1973 Steering Gear

[Tom K.]

Hello again everyone,

I am working on the steering gear of my 1973 Corvette. There was a good 15 degrees of slop in the steering wheel and I was leaking power steering fluid, so among other things, I bought a rebuilt power steering control valve from a chain type auto parts store and it looks like an original GM part. I did some research here in the technical discussion archives and the new JG for 1973 Corvettes. The valve that was on the car appears to be the original (no hose guide bracket) and I have removed the 12-point bolts holding it together, the pinch bolt and the dust cap with the 'X' stamped in the end. I plan to remove the hose guide bracket from the rebuilt unit, and install the correct bolts and dust cap. I dont see any other differences between my original and the rebuilt unit. Can someone advise if there is something else I should look for or am I wrong about the rebuilt valve being a GM original part? Also, the new JG says the valve was painted semi-gloss black. Should the valve be taken apart and painted without the copper gasket, or after assembly with the gasket and bolts in place so the whole assembly is painted? I'm not sure because I did see black paint on the original dust cap, but not on the bolts. I was surprised the bolts did not look painted because I find it hard to believe they would paint these items separately when they would have had to be masked off to keep paint out of machined surfaces.
As always, I appreciate your advice on the details.

Thanks

Tom K

[Edward D.]

Re: 1973 Steering Gear

I have seen a lot of these and rebuild plenty as they do tend to leak as the seals age and go. CSSB provides a nice rebuild process instruction on their website. So, in terms off originality, you do want to remove the shield, use the 12 point bolts and the "X" end cap. Change the bolts one at a time so it doesn't come apart on you. On the grease side, there were a number of GM numbers embossed on the casting over the years, there is no definitive guide on these. Some of the rebuilders only accept GM castings, I really don't know how they tell the difference. But that said, your leaky original does have value so don't throw it out. I believe these were painted black at assembly including the dichromate boot retainer. That said, most of the ones I see have the dichromate retainer unpainted. Lastly, be aware you probably will have to balance the control valve after installation. If the steering wheel wants to pull left or right the valve is out of balance. The 7/16 nut under the end cap is where you balance. You can lookup the procedure, if you cannot find it just message me and I'll give you a step by step.

[Joe L.]

Re: 1973 Steering Gear

Hello again everyone,

I am working on the steering gear of my 1973 Corvette. There was a good 15 degrees of slop in the steering wheel and I was leaking power steering fluid, so among other things, I bought a rebuilt power steering control valve from a chain type auto parts store and it looks like an original GM part. I did some research here in the technical discussion archives and the new JG for 1973 Corvettes. The valve that was on the car appears to be the original (no hose guide bracket) and I have removed the 12-point bolts holding it together, the pinch bolt and the dust cap with the 'X' stamped in the end. I plan to remove the hose guide bracket from the rebuilt unit, and install the correct bolts and dust cap. I dont see any other differences between my original and the rebuilt unit. Can someone advise if there is something else I should look for or am I wrong about the rebuilt valve being a GM original part? Also, the new JG says the valve was painted semi-gloss black. Should the valve be taken apart and painted without the copper gasket, or after assembly with the gasket and bolts in place so the whole assembly is painted? I'm not sure because I did see black paint on the original dust cap, but not on the bolts. I was surprised the bolts did not look painted because I find it hard to believe they would paint these items separately when they would have had to be masked off to keep paint out of machined surfaces.
As always, I appreciate your advice on the details.

Thanks

Tom K

Tom------


This not an original GM valve but its configuration is virtually the same as a GM valve. GM valves usually have GM casting numbers on the valve and adapter sections of the unit.

[Tom K.]

