67 Power Steering Added, Not Working Right

[Gerard F.]

Re: 67 Power Steering Added, Not Working Right

Gary,

Before I'd buy any new parts, or take apart the valve, I'd get the front end realigned and increase the caster to 2.5 degrees. If you are running with radials, camber should be 0, toe in should be 1/16" or less. Then take a cruise and check the power steering.

Manual steering specs are 1.5 to 2.0 caster, Power Steering specs are 2.0 to 2.5. The higher the caster, the better the tracking at speed.

If I'm standing still in my 67, the power steering will always jerk when I turn the wheel. But if I'm moving the P/S works perfectly.

Seems to me, that if you did the test with the front wheels off the floor, and the wheels go side to side and center (and with no foaming), then the valve would be OK.

After that, maybe pump pressure or kinking of the hoses is a factor.

Pumps are cheap, I just got (earlier this year) a very correct rebuilt pump for my 67 from "larescorp" on ebay for $66. Look for a 1963-74 AMC & Chevrolet Car Power Steering Pump.
I found that the pump that came with my kit in 2004, was not as correct (although functional) as the one I more recently acquired and put on my car.

Also, I have heard that there is something about Corvettes using a different valve spring than other GMC cars of the era. I remember something about this in the forum archives, but can't say for sure.

Have fun,

[Chuck G.]

Re: 67 Power Steering Added, Not Working Right

Sorry to hear you're still having troubles with this, Gary. The installation sure went well. Hope you figure it out.

Chuck

[Jim S.]

Re: 67 Power Steering Added, Not Working Right

The Corvette steering system had the "valve and adapter" booster system with special 1/4 inch ID pressure hoses between the valve and the assist cylinder. Those hoses were only designed for 1000 psi maximum pressure. Typical GM integral power steering gear systems used pressures in the 1400-1500 psi range. So just don't replace the OEM flow control valve inside your Corvette pump with a typical GM valve. It could really shorten the life of your hoses.

The major difference in reservoir designs were the reservoir types with a large brazed fill neck and the "ham can" reservoir design. I just don't remember exactly when Corvette changed to the "ham can" design, (it could have been around 1974?)


Otherwise, the differences in power steering P-pumps would be in the location, direction, and bends in the return spout on the back side of the reservoir.
Jim

[John H.]

Re: 67 Power Steering Added, Not Working Right

It seems to steer a little easier, but the pressure varies with some spurts of it steering easy like you would expect from PS.

Gary -

The control valve on the relay rod supplies assist pressure to the power cylinder when the pitman arm stud applies enough lateral pressure to overcome the tension of the valve spring, which then moves the spool, supplying pressure from the valve output to the power cylinder input. The "pressure varies" and "spurts" description suggests that the spool may be sticking in the valve bore. The pump doesn't know (or care) about any of this; I'd go back into the control valve and verify correct assembly and freedom of movement of the spool.

[Joe L.]

Re: 67 Power Steering Added, Not Working Right

The Corvette steering system had the "valve and adapter" booster system with special 1/4 inch ID pressure hoses between the valve and the assist cylinder. Those hoses were only designed for 1000 psi maximum pressure. Typical GM integral power steering gear systems used pressures in the 1400-1500 psi range. So just don't replace the OEM flow control valve inside your Corvette pump with a typical GM valve. It could really shorten the life of your hoses.

The major difference in reservoir designs were the reservoir types with a large brazed fill neck and the "ham can" reservoir design. I just don't remember exactly when Corvette changed to the "ham can" design, (it could have been around 1974?)


Otherwise, the differences in power steering P-pumps would be in the location, direction, and bends in the return spout on the back side of the reservoir.
Jim

Jim------


You're close. The "ham can" reservoir for Corvettes started for the 1975 model year and was coincident with the change to the pressed-on pulley type shafts.

[Gary S.]

Re: 67 Power Steering Added, Not Working Right

You guys are a wealth of information for sure. Unfortunately, I keep this car at my winter home in Florida and I have few tools and no books. Chuck Gongloff and Jim Moran live near and helped me put this Zip Products after-market PS unit on at the garage of their friend. However, we did not test it thoroughly as it was late when we got done. I think John Hinckley has a point with the drag link valve worth checking out. I say this because if I jerk the steering wheel back and forth quickly five or six inches, there is power help there. Maybe I will just buy another one unless there is some easy adjustment to the pressure sensor on that valve. I do need to get the front aligned again since I did a temporary setting using the "string" method. I will take Jerry's specs with me for that. Will write when I know more. Thanks so much to all for your input.

