Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 09-23-2012, 09:35 AM   #1
steamgas
Senior Member
 
steamgas's Avatar
 
Join Date: May 2010
Location: va
Posts: 138
Default a vibration problem at 40 mph

i have a vibration at 40 mph that i just can't find the cause of.i have had severial motors put in and out of the car,rebuilt the transmition,rebuilt the front end,rebuilt the steering all the way through.all of this work has not done any good at solving the vibration problem.all that is left is to remove the rear end and start rebuilding from top to bottlem but before i do that i want to run it by you guys to get your opinion.there is no noise at all from the rear end.it all apears good except the rear axel keyseats are a bit lose but i keep the rear drums tight to prevent anymore wear.i just don't think the vibration is found there.i did put in a new universal jount when i overhauled the transmition however from that point back i have not touched anything.what is the runout spec.on the driveshaft if i decide to take it out and check it?
steamgas is offline   Reply With Quote
Old 09-23-2012, 09:42 AM   #2
steve s
Senior Member
 
steve s's Avatar
 
Join Date: May 2010
Location: Kalamazoo
Posts: 1,656
Default Re: a vibration problem at 40 mph

tires balanced?
steve s is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 09-23-2012, 09:47 AM   #3
Louis
Senior Member
 
Join Date: May 2010
Location: Marietta GA.
Posts: 647
Default Re: a vibration problem at 40 mph

On my 31 coupe I have a vib. at about 40 mph, if I stay at 38 or go a little over 40 it will smooth out, It also depends on the slope of the road, no vib. on a slight up hill grade, but the vib. comes back with a slight down hill grade. stright and level is ok, but I still have to stay below 40 or above 40.
Have you drove another "A" model to compare?...I think there is some vib. in all of them due to the 4 cly. motor of the 20's and 30', JMO
__________________
I've suffered a great many Catastrophe's in my life.....most of them never Happened.
Louis is offline   Reply With Quote
Old 09-23-2012, 10:08 AM   #4
steamgas
Senior Member
 
steamgas's Avatar
 
Join Date: May 2010
Location: va
Posts: 138
Default Re: a vibration problem at 40 mph

i have tryed too balance the tires.it seems to be coming fron the drivetrain and not the tires.
steamgas is offline   Reply With Quote
Old 09-23-2012, 10:37 AM   #5
30Ford
Senior Member
 
Join Date: Jan 2012
Location: Eastern Canada NB
Posts: 166
Default Re: a vibration problem at 40 mph

My 30 coupe is exactly the same...all new except the rear end
30Ford is offline   Reply With Quote
Old 09-23-2012, 10:47 AM   #6
1937roadsterdeluxe
Junior Member
 
Join Date: Aug 2012
Location: VIRGINIA
Posts: 28
Default Re: a vibration problem at 40 mph

Sponsored Links (Register now to hide all advertisements)
the "driveshaft " balance it .
1937roadsterdeluxe is offline   Reply With Quote
Old 09-23-2012, 10:48 AM   #7
1937roadsterdeluxe
Junior Member
 
Join Date: Aug 2012
Location: VIRGINIA
Posts: 28
Default Re: a vibration problem at 40 mph

if u can fell the vibration going front to back is the driveshaft ..
1937roadsterdeluxe is offline   Reply With Quote
Old 09-23-2012, 11:24 AM   #8
Kurt in NJ
Senior Member
 
Kurt in NJ's Avatar
 
Join Date: May 2010
Location: on the Littlefield
Posts: 6,140
Default Re: a vibration problem at 40 mph

You could take off the speedometer "turtle" and look for movement and play in the front driveshaft bearing ---have you run the car with the wheels off the ground, perhaps on a lift and looked for the vibration
Kurt in NJ is offline   Reply With Quote
Old 09-23-2012, 11:45 AM   #9
steamgas
Senior Member
 
steamgas's Avatar
 
Join Date: May 2010
Location: va
Posts: 138
Default Re: a vibration problem at 40 mph

i am going to jack the rearend up tommorrow and get it up to 40 mph and see what i can find.i may also take the rear wheels off to eleminate that being the problem.so far i think it is the drive shaft but i would like too get more input from you guy,s.
steamgas is offline   Reply With Quote
Old 09-23-2012, 12:00 PM   #10
FL&WVMIKE
Senior Member
 
