Alternator Bracket Help

[mrein3]

Last summer/fall I rebuilt/stroked the 350 out of the Monte I junked a few years ago. I put the resulting 383 in place of the overly tired 350 in my truck.

Now my truck was a pure mutt when I got it. 1970 cab and bed. 1971 chassis. Mid to late 70s 350 truck block. 1968 (golden anniversary) seat. 3-speed on the column, manual in front of a np205. 2bbl factory looking carb and intake.

Basically somebody walked through a junk yard and assembled my truck.

Which leads to my problems.

I forgot I used to have troubles with my alternator bracket mounting bolts breaking off - until this past Thursday. On the way to a bass club tournament the bolt I circled on the right broke. In the past the other one usually broke.

Since I just spent a bunch of money on the 383, the manual to auto tranny swap, 2-row to 4-row radiator, and converting the cab to AC from non-AC, I want to get these dumb brackets straightened out.

I think, like the rest of the truck, the brackets are an assortment assembled by some ambitious cowboy who had access to a junk yard. (I bought the truck from my friend who lives in Wyoming who sort of knows the person who built it - I have nothing against cowboys.)

The alternator I think is correct for a 69-72, short water pump truck. I think the power steering pump and bracket is from something else. The bottom pulleys, a two groove in front of another two groove, wobble. If they are correct I need new ones. This past weekend I took everything off the front and started the engine. The new harmonic balancer doesn't wobble. When I bolt the four bottom pulleys on with nothing attached to them they wobble.

So the help I need is:
1. Are those bottom pulleys correct?
2. Is the alternator bracket assmebly correct?
3. Power steering - is that correct?

The first picture is of the darn bolts that shear off.
The second shows the bottom pulleys from the driver's side.
The third shows the bottom pulleys from the passenger side.
The fourth shows parts of the AC brackets I've installed.
The fifth shows a closeup of my 71 Chevelle convertable. It has AC but the brackets are swapped side-to-side and it uses the long water pump. I have a complete set of these pulleys and accessories from the Monte I could use. All I would need to do is get a new, long water pump, bolt everything on, then deal with the fan shroud being too long, the bottom AC bracket not working with factory 4x4 exhaust manifolds, and having to find AC hoses (which probably would work off of my A-bodies). I bolted the Monte bottom pulley on when I was messing around this past weekend and it doesn't wobble. However I'd like to stay stock so I can finish the AC job with stock components. Help.

[pjmoreland]

Maybe the wobbling crank pulley is causing a bunch of vibration that is eventually fatiguing the alternator mounting bolts. Sounds like it's time to find a replacement pulley (easier said than done). You might try using grade 8 bolts for your alternator bracket.

[mrein3]

Originally Posted by pjmoreland

Maybe the wobbling crank pulley is causing a bunch of vibration that is eventually fatiguing the alternator mounting bolts. Sounds like it's time to find a replacement pulley (easier said than done). You might try using grade 8 bolts for your alternator bracket.

I'm 99.9% sure the wobble is causing the breaking bolts. That is why I need to know if that pulley assembly is correct before I try to find a new one.

Grade 8, which is more brittle than 5, is what I dug out of the head this last time.

[Harold Shepard]

You are half way home if you have the double grove top pulley. I am going to the junk yard today to look at a blazer and a coule of 2wd trucks, the blazer did have power steering so there is a chance the pullies are still in place, I will let you know. I think that I would check with Randy AKA Teeitup for some bottom pullies. He regularly parts trucks out and may have a set. Harold

[silvertonguedevil]

I'm so glad to see this post here. I just recently purchased a '71 with a 350 in it and the PO cobbled this truck together something fierce. My other all-stock '71 is basically going to be used as a comparison model. As best as I can tell, it looks like a later engine was installed in it. The alternator is on the pass side and I'm not sure about the brackets. There's a bunch of hardware store washers and it's bolted to the t-stat housing And then the power steering pump on the driver's side is also much higher than my other truck's is. I'll be hanging around watching this because I'm about to start ripping mine apart so that it can be put back the way it should be.

[mrein3]

TTT
Silvertounge,
It sounds like your alternator bracket is what my a-bodies have. Long water pump, alt bracket on the passenger side. If I wasn't planning on using stock brackets for AC I'd go with my extra set of A-body stuff. I attached a shot of my 72's alt bracket for you to compare against.

Can you post pictures of your stock setup?
Matt

[pjmoreland]

My truck still has all of the original factory pulleys for A/C and power steering. I only have three grooves on the crankshaft pulleys. I'm not sure what your fourth groove would be for. Maybe an a.i.r. pump??

[mrein3]

Originally Posted by pjmoreland

My truck still has all of the original factory pulleys for A/C and power steering. I only have three grooves on the crankshaft pulleys. I'm not sure what your fourth groove would be for. Maybe an a.i.r. pump??

Are the pulley grooves right up tight to the harmonic balancer? If so I just need to replace what I have with a set that doesn't wobble.