Re: 1973 Steering Gear

Hi Joe & Edward,

I let my original PSCV soak in simple green for about a day and a half - it was impressively nasty!
So as usual, you guys were absolutely right - there are casting numbers on my original, and my rebuilt valve is not likely to be a GM casting. I think the original was leaking around the fitting - see the casting boss all beat up? -- How does that even happen?
Anyway, Plan 'B' - use the rebuilt one to get the car on the road, buy a rebuild kit for the original and see if I can find a replacement for the housing with the hose connections. I will save the original bolts and dust cap with the 'X' for the original when it is rebuilt. After I got all the crud off the valve I could see some paint left on the the castings and the retainer for the boot seal, and it looks like there was some in the recess on the heads for the 12-point bolts. It was definitely painted after it was all together. I assume it was painted and delivered to the assembly plant with plastic caps protecting the hose connections and there should be no over-spray on the hoses.
Now on to the the re-installation of my steering gear box - very expertly rebuilt by Gary Ramadei - the torque to turn is smooth and consistent all through the travel and the backlash is minimal. I see a lot of gear boxes and spindles of all types in my job. Gary's work is first rate. If anyone is considering getting this done Gary R. is your man! I will post some pix before I install it for others to refer to.
Again - thanks for your help guys!


Tom Krause

[Edward D.]

Re: 1973 Steering Gear

Most of these are rebuildable. Chips around the ports of the head housing shouldn't be a problem unless the housing is cracked down to the seat through the threads. Like I said earlier, CSSB has a nice tutorial posted on their website on how to teardown, inspect, and rebuild the valve. If you are replacing the hoses, which you probably should do, don't use the cheap chinese made set, I've seen a lot of bad flares on these resulting in leaks. The US made ones are better quality and work well. The best in my opinion are the A/C Delco reissue made in the Mexico Delco plant. I think these look better as well since the crimp fittings are clear silver zinc vs the dichromate on the other repos.

[Tom K.]

Re: 1973 Steering Gear

Hi Edward,

Here is a picture showing the cracked boss. It doesnt look like the crack goes all the way down to the seat for the fitting. Maybe I should try to use the original? I would definitely prefer using the original if I can. I saw the CSSB instructions and they are very clear. In the CSSB and several other different manufacturers rebuild kits I dont see the ball stud as part of the kit. A few out there do, but at this time they are out of stock. Im planning to wait until I can get the kit with a new ball stud to rebuild my PSCV.
I bought a set of the power steering hoses already and they are tagged as made in the US. I already checked the flares because of an ugly experience I had previously with a stainless steel brake line that had a crappy flare. I wish I had thought to check AC Delco for replacement hoses first. I will start doing that from now on so they are at least part of the mix when Im making decisions on parts. Would you expect AC Delco to be the closest to original of the various replacement parts they make as they would have access to all the original drawings?

Tom Krause

[Patrick H.]

Re: 1973 Steering Gear

I would bet that the ACDelco are repackaged parts from someone else. as ACDelco makes nothing any more; it's a marketing company. I've seen more than once the exact same part for 20% less money under someone else's label.

Check the shape of your hoses vs your originals very closely. The metal bends on last couple sets of replacement hoses I used had to be reshaped a bit to fit properly.

[Edward D.]

Re: 1973 Steering Gear

Tom,
If fitting will screw down tightly and compress the tube into the seat your original head may be OK. Don't worry about the ball stud, these don't wear much and you should be able to reuse the one you have. On the hoses, I have attached a picture of a new AC Delco return hose and an aftermarket hose. I don't know if Delco outsources production of these, repackages, or whatever. What I do know is they are made in Mexico (where Delco does have parts manufacturing operations) and they look and fit right. The materials and bends are top notch IMHO. Delco hose on the left in picture.

[Joe L.]

Re: 1973 Steering Gear

Hi Edward,

Here is a picture showing the cracked boss. It doesnt look like the crack goes all the way down to the seat for the fitting. Maybe I should try to use the original? I would definitely prefer using the original if I can. I saw the CSSB instructions and they are very clear. In the CSSB and several other different manufacturers rebuild kits I dont see the ball stud as part of the kit. A few out there do, but at this time they are out of stock. Im planning to wait until I can get the kit with a new ball stud to rebuild my PSCV.
I bought a set of the power steering hoses already and they are tagged as made in the US. I already checked the flares because of an ugly experience I had previously with a stainless steel brake line that had a crappy flare. I wish I had thought to check AC Delco for replacement hoses first. I will start doing that from now on so they are at least part of the mix when Im making decisions on parts. Would you expect AC Delco to be the closest to original of the various replacement parts they make as they would have access to all the original drawings?

