harmonic balancer replacement procedure
 

I need to replace it and was wondering what would be the best/easiest method. I'ts an 89 740T and I think the rubber is shot. Timing mark is bouncing all over. I'm hoping I can leave the belts on to hold the crank,remove the fan for clearance, take the bolts off and hopefully the pulley will come off. Do I need a puller to get it off? Does the radiator need to come off? Is there a site with the precedure? I haven't been able to find one. Thanks

RE: harmonic balancer replacement procedure
 

Just did it on my 1990 740Turbo.

Remove radiator, remove acc. belts.

Lift car up onto some stands, get under it and take the crank bolt loose, an impact helps.

Now use a mallet to hit the harmonic balancer, off it slides.

Mine took about 2 hours start to finish and I had a jack issue.

RE: harmonic balancer replacement procedure
 

Thanks Red. Just got the balancer so gonna try and get it in this week. HOping the crank stays in place getting the bolt off.

Were you able to get your harmonic balancer off and on ok?

Why has no one mentioned the KEY that must be installed on the crank pulley(harmonic balancer) and end of crank. Both pulley and crankshaft have a machined keyway on them for the key to be placed to prevent the pulley from rotating on the crankshaft. The pulley bolt is not enough to secure the pulley.

The key is on the gear behind the pulley. If it breaks off you need a new gear.

The vehicle is a 1992 Volvo 740 turbo wagon. THERE IS NO "GEAR" behind the pulley. There is NOTHING behind the pulley.

Let's try and be nice to each other.

Behind the harmonic balancer is a timing belt sprocket for the crankshaft. That sprocket or "gear" is held in place by a raised area that matches with the crankshaft so the sprocket doesn't spin out of timing.

The harmonic balancer is relatively inexpensive and easy to change. You will probably need an impact gun to remove the large center bolt then you just wiggle it off. Yes, there is a keyway there so pay attention and don't lose it.

Right! That "raised area" of the sprocket is the only "key' there is! If it breaks, you need to replace the sprocket. And yes, it is BEHIND the pulley and the plastic cover. The timing belt is run by that gear.



You don't use an impact wrench for that operation, there is no room! You have to immobilize the crankshaft (several ways to do it), and use a breaker bar to get the bolt loose.

I've used a 1/2 inch battery powered impact gun that was just small enough to get it and the 24mm(?) socket on the crankshaft bolt... and just strong enough to zip the bolt loose.

It was a tight squeeze and ya gotta watch out to not damage the radiator...but it did work for me.

I use the "rope trick" to immobilize the crank when replacing the timing belt. I googled it and came up with this link https://community.cartalk.com/t/crankshaft-pulley/54663

My Snap-On gun fit under the hood. On the electric fan models I'd remove the fan for clearance.

At my shop we use the impact gun to remove those tight crankshaft bolts. By locking something in place and then using a breaker bar, you can break components including the holding tool. Everyone has their own methods and I'm saying that using the impact gun is quicker for us.

One bad experience that I had was on an old 124 chassis Mercedes where I ended up pulling the cylinder head. I changed the timing chain guides as well. To remove the front cover, the harmonic balancer had to come off.

I bought the tool that holds the teeth on the flywheel and bolts to the transmission case. We ended up pulling the bolt out of the transmission case and resorted to jambing a tire iron in the flywheel opening to hold the crank while we used a breaker bar and big piece of pipe. We retightened it the same way but after that experience I will use the impact gun if at all possible.

That "sprocket" thing, yet again.
 

I never intended to be a snot to anyone on this site, but for the life of me (I/m an aircraft mechanic), I cannot understand what you folks are talking about. I have had this car since NEW, it has 101k miles on it & have replaced the timing belt twice. In THIS car, NOYHING behind the harmonic balancer drives ANYTNING that has to do with the timing mechanism. All I wanted to know was if & where I could buy a new key for the balancer.

Don't sweat it, you are not being a "snot"... I can't find a picture of that part right now, BUT, if you pull the balancer off the crank, remove the lower plastic shield, you see the gear which actually drives the timing belt. There is a washer in front which keeps the belt from sliding out. The gear has a nub, is that the "key" you are speaking of?

He has probably never removed the crankshaft timing gear/sprocket to change an oil seal, so probably doesn't know about same. However, if you pull the cover off as mentioned above, with the balancer and belt off, the sprocket/gear will slide right off.

I was always concerned that the sprocket/gear was set properly in place.

He says he has changed the belt twice. I don't know how you can do this without removing the cover and the gear and so on. That gear is what runs the timing belt.

Hard to find parts can often be found by posting in the " wanted " forum on turbobricks.com

He probably never realized that it floated on the end of the crankshaft. Had he ever changed the front crankshaft seal, it would have been obvious. Oh the number of those things that I changed over the years.

I think all of us are beating this harmonic balancer thing to death. I am aware of the upper & lower plastic covers covering the timing belt & gearing that aids in the timing of the crank/camshaft, All I wanted to know is where I could buy the KEY (and its a very odd key indeed) that fits the machined keyways on the end of the crank & the balancer. Those of you that have never heard of such key may find it by Google' ing it. BTW. I have so far replaced the orig. balancer with 2 new ones, both of which ran out of round. Both I believe were Chinese junk, one cost $70, the other $44. I have on order now an authentic Volvo balancer. Stay tuned.

https://cimg8.ibsrv.net/gimg/volvofo...27215ae2be.jpg
https://cimg0.ibsrv.net/gimg/volvofo...61bb8d2d49.jpg
See the circled image

Going to attempt to attach a pic of this elusive "key"