[Bob Bowman 1968]

I own a 68 LeMans and my buddy owns a 70 Firebird. We were talking about the power steering in the older cars vs newer cars. Old cars have the steer with one finger feel while new cars have less assist when you are traveling at highway speeds and more assist when you are stopped. Are there any articles online on how to change the power steering assist on older cars?

[Grand73Am]

Someone else may know better, but I don't think there is much difference to be had with the pump. I believe the main difference is in the modern steering gear box or rack and pinion steering versus your old steering gear box. Most new vehicles have rack and pinion steering, which feels differently from the old steering gear box. Or, in the case of some trucks, there are steering gear boxes with "rack and pinion" valving, which is more precise with more steering effort required.
The modern type of steering box in the trucks is called the Delphi 600 series, and it is available from companies that specialize in selling them for use in older vehicles. With a compatible flex coupler, also available, the box is a direct bolt-on for your car. You can Google it to read more about them.

[amcmike]

Some use electronic steering assist.

A few things to consider.

Our old cars had power steering as an option. Therefore the cars were setup to have minimal effort at low speed for parking maneuvers (regardless if they had power assist or not).

Alignment:
The alignment settings typically covered power and manual steering with the same specs. Also, they used bias ply tires. So they typically had a range of positive camber to very little negative camber. This assisted low speed steering at the sacrifice of inducing a lot of understeer (although that was somewhat offset by the bias ply tires difference in slip angles). They also used very little positive caster to negative caster. Again, this helped for low speed steering, but at the sacrifice of high speed stability.

The steering wheels were often much larger, which gives you more leverage.

The t-bar size impacts effort, and internally the boxes can be adjusted for more effort.

Finally there's the scrub radius. Large positive values of scrub radius, were used in cars for many years. The advantage of this is that the tire rolls as the wheel is steered, which reduces the effort when parking. Wheel offset can be used to adjust the scrub radius.

[guccieng]

corvettes have been using 'magna-steer' for awhile, like mike said. the benefit is so that you won't jerk yourself off the highway at high speeds. keep in mind that our old cars were supposed to only legally cruise at 55mph! now days, 85 is the norm on cali freeways. for your second-gen firebird, you can get the '80s iroc/ws-6 steering box; it's quick ratio and heavy feel. it takes only a little more effort to turn, but feels the same in the parking lot (even with wide tires) as on the freeway. i've got that box on both cars. love it! if you want a fully dynoed and calibrated pump and box, give lee manufacturing a call. he'll build you a box/pump set exactly as you describe you need.

[65catalina]

I sent my original steering box to Lee's. After discussions with them, we decided to install a 12:1 ratio and a 36 pound (if I remember correctly) torsion bar. I took the original power steering pump and modified it myself per an old Car Craft article to give it more pressure and it made a world of difference. The steering feels like a modern car and is quick. I really like it, but then I HATE the feel of these old steering systems. Now it is NOT a variable box, but is still very nice. I don't like the variable boxes are they are not linear and do not perform well IMO.

[lust4speed]

I prefer the light steering feel of the older GM cars, and one of my pet peeves is that most cheap rebuilt units have too much added resistance. If you have driven a late 50's or very early 60's Chrysler product, you would never argue that the GM system lacks feel or is too light. You could move the front of a big Chrysler sideways away from the curb by using one finger on the wheel and never feel any resistance. They really put the power in their power steering.

One of the signature trademarks of our older cars is the easy steering, and removing this just robs you of one of the cool sensations of reliving the old muscle car experience. People install a corporate LS engine, rack-and-pinion steering, and other upgrades, but pretty soon they're close to driving a mid-nineties Firebird with an old body hung over it.

65catalina, you wouldn't have the article or remember what was done? Many years ago I remember altering the pump pressure relief valve right at the exit from the pump, but can't remember what needed to be changed.

[Grand73Am]

Originally Posted by guccieng

keep in mind that our old cars were supposed to only legally cruise at 55mph!

Not true. The 55 mph national speed limit didn't come into existence until 1974, after the oil embargo of 1973. Prior to that there were 70 mph highways. What a pain it was having to endure those years of 55 mph speed limits. Glad that insanity is over.

[Steve C.]

As mentioned Lee, and other companies, can change your origional box if desired. I choose to upgrade my '70 Trans Am with a new 12:1 box from AGR Performance. You can order their different types of steering boxes with differant ratio and valving combinations to suit specific performance and handling. See the "race section" on their web site for valving examples. Since most of my driving is out on the open road I choose to have them make a 292117 street box, that normaly comes with 0.210 valving, with a firmer 0.220 valving for a much improved road feel.

http://www.agrperformance.com/

I also for apperance choose not to use a factory power steering pump. Instead I used a KRC aluminium pump.
Picture here:
http://www.popularhotrodding.com/fea.../photo_13.html

[Keith Seymore]

Good thread.