Tom Krause

Tom------


I've reviewed the CSSB control valve rebuilding instructions. A few comments:

1) They refer to the sheet metal "shield" found on valves from 1975+ (and SERVICE valves for 1963-74 after about 1975) as being a "stone guard". It is NOT a "stone guard" although many folks refer to it as such. It is a HOSE GUIDE for the extend and retract hoses. While not correct for 1963-74, it will be found on those cars with a SERVICE valve. Is it important and should someone with a 1963-74 having the hose guide remove it? Well, for "correctness" I expect so. Otherwise, you don't suppose that GM added this part because the power steering system worked just as well without it, do you? By the way, the hose guide used for 1975 was unique to that year;

2) The CSSB instructions mention re-using the metal gasket between the adapter and valve section (the adapter is the part with the ball stud; the valve is the part with the hose connections). This gasket, known as GM #5691581 and a compression-type aluminum gasket, is actually critical and non-reusable. Unfortunately, it is long-since GM discontinued and, as far as I know, not reproduced. Its re-use is the reason that many rebuilt valves, including commercially rebuild valves, leak. But, as things are, one has no option but to re-use it. Below are photos of an NOS gasket[not for sale]:

[Edward D.]

Re: 1973 Steering Gear

Joe,
The thin aluminum gasket sits next to a thicker plate between the two halves of the valve on the "grease side". The grease side where the ball stud is has no hydraulic pressure. All the pressure is on the outboard head side where the lines connect. Neither the middle plate nor the aluminum gasket seal hydraulic pressure. What does this are the lip ring seals on the inner and outer spools inside the pressure housing. If a control valve is leaking at the joint, the fault is in the lip seals or the cylinder walls (scored) of the pressure head. If the joint between the housings was sealed and hydraulic oil is getting past the pressure head lip seals then it would quickly dissolve the grease and leak out the ball stud opening. I have also seen this many times. In sum, reusing the thin aluminum gasket hurts nothing and will not cause a hydraulic leak.

Tom------


I've reviewed the CSSB control valve rebuilding instructions. A few comments:

1) They refer to the sheet metal "shield" found on valves from 1975+ (and SERVICE valves for 1963-74 after about 1975) as being a "stone guard". It is NOT a "stone guard" although many folks refer to it as such. It is a HOSE GUIDE for the extend and retract hoses. While not correct for 1963-74, it will be found on those cars with a SERVICE valve. Is it important and should someone with a 1963-74 having the hose guide remove it? Well, for "correctness" I expect so. Otherwise, you don't suppose that GM added this part because the power steering system worked just as well without it, do you? By the way, the hose guide used for 1975 was unique to that year;

2) The CSSB instructions mention re-using the metal gasket between the adapter and valve section (the adapter is the part with the ball stud; the valve is the part with the hose connections). This gasket, known as GM #5691581 and a compression-type aluminum gasket, is actually critical and non-reusable. Unfortunately, it is long-since GM discontinued and, as far as I know, not reproduced. Its re-use is the reason that many rebuilt valves, including commercially rebuild valves, leak. But, as things are, one has no option but to re-use it. Below are photos of an NOS gasket[not for sale]:

[Joe L.]

Re: 1973 Steering Gear

Joe,
The thin aluminum gasket sits next to a thicker plate between the two halves of the valve on the "grease side". The grease side where the ball stud is has no hydraulic pressure. All the pressure is on the outboard head side where the lines connect. Neither the middle plate nor the aluminum gasket seal hydraulic pressure. What does this are the lip ring seals on the inner and outer spools inside the pressure housing. If a control valve is leaking at the joint, the fault is in the lip seals or the cylinder walls (scored) of the pressure head. If the joint between the housings was sealed and hydraulic oil is getting past the pressure head lip seals then it would quickly dissolve the grease and leak out the ball stud opening. I have also seen this many times. In sum, reusing the thin aluminum gasket hurts nothing and will not cause a hydraulic leak.

Edward----


Yes, I realize that the gasket is not on the pressure side of the control valve assembly. However, I have been told by many that this gasket is the source of control valve leaks. I have never personally confirmed it, though. If this gasket is not there to prevent leaks, what would its purpose be? Usually, compression type, metal gaskets like this are used for difficult sealing situations.

