PS valve finish and hardware

[Michael L.]

I'm putting the steering components together for this frame-off resto. I have a replacement PS valve and piston. I have read the TIMJG and posts in this forum about these units, and am trying to decide on just painting these (they are painted the replacement grey) and using them vs. trying to obtain date coded ones vs. trying to date code the piston myself. Assuming I will paint them, can anyone tell me if the bolts that hold the valve together are painted as well, or is it painted and then assembled? I have read about the fact that the bolts are special 12 point bolts, I can work on getting these, but can anybody tell me their finish? Also, is the small dust cap on the end painted or is this plated and in what finish? Does anyone know where correct date coded pieces can be obtained if I decide to go this route?

Thanks,
Mike

[Chuck S.]

Re: PS valve finish and hardware

...Also, is the small dust cap on the end painted or is this plated and in what finish? Does anyone know where correct date coded pieces can be obtained if I decide to go this route?...

I seem to remember the dust cap being natural or zinc plated; I don't remember it being painted.

Original production dust caps on Corvette PS valves are stamped with a different letter code (C?) than other applications of the same valve, or later replacements (X?). I believe the dust cap is being reproduced with the original Corvette code, but otherwise, the only way to get one is to recover and reuse the original.

Similarly, the only way you are going to find a properly date coded PS valve, is to find an original production PS valve on a Corvette in the junk yard. Like all other date coded parts, vendors may be date coding PS valves...their efforts may be more or less successful as far as looking authentic; vendor date coding has had mixed results on other parts.

[Michael L.]

Re: PS valve finish and hardware

Thanks, Chuck. My TIMJG states that the dust cap has an X, but the valve I have has a C. Do you know if a C could be correct? Also, do you know if the bolts were painted on the PS valve? If not, do you know the finish? How about the finish on the castle nuts on the valve?

Mike

[Joe L.]

Re: PS valve finish and hardware

Thanks, Chuck. My TIMJG states that the dust cap has an X, but the valve I have has a C. Do you know if a C could be correct? Also, do you know if the bolts were painted on the PS valve? If not, do you know the finish? How about the finish on the castle nuts on the valve?

Mike

Mike-----


Original Corvette power steering control valves had an "X" stamped on the end cover; later SERVICE valves had a "C". The stampings indicate the installed spring in the valve assembly. I believe the Corvette application used a unique spring. Otherwise, the control valve was the same as that used for other applications (mostly 50's passenger cars).

I believe the valve and adapter assembly was painted as a unit after assembly. A cardboard tube was placed over the ball stud to shield it from paint.

The 12 point bolts retaining the valve to the adapter were phosphate-finished. However, I don't recall if these were painted over, or not. It may be that the valve and the adapter were painted as an assembly but separately and then fastened together with the bolts. In this case, the bolts would have been unpainted. However, it may also be that the valve + adapter assembly were painted together, in which case the bolts would have been painted. I just don't recall if the bolts were painted, or not. Vaguely, I seem to recall they were not.

The SLOTTED NUT used to retain the ball stud of the valve assembly to the relay rod was of "PLAIN" finish. "PLAIN" does not mean "shiny steel". It means an as-manufactured finish which varies but sometimes APPEARS LIKE a phosphate finish. It rusts MUCH faster, though. There were NO phosphate-finished slotted nuts originally used at ANY location on a 1963-82 Corvette.

[Jim S.]

Re: PS valve finish and hardware

Joe,
Here is what the Saginaw engineering drawings are telling me:
First Valve & Adapter
5691955 Released 7-23-62. First used 1964.
1). Aways painted. (Valve & Adapter most likely always bolted together before paint.)
2). "X" added to the cap on 4-10-64.
3). Zerk fitting for grease.
4). 12 point bolts used at start to connect valve to adapter but changed to hex bolts on 5-14-74. So the whole time this valve was in production it would have had 12 point bolts.
5). Date code stamped on flat boss on valve body.
6). The bolt that tightened the adapter to the relay rod was not included with the valve and there is a note saying that the adapter threads must be free of paint.

7816806 Released for Production 2-16-73. First used 1974.
1). Hose guide bracket added 2-28-73. Bracket stuck out past the end cap. Guide ears bent out away from the valve.
2). Released with "C" on cap.
3). Date code, zerk, paint same as 5691955.
4). 12 point bolts used to connect valve to adapter.

7819980 Released 9-13-74; obsoleted 2-14-75; and reinstated 4-17-75.
First used 1975.
1). All parts the same as 7816806 except hose guide bracket. This bracket was shorter (bracket even with end cap.) Guide ears bent in toward adapter.
2). Valve to adapter attaching bolts changed on drawing from 12 point to hex on 3-20-79.

