Hi, quick steering question - Impala Tech
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post #1 of 32 (permalink) Old 08-20-2012, 04:50 PM Thread Starter
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Hi, quick steering question

Hi, everyone... Still ironing out gremlins...

I hope I'm posting this in the right section.

66 Impala, new components all in the front suspension, stock. The car came with manual steering, and was converted over to a saginaw power steering setup...

vehicle was aligned without a hitch, tracks straight and true. I'm running now P245 60R15's in the front with power disc brakes. (p275 60R 15's in the rear)

Everything is fine until I turn the wheel, left or right, and it seems to pull/ or dart in the direction I'm turning...

I hope I described this well...

Any ideas? I't's not overly drastic, but it is disconcerting. It happens all the time, not intermittent, and of course, seems worse at speed, as that exaggerates the effect...

Thank you all in advance.
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post #2 of 32 (permalink) Old 08-20-2012, 05:10 PM
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I think your problem is due to the wrong length Pittman arm which will aggravate the faster turning reaction of the variable rate fast action box that provides power input from just off center. I would have to research it but I believe the power steering and the manual steering have two different lengths because manual needs extra leverage that the power assist doesn't.

Big Dave
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post #3 of 32 (permalink) Old 08-21-2012, 03:00 PM Thread Starter
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Thank you! I'll try to see what length I need, with a search. If you have any further info available, I'll be very grateful.

Regardless, thank you for the advice!

I do know that the power steering kit came with a new pitman arm, which we installed, but that doesn't mean it was correct. The parts came with the car when I bought it.

Last edited by Kabous66; 08-21-2012 at 03:06 PM. Reason: more info
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post #4 of 32 (permalink) Old 08-22-2012, 08:19 AM Thread Starter
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I've also read that I may need to add more positive caster to the front, as I'm running larger, radial tires... Of course, this is a google search. Is that also a possibility, or no?
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post #5 of 32 (permalink) Old 09-05-2012, 06:13 AM
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Check your caster......too little caster will make the car dart.

Donnie
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post #6 of 32 (permalink) Old 10-11-2012, 06:58 AM
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question for fast steer guys

I have driven my car 2 times since having it aligned & the steering is very tight. It takes too much force to move the steering wheel.

I have a 1984 Z-28 box & a stock pump.

Has anyone else experienced this condition & if so, have you changed the valve in your pump?

Don
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post #7 of 32 (permalink) Old 10-11-2012, 07:27 AM
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Power assist means you should be able to turn the wheel with your pinky finger; even with the larger diameter sector rod that allows you to feel the road. I believe your resistance is in the rag joint which is metric so the holes are a different size and has to be ground open to clear the larger diameter English pins and bolts that connect the steering column to the steering gear box input shaft.

Big Dave
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post #8 of 32 (permalink) Old 10-11-2012, 08:18 PM
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Did you use the 65 pitman arm? Or the Camaro?
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post #9 of 32 (permalink) Old 10-12-2012, 08:34 AM
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I used my stock arm....Don
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post #10 of 32 (permalink) Old 10-12-2012, 11:24 AM
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I lean toward the pump pressure also. Can you tell a difference in the steering with the front wheels off the ground as to them on the ground?
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post #11 of 32 (permalink) Old 10-15-2012, 03:25 AM
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Smile

yes..very easy off the ground. I think I will take the pump apart & increase the flow rate By opening up the pressure adapter hole diameter & increase the pressure by removing washers.

Don
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post #12 of 32 (permalink) Old 10-15-2012, 05:27 AM
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I have not experienced your problem. Maybe something I should watch for as I'm using a stock pump also. Let us know if this cures your steering.
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post #13 of 32 (permalink) Old 10-17-2012, 06:50 PM
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Dadstoy....I drilled the flow valve hole larger to make it the same as the new
style pump to increase the flow rate & removed one washer from
the valve. This improved the steering but, I am not there yet.

I will disassemble the pump one more time & remove one more washer.
This will increase the pressure by 100 psi thus, ending up with 1200 PSI
from 1000 PSI. The number of pressure washers will be reduced from
3 to 1.

I'll keep you all informed ........Donnie
PS-all this could be avoided by using a latter style pump
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post #14 of 32 (permalink) Old 10-17-2012, 07:55 PM
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With all of the shims out the pressure will max out at around 2,200 pounds per square inch.

The pumps varied pressure from 300 to 2,200 psi by the spring rate and the thickness of the shim pack installed in the outlet. The orifice is a very precise volume control and and will have no affect on the line pressure as it is how the engineers designed in a control of the volume of fluid in circulation. If you drill out the hole you may evacuate the reservoir when the pump hits the stops and burn up the pump (not to mention aerating the fluid).

Have you put a gauge on the high pressure side to see what the line pressure is (you can use the same gauge that you use to test brake line pressure).

http://www.northerntool.com/shop/too...2889_200322889

Big Dave
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post #15 of 32 (permalink) Old 10-18-2012, 11:49 AM
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Dave.....I bought a kit a few yrs ago to reduce the pressure in the Chevy pump when used w/a T-Bird R&P from Borgeson(this was for a streetrod). The chart that came with this kit said the max pressure would be 1350 psi in the pump w/all the washers removed.

My pump had 3 washers in it when I tore it apart which would yeild 1000 psi according to a chart
that came w/the kit. I removed 1 washer which gave me1100 psi. This was still not enough pressure to eliminate my problem.

Lee Engr, which makes a fast steer kit for Camaros said to remove all washers,thus
giving 1350 psi. so thats my current plan.

I'll keep everyone informed as to the outcome.

