Power Steering Pump

**Harmon C.** · October 27, 2006, 12:32 PM

Re: Power Steering Pump

Lee
I had a 73 454 it did not have A/C but it had no idler pulley. Have you checked to see if the idler was part of the original setup? I belive the P/S pump for 74 was the one with the bent filler neck and in 75 they were straight.
Lyle

**Joe L.** · October 27, 2006, 06:00 PM

Re: Power Steering Pump

Lee-----

First of all, it is very likely that you have the correct pulley. Only 1 pulley was ever used for 65-74 Corvette big blocks and it's a 2 groove, cast iron pulley.

There is no way that I know of to shim the power steering pulley further forward. The pulley has a very slightly tapered shaft hole which mates with the very slightly tapered pump shaft. It is retained by a special, self-locking nut. There is no way to adjust this at the shaft/pulley interface. The only way to "adjust" the pulley is to adjust the entire pump in the bracket.

I don't understand what you mean by the pump and idler pulley sharing the same bracket. The pump and idler pulley used for all 1969-74 Corvettes with big block, C-60, and N-40 do not share the same bracket. However, they do share one mounting point on the block. Still, they are not sharing the same bracket so I would think that it would be possible to shim the 2 brackets seperately, even though I've never known that to be required.

The 1974 power steering pump is unique to 1974. It was GM #7816847. How it is different from other year pumps I do not know (even though I have an NOS example of this pump [not for sale] in my collection). However, I can tell you this: the pump has no APPARENT difference between it and the earlier pumps (further close evaluation and comparison will have to wait until I get the time to do it). Also, I can tell you that the resevoir and the shaft are the same as earlier (but not the same as later) pumps. There was only 1 shaft length used for all 1963-74 Corvette pumps (although several different shaft part numbers were used).

Beyond all of the above, the rest of the components of the 1974 belt drive and power steering system for big blocks with C-60 and power steering are exactly the same as those used for similarly equipped 1971-73 models and virtually the same as that used for 69-70 models. So, while the p/s pump part number for 1974 might be unique to that model year, the rest of the system is just like earlier years. Ergo, I doubt that the 1974-only power steering pump has anything to do with your problem, whether or not you actually have that pump.

So, where does that leave us? Well, I would say that there is likely some sort of installation problem or some sort of problem with adjustment of the various components.

**Lee S.** · October 28, 2006, 11:58 AM

Re: Power Steering Pump

Joe -
Thank you for your response. Yes, the car does have the correct pulley and the pulley is machined to accomodate the tapered shaft of the pump.

I guess a better way to describe the pump and idler pully mounting is that they are both anchored to the same bracket. This bracket is formed to an exact fit to the PS pump. I don't see any leeway to shim or adjust the pump or bracket without similiarily affecting the idler pulley. See photo.

Now, there is another factor. It seems that the new idler pulley is not pressed on to the shaft as far as the old one, which has a bad bearing. I have attached another photo below. This new pulley is the best one I could find after looking at several from two manufacturers. I don't have a press and I'm afraid to slide an impact socket over the bearing and give it a hit with a stout ball peen hammer.

Regarding the idler pulley, I have found there are two different mounting kits, 1) with Power Steering, and 2) without Power Steering. I surmise that the bolt/spacer lengths are different. I have verified (by comparison to the new parts) that I am using the correct mounting kit.

I seem to be running out of options short of taking the idler pulley mounting spacers to a grinding wheel and know off a couple thousands.

Comments?

Attached Files

**Joe L.** · October 28, 2006, 12:42 PM

Re: Power Steering Pump

Lee-----

I think that the idler pulley spacing difference could well be the entire problem here. I'd take it to someone that has a press and press the pulley further onto the shaft to match the original. It's very simple to do this and will take only a few minutes. You're correct, though---you don't want to pound on this to make the adjustment.

**Joe L.** · October 28, 2006, 12:57 PM

Addendum

Lee------

By the way, don't discard the original idler pulley assembly. You can rebuild it using a bearing assembly still available from GM for about 28 bucks, GM list. That bearing is GM #908076. It does require a press to do it but you could retain the rest of the original components of the assembly.

Any machine shop could easily and, likely, inexpensively do this for you. Or, you could purchase an inexpensive arbor press from a source like Harbor Freight Tools. You can get one of these things for about 30 bucks. An arbor press is sufficient to do many automotive pressing operations----not all but many.

In fact, if you had done this before purchasing the replacement idler pulley assembly you could probably have purchased the new GM bearing + the arbor press for less than the cost of the new idler pulley assembly. And, when it was all done, you'd still have the arbor press for the next job.

**Lee S.** · October 28, 2006, 02:40 PM

Re: Addendum

Joe - You're a heck of a guy! I wish I had talked to you first. Thank you very much.

**Lee S.** · October 30, 2006, 08:08 PM

Re: Addendum

Joe -

Local parts store pressed it about 1/8" ... no charge. Reinstalled. All fixed. I did save the old one. In fact the parts store practiced on this one first. I'll hang on to it. Thanks again.

Power Steering Pump

Power Steering Pump

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