Gary

[Gene M.]

Re: 67 Power Steering Added, Not Working Right

Hey Gary,
If all else fails take a trip to the gym, strengthen up the arms and take off the power steering....

I assume you are not getting air spitting back (makes a mess if it does) when you rev the engine with the pump cap off.
If you can get the fan belt to scream on full lock turns, you are building good pump pressure. Problem must be cylinder.
Gene

[Richard M.]

Re: 67 Power Steering Added, Not Working Right

Gary,

Last year I installed that exact Zip supplied kit on a 1967. I had the exact same problem you are presently having.....no assist. Lone Star supplies these kits for Zip. After spending much time on the phone with the owner at Lone Star, we discovered that the pump was at fault. These are units rebuilt by them, occasionally with new housings. What we discovered was debris in the rebuilt pump, blocking flow at the pump valve. He said that even very small particles can cause this. I removed the pump and removed the valve. There were small rock particles in the valve housing, and one was quite large, blocking flow. The owner summarized that it wasn't properly cleaned out after their "beadblasting" process when rebuilding the pump. I replaced the pump.

I'm wondering if this could be your problem also. You may want to remove the pump and carefully check it. Remove the valve and carefully look in the bore of the valve for anything which may be lodged in the bore. It is also possible that if any debris was inside the pump, it may have lodged in the control valve at the cylinder.

Either way, if you discover any debris in the system, I would recommend installing a Power Steering filter in the low pressure side for a while to catch anything if present. I did that on the '67 for a while then removed the filter later. All was fine after that.

Rich

[Gary S.]

Re: 67 Power Steering Added, Not Working Right

Gary,

Last year I installed that exact Zip supplied kit on a 1967. I had the exact same problem you are presently having.....no assist. Lone Star supplies these kits for Zip. After spending much time on the phone with the owner at Lone Star, we discovered that the pump was at fault.

Rich

Rich...that is really good to know and thanks for writing and posting the great pictures. I may be assuming too much with my pump as I did not remove it from the car when I took out the control valve. Thus, I did not get a look inside. I might call Ken at Lone Star. Thanks again. Gary

[Gary S.]

Re: 67 Power Steering Added, Not Working Right

I talked to Lonestar a few days ago and they think it is the control valve on the drag link. They wanted me to send it to them. I sent it yesterday and threw in the pump for kicks to be checked out. I found them to be very interested in my problem which was typical of my other dealings with them. Will let you know when I hear back.

Gary

[Gary S.]

Re: 67 Power Steering Added, Not Working Right

I talked to Lonestar a few days ago and they think it is the control valve on the drag link. They wanted me to send it to them. I sent it yesterday and threw in the pump for kicks to be checked out. I found them to be very interested in my problem which was typical of my other dealings with them. Will let you know when I hear back.

Gary

FIXED!

I can't say enough good about the service and warranty from Lone Star. To summarize, I bought a used Zip Products power steering kit for my 67 350 HP conv a year ago and just got it on in January. I would guess the kit was 2 years old by the time I got it on, but only had about 200 miles on it. I sent my pump and control valve to Lone Star after a phone call to them about my problem. I sent them on the 13th, arrived there on the 18th, received back on the 24th via FedEx. They found some "gunk" (their word) in the pump but not enough to cause a problem. But they found lots in the control valve. They sent me a rebuilt pump and new control valve...no charge...and paid for the shipping back!! I told them I did not expect any warranty because I bought it used. I tried to pay them for their work and transportation, but they refused.

Today I put them on and they worked perfectly. Did not have to balance the control valve either....and no leaks!

I did add a small power steering fluid filter because of Rich Mazzetta's suggestion. It is NAPA #81-0589F or Cardone #20-0038F and cost about $15.

Thanks to all for your help!!

Gary

PSfilterNapaBox.JPG

PSfilter.JPG

[Joe L.]

Re: 67 Power Steering Added, Not Working Right

FIXED!