FL&WVMIKE's Avatar
 
Join Date: May 2010
Location: Daytona Beach, Fl & Spencer, W. Va,
Posts: 4,442
Default Re: a vibration problem at 40 mph

Steamgas ..............
If you push in the clutch at 40 mph and it doesn't stop, it is, probably your tires or driveshaft componants.
MIKE
FL&WVMIKE is offline   Reply With Quote
Old 09-23-2012, 01:10 PM   #11
George Miller
Senior Member
 
George Miller's Avatar
 
Join Date: May 2010
Location: NC
Posts: 2,975
Default Re: a vibration problem at 40 mph

Do you have the bearing and race in the torque tube.
George Miller is offline   Reply With Quote
Old 09-23-2012, 01:16 PM   #12
steamgas
Senior Member
 
steamgas's Avatar
 
Join Date: May 2010
Location: va
Posts: 138
Default Re: a vibration problem at 40 mph

i just jacked up the rear end and ran the speed up to 50 mph and pushed in the clutch and tried too tell the differance between the drivetrian and the wheels.the wheels are out of round and do wobble a bit but the vibration is coming from the drivetrian.i know how too square up the flywheel housing(.005)and the flywheel(.003).all things point too the driveshaft.i may take the speedometer out tommorrow and look for endplay there before i take everything out from underneath it.
steamgas is offline   Reply With Quote
Old 09-23-2012, 01:18 PM   #13
steamgas
Senior Member
 
steamgas's Avatar
 
Join Date: May 2010
Location: va
Posts: 138
Default Re: a vibration problem at 40 mph

this is a 1929 truck.which bearing do you mean?the one at the transmisson or the one at the banjo housing?
steamgas is offline   Reply With Quote
Old 09-23-2012, 01:29 PM   #14
juke joint johnny
Senior Member
 
juke joint johnny's Avatar
 
Join Date: Feb 2012
Location: London England
Posts: 908
Default Re: a vibration problem at 40 mph

I think George means the one inside the front of the torque tube !!
John Cochran
juke joint johnny is offline   Reply With Quote
Old 09-23-2012, 01:40 PM   #15
Dave in MN
Senior Member
 
Dave in MN's Avatar
 
Join Date: May 2010
Location: Jordan, MN
Posts: 1,410
Default Re: a vibration problem at 40 mph

Most Model A's have a vibration at this speed. I lightened and balanced the flywheel many years ago and it helped but still has a bit between 42 and 45mph. I have driven many A's with the same vibration around this speed/rpm. Some are worse than others.
Good luck in your search.
Dave in MN is offline   Reply With Quote
Old 09-23-2012, 01:40 PM   #16
steve s
Senior Member
 
steve s's Avatar
 
Join Date: May 2010
Location: Kalamazoo
Posts: 1,656
Default Re: a vibration problem at 40 mph

Well, I'll be interested in how this turns out. I'll be amazed if it's the driveshaft--a straight solid rod that lives its life rotating not very fast about its long axis in a protective torque tube.

Is there a growely or rumbley noise, or any other "new" noise that occurs along with the vibration--like a bearing may be involved?

As others have said, some vibration around 40 is common; mine has a vibration point at 35 mph; If I pay close attention, I can detect it at the same rpm in 1st and 2nd gear--that's the motor.

In my experience, because of how everything is connected to everything else, it's very hard to be sure where a vibration is originating. Exactly what happens when you push in the clutch at 40 mph? I remember shearing an axle key and being absolutely certain that my transmission had exploded.

