This topic originally had a different title. The rules don't allow asking a second question in another topic, so I've changed the title and this top post to ask my next question.

(Originally posted: Mon Jan 28, 2008 3:22 am
Post subject: How to replace crankcase pulley balancer?)
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My next question is how to remove and install the part. I'm not familiar with working on this vehicle. Money, cold weather, and anti-street-repair rules are serious issues. If I try to drive very far to work on the car, I may get stranded if the non-OEM plastic pulley or serpentine belt breaks.

The biggest problem appears to be that an air conditioning pipe-to-hose joint may be in the way. Will the metal hose flex out of the way? Or does that pipe and hose mean I just can't do the job?

I also can't find a pulley puller from the Autozone free tool loan collection that will work. It requires a triple hook type puller in holes on a 4mm radius out from the center of the pulley. There is also a 5mm stop pin hole in the pulley.

Now please skip down to Alibi'* post of Jan 28, 2008 5:15 am.


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How to see number on crankcase pulley balancer? (answered, thanks)
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Hi, my crankcase pulley, a harmonic "pulley balancer", is failing with the outside ring section wobbling with a rattling noise. I don't know how far I can drive before it breaks. I need to try to replace it myself to save money. The car is outside and it'* cold weather.

There was a design change and two pulley types for the same LG3 engine. The VIN number doesn't reveal which part is installed.

There is probably a pulley available at a used parts yard 15 miles away, but they told me I must remove mine first and count the [magnetic timing?] "notches" hidden on the back [they look more like shallow drillout balancing holes on a new aftermarket part]. There will either be three notches or "more than three". Removal just to look is obviously undesirable in my situation.

The pro mechanics at the dealer would remove the pulley and order whatever GM part number is on it:
25527009 "a common type"
25527381 "a common type"
25532179 "an unusual type"
The same aftermarket pulley will replace the first two, but I don't know for sure if they will interchange with each other. Sounds like the parts yard guy thinks they will interchange.

How can I see the part number on the pulley without removing it from the engine?

Thanks in advance,
Jim

First off, welcome to Bonneville Club.
I drove mine for a couple of hundred miles before I changed it. It is somewhat embarrassing because it sounds like the world is coming to an end. I know of others that have driven them clanking for several thousand miles. It doesn't hurt the way it runs because the part that triggers the hall effect switch is always oriented the same way on the crankshaft. Over time, I guess it is possible for the hammering to effect the other belt driven accessories or the crank sensor.
Have you pulled off the right front wheel and put your eye real close to the pulley? I don't remember where the number on it is located, but if it is on the back, you will have to remove it to see it or try using a mirror.
Have you asked about this at a parts store? It may be worth it to buy one for $100 if you know it is going to fit. I paid right at $95 after tax for my VIN C. Buying a used one might put you right back where you started in short order.
I found this one on the O'Reilly website that just says it fits VIN 3. But they also have specific parts that fit the numbers you listed. Aren't they all engine code 3 in 1987? I guess I'm missing something.
Best thing I can tell you is to have your local parts store order them all, and then take yours off and get a ride to the parts store to match it. The parts store can always just send back the ones they don't sell and it will ensure that you have the correct one available once you take yours off. Or you could just gamble and get the common type that will fit most of them. Maybe someone else will have a better plan.

It may not apply here, but I remember my original balancer had the part number stamped on the back side of the pulley.

Thanks

Yes, Sunday evening I went to Autozone to get a harmonic balancer puller tool loan, and the parts guy had time to give me some help with examining a replacement part. Unfortunately, no puller they had would fit it. He also looked at my engine and said an air conditioning pipe may be in the way of doing pulley replacement. :(

Unfortunately, I just found out this is not a OEM part. It is a plastic aftermarket pulley with the outer grooved section partly broken away from the inner section, just under its rim.

That may depend on whether the OEM from the parts yard is plastic??

The new part they had in the store I visited had three round holes in the rim weight, that looked like drillout balance holes rather than "notches" as the yard guy described. Are those three holes actually for Hall effect pickup rather than manufacturing wheel balance?

The dealer'* catalog says there was an LG3 engine design change during production, apparently resulting in two or three different pulley balancers. If those really are Hall effect pickup holes, the change in the number of them could be related.

The serpentine belt is definitely shredding, so I have only a limited number of miles left before it breaks.

No, I didn't know that one could. The parts guy mentioned there'* a panel that might be removable behind the wheel, and I see some hex head bolts in that area.

Looking at the new aftermarket part, it had numbers on the front. I did use an inspection mirror Sunday evening at the parts store, and found "5012472 CHINA 442" molded on the front of the pulley. That number does not appear in a web search.

