an independent repair shop give you a diagnosis based upon lookin at it and go from there.

    Good luck to you. Let us know what was or wasn't found as I'm very interested in the eventual outcome.


    ˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„

    Regis Widebody1990 Barth Regis Widebody
    8908 0128 40RDS-C1
    L-10 Cummins
    Allison MT647 Transmission
    Spartan Chassis
    Regal Conversion1991 Medical Lab Conversion
    9102 3709 33S-12
    Ford 460 MPFI
    C6 Transmission
    Oshkosh Chassis



    Quick Link: Members Only Link To Send Me A Private Message
  •  
    Posts: 5924 | Location: Newburgh, New York | Member Since: 05-10-2003Reply With QuoteReport This Post
      Powered by Social Strata Page 1 2 3  
     

        Forums    General Discussions    Gear Vendors

    This website is dedicated to the Barth Custom Coach, their owners and those who admire this American made, quality crafted, motor coach.
    We are committed to the history, preservation and restoration of the Barth Custom Coach.