• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

when should harmonic balancer be replaced?

mitzel

Contributor
Sr. Member
Joined
Feb 18, 2004
Messages
562
Loc.
Googleplex
I'm in the middle of replacing timing chain, waterpump, etc. When I
pulled the balancer I note a bit of cracking in the outer part of the
rubbery section of the balancer. The cracks don't go all the way through
and no obvious movement between the inner and outer rings. So I'm
wondering should balancer automatically be replaced if there's some
visible cracking? Or is that normal wear&tear and still good for a long
service life?

I've attached picture but [lack of] clarity and detail may not add much
useful information.
 

Attachments

  • dcp_0628-small.jpg
    dcp_0628-small.jpg
    49.7 KB · Views: 59

Bronchopper

Full Member
Joined
May 4, 2005
Messages
173
Loc.
Incirlik, Turkey
I'm in the middle of replacing timing chain, waterpump, etc. When I
pulled the balancer I note a bit of cracking in the outer part of the
rubbery section of the balancer. The cracks don't go all the way through
and no obvious movement between the inner and outer rings. So I'm
wondering should balancer automatically be replaced if there's some
visible cracking? Or is that normal wear&tear and still good for a long
service life?

I've attached picture but [lack of] clarity and detail may not add much
useful information.

look at it this way... a new ballancer cost about as much as a sack of peanuts. i can tell you that you do not want to see what that sucker will do when it lets go. at the very least, you are gonna get some bad vibration that could screw up the crank snout or the motor, at the worst, think about 2 lbs of steel spinning about 5k rpm zinging around under your hood.

plus you already have it removed. seems like a no brainer to me.
 

phred

Contributor
Bronco Guru
Joined
Aug 25, 2006
Messages
3,432
Loc.
Earth
X2 on jsut replacing it now.
I had one come apart while running 70 miles/hour. Made a heck of a racked. I was luck it didn't tear anything up.
 

ugly74

Bronco abuser
Joined
Apr 17, 2006
Messages
2,847
I dunno, I think the cracks aren't a big deal. if the rubber were starting to push out, then I'd worry. I replaced mine once cuz the outer ring was starting to walk off. the "good used" one I replaced it with had cracked rubber too, and a decade later, it's still fine.
but then again, they aren't very expensive, and that'd be one less thing for you to worry about.
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,341
While basically its normal wear and tear. Since its probably at least 22 years old at the least I'd replace it. Cracks, big chunks, while they may not appear to go all the way through probably go deeper than you think. Add that to the years of useage and its time to replace it. Sooner or later it will let go I had a friend with a 85 bronco and his balancer let go luckily it didnt do any damage but I've seen others bounce around the engine compartment destroying stuff and go through the hood.
 

Devin

Bronco Kineticist
Joined
Apr 29, 2004
Messages
3,956
look at it this way... a new ballancer cost about as much as a sack of peanuts. i can tell you that you do not want to see what that sucker will do when it lets go. at the very least, you are gonna get some bad vibration that could screw up the crank snout or the motor, at the worst, think about 2 lbs of steel spinning about 5k rpm zinging around under your hood.

plus you already have it removed. seems like a no brainer to me.

X2. They don't cost that much.
 

Jeepster

Bronco Guru
Joined
Jul 13, 2001
Messages
1,507
Replace it.Its just a question of time. Another thing is its possible that it might have spun a little throwing your timing marks off. Damper Dudes is another place to check out for a rebuilt balancer.
 
OP
OP
M

mitzel

Contributor
Sr. Member
Joined
Feb 18, 2004
Messages
562
Loc.
Googleplex
Thanks for the feedback everyone. Pretty much matches my thoughts
that I should just replace it given the moderate expense. I'm gonna give
damper dudes a call tomorrow.


cheers,danny
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
Be sure to take the old one with you when buying a new one. Make sure the balance weight, timing marks, and bolt pattern are the same. The guy at the part store told me that Broncos use the old 289 balancer even in the 302. Other Ford products went to a four bolt balancer. Be sure to check the torque specs for your specific year model. I torqued mine to the wrong specs (75 ft lbs) and broke the bolt off. My '77 should be 35-50ft lbs.
I like to put the balancer in before tightening up the cover bolts. There is no fit or dowels to align the cover and it can be bolted on a little crooked causing the seal to wear out or leak.
 
OP
OP
M

mitzel

Contributor
Sr. Member
Joined
Feb 18, 2004
Messages
562
Loc.
Googleplex
blubuckaroo
> Be sure to take the old one with you when buying a new one. Make sure
> the balance weight, timing marks, and bolt pattern are the same. The guy
> at the part store told me that Broncos use the old 289 balancer even in
> the 302. Other Ford products went to a four bolt balancer.

I talked to DamperDudes on the phone yesterday. He was able to match
the exact part number in their inventory. Box was on my doorstep this
morning so I did a very close inspection and looks like a perfect match.
Guy said the Bronco application is somewhat unique on the use of a raised lip
around the center hole for centering/locating the accessory drive pully
rather than just relying on the bolts.


> Be sure to check the torque specs for your specific year model. I torqued
> mine to the wrong specs (75 ft lbs) and broke the bolt off. My '77 should
> be 35-50ft lbs.

hmm, I'll need to check my shop manual to see if it has a specific torque
spec. I sorta only remember one value listed for all applications in the
Tom Monroe book and seems that was something like the 75lbs you mention.
Seems odd that jumbo bolt would yield from that amount of torque, I would
suspect your bolt was cracked/damaged?


> I like to put the balancer in before tightening up the cover bolts. There is
> no fit or dowels to align the cover and it can be bolted on a little crooked
> causing the seal to wear out or leak.

The Tom Monroe book mentions that too, that's the reference I use for
step-by-step procedures.


Thanks for the followup comments and recommendations. danny
 

Madgyver

Bronco Madman
Joined
Jul 30, 2001
Messages
14,678
when should harmonic balancer be replaced?




I replaced it after I traced an oil leak from the front of the motor.. There was a hole in the timing chain cover from the outer ring on the HB... It got loose enough to move back into the engine... Good thing I had spare usable parts on a parts EB..
 
Top