View Full Version : How difficult is it to replace a Harmonic Balancer

04-19-2003, 11:42 PM
As you can see here...


It appears my harmonic balancer is all messed up.

It looks like I need to buy a new one and put it in there, but I dont know how hard this is going to be.

Is it as simple as removing the bolt holding it on, and bolting a new one in it's place? Is it more complex? What should I know about doing this? (I understand the bolts are easy to break, what can I do to avoid this?)

Finally, how much will a HB run me? Should I buy a new one from a dealership or see about getting a used one?

04-20-2003, 12:00 AM
it's that simple. you will need a balancer puller to get the old one off though. i suggest a bhj balancer. they arent rubber and they look nice to.
good luck

04-20-2003, 12:13 AM
BHJ balancer is around $350. Around a hundred more than from Ford but will never fail you again. Don't get a used one. They are pressed fit and are not designed to be reinstalled. With the BHJ balancer you need to have the crank pulley zero balanced or its a good time to add the underdrive pulleys which already are zero balanced. Your crank sensor must be okay if the engine still runs so it should be a easy fix to just change the balancer and pulley.


04-20-2003, 12:54 AM
The possibility has been raised that maybe the HB is fine. Someone suggested (the person I bought the car from actually) that maybe one or two of the 4 surrounding bolts was sheared. This would make it considerably easier wouldnt it? I wouldnt need a new HB at all.

04-20-2003, 01:01 AM
Have you actually checked them? See if any of the pulley bolt heads or the Balancer bolt in the crank are missing.

I suggested that the pulley bolts may have sheared in the other thread.

Do a search on that topic you will see that has happened a few times to other folks. I also recall reading that the balancer ended up being broken on one of them. My balancer looked fine when I took it off. But the Bolt was broken off in the crank.

So check and see if any bolts are broken and go from their.

04-20-2003, 01:04 AM
I'll check on that tomorrow when there's a bit more light out. I didn't fully realize what the problem was and what I had to do to fix it until night had already fallen.

04-20-2003, 05:24 AM

"Here" (http://www.sccoa.com/forums/showthread.php?s=&threadid=17843&perpage=40&pagenumber=1) was my experience. hope it helps.

04-20-2003, 06:48 PM
Ok, update.

I cant get my head in between the radiator and pulley to see exactly what's wrong, but here's what I've noticed so far.

I pulled of the belts and tried to turn the crank pulley by hand. It won't spin, but it wiggles back and forth a good deal.

I tried to see the bolts holding it on, and I'm reasonably sure at least 1 of the 4 surrounding bolts is gone. I have to jack the car up more to get my head in there though.

Is this a possibility... Could just one of the crank pulley bolts be broken? Can my job be as simple as pulling the remaining 3 bolts and removing the pulley, tapping out that one broken bolt, and bolting my pulley back on? Could it be that simple?

The car still runs, so for whatever reason, the crank sensor is still fine, which leads me to believe the HB is still fine.

04-20-2003, 08:27 PM
that could be a possibility. I assume if the pulley has play in it when you move it by hand, that it has to be clunking around and making noise when the engine is running.

04-21-2003, 02:50 AM
there should be a big bolt in the center of the 4 bolts that hold the pulley on to the balancer. it will be around an inch deeper than those. you should be able to feel around in there to see if its there, if not you've got problems. i imagine though (and will probably be corrected) if it were your balancer wobbling i imagine that you would not be able to drive the car, as the hall effect ring would have most likely demolished the cps or would be moved to far out of the cps for it to make a good reading. when you get the pulley to move back and forth (we are talking left to right, right?) are the bolts moving with it? if so, you may still have issues. what happens is that the balancer is press fit onto the crank, as it wiggles forward, it snaps the head off of the retaining bolt, but because it was pressed onto the crank, it doesn't just slide off.

good luck, keep us updated.