Just before this post, I found out that A1Auto says the pulleys are different sizes:

OE #: 25527009 & 25527381
7 inch diameter
3.75 inch width
picture:
http://www.1aauto.com/1A/HarmonicBal...HB00002/322828

OE part number - GM 25532179
Diameter - 7.22(inches)
Width - 3.71 (inches)
picture:
http://www.1aauto.com/1A/HarmonicBal...HB00089/323546

So measuring should be the breakthrough step toward identifying the correct part. Getting a puller and getting the part replaced is a whole other problem, so I think I should write a different post about that issue.

I'm going to be your bestest buddy for a sec:

1. Your HB requires no puller. The early 3800'* used a slip-fit balancer, wheras later versions had theirs pressed on which require a puller to yank it off.
2. I replacing the timing gear in an 87 Olds 88 with a vin 3 engine and I had no problems getting the HB off around the air conditioning lines.
3. The plastic panels to reach the HB are just push-riveted in. You simply pull the center pin out and the rest of the rivet just falls out after it.
4. Read this: http://lesabret.com/phpBB/viewtopic.php?t=5516 Its a detailed description of how to change out a timing chain on a Vin C motor (the one right after yours), and it includes methods of how to remove the balancer (mostly in the comments after the initial tutorial). Should be basically the same as on the vin 3.

About all I don't know off the top of my head is the exact part number of the balancer.

Your car shouldn't require a puller, but you may find it useful to use a long prytool behind the pulley to help coax it off. If you do, be careful to not disturb the crank position sensor behind the pulley. Mine just needed a little wiggling and outward pressure to slide it free. And make absolutely certain that your car is supported safely on jackstands or a lift before you crawl under it and pry on anything. Or a shredding belt and a separated pulley will be the least of your worries.
The original equipment pulley is known to separate, and buying a used one means you don't know how old it is, if it will fit, how long before it separates, etc. If you only want to change pulleys once, I recommend getting a new one. Both the original pulley on my car and the new one I replaced it with were constructed of metal and rubber, no plastic. You have found out the hard way not to use a cheap plastic China pulley. Make sure that your new pulley is metal and rubber.
My car is a 1990, so it may be slightly different from yours. As I recall, the AC hoses are routed above the fender well area. To change the pulley, you'll need to jack up and safely support the right front, remove the right front wheel, and take off the plastic skirt between the wheel and the engine. This will get you close enough to the pulley that you can kiss it.
To get the pulley off, you'll need to loosen the bolt in the center of it. The easiest way to do this is to use a pneumatic impact wrench, since it is torqued on there pretty tight and the engine will try to spin if you use a box wrench or hand socket. There is a way to hold the engine still by taking off the flywheel inspection cover behind the starter and physically grabbing the flywheel to lock it and keep it from moving as you apply torque to the crank pulley bolt to remove it. But if you use an impact wrench this step is unnecessary. At least it was for me. I have a picture laying around here somewhere that points out the inspection cover, let me know if you go that route, and I'll try to find it for you.
Regarding the Hall effect switch:This an overly simplified version of how it works, but will give you the basic idea.
The Hall effect switch is called that because the metal ring affixed to the back of the pulley (the interrupter ring) passes between the grooves ( the hall) in the crank position sensor. The sides of the hall are electromagnets which create a force field (for you Star Trek fans) that gets broken or interrupted by the interrupter ring. Each notch in the interrupter ring is precisely located to trigger a signal in the crank position sensor that lets the car'* computer know the position of the engine and allow the computer to determine when to send trigger signals to other systems like fuel injection and spark timing. The drilled holes you described in the replacement pulley are for balance and have nothing to do with the Hall effect switch (crank position sensor) interrupter rings on the back.
I only find one listing online for a crank position sensor for your car. You should do your own research on this, but I am guessing that there is no difference in the pulleys with regard to the interrupter rings, and that the difference is most likely just the diameter of where the belt rides and a slight alignment difference, and maybe a slight change in the balance of the pulley. You may notice that the belt rides very close to the oil filter adapter housing, and GM Powertrain might have decided that is too close for comfort and changed it after they broke a couple and had to warranty them . Don't know, just a guess.
The easiest way is still going to be to pull off your current pulley and make sure it matches your new one. Or just buy the common one that fits two of the part #* and make sure that you are able to return it if it winds up being the wrong part. But since you know that your new one is an odd ball China plastic one, there maybe no match for it in which case I would still get the most common one and go from there.

And it will make your thread a lot easier to read if you ask your questions sequentially instead of editing the first post. They don't charge per post here on BC, and it makes it easier to follow the topic if it'* kept in order. Just a suggestion.

I like the concept

Thanks, this pictorial is terrific. You really came through on "bestest buddy for a sec".

Ah, from seeing the pics, those dust covered "hex bolts" are actually the plastic push rivets.

Ok, thanks for the explanation, that really helps. Now I get it, the parts yard guy was referring to what one sees of the HB in these pictures: http://lesabret.com/phpBB/viewtopic.php?t=5516 find down to the picture under the word "lucky". Its got "more than three" notches in the interrupter ring. Now nav to http://www.1aauto.com/scripts/view_f...tion_id=322828 (which is my part) and look carefully at the interrupter ring, which has three long notches.