My '97 Suburban has "too much" assist for my liking, and has a couple strange behaviors I'd like to correct. I wasn't sure how I was going to address those prior to seeing this thread.

I'll follow up with those suppliers mentioned here.

Thanks for posting!

K

[65catalina]

Originally Posted by lust4speed

I prefer the light steering feel of the older GM cars, and one of my pet peeves is that most cheap rebuilt units have too much added resistance. If you have driven a late 50's or very early 60's Chrysler product, you would never argue that the GM system lacks feel or is too light. You could move the front of a big Chrysler sideways away from the curb by using one finger on the wheel and never feel any resistance. They really put the power in their power steering.

One of the signature trademarks of our older cars is the easy steering, and removing this just robs you of one of the cool sensations of reliving the old muscle car experience. People install a corporate LS engine, rack-and-pinion steering, and other upgrades, but pretty soon they're close to driving a mid-nineties Firebird with an old body hung over it.

65catalina, you wouldn't have the article or remember what was done? Many years ago I remember altering the pump pressure relief valve right at the exit from the pump, but can't remember what needed to be changed.

Sadly, no. I misplaced the article a couple years ago and have looked extensively for it. It did modify the pressure relief valve at the pump exit. If I remember correctly, you just remove part of it.

I do have to disagree with you though. The over-assisted power steering of these old cars is one of the worst traits. I have driven many and hate all of them. I even hated them back when there was nothing better in the mid-seventies. My college car was a 75 Mercury. I drive my dad's 68 Cadillac sometimes and just a couple minutes behind the wheel leaves me wanting my car back.

[65catalina]

Originally Posted by Keith Seymore

Good thread.

My '97 Suburban has "too much" assist for my liking, and has a couple strange behaviors I'd like to correct. I wasn't sure how I was going to address those prior to seeing this thread.

I'll follow up with those suppliers mentioned here.

Thanks for posting!

K

Keith,
It isn't cheap though. My rebuild was around $400-450 about 6-8 years ago.

[hgerhardt]

I wrote that stuff for Car Craft over 10 years ago. I searched for it online, but the article doesn't exist anymore. Original parts that work really well are a YA-code Monte Carlo SS box (high-effort, quick ratio) along with the flow control valve and hose adapter from that same Monte SS pump. Just unscrew the big 1" hose fitting from the back of your original Pontiac pump and pull out the valve and spring and replace it with the O-ring hose fitting and valve/spring from the Monte SS. Then use a pressure hose for an '87 Cutlass Supreme with Olds 307 engine. The return fitting is low pressure and hose-clamped on, so just use the fitting that came with the box. The other missing part is the rag joint to connect the box to the steering column. Use a large-diameter, small-shaft rag joint from an '83 full-size 1/2 ton Chevy pickup.

This is the single-best thing I ever did to my '66 GTO from all the mods I've done over the years. The 2nd, 3rd and 4th best things were EFI, 200-4R trans and 4-wheel discs.

I did find some similar articles: http://www.carcraft.com/techarticles...ade/index.html
and http://jeffd.50megs.com/Pump_valve_mod_page.htm

[lust4speed]

Heinrich, good to see you posting. I suspect that enlarging the orifice size allows greater flow but nothing else. Is the shorter spring a firmer spring, and that increases pump output pressure? Also, are the changes to the pump only made to insure enough volume and pressure at high demands, or does this really change steering feel? I see that Lee makes reference to a torsion spring in the PS unit - is this the piece that really needs changing to alter total resistance?

I injured my hand and it's going to be 6 months or more before I can drive two handed so I really appreciate easy steering. I've been arguing with my Chevy dealer about the initial pressure to turn the steering wheel on my Duramax. The resistance is really up there, and I've had three other truck owners drive my truck and concur that mine takes another 50% effort over theirs to turn. Dealer swears that while effort is high, it still falls in spec. I just hate to give in when it's under warranty and ship the box off to Lee. It was just unpleasant to drive before my mishap, but now is tough to maneuver around a parking lot with one hand.

[hgerhardt]

Mick, I suspect you're right about the orifice size. I've never tried to modify that, just use the regulator, spring, and hose adapter from the MonteSS pump or equivalent. This does two things: raises the pressure limit so that when you really tug on the wheel you don't run out of boost, and 2nd it allows you to use an off-the-shelf pressure hose, since the post '79 boxes all have O-ring fittings. The higher pressure capability of the newer regulator of course doesn't change anything until you demand it from the system. During straight-ahead driving, it will output the same pressure as originally (virtually nothing). Flow is constant no matter which regulator is in the system, since that's a function of the pump displacement. And, no, the pressure has no influence on steering feel. That's strictly a function of the torsion rod in the spool valve. The bigger the torsion rod, the more effort is required to turn the wheel. And, with more effort comes better communication from the tires and suspension to the driver. Although, you'll never get Porsche-level communication from these cars. Heck, not even the current Corvette has the greatest steering feel. It is precise, however.