[Joe L.]

Re: 1973 Steering Gear

I would bet that the ACDelco are repackaged parts from someone else. as ACDelco makes nothing any more; it's a marketing company. I've seen more than once the exact same part for 20% less money under someone else's label.

Check the shape of your hoses vs your originals very closely. The metal bends on last couple sets of replacement hoses I used had to be reshaped a bit to fit properly.

Patrick-------


The power steering hoses available today, including those available through Delco, are not OEM quality pieces. They are aftermarket quality. That's not to say they are bad but they are not of the same quality as original. The original hoses when they were last available cost about 4-5 times what the aftermarket versions cost. One could "feel the difference". These original hoses fit PERFECTLY. Aftermarket often do not. I do not know where the originals were manufactured or if they were of internal GM manufacture. But, they were different than ANY aftermarket available hoses, then or now. There's also an easily discernible configuration difference, too. The original hoses (except for later manufactured examples of the return hose) used a wide, single crimp. The aftermarket hoses use very narrow double crimps. Curiously, when the GM OEM return hose was changed to the double crimps, the price dropped by a large amount.

[Joe L.]

Re: 1973 Steering Gear

Tom,
If fitting will screw down tightly and compress the tube into the seat your original head may be OK. Don't worry about the ball stud, these don't wear much and you should be able to reuse the one you have. On the hoses, I have attached a picture of a new AC Delco return hose and an aftermarket hose. I don't know if Delco outsources production of these, repackages, or whatever. What I do know is they are made in Mexico (where Delco does have parts manufacturing operations) and they look and fit right. The materials and bends are top notch IMHO. Delco hose on the left in picture.

Edward-------


I don't know of any Delco parts manufacturing operations in Mexico or, for that matter, anywhere else. GM certainly does have vehicle assembly operations in Mexico as well as powertrain manufacturing operations there. However, I know of no component parts manufacturing operations there. GM "spun off" most of the Delco parts manufacturing operations to DELPHI quite a few years ago. Some operations such as Delco chassis parts were sold to Tenneco Automotive or other independent manufacturers. Some of what used to be Delco-Remy is now Remy International. GM did wind up taking back Harrison Thermal Products from DELPHI (so, I guess DELPHI must now be DELPI) after the DELPHI bankruptcy filing. It's possible that Harrison (now called GM Thermal Products) might have some manufacturing operations in Mexico and supply some thermal products to AC Delco. Primarily, GM Thermal Products manufactures in Lockport, New York.

For the most part and as Patrick mentioned, ACDelco is a marketing organization and not a parts manufacturing organization. Most, if not all, of AC Delco parts are outsourced, some to former GM parts manufacturing companies now independent of GM. However, I expect that the power steering hoses are manufactured by Edelman or Gates.

By the way, that AC Delco return hose you picture is nothing like the original GM return hose. The original GM hose did not use a banded connection between the hose and pipe. In fact, the other aftermarket hose you picture is much closer in configuration to the original GM return hose.

[Edward D.]

Re: 1973 Steering Gear

Joe,
Not sure why GM originally put this gasket in there, but it really doesn't do anything in sealing hydraulic pressure or preventing leaks. I have seen many valves without the gasket at all. Some heads also have an o-ring between the head and the middle plate, others don't. The assembly works just the same with or without it. Every leaky valve I have encountered (and its a lot of them) leaked because spool lip seals were bad or cylinder walls scored by debris. The lip seals are easily replaced, scored walls require sleeving to repair properly. Most of the leaking "rebuilt" units I see have scored wall problems as the rebuilders typically only replace the lip seals.

Edward----


Yes, I realize that the gasket is not on the pressure side of the control valve assembly. However, I have been told by many that this gasket is the source of control valve leaks. I have never personally confirmed it, though. If this gasket is not there to prevent leaks, what would its purpose be? Usually, compression type, metal gaskets like this are used for difficult sealing situations.

[Tom K.]

Re: 1973 Steering Gear

Hello Edward & Joe,

I dont really know the relevance, but I noticed the chain store rebuilt unit I bought has a copper gasket of some sort in the location the aluminum gasket would go on the original PSCV's

Tom