Tricks for Tightening Alt Belt

I put a new alt-vacuum pump belt on my truck today, but don't want to tear down the truck to replace the alternator belt, which is in good shape.

How on God's green earth can I get this thing tight? I got it reasonably tight, but not tight enough. I need something to pry against for more leverage, but have no idea what to use as a fulcrum.


Mike

What does your alternator look like?

I'm attaching a picture of what my alternator looks like. Note the tab that's pointed out (where the top bolt goes through). This tab is there specifically so you can put a wrench (I usually use a large crescent wrench) on it to pry on the alternator to get the alternator belt tight. Maybe not all alternators are set up like this?

Also, you probably already know this, but you can tighten the vacuum pump belt independently of the alternator belt. IIRC, there are three bolts to loosen on the vacuum pump mounting assembly (no pictures, sorry ), and once those are loosened, there's a hole in the mounting bracket to put a 3/8" drive ratchet or breaker bar on to pull the vacuum pump tight.

Hope this helps...good luck!

You could get a 4"OD pulley at autoparts store and a bolt long enough to go thru pulley and a few washers to line it up with the other pulleys. It doesn't remove all the flopping but it does take out enough that the belt doesn't hit anything. OkieGringo

i pried off the bolt that holds the top alternator mount to get mine tight, if that makes any sense, i wish i could explain it in pictures but my trucks @ work

There is a special tool to make grabbin ghte alt easier to tighten. I got mine from Lisle and didn't cost very much. Mostly it is a hook that goes over the alt and the other end for a ratchet or breaker bar.

OkieGringo said:

You could get a 4"OD pulley at autoparts store and a bolt long enough to go thru pulley and a few washers to line it up with the other pulleys. It doesn't remove all the flopping but it does take out enough that the belt doesn't hit anything. OkieGringo

Click to expand...

4" outer dia. on the edge of the pulley or where the belt would run inside the groove?

chinsmackers said:

4" outer dia. on the edge of the pulley or where the belt would run inside the groove?

Click to expand...

4" outer dia. on the edge of the pulley. OkieGringo

Thanks, everyone. I got things tightened up just perfectly, thanks to y'alls advice. Couldn't find a wrench big enough to get on the tab of the alternator, so pulled like crazy and tightened at the same time with help from a very long socket on my socket wrench. Belt is as tight as I've ever felt it... Tidied up the alt-vac belt as well...

Buttoned most things up and started the truck to see how things are going. The first time she's been run in 2+ weeks. Can you believe she fired RIGHT off the second I hit the starter, without even so much as a SPUTTER?!?!?

The fact that nothing flew apart, burned up, or otherwise destructed is amazing enough. She's been in pieces for a couple weeks now.

The lights no longer flicker, and are NICE AND BRIGHT inside and out. I didn't smell anything burning, so will put the dash back together tomorrow and take her for a spin.

She's also sporting a CirKit Boss setup now, installed with excruciating detail. Hope to get that hooked up later on... all the hard parts are mounted, just need to lengthen some wires and shorten some others before making the electrical connections...

Ahhhhhhh... back to truckdom again. Thanks again!! Love that sound!!!

Mikes91 said:

Thanks, everyone. I got things tightened up just perfectly, thanks to y'alls advice. Couldn't find a wrench big enough to get on the tab of the alternator, so pulled like crazy and tightened at the same time with help from a very long socket on my socket wrench. Belt is as tight as I've ever felt it...

Click to expand...

Hmmm, kiss that alt bearing goodbye in short time

no need to put that much tension on any bearing like that...it just shortens it's the life. One simple fix is running the "smaller alt belt" (or) adding the pulley as above.
I've been running the short alt belt for years now...perfect!

HammerDown said:

Hmmm, kiss that alt bearing goodbye in short time

no need to put that much tension on any bearing like that...it just shortens it's the life. One simple fix is running the "smaller alt belt" (or) adding the pulley as above.
I've been running the short alt belt for years now...perfect!

Click to expand...

I'll check into it. It isn't any tighter than it has been for the 2 years the alternator's been installed, so I should be fine (knock on wood). I like the additional pulley mentioned earlier... just have limited time to do the job right now and other things need fixin' (i.e., headlight relays and a check into the trailer hookup connections).

Okie, did you have a NAPA or other chain's P/N for the pulley you used?

Jim

Jim73 said:

Okie, did you have a NAPA or other chain's P/N for the pulley you used?

Jim

Click to expand...

Well, I got mine when I lived in Baja. I went to parts store told him what I wanted and he went back to the shelves and came back with one. Worked perfect. But, dlblack over on TDS saw my post about the mod and went to Autozone and got one, part # 45954 and a 3/8"-16 x 1-1/2" hex flanged cap screw and some washers to line it up. He has photos in his gallery "over there". Hasta Luego, OkieGringo

Gracias, Senor!

Jim

OkieGringo said:

You could get a 4"OD pulley at autoparts store and a bolt long enough to go thru pulley and a few washers to line it up with the other pulleys. It doesn't remove all the flopping but it does take out enough that the belt doesn't hit anything. OkieGringo

Click to expand...

Hey Okie, Thanx a million for this idea. I just put one on my 91 and it works
F A N T A S T I C, I mean when you put on a GATES belt and this pulley and then get it just tight enough, NO BELT POPPING left. Anyone that has not done this, REALLY NEEDS TO.

One question, I used the bolt size you had stated, but I would really like to get the bolt that really goes through this pulley. It has to be designed for some type of engine. It should have a fatter shank before the threads, that way it would fit snugger and be even farther from the water pump pulley.

bolts

I found some airconditioner idler mounting bolts on older ford cars have the perfect shank, also maybe a good hardware store would have shoulder bolts, they usually have an allen head tho. I may have my bolt guy get us a box and ship them around, I will get on that.
russ