04-21-2003, 06:44 PM
So to replace my leaky front seal, you say I would have to replace the HB as well?:( The Ford manual says to reinstall the HB and all the old bolts as well.:confused:

04-21-2003, 07:08 PM
Originally posted by talon660
The Ford manual says to reinstall the HB and all the old bolts as well. :confused:

ford also said: in 1988 when asked about rumors of head gasket problems with the 3.8 sc, that they were just teething issues and were fixed with tuning, "the engine is bullet proof now" :rolleyes:

lol, j/k. seriously, i don't believe it would be a good idea, based upon what others have said, it would only open the balancer up and weaken the press fit that it partially relies on to stay on the crank.

maybe if you were to use the new mustang crank bolt it would have the strength to hold it on :confused: i would recommend the new balancer, but definitely understand that the words "budget" and "supercoupe" usually don't go well together. at the very minimum, use the new(er) mustang crank bolt.

good luck,

Mike Puckett
04-22-2003, 12:02 AM
The balancer on my 90 racer has been on and off 3 times with a new bolt and washer each time and was originally a replacement balancer installed by a Ford dealer on the original engine that eventually blew. And yes I do worry about it and check it constantly for wobble as I race it 2-3 weekends a month. I have the aluminum underdrive pulley on it so maybe that makes a difference. I do have a spare.

04-22-2003, 01:17 AM
How difficult is it to just pull the pulley off the balancer and replace it?

04-22-2003, 02:54 PM
ive got a used one on my car and i ahavent had a problem with it, the only reason i put on a used one is because im on a college student budget and i couoldnt afford a brand new one. But everyone i talked to told me to put on a new one, lol oops

Mike Puckett
04-22-2003, 08:23 PM
To take off the pulley, just remove both belts and then remove the 4 smaller bolts inside. Feel for it rather try to look at it. You should be able to do it blind, it's pretty easy actually. Feel for the large main center bolt but don't remove it. If it ain't there they're both broken.

04-22-2003, 09:46 PM
Alright guys, today after work I went out to my car and started working on it a bit. I pulled the radiator fan for more working room, then stuck my fingers in the middle of the pulley to feel around.

Get this... I thought there might have been 3 bolts still holding the pulley on... well I was wrong. There was only 1 bolt holding the pulley on, and it was barely hand tight!

Actually, I have to elaborate. I felt 2 bolts, and 2 empty holes where the bolts broke off. I wiggled around and I noticed that 1 of the remaining bolts was hand tight! i removed that bolt, and the last bolt seemed ok.

After wrenching the bolt off, I noticed that it was significantly shorter than the other. It appears the bolt broke about halfway down the threads. Here's a pic of the two bolts I pulled out


Here is a pic of the Harmonic Balancer, which still feels rock solid and I dont believe needs replacing.


As you can see, there is one bolt with enough threads sticking out that I can probably get it off with some vice grips... one bolt with barely any threads sticking out, and one bolt stuck halfway into one of the bolt holes.

How hard is it exactly to remove bolts from holes like this? Is it going to be extra hard because there isnt much room to work with? Is there a serious danger of messing everything else up when I do it?

Mike Puckett
04-22-2003, 11:06 PM
The good news is that the main bolt is clearly visible and looks Ok. With a moto-tool and stone cutting disc you can carefully cut a slot in the shorter one and use a screwdriver on it. Those bolts are in a pattern and their spacing is not symmetrical. You'll need to rotate the pulley to find the correct orientation so the bolts fit correctly. Use automotive grade bolts, too.

04-23-2003, 01:12 AM
Originally posted by Mike Puckett
Use automotive grade bolts, too.

Automotive grade? Explain?

I was just about to ask that, I picked up some bolts from my local Lowe's and they're the same size and all, but I was wondering if they'd work alright. Should I get some through the dealer or an auto store instead?

04-23-2003, 06:11 AM
Sorry to bump my own thread, but does anyone happen to know the torque specs of the 4 bolts holding the Crank pulley to the Harmonic Balancer? Don't wanna over-torque and mess things up :-)

04-23-2003, 08:23 AM
the pully bolts are 20-28 ft lbs. you should get some hardend bolts, i wouldn't use them unless they are hardened. try napa. tighten them in a cross like pattern just like your lug nuts.

04-23-2003, 11:08 AM
The pulley bolts are grade 10 bolts - You should not use anything less. Also use a thread locker (locktite) when replacing them.

Use a torque wrench and and torque in three steps (10,20,25)with a cross pattern.