I can't say enough good about the service and warranty from Lone Star. To summarize, I bought a used Zip Products power steering kit for my 67 350 HP conv a year ago and just got it on in January. I would guess the kit was 2 years old by the time I got it on, but only had about 200 miles on it. I sent my pump and control valve to Lone Star after a phone call to them about my problem. I sent them on the 13th, arrived there on the 18th, received back on the 24th via FedEx. They found some "gunk" (their word) in the pump but not enough to cause a problem. But they found lots in the control valve. They sent me a rebuilt pump and new control valve...no charge...and paid for the shipping back!! I told them I did not expect any warranty because I bought it used. I tried to pay them for their work and transportation, but they refused.

Today I put them on and they worked perfectly. Did not have to balance the control valve either....and no leaks!

I did add a small power steering fluid filter because of Rich Mazzetta's suggestion. It is NAPA #81-0589F or Cardone #20-0038F and cost about $15.

Thanks to all for your help!!

Gary

[ATTACH=CONFIG]39334[/ATTACH]

[ATTACH=CONFIG]39337[/ATTACH]

Gary------


Little known fact: most original Corvette power steering pumps had an INTERNAL fluid filter. This was shared with some MD/HD truck applications but no others. Unfortunately, elements for these filters are long-since GM-discontinued and not otherwise available. Commercial rebuilders generally remove the filter and element when they come across them. So, once a Corvette pump is rebuilt it usually loses its filter.

[Jim S.]

Re: 67 Power Steering Added, Not Working Right

Joe,
The internal filter is something I was not aware of. I am going to try and find an engineering retiree that might remember about the filter.

For a short period of time, (back in the 70s or early 80s) there were some lawsuits that alleged that at 2 A.M. in the morning (after only 1 beer at the bar) the plaintifs power steering "locked up" and there was a collision as he/she was driving home. The alleged "lock up" was caused by very fine particles that jammed the rotary valve in the steering gear. We called them "particles cases."

One of the things that our engineering experts would do just before a trial was to purchase a car similar to the complaint vehicle. Then install a complete new power steering system in that vehicle. Then we would make a video or movie of us collecting floor sweeps, chips, and other debris from the manufacturing plant. Then we would take a paper cup full of that debris and pour it into the pump reservoir. Our engineering expert would then drive that car all the way to the site of the trail. (Many times this was across the USA.) At no time did we ever experience a "lock up" as was alleged. General Motors never lost a "particles case" with this type of engineering demo.

After we won a couple cases with this type of demonstration, guess what? The "particle cases" ceased. (Lawyers have a real network for jumping on certain types of product litigation cases.)

This isn't to say that people should become careless with respect to rebuilding pumps and gears.

The above is probably one reason why the filter eventually disappeared from the Saginaw pumps.
Jim

[Joe L.]

Re: 67 Power Steering Added, Not Working Right

Joe,
The internal filter is something I was not aware of. I am going to try and find an engineering retiree that might remember about the filter.

For a short period of time, (back in the 70s or early 80s) there were some lawsuits that alleged that at 2 A.M. in the morning (after only 1 beer at the bar) the plaintifs power steering "locked up" and there was a collision as he/she was driving home. The alleged "lock up" was caused by very fine particles that jammed the rotary valve in the steering gear. We called them "particles cases."

One of the things that our engineering experts would do just before a trial was to purchase a car similar to the complaint vehicle. Then install a complete new power steering system in that vehicle. Then we would make a video or movie of us collecting floor sweeps, chips, and other debris from the manufacturing plant. Then we would take a paper cup full of that debris and pour it into the pump reservoir. Our engineering expert would then drive that car all the way to the site of the trail. (Many times this was across the USA.) At no time did we ever experience a "lock up" as was alleged. General Motors never lost a "particles case" with this type of engineering demo.

After we won a couple cases with this type of demonstration, guess what? The "particle cases" ceased. (Lawyers have a real network for jumping on certain types of product litigation cases.)

This isn't to say that people should become careless with respect to rebuilding pumps and gears.

The above is probably one reason why the filter eventually disappeared from the Saginaw pumps.
Jim

Jim------


The filter assembly was GM #5689351 and the element was GM #5689352. They were used from 1963 to at least 1973. I have a few NOS examples of the filter assembly and many of the element.

[Jim S.]

Re: 67 Power Steering Added, Not Working Right

I see that the filter and element were inside the reservoir right behind the return spout. It does show up on the early pump assembly drawings. You just have to know what you are looking for. The filter does not show up in the 1975 Corvette pump, (there is a magnet inside the reservoir.)

BTW, I am pretty sure that the filter was eliminated when the little round (hockey puck) magnet was added to all the Saginaw power steering pumps or steering systems.

Jim