How can I tell if Power Steering was factory original?

[Frederick W.]

My 63 has stock style power steering
PO (3rd owner) said he thought it was added, but I spoke with the 2nd owner today and he said he thought it was original and that it had power steering when he owned it 35 years ago.

Anyway to tell?

Fred

[Tracy C.]

Re: How can I tell if Power Steering was factory original?

Fred,

Get the part number off of the idler arm and the pitman arm on the bottom of the steering gear box and post them here. Both of these parts should be different than a manual steering setup. If these are correct original GM pieces, I'd lean towards a factory installation.

Aftermartket add-on P/S kits do not use the correct GM parts.

tc

[John H.]

Re: How can I tell if Power Steering was factory original?

My 63 has stock style power steering
PO (3rd owner) said he thought it was added, but I spoke with the 2nd owner today and he said he thought it was original and that it had power steering when he owned it 35 years ago.

Anyway to tell?

Fred

Fred -

As I recall, both the pump reservoir and the power cylinder are dated.

[Frederick W.]

Re: How can I tell if Power Steering was factory original?

Fred,

Get the part number off of the idler arm and the pitman arm on the bottom of the steering gear box and post them here. Both of these parts should be different than a manual steering setup. If these are correct original GM pieces, I'd lean towards a factory installation.

Aftermartket add-on P/S kits do not use the correct GM parts.

tc

Pittman arm:
3741383
GMT 171

Idler arm:
770185 (the 0 very hard to read, could be a 3 or 6, looks like a backward C)
GM

I know the pump was replaced with a rebuilt unit a couple of years ago.

thanks
Fred

[Frederick W.]

Re: How can I tell if Power Steering was factory original?

Fred -

As I recall, both the pump reservoir and the power cylinder are dated.

pump is a replacement rebuild unit, not sure about the cylinder, I'll see if I can find a code
thanks John
FW

[Tracy C.]

Re: How can I tell if Power Steering was factory original?

Pittman arm:
3741383
GMT 171

Idler arm:
770185 (the 0 very hard to read, could be a 3 or 6, looks like a backward C)
GM

I know the pump was replaced with a rebuilt unit a couple of years ago.

thanks
Fred

Sounds like your pitman arm is correct for P/S. The correct power steering idler arm has about a 10 digit part number cast onto it. (The number is in the 63/4 JG). I also have one of these idler arms at home, but would need to get back to you later this evening for the part number.

Your idler arm may have been replaced in service at some point as I don't think the P/S part number was availible in service. (per Joe Lucia post in archives)

tc

[Timothy B.]

Re: How can I tell if Power Steering was factory original?

Frederick,

Take a look at the steering arms, there should be two holes where the tie rods can be installed, the power steering cars go in the front hole. Factory P/S cars have a aluminum rivet in the rear hole to prevent installation.

This is a good tele tale of original P/S cars..

[Joe L.]

Re: How can I tell if Power Steering was factory original?

Frederick,

Take a look at the steering arms, there should be two holes where the tie rods can be installed, the power steering cars go in the front hole. Factory P/S cars have a aluminum rivet in the rear hole to prevent installation.

This is a good tele tale of original P/S cars..

Timothy-----



Yes, that's the best way to tell if it's original, or not. The rivets can be added, of course, but it's rarely done. Plus, at the time this would have been added, if it actually was added, I doubt that anyone would have installed the rivets.

[Tracy C.]

Re: How can I tell if Power Steering was factory original?

Fred,

Here is a pic of an original Idler Arm off of a factory P/S equipped 63. The part number on the bottom is 191GMT3779185B. The part number in the 63/4 JG is stated to be 335GMT3779185B. I'm not sure why the first 3 digits vary, but they do.

Also shown are 2 of the original rivets Tim and Joe discussed. These should be installed with the head on the bottom of the steering arm and in the rear hole.

tc

[Jim L.]

Re: How can I tell if Power Steering was factory original?

Hi Fred Look under the dash where the shaft goes thru for the clutch and brake arm. If there is a spring on that shaft then the PS was added. Fact PS never had that spring. No one knows to remove it and do not want to remove this assembly that has the spring. Regards JR

[Frederick W.]