[tomatocity]

If you go to a long water pump you will probably need to change all the pulleys. Because of the fan issue, I would stay with the short water pump and find a functioning set of pulleys and brackets and buy them. Call a local wrecking yard and ask for their help. If they don't have it they can put it on the hot line and get it. Mixing and matching GM pulleys really sucks. I had the same issue with a 62 Impala SS and it took me forever to get them all to align. Spend the money and less time which should equal zero headaches. There is a used parts seller in this group that posted a ton of parts yesterday. His name is Randy and his user name is "teeitup". Hope this helps. Tim

Originally Posted by mrein3

Last summer/fall I rebuilt/stroked the 350 out of the Monte I junked a few years ago. I put the resulting 383 in place of the overly tired 350 in my truck.

Now my truck was a pure mutt when I got it. 1970 cab and bed. 1971 chassis. Mid to late 70s 350 truck block. 1968 (golden anniversary) seat. 3-speed on the column, manual in front of a np205. 2bbl factory looking carb and intake.

Basically somebody walked through a junk yard and assembled my truck.

Which leads to my problems.

I forgot I used to have troubles with my alternator bracket mounting bolts breaking off - until this past Thursday. On the way to a bass club tournament the bolt I circled on the right broke. In the past the other one usually broke.

Since I just spent a bunch of money on the 383, the manual to auto tranny swap, 2-row to 4-row radiator, and converting the cab to AC from non-AC, I want to get these dumb brackets straightened out.

I think, like the rest of the truck, the brackets are an assortment assembled by some ambitious cowboy who had access to a junk yard. (I bought the truck from my friend who lives in Wyoming who sort of knows the person who built it - I have nothing against cowboys.)

The alternator I think is correct for a 69-72, short water pump truck. I think the power steering pump and bracket is from something else. The bottom pulleys, a two groove in front of another two groove, wobble. If they are correct I need new ones. This past weekend I took everything off the front and started the engine. The new harmonic balancer doesn't wobble. When I bolt the four bottom pulleys on with nothing attached to them they wobble.

So the help I need is:
1. Are those bottom pulleys correct?
2. Is the alternator bracket assmebly correct?
3. Power steering - is that correct?

The first picture is of the darn bolts that shear off.
The second shows the bottom pulleys from the driver's side.
The third shows the bottom pulleys from the passenger side.
The fourth shows parts of the AC brackets I've installed.
The fifth shows a closeup of my 71 Chevelle convertable. It has AC but the brackets are swapped side-to-side and it uses the long water pump. I have a complete set of these pulleys and accessories from the Monte I could use. All I would need to do is get a new, long water pump, bolt everything on, then deal with the fan shroud being too long, the bottom AC bracket not working with factory 4x4 exhaust manifolds, and having to find AC hoses (which probably would work off of my A-bodies). I bolted the Monte bottom pulley on when I was messing around this past weekend and it doesn't wobble. However I'd like to stay stock so I can finish the AC job with stock components. Help.

[mrein3]

Originally Posted by tomatocity

If you go to a long water pump you will probably need to change all the pulleys. Because of the fan issue, I would stay with the short water pump and find a functioning set of pulleys and brackets and buy them. Call a local wrecking yard and ask for their help. If they don't have it they can put it on the hot line and get it. Mixing and matching GM pulleys really sucks. I had the same issue with a 62 Impala SS and it took me forever to get them all to align. Spend the money and less time which should equal zero headaches. There is a used parts seller in this group that posted a ton of parts yesterday. His name is Randy and his user name is "teeitup". Hope this helps. Tim

I don't want to switch. I want to get it back to stock. I have no idea if what I got is stock or mutt.
I plan on buying a new set of front crank shaft pulleys. I just don't want to replace a mutt with another mutt and continue to snap off alternator moutning brackets.

Could somebody post a picture of a stock setup or describe a stock setup?
Especially relating to the crank shaft pulleys. Are the grooves in a stock set right up tight to the harmonic balancer like in my picture at the top?

[pjmoreland]

I just went and took a look at my crank pulleys. The inner pulley is right up against the harmonic balancer. The inner two grooves are on one pulley, and then the outer groove is a separate pulley that sits right up against the other pulley. All three grooves are equally spaced. Sorry I don't have a digital camera handy right now.

[mrein3]

Originally Posted by pjmoreland

I just went and took a look at my crank pulleys. The inner pulley is right up against the harmonic balancer. The inner two grooves are on one pulley, and then the outer groove is a separate pulley that sits right up against the other pulley. All three grooves are equally spaced. Sorry I don't have a digital camera handy right now.

Thanks a million! I don't need a picture your description is fine.

So I have the correct crank pulley. Now all I need to do is find a set that isn't out of round.

[71meangreenc10]

Grade 8 more brittle than 5? Some one please explain that one.........

[pjmoreland]

Grade 8 bolts can withstand more load than grade 5 bolts. When grade 8 bolts fail, they snap off. When grade 5 or lower grade bolts fail they bend.