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Discussion Starter · #1 · (Edited)
38 chev 2 dr. I have a power rack MII IFS with saginaw pump,using Heitds pressure valve. My rack started leaking while the car was hybernating last winter.I just got an 88 rack cause I read they will take more pressure, the boots are fatter causing a tighter fit. Didn't think much of it but cardboard it was shrink wrapped to had oil stain, and when I just about had everything together I noticed the boot leaking. This rack really leaks.My allignment was out due to spring and spindle changes, so I played with it. The shop that did my allignment previously couldn't get any positive caster, said the A-arms were hitting, A-arms were set forward. I just set the camber as close to zero as I could and swung the A-arms as far back as I could(alot),toe in is 1/4''. I have the Heidts valve almost completely open. The car isn't as touchy with more positive caster but I don't like driving it over 50mph.Not enough road feel and steering still seems too touchy/quick, 3;1 ratio rack. I'm thinking of going to a manual rack, but I've bought the pump and bracket, Heidts stainless hose and valve kit and hate to just scrap it and may find manual steering too hard.
So how many of you switched to manual steering and are happier? or were you able to overcome the touchy highway feel?
 

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If the vehicle is very heavy or engine is heavy, don't do it. You wont be happy.
Although, I have a 76 Chevy Luv P'up, SBC400 with Manual steering and it turns much easier than my 86 Toyota P'up with a 22R 4cyl. & manual steering :eek: Makes no sense. :confused:
 

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SSedan64 said:
If the vehicle is very heavy or engine is heavy, don't do it. You wont be happy.
Although, I have a 76 Chevy Luv P'up, SBC400 with Manual steering and it turns much easier than my 86 Toyota P'up with a 22R 4cyl. & manual steering :eek: Makes no sense. :confused:
Most likely due to the different ratios of the steering boxes dontya think?
 

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TheCiscoKid said:
38 chev 2 dr. I have a power rack MII IFS with saginaw pump,using Heitds pressure valve. My rack started leaking while the car was hybernating last winter.I just got an 88 rack cause I read they will take more pressure, the boots are fatter causing a tighter fit. Didn't think much of it but cardboard it was shrink wrapped to had oil stain, and when I just about had everything together I noticed the boot leaking. This rack really leaks.My allignment was out due to spring and spindle changes, so I played with it. The shop that did my allignment previously couldn't get any positive caster, said the A-arms were hitting, A-arms were set forward. I just set the camber as close to zero as I could and swung the A-arms as far back as I could(alot),toe in is 1/4''. I have the Heidts valve almost completely open. The car isn't as touchy with more positive caster but I don't like driving it over 50mph.Not enough road feel and steering still seems too touchy/quick, 3;1 ratio rack. I'm thinking of going to a manual rack, but I've bought the pump and bracket, Heidts stainless hose and valve kit and hate to just scrap it and may find manual steering too hard.
So how many of you switched to manual steering and are happier? or were you able to overcome the touchy highway feel?
How much caster do you have, I would think you need at least 8*.
 

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The trick to adjusting the "feel" of power steering is adjusting the pressure of the pump along with the volume of fluid being pumped. I did early development work on the valve that was sold by a hot rod parts company here in the northwest up until they closed their doors a couple of years ago.

The combination of reduction of volume and pressure together worked very well in reducing the light steering feel when using a pump designed for a worm and sector steering gear on a rack and pinion unit. As some folks note, you can add washers under the pressure relief valve in the pump to reduce pressure, but that doesn't alter the fluid volume moving through the rack.

I would recommend searching out pressure relief valves from small GM cars that ran the pump you are using (cars with 4 cyl engines for example), then reduce the pressure on those valves with more washers under the nut. When you look at the valve, the units from the 4cyl cars had a smaller port than from V8 cars.

As far as your caster setting, 3 to 3.5 degrees positive will be sufficient, that along with about 1/2 degree negative camber and 1/8-1/4" toe-in is what you should be after for alignment settings.

Andy
 

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Discussion Starter · #7 ·
I'm using to heidts pressure reducing valve, undone to 1/2 thread. i was hoping to get an alignment done, but since this new rack leaks i eye balled it, 1/4'' camber. 1/4'' toe and as much caster as I could, but i can't measure that. I just did it to test drive. It's still too touchy, nice to drive to 50, after that it's too touchy.
I've bought the pump bracket, pump, chrome pulley and cap, heidts stainless hose kit and valve and I'm thinking of using a manual rack but I've spent alot hoping to use PS. So before I install a manual rack I was wondering if anyone changed and was way happier or not.
I just read a post that a 72 PS rack is 4:1 turns and better, is this true?
 