Donnie
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post #16 of 32 (permalink) Old 10-20-2012, 10:27 PM
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Your 1966 Chevrolet B-car has an original power gear with a pitman shaft sweep of 87 degrees (full travel gear), it had a ratio of 17.5:1 (quite a few turns lock to lock) and pinky finger valve rated at 17 inch-lbs. The input shaft on the power gear was 13/16 diameter. The diameter was the same on all GM power gears until the 1977 model year. After 1976 all GM power steering gears had input shafts that were 3/4 diameter.

Your 1984 Z28 gear box has a pitman shaft sweep of only 70 degrees (there are mechanical stops inside the gear that restrict travel). It most likely has a very quick 12.7:1 ratio, and a valve rated at 27 inch-lbs (much higher effort).

One drawback to the Z28 gear is that it will increase your turning circle because the sweep of that gear is greatly reduced from full travel original gear.

I do not understand Big Daves information on the flexible coupling. When the input shaft size was reduced in 1977 the bow tie flange on the flexible coupling was redesigned to match the new 3/4 diameter shaft. The rest of the flexible coupling did not change. GM vehicles with flexible couplings and 3/4 bow tie flanges were as follows:
1977 thru 1982 Chevrolet and GMC C/K (2 and 4 wheel drive) pick up trucks.
1977 and 1978 Camaro, Firebird, and Nova
1979 Nova
1983 thru 1986 Chevrolet and GMC C (2 wheel drive) pickups

The flexible couplings from these vehicles will bolt right on your 1984 Z28 gear. The stop pins and bolts on the above flex couplings will require that the flange on your 1966 steering column will need to be modified.

Jim
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post #17 of 32 (permalink) Old 10-21-2012, 07:11 PM
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I have now taken all 3 washers from the pumps valve. The steering effort is still higher than I would like but, I can now live with it.

Donnie
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post #18 of 32 (permalink) Old 10-21-2012, 07:47 PM
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I know that it would seem to make sense that the pump output pressure should cause the steering to feel heavier or lighter. But here is what is incorrect about what you have done.

The spring and washers in the flow control valve control the maximum pressure that the pump will produce before going into pressure relief. Driving down the road and anytime that you are steering with the car in motion, your pump only has to produce a couple hundred psi in order to help you steer. Only with the engine running, car stopped on concrete or asphalt, foot on the brake, and now steering near full lock; does you pump have to produce pressure in the 1000 psi or greater range.

So as long as you can steer full lock to lock with the car stopped, your pump is producing sufficient power. The part that controls 90% of the feel is inside the valve in the power steering gear. That is the torsion bar (t-bar).

Chevolet Caprice B-cars (1988 thru 1996) with F41, FE2 suspensions, police cars, etc had t-bars in the 0.195 to 0.204 range and would have a heavier steering feel. These gears would also be fast 12.7:1 ratio.

The 1982 1/2 through 1998 Jeep Grand Cherokee power gear will also have a large size t-bar, full travel, and a fast 12.7:1 ratio as well.
Jim
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post #19 of 32 (permalink) Old 10-25-2012, 07:12 AM
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Jim....what do you suggest to solve my problem?

Donnie
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post #20 of 32 (permalink) Old 10-25-2012, 09:30 PM
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I would install a 1992 1/2 thru 1998 Jeep Grand Cherokee power gear. It is a fast 12.7:1 ratio, will have full travel, and has a valve rated at 24 inch-lbs. Definately a good replacement and lower effort than your Z28 gear.

I would think that your new Z28 power gear should be worth nearly as much as the Jeep Gear.

Jim
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post #21 of 32 (permalink) Old 10-26-2012, 08:16 AM
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Goodmorning Jim, I appreciate your knowledge & willness to help....
I will follow your recommendations. I looked on-line for the box
(1994 jeep Grand ch)- Napa & Autozone show a box 3.3 turns
lock to lock is this the correct box?

Thanks Don(they do not show a 2 1/2 turn)

PS-thats the only box they show for the car

Last edited by weldvair; 10-27-2012 at 10:21 AM.
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post #22 of 32 (permalink) Old 10-26-2012, 06:50 PM
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Donnie Check some of the local salvage yards for a used one. They typically can go 150,000 miles before requiring a rebuild and many used Jeep SUV's get wiped out with a lot less miles than that due to their rough suspension, high center of gravity, and soccer mom drivers that think they are BMW sports cars that should handle well on wet roads due to their rock hard truck tires with M&S tread.

Big Dave
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post #23 of 32 (permalink) Old 10-28-2012, 01:04 AM
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Dave....I checked a local yard today & They had one Jeep GC but, the box
was sold.

There are several more within 25 miles I can check Monday but, I still do not know if the 3.3 lock to lock is what I am looking for, At this point it looks like it is the only ratio available??? (3.3 is so close to 2.5 that it might also
give good road feel).

I sure do not want to change the box for a 3rd time. I will be going into
the hospital within days to have open heart surgery & would like to get
this box changed before that.


Donnie

Last edited by weldvair; 10-28-2012 at 01:47 PM.
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post #24 of 32 (permalink) Old 10-28-2012, 09:30 AM
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The 3.3 ratio is not the quick turn box, you do want the 2.7 to save that half turn of the wheel.

Big Dave
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post #25 of 32 (permalink) Old 10-28-2012, 04:40 PM
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Dave...let me run this by you. My 1984 Z28 is 2 1/2 turns lock to lock.
if the Jeep box turns further(pitman arm goes thru a larger arc) would
you not have to turn the wheel more than 2 1/2 turns.

The reason for the question is I can find no where a Jeep GC box other
than 3.3 turns. I have spent hours searching the web for this box

Where did you find reference to the box you are talking about?

Donnie
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