water pump pulley hitting, crank pulley?

[jim #42767]

Just got the water pump back from rebuild from those guys in NY. Excellent work. The problem now it after putting it all back togather the water pump pulley seems to be just barely hitting the crank pulley and a small squeak sqeak, will ensue. I powder coated the pulleys when they were off. But it seems they should have more clearance than that?

Any ideas?

[Phil P.]

Re: water pump pulley hitting, crank pulley? *NM*

[Mark #28455]

you sure it's not hitting the water pump?

When the flange for the water pump pulley is pressed into place, it may be possible to press it too close to the pump housing - I had a BB one like that. Had to put a 5/8" flat washer behind the pulley to space it away from the pump.
Mark

[Phil P.]

Re: water pump pulley hitting, crank pulley?

sorry---hit the wrong button---use a pitman arm puller tool---dimple the center of the water pump shaft so the puller does'nt wobble off and make a mess---apply pressure and move the fan flange to where you need it---do this with the water pump and crank pulley installed---you will be fit checking the water pump pulley as you go---no need for spacers---take your time and you can make it perfect---puller (buy quality) should be well under $25---and well worth the grief of anything else you go through---have done this alot---works perfect---might be others out there that have done this and can validate---good "seceret" that has been "bogarted"---good luck

[Mike McKown]

I just did this two days ago

and it's not the first time. There is very little clearance between the pulley and the pump on a C-2. Wrap a piece of tape around the pump shaft say, .020 in front of the hub. This will give you a starting point to guage how far you've moved the hub.

[Jack H.]

Re: water pump pulley hitting, crank pulley?

The pulley hub is press-fit onto the water pump shaft and there's a correct dimension with appropriate tolerance. Once in a while a hub gets pressed either too far onto the water pump's shaft (pulley rides closer to the engine) or not far enough (pulley rides outboard and belt alignment is slightly off-center).

If the hub isn't pressed far enough onto the shaft, that can be corrected by pressing it a bit further on. Unfortunately, the pump has to come off the car, the water pump disassembled so the impeller can be supported in an arbor press and the hub moved further onto the shaft).

If the hub is pressed too far onto the shaft, that's a problem that can only be properly fixed with a new shaft/new hub. You don't want the press-fit joint to let go!

Tricks that pros know include:

(1) Measuring the hub to shaft press distance and TELLING the water pump rebuilder up front, what final press distance you want/need to match that engine and those pulleys. But, few think of this and simply send their pumps out for a 'standard' rebuild.

(2) Use shims to move the pulley relative to the water pump hub. One approach is to install a pulley reinforcement plate (3720616) between the hub and the pulley. This will space the pulley out from the water pump by the thickness of the plate and also reinforce the back side of the pulley to thwart cracking due to excessive strain and/or pulley side loading.

[Mike McKown]

Ya' got me

"If the hub is pressed too far onto the shaft, that's a problem that can only be properly fixed with a new shaft/new hub. You don't want the press-fit joint to let go!"

You make this sound like mandatory compliance?

[Jack H.]

Re: Ya' got me

"You make this sound like mandatory compliance?"

No, it's not a mandatory compliance issue. You can take your chances and they're probably not that bad especially if you install a fresh hub that hasn't been pressed on before.

But, there is a risk factor here and neither of the two water pump rebuild shops in town will take that gamble considering the potential liability of a hub letting go... Both, shops consider hubs and shafts a one-shot press job.

[John H.]

Re: Ya' got me

If the hub is too close to the pump such that the pulley scrapes the pump casting, Moroso (and others) have pulley shim kits that will space the pulley forward and still let the pulley run true. Using four flat washers instead isn't a great idea, as that creates four stress risers at the bolt hole locations on the pulley; the proper shims allow the load to be spread across the full face of the pulley.

If the O.D. of the crank and water pump pulleys are actually touching each other, I'd check to see if you have the correct pair of pulleys.