Steve
steve s is offline   Reply With Quote
Old 09-23-2012, 02:22 PM   #17
steamgas
Senior Member
 
steamgas's Avatar
 
Join Date: May 2010
Location: va
Posts: 138
Default Re: a vibration problem at 40 mph

the vibration quits when i push the clutch in.there is no noise in the rearend.nothing scrubing,draging etc.mabe i just expect too much from it.i hear of people taking long raod trips in their car.how could the car or truck hold togather with a vibration at 40 mph.i would not take mine past the post office and even then i had better have the phone number to the wrecker crew with me.
steamgas is offline   Reply With Quote
Old 09-23-2012, 02:42 PM   #18
Gary WA
Senior Member
 
Gary WA's Avatar
 
Join Date: May 2010
Location: Clinton,WA/Whidbey Island
Posts: 4,088
Default Re: a vibration problem at 40 mph

As long as the wheels don't fall off go past the post office.!! Have Fun!!!
Attached Images
File Type: jpg 02.jpg (76.3 KB, 5 views)
__________________
www.whidbeymodelaclub.com
Gary WA is offline   Reply With Quote
Old 09-23-2012, 02:45 PM   #19
TinCup
Senior Member
 
TinCup's Avatar
 
Join Date: May 2010
Location: OKC / Tonkawa, Ok.
Posts: 1,977
Default Re: a vibration problem at 40 mph

My coupe did the same thing until I replaced the clutch and flywheel with a balanced and lightend flywheel. Yes it stll vibrates but at higher speeds 50-55. I typicaly drive 45 max.
TinCup is offline   Reply With Quote
Old 09-23-2012, 03:15 PM   #20
steve s
Senior Member
 
steve s's Avatar
 
Join Date: May 2010
Location: Kalamazoo
Posts: 1,656
Default Re: a vibration problem at 40 mph

Quote:
Originally Posted by steamgas View Post
the vibration quits when i push the clutch in. ....
I assume this is while on the jack stands. You could take tire imbalance out of the equation (or put it in for sure) by doing the same test with the wheels removed.

If the vibration goes away above 40, I agree with the others about just driving it.

I'm still betting on the wheels/tires. Have you taken them to a shop that has the mounting adapters to spin balance them? Discount Tire did my new Firestones using stickon weights when I bought them thru them, however my prior set of Universals were ruled basically unbalanceable--the guy said he'd have to double stack the weights and even then couldn't do anything about their side-to-side issue.

Steve
steve s is offline   Reply With Quote
Old 09-23-2012, 03:46 PM   #21
mach0415
Senior Member
 
mach0415's Avatar
 
Join Date: Jul 2011
Location: Chester, SC
Posts: 162
Default Re: a vibration problem at 40 mph

I would also check the u-joint. FWIW A u-joint will vibrate at those higher speeds under power and then when power is removed in a coast down, vibration will decrease.
__________________
Thanks,
Mark in SC


"We the unwilling, led by the unknowing, are doing the impossible for the ungrateful." -- By society, who is still arguing over who said it.
mach0415 is offline   Reply With Quote
Old 09-23-2012, 04:00 PM   #22
George Miller
Senior Member
 
George Miller's Avatar
 
Join Date: May 2010
Location: NC
Posts: 2,975
Default Re: a vibration problem at 40 mph

Quote:
Originally Posted by juke joint johnny View Post
I think George means the one inside the front of the torque tube !!
John Cochran
Yes that is the one, very important. When the drive shaft is turning in the 2000 rpm range, it will let the U joint move around on the back side, if it is not there.
George Miller is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 09-23-2012, 10:27 PM   #23
columbiA
Senior Member
 
Join Date: Nov 2011
Location: B.C. Canada
Posts: 1,746
Default Re: a vibration problem at 40 mph

A friends car had a bad vibration over 35 mph.The problem was that the inner ball cap around U-joint was not installed.Front of TTwas free to jump up & down & DS moved forward enough to knock out the brg stop on trans case & required another case to repair.
columbiA is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 03:29 PM.