72 Base Motor Vibration Damper

[Ed D.]

Starting to get a small wobble on the original VD on my 72 base SB. I found a new GM replacement part #12551537. I have never changed a VB before. How much of a job is it with the motor in the car, and what needs to be removed to get at it? Does the bolt need to be changed? Does a stock GM VB need any special tool to install? Lots of questions and any help is appreciated.
Ed

[Joe L.]

Re: 72 Base Motor Vibration Damper

Starting to get a small wobble on the original VD on my 72 base SB. I found a new GM replacement part #12551537. I have never changed a VB before. How much of a job is it with the motor in the car, and what needs to be removed to get at it? Does the bolt need to be changed? Does a stock GM VB need any special tool to install? Lots of questions and any help is appreciated.
Ed

Ed-------

GM #12551537 is the correct GM current replacement balancer. The balancer can be removed and installed with the engine installed in the car. You will have to first remove, at a minimum, the fan shroud and fan/fan clutch. It may help to also remove the radiator and water pump. You will need a harmonic balancer puller and installer. My advice is to get a good one, not a cheapo or beat-up used one. Also, you want to use one that uses a thrust bearing and not just a washer.

OTC or Kent-Moore are the best remover/installer tools but they're expensive.

[Tom R.]

Re: 72 Base Motor Vibration Damper

Ed

Joe summarizes the tasks well as you plan on replacing the balancer. I would suggest you devise a method to track the removal of parts, bolts, etc as you wade into this project. For example, I had to replace engine gaskets, including timing chain cover and made copies of the relevant AIM pages, to add head markings, bolt lengths and track what went where. The schematics help immensely as you put parts back together. Also used paper cups to keep bolts in by part, like water pump, fan shroud, radiator, fan blade, fan clutch, etc. Each cup was marked with part description. I did not trust my memory but yours may be better at keeping up with this sort of thing. But once you get ready to reassembly, it goes smoothly.

[Patrick H.]

Re: 72 Base Motor Vibration Damper

It's easier if you remove the fan shroud, but with AC that's a PITA as well. It's not a necessity, though. I would not remove the radiator, and I've done it with fan shroud and radiator in place.

The fan/clutch and pulleys need to come off.
Pay attention to the end of the crankshaft, as there may be a groove worn by the current balancer. If so, they do make a sleeve to go on the crank and "fix" this.
If yours is still original, there are businesses that will restore/repair your balancer and send it back to you. Given that you're in NJ, it's an easy thing to do over the winter when you're not using the car, and have time to let it sit.

Having a good removal puller and installation tool are very important. The rest of the job is easy.

Patrick

[Ed D.]

Re: 72 Base Motor Vibration Damper

Thanks guys for the help. Joe I got the part number for the damper off of an old post of yours form 2009 and it is still good. Patrick I do plan on doing this over the winter. The reason I went for the new damper is that I read problems with getting the same damper back from the rebuilder. I dont think there is much of a visual difference with the pulley attached, we will see. If I dont like the new one I can always get the old one rebuilt, as I will be a pro at the replacement by then, HA. Tom organization of the project is always a big plus and appreciate your suggestion.
I did not get any recommendations on replacing the center bolt. I doubt the the original marked head is available, and would like to use the old bolt if I can.
Ed

[Richard G.]

Re: 72 Base Motor Vibration Damper

Dale Manufacturing (in Oregon) will return your harmonic balancer.

http://www.hbrepair.com/

He is closed some months so check the dates before you send anything in.

Don't forget to have a slug of some kind to insert into the end of the crank for the puller to push on.
I have seen more than a few cranks that were damaged this way.

[Joe L.]

Re: 72 Base Motor Vibration Damper

Thanks guys for the help. Joe I got the part number for the damper off of an old post of yours form 2009 and it is still good. Patrick I do plan on doing this over the winter. The reason I went for the new damper is that I read problems with getting the same damper back from the rebuilder. I dont think there is much of a visual difference with the pulley attached, we will see. If I dont like the new one I can always get the old one rebuilt, as I will be a pro at the replacement by then, HA. Tom organization of the project is always a big plus and appreciate your suggestion.
I did not get any recommendations on replacing the center bolt. I doubt the the original marked head is available, and would like to use the old bolt if I can.
Ed

Ed-------


I think you will find that the GM #12551537 balancer is identical to your original balancer. Dates, if present, will be different but these cannot be seen with the pulley installed.