The other part of the equation of improving the steering feel is to put in as much positive caster as you can get out of your car. That improves straight-line stability and helps to ensure proper steering return to center. Remember, today's tires are light-years better (and different in how they work) than the originals... the improvements are amazing.

Now, as for your Duramax... That has a recirculating-ball gear like our GTO's, doesn't it? I wonder if there is something binding in the spool valve, since you say it's only during initial turn-in that it's a problem. I suppose you could try a different dealer to see if they'll replace the gear. Those trucks must all have the same torsion rods in the spool valve, I'd suspect, since there wasn't a "sports" option on the HD trucks.

[rohrt]

Originally Posted by 65catalina

I sent my original steering box to Lee's. After discussions with them, we decided to install a 12:1 ratio and a 36 pound (if I remember correctly) torsion bar. I took the original power steering pump and modified it myself per an old Car Craft article to give it more pressure and it made a world of difference. The steering feels like a modern car and is quick. I really like it, but then I HATE the feel of these old steering systems. Now it is NOT a variable box, but is still very nice. I don't like the variable boxes are they are not linear and do not perform well IMO.

I sent my box to Lee as well but I don't have that new car feel. After talking to both a rep from AGR and from Lee and It sounds like its because of the torsion bar. I must not have got this replaced with my 12:1 ratio install. If he did I'm not happy with and would like to send it back at some point. That is what makes the steering want to turn its self back to strait or what I call a higher effort turning. I asked Lee what size torsion bar he put in but he could not tell me. They measure the torque not the size of the bar as the metal quality can change the torque.

When it comes to the pump, AGR makes a hi volume pump and it seems like kinda a hit or miss venture, as both guys told me you only need from the pump what the steering box requires.

I know + caster plays a roll as well.

[Qball]

Originally Posted by hgerhardt

I wrote that stuff for Car Craft over 10 years ago. I searched for it online, but the article doesn't exist anymore. Original parts that work really well are a YA-code Monte Carlo SS box (high-effort, quick ratio) along with the flow control valve and hose adapter from that same Monte SS pump. Just unscrew the big 1" hose fitting from the back of your original Pontiac pump and pull out the valve and spring and replace it with the O-ring hose fitting and valve/spring from the Monte SS. Then use a pressure hose for an '87 Cutlass Supreme with Olds 307 engine. The return fitting is low pressure and hose-clamped on, so just use the fitting that came with the box. The other missing part is the rag joint to connect the box to the steering column. Use a large-diameter, small-shaft rag joint from an '83 full-size 1/2 ton Chevy pickup.

This is the single-best thing I ever did to my '66 GTO from all the mods I've done over the years. The 2nd, 3rd and 4th best things were EFI, 200-4R trans and 4-wheel discs.

I did find some similar articles: http://www.carcraft.com/techarticles...ade/index.html
and http://jeffd.50megs.com/Pump_valve_mod_page.htm

Will this affect your turning circle?

[cutlas]

I don't post that much but this is something I looked into for my 67 Firebird.
Here is a ling to Jim Shea's steering papers.
It shows what steering boxes will exchange with what.
It also has information on steering columns.
Hope it helps.

http://jimshea.corvettefaq.com/?page_id=5

[65catalina]

Originally Posted by rohrt

I sent my box to Lee as well but I don't have that new car feel. After talking to both a rep from AGR and from Lee and It sounds like its because of the torsion bar. I must not have got this replaced with my 12:1 ratio install. If he did I'm not happy with and would like to send it back at some point. That is what makes the steering want to turn its self back to strait or what I call a higher effort turning. I asked Lee what size torsion bar he put in but he could not tell me. They measure the torque not the size of the bar as the metal quality can change the torque.

When it comes to the pump, AGR makes a hi volume pump and it seems like kinda a hit or miss venture, as both guys told me you only need from the pump what the steering box requires.

I know + caster plays a roll as well.

I believe that unless you specify you want an increase in steering feel, they just replace the gear. I know that I discussed this with them prior to sending the box in and I just love my steering feel.

[rohrt]

Originally Posted by cutlas

I don't post that much but this is something I looked into for my 67 Firebird.
Here is a ling to Jim Shea's steering papers.
It shows what steering boxes will exchange with what.
It also has information on steering columns.
Hope it helps.

http://jimshea.corvettefaq.com/?page_id=5

That is an awsome spreadsheet!

[rohrt]

Originally Posted by 65catalina

I believe that unless you specify you want an increase in steering feel, they just replace the gear. I know that I discussed this with them prior to sending the box in and I just love my steering feel.

That bums me out. Looks like I will be sending my box back to them at some point.