I measured the diameter of my broken HB still on the vehicle, and its 7" (not 7.22" which was the other possibility). The 7" includes an outermost ridge which is a bit above where the belt rides. I can also see a three notch interrupter ring (maybe exposed by the partly broken outer rim). That means my OEM GM part was probably either 25527009 or 25527381 ("common types") replaced by this aftermarket part:
http://www.1aauto.com/1A/HarmonicBal...HB00002/322828

Well, there'* some good news. (I wonder why they put those three front cover holes in the parts counter aftermarket pulley that no Autozone puller will fit)?

Here'* the best pic of the A/C joint area in the LeSabre: http://i38.photobucket.com/albums/e1...n/DSC00600.jpg The hidden A/C joint is connected to the dusty flex hose seen between the man'* knuckle and the white-looking pipe. I have a bit more than 1" between the HB and the A/C joint in the '87 Bonne LE. How much clearance did you have in the '87 Olds 88?

That'* an odd thing. The new aftermarket pulley at the parts counter seems entirely cast steel (a two piece assembly). At least I couldn't see any rubber parts. But I don't know what the OEM part looks like.

The Lesabret.com pictorial says 220 ft/lb is needed. A friend of mine says he'* not sure a small home air compressor can deliver that much torque to an air wrench. How much air pressure and tank capacity did you use? A poster to Lesabret.com said he got a 24V battery impact gun to work, but it might be an expensive professional race track tool.

Loosening this bolt and retightening it to spec looks really difficult to do without professional tools. Among other things, my torque wrench maxes at 100 ft/lb.

However, there'* a difference from the vin C LeSabre pictorial. He says the vin C pulley bolt has a 1-1/8" head. My vin 3 pulley bolt head measures perhaps a millimeter less than 15/16". What'* the real torque spec for mine?

Torque Specs: I think that as long as you get it as tight as you can, you should be ok. As for the actual balancer bolt size, there seems to be quite a bit of different sizes that GM used. At least 3 on the Vin C.

The battery powered impact gun can be had from harbor freight for like $50, IIRC so nothing special. On my 87 Olds, I did use impact tools, but they were on a small compressor so maybe 100PSI tops? It should come off if you just pound at it for a bit. I've got a compressor that can push about 140PSI now but I haven't tried it on a Vin C balancer. Anyway, I don't think that the vin 3 balancer was torqued as high as the later vin C, but I'm not certain. If air tools don't get it off, then there are other methods involving holding the flywheel in place and using a big breaker bar to get the bolt loose.

For the AC line clearance, could you post a pic? I honestly don't remember what my '87 Olds looked like as that was done like 3 years ago. But I still don't think you'll have any clearance issues off the top of my head.

"Plastic Push-Rivets" may not be the right name for 'em, but I like the description. If you happen to break any (they do get a bit brittle with age) you can get new ones from Lowes in their fastener department. I think Autozone also carries some, but they aren't as good as the ones Lowes has.

The factory balancer on my Olds had the pre-tapped holes in it for a balancer too... I actually tried using a puller first before just getting angry at it and giving it a yank... to my surprise I fell backwards, pulley in hand :P

It is the diameter, pitch and metal composition of the threaded portion of a bolt that determines how much tension you can apply by tightening. Sometimes the bolt head size is not related to the bolt diameter where it counts - where it is threaded. Look up the torque spec for your car.

You don't need air tools or other fancy stuff to tighten or loosen these big bolts. With the car jacked up and supported as others have described, remove the flywheel cover and slip a big phillips screwdriver through one of the holes in the flex plate. Turn the engine one way or the other until the shaft of the screwdriver jams against something solid. Don't let the screwdriver jam against anything that will break and keep the shaft perpendicular to the flex plate. That will hold the engine in place while you loosen or tighten the crank pulley bolt. Outside the fender, set up a jackstand to support a long 1/2" drive extension near the end where the handle will attach. A breaker bar is best here but a stout flex handle MAY not break if you are lucky. You may have to block the jackstand up to get it high enough. Make sure the socket is square and all the way on the bolt head. A six-point socket is best. Slip a cheater bar over the handle and apply torque by standing on the cheater. Torque = your weight in pounds x distance in feet from the center of the extension (axis of the bolt). So, if you weigh 150 lbs, stand twelve inches out on the bar and you are applying 150 ft-lbs of torque. Stand twenty four inches out from where the handle attaches to the extension and you are applying 300 ft-lbs, etc. To get a correct torque application, you must balance yourself on the lever arm and not lean on the car for support. The setup looks something like this:

NEVER use a used one. The rubber dries and cracks with age. Get a new replacement, either OEM or aftermarket.

The 87-91 are an absolute snap to change. Even the 92-99 aren't half bad.