Re: How can I tell if Power Steering was factory original?

Hi Fred Look under the dash where the shaft goes thru for the clutch and brake arm. If there is a spring on that shaft then the PS was added. Fact PS never had that spring. No one knows to remove it and do not want to remove this assembly that has the spring. Regards JR

A spring on the brake pedal?

[Jim L.]

Re: How can I tell if Power Steering was factory original?

Hi Fred Man I blew that one and I blame my old age(72) for the blooper. The spring is for installing power brakes..JR

[Joe L.]

Re: How can I tell if Power Steering was factory original?

Fred,

Here is a pic of an original Idler Arm off of a factory P/S equipped 63. The part number on the bottom is 191GMT3779185B. The part number in the 63/4 JG is stated to be 335GMT3779185B. I'm not sure why the first 3 digits vary, but they do.

Also shown are 2 of the original rivets Tim and Joe discussed. These should be installed with the head on the bottom of the steering arm and in the rear hole.

tc

Tracy------

The numbers before the "GMT" are some sort of forging numbers or other manufacturing codes and I don't think they have anything to do with the functionality of the part, at all.

Second, the forging number for the shaft section of the idler arm for ALL 1963-81 Corvettes was 3779185. The only difference I have ever seen is that the number is sometimes suffixed by an "A" or "B" and, sometimes, no suffix, at all. Some think that the "A" or "B" relates to power steering, or not. I do not think so.

From 1963-1981 all P&A Catalogs listed only one idler arm for all 63-81 applications and that idler arm was GM PART #3779184 with forging number 3779185. For some strange reason, beginning in 1982 the catalogs show this number for 63-81 Corvettes with power steering. There is no listing for Corvettes without power steering. I believe this crept into the system as some sort of error. I do not really think there was any difference between the idler arms used in PRODUCTION for cars with or without power steering. However, IF there was a difference, only one of the two was ever available in SERVICE.

Beyond everything else, I can see absolutely no reason why a different idler arm would have been necessary for power steering and non-power steering equipped cars.

By the way, there was once another idler arm which used the same shaft section as the Corvette idler arm assembly right down to the same 3779185 forging number. That idler am was GM PART #3817956 and was used for 1963 series 10 pick-up trucks. It is easily discerned from the Corvette piece, though, since the bracket section has a double off-set whereas the Corvette bracket section has a single off-set. The 2 assemblies are definitely not interchangeable even though the arms on both have the 3779185 forging number.

It's also possible that there were other idler arm assemblies that used the 3779185 forging. I can't find what they were but that forging number looks to me like it dates back to about 1960 or 1961.

[Joe L.]

Re: How can I tell if Power Steering was factory original?

Hi Fred Man I blew that one and I blame my old age(72) for the blooper. The spring is for installing power brakes..JR

Jim-----

Yes, I was "scratching my head" on that one. However, I figured this was some really strange thing that I didn't know about 1963's.

[Tracy C.]

Re: How can I tell if Power Steering was factory original?

Tracy------

...From 1963-1981 all P&A Catalogs listed only one idler arm for all 63-81 applications and that idler arm was GM PART #3779184 with forging number 3779185. For some strange reason, beginning in 1982 the catalogs show this number for 63-81 Corvettes with power steering. There is no listing for Corvettes without power steering. I believe this crept into the system as some sort of error. I do not really think there was any difference between the idler arms used in PRODUCTION for cars with or without power steering. However, IF there was a difference, only one of the two was ever available in SERVICE........

Interesting stuff Joe.,,very curious indeed.

I agree there appears to be no external configuration difference between the P/S idler arm and the non P/S idler arm....other than the forging number on the bottom as shown in my pic. Frankly, I can't seem to grasp any technical reason for an internal difference (ie. rotational resistance) either. However, the 63/4 JG identifies the non P/S idler arm as just having the 3779185 forging number.

Is the number you reference in your reply (see bold/red font above) the expanded forging number as shown on the part in my picture or some other number?

tc