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Did ya catch the part on my last post about finding a different pressure relief valve for your current pump? It will make a big difference...apparently the Heidt's valve isn't capable of overcoming the high volume and pressure of your system.

Andy
 

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I have a 31 chevy with a power mII rack and no pump. The steering is not to bad. Of course I don;t intend to parellel park it. And I get plenty of road feel. Have not done much driving over 50 yet.
Try it without the pump and see. :welcome:
 

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Discussion Starter · #10 ·
sorry Aosborn, missed it. I've been reading previous posts elsewhere here and see conflicting info, ei; even with a Ford pump car will be twichey, need 7* caster,need 2* caster. I thought the Heitds valve was the way to go? I have it on the last thread, not much assist for parking, nice at moderate speed, scarey faster. What's better ?? Can the set up ever be good without going to an extreme caster?
 

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It absolutely can be good with the power steering. Without major mods you would never be able to get to 7 degrees positive caster on a Mustang II front end, and if you did you wouldn't like the result. The front end geometry of that suspension wasn't designed to run anywhere near that much positive caster. 3 to 3 1/2 degrees is all you should ever need, and even getting that much is a stretch if you want to run negative camber (which I highly recommend, it greatly helps to reduce under-steer).

What I do to set up one of these front ends is to set the camber at 1/2 degree negative on both sides, and then adjust caster to get as much positive as the adjustment travel will allow on the right side and then adjust to 1/4 to 1/2 degrees less on the left, then 1/8 to 1/4 inch toe-in. Then work on the assist to get the feel you want. I am most familiar with the GM pumps as far as adjusting the volume and pressure, but really, a pump is a pump and there must be a way to adjust the Ford units, you just may have to get creative (larger OD pump pulley?). In theory the Heidt's valve should work as advertised, but like I stated previously, the pump may just be overpowering it, or the relief valve in it is defective.

Make sure everything on the front end is tight and installed correctly, then have it properly aligned by someone who will put it to the specs noted above, and go from there. If you have the option, try some different front tires and see how it feels.

If you do all that and still don't like the feel, swap out the power rack for manual, reset the toe-in and you are good to go, leave the alignment settings as described above.

Good luck,
Andy
 

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Discussion Starter · #12 ·
Aosborn,thankyou for replying.
hhmmmm so I don't know if I can do anything about the PS then.
I installed a manual rack, steering when parking is not that hard (positive caster), turn ratio is 4 to 1 vs PS 3 to 1, still seems quick at faster speed (again needs proper alignment).
What alignment specs would you use? Doesn't negative caster make car wander? I have a vibration coming up through the steering, never felt anything before.
 

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Check out my last post for the alignment spec details. In brief...

Camber 1/2 degree negative (tire in at the top)

Caster 3 to 3 1/2 degress positive (upper ball joint more to the rear of the car than the lower)(slightly more positive caster on the right side)

Toe 1/8 to 1/4 inch in (go with the smaller spec if tires are wide, more toe-in if the tires are narrower)

Good luck,
Andy
 

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Discussion Starter · #14 ·
got my alignment today, took car in without fenders, alignment took 20 minutes, the eyeball job wasn't far out.
With all the treads i've read on no feeling with PS, I recommend manual, I had to wrestle abit to get out of the parking lot, but nothing really hard, the car has good road feeling, still haven't been over 80, but here cars can be seized for doing 30mph /50kms over also.
 

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Discussion Starter · #16 ·
The shop guy spoke another language, toe was .009" each side, -1/2* camber, caster +3 left. I think he said 3/8* difference on right.
I've only driving the car locally,maybe a cruise night and garages. Wednesday I took a 400 mile day trip.The car runs smooth, feels like a new car except the suspension rides hard. Steering felt more like the PS in my regular car.
I've change coils springs 3 times and shocks on the front, it's not too harsh,325 lb spring, but I'm going to take a leaf out rear as it rode so hard that I couldn't drive 401 highway due to the constant bumping, found secondary highyways to be better.I had the trunk loaded ,even had 4 people in for awhile. I weighed the car today, front 1600, whole car 3380, rear 1800. I didn't think the rear would weigh that much. The rear springs are Chassis Engineering, I think the suspension kits need more engineering, they suck.
 
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