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Drums out of balance?

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Dyn Blin

Drums out of balance?

This may be a draft question, but do drums ever become out of balance as they wear?

After swapping out both when I rebuilt the rear sets last week, I drove it on the freeway tonight for the first time. An annoying vibration I haven't been able to find between 45 and 55 is gone.

That's the only recent change to anything that would remotely affect driving. U joints seem OK as part of of my overall attempts to track it down.

Sonoma County,CA
1982 F150 Flareside XLS
NP435 4x4
351W Motorcraft 2150

Angelo Voltura

Re: Drums out of balance?

The short answer is yes, they do. But the chances of you actually noticing or feeling it are next to none. You would feel a warped brake rotor first.

I would be checking your driveshaft. An out of balance driveshaft, which is possible especially after replacing u-joints, will cause an on/off vibration at cruising speeds.

I would doubt that brand new drums wore /that/ fast to cause amounts of vibration that would be noticeable. As someone who has 400k miles on original drums and does not have vibration from them, I would be skeptical.

However in your case they could have very well have been. Sounds like you've fixed the issue.

1978 F150 351W
1979 F150 "410M"
1979 F100 302
1979 F250 400
1987 F150 300
1990 F150 302
1991 F150 300
1995 F150 (1985 clip swapped) 300
1997 F250 351W

Gary Lewis

Re: Drums out of balance?

Administrator

In reply to this post by Dyn Blin

If you are saying they are new drums, then they may not have been balanced from the factory. They won't wear very far out of balance, like Angelo said, but they may have gotten out of the factory w/o being balanced.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

ArdWrknTrk

Re: Drums out of balance?

Administrator

In reply to this post by Dyn Blin

Drums can warp and then shoe action can wear them out of balance.

I'd tend to think there is a harmonic in the drive shaft as Angelo mentioned, OR you have a pinion engagement (backlash) issue.

This might show up at a certain road speed because there is neutral throttle.
Does it happen while accelerating, or braking through this speed?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Whisler

Re: Drums out of balance?

I read the OP as saying the new drums eliminated the vibration. Am I mis-reading?

God Bless
Whisler

Frankenstein: 1989 F250 4X4, C-6, Hurst Pro-Matic 2 shifter, carbed '84 351W, Edelbrock manifold, Edlbrock AVS, DS2 ignition, 3G alternator, JBA shorty headers, no cats, dual exhaust with H pipe.

ArdWrknTrk

Re: Drums out of balance?

Administrator

In retrospect it seems you are absolutely correct.

I was following Gary's lead and lost sight of the OP.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Drums out of balance?

Administrator

Yep, I mis-read it. My bad.

Gary, AKA "Gary fellow": Profile

Angelo Voltura

Re: Drums out of balance?

Glad I was not the only one!

1978 F150 351W
1979 F150 "410M"
1979 F100 302
1979 F250 400
1987 F150 300
1990 F150 302
1991 F150 300
1995 F150 (1985 clip swapped) 300
1997 F250 351W

Dyn Blin

Re: Drums out of balance?

In reply to this post by Dyn Blin

Thanks gentlemen. I got an unexpected shift and couldn't check back- thanks for the responses.

Yes, the drums are the only recent change. I've had 3 more freeway runs since the note and it's still smooth in that range.

I kept the old drums. I suppose I could put them on again and go for another run, or take them to get them turned and see if the shop can tell me anything.

I keep expecting the vibration to come back, if it does, I'll update.

Sonoma County,CA
1982 F150 Flareside XLS
NP435 4x4
351W Motorcraft 2150

ArdWrknTrk

Re: Drums out of balance?

Administrator

Please try not to expect the worst.
Having no expectation is better than raising your cortisol levels.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

RenoHuskerDu

Re: Drums out of balance?

In reply to this post by Dyn Blin

My master tech buddy has noticed a spate of inexpensive drums as sold on fleabay and amazon that are not round from the git go.

Encountered this myself on our Bully whilst fighting a lengthy brake issue. Bad drums was a root cause, but not the only one. I bought some name brand drums and that solved the grabbiness when cold. Pulsing was only evident to the trained driver (not my driving daughters).

Reno in Central Texas, 86 F250 XLT Lariat eclb 2wd 6.9, plus 2 Bricknoses, 1 Aeronose that's getting a Bullnose front clip, and parts trucks. Busy lads, father and sons wrenchers.