7825636 Released 3-12-75. First used 1976 Corvette.
1). "C" on cap removed 7-20-77.
2). Bracket, paint, date code, zerk all the same as 7819980.
3). 12 point valve to adapter attaching bolts changed to hex on 3-20-79.
4). Revision block shows new design boot clamp and date code location moved to the boot clamp in 1984. (After C3 production, therefore all production valves had date coding stamped on the valve body (XXX-Y for day of year 1-365 and Y for year 2 1962, 1972, or 1982).

Jim

PS: It is funny that I cannot find any trail as to the elimination of the zerk fitting. I know sometime in the late life of the valve and adapter assembly the unit was "greased for life." That is the zerk was eliminated and the rubber boot on the ball stud was changed from a purge design that allowed excess grease to leak out a small slit in the boot to a boot that was totally sealed.



PSS: 12 point to hex bolt changes do not make a lot of sense.
Earliest valve used 12 points and was changed to hex bolts (service part change in 1974).
2nd valve used in 1974 had 12 point bolts.
3rd valve used in 1975 went from 12 point to hex bolts in 1979 (service change).
4th valve used in 1976 onward went from 12 point to hex bolts in 1979 (running production change).

[Chuck S.]

Re: PS valve finish and hardware

I seem to remember the dust cap being natural or zinc plated; I don't remember it being painted.

Original production dust caps on Corvette PS valves are stamped with a different letter code (C?) than other applications of the same valve, or later replacements (X?). I believe the dust cap is being reproduced with the original Corvette code, but otherwise, the only way to get one is to recover and reuse the original.

Similarly, the only way you are going to find a properly date coded PS valve, is to find an original production PS valve on a Corvette in the junk yard. Like all other date coded parts, vendors may be date coding PS valves...their efforts may be more or less successful as far as looking authentic; vendor date coding has had mixed results on other parts.

Post Script: I wouldn't be too concerned about having the proper date code on the PS control valve...for authenticity, it would be nice to have the original, but it isn't worth pursuing unless you have an extremely rare, high-dollar car you're restoring. JMHO.

The date code on the PS valve is hardly discernible when you have it right in front of your bifocals, and it will not be judged for obvious reasons. For chassis judging, be concerned about those characteristics that can be easily observed from one to two feet away. In general, judging date codes of chassis components is more difficult, and it is not typically done to my knowledge...chassis date codes are harder to find, harder to observe, and generally have less gravitas than engine compartment and major driveline components. That's not to say you wouldn't like to have proper date codes on everything, but sometimes stuff happens.

[Terry B.]

Re: PS valve finish and hardware

Here is a picture of a cap with the X, taken off an origin (I think) power steering valve from a friend's '70 Corvette. I need one but he would not part with his. Does anyone know where to find one?

[Jack H.]

Re: PS valve finish and hardware

How about Long Island's part 41-25, power steering valve nut & cap @ $10/set. I can't say whether or not the cap has an X embossed, but you ought to be able to stamp it yourself...

[Michael L.]

Re: PS valve finish and hardware

Thanks, guys. I appreciate your advice, Chuck. I'm going to paint the stuff I have and stay on the lookout for a replacement X style cap. This is not an ultra-rare high-dollar car, so I'm not going to sweat the small stuff. As for the castle nuts, I think I will use a black phosphate finish to be pratical. Based on what Jim said, it sounds like I will be painting the bolts that hold the valve together, since it was originally assembled before painting.

Thanks to all those who contributed their knowledge.

Mike

[Joe L.]

Re: PS valve finish and hardware

Thanks, guys. I appreciate your advice, Chuck. I'm going to paint the stuff I have and stay on the lookout for a replacement X style cap. This is not an ultra-rare high-dollar car, so I'm not going to sweat the small stuff. As for the castle nuts, I think I will use a black phosphate finish to be pratical. Based on what Jim said, it sounds like I will be painting the bolts that hold the valve together, since it was originally assembled before painting.

Thanks to all those who contributed their knowledge.

Mike

Mike-----


You may find that you will have a very difficult time finding either "plain" or phosphate-finished slotted nuts. Most on the market today are zinc finished and most of those are ungraded or grade 2 material. These are NOT suitable for use in an automotive application. All Corvette slotted nuts were SAE grade 5 or grade 8 material and no slotted nut should be used on a Corvette which anything less than grade 5.

You can find grade 5 slotted nuts in zinc finish if you look hard enough.

Also, NO Corvette slotted nut was ever of the castle style; all were standard slotted.