Modifying Powersteer Pump

[cjsupra90]

OK so far...
Mine IS a Crown (mid-sump). Why I was asking is because the Crown had a steering box and linkages, not a rack, so hence my question above about all pumps being the same.
Ie, would a pump for a steering box be the same as one for a rack?
But it does sound a s though the pump I have is the same as your's.

The could be different being that the Crown had a gear box instead of a rack. This shouldn't make a differance though. I've converted other cars in the past from gear box to rack & pinnion and reused the gearbox pump and it worked perfectly fine. Granted this was not a UZ pump but for the most part, a PS pump is a PS pump regardless of what its from...

 

[LXS-180]

Can i ask you to explain in a bit more detail about this scrub radius, as i have never heard of this before.. thanx

 

[Peewee]

Pumps will be identical between all models.
Although I'm pretty sure the UZZ30 ones didn't have the idle up valve on them.
I've use a Crown pump in a car with a rack, everything worked as per factory.

Longer hose won't make a difference either.

As mentioned self centering is purely to do with the caster.
Get an alignment done at a suspension shop, and let them know your symptons.

 

[cjsupra90]

Can i ask you to explain in a bit more detail about this scrub radius, as i have never heard of this before.. thanx

Scrub Radius is the distance between the the tire center line at the ground and the point where the steering axis intersects the ground....

To give you a better idea, lets assume you have a double wish bone suspension sent up. If you were to draw a line form intersecting the top and bottom ball joint and extending it to the ground at the same angle. The distance between that point at the ground and the center line of the tire / wheel at the ground is the scrub radius... The name is kinda misleading cause its a straight line dimension and not an arc or radius... Anyways, the greater this distance, the more the tire has to scub or scuff on the ground surface as the steering turned about its axis... This obviously cause more resistance to the twisting about the steering axis.

This is why getting the correct offset wheels is so important. The offset directly effects this distance.... Basically a car with Zero scrub radius would easily be able to be steered without any assist yet would feel like there was assist...

If you search Google or yahoo or what ever, you'll be able to find more detailed explainations of scrub radius, but that pretty much sums it up...

 

[LXS-180]

Something i thought i should add as it just adds to the confusion.. Well for my head anyway.. Not sure if this supports the Scrub Radius or not, but when i pulled out of a parking spot last night (reversed out) and put it in first, while still rolling back and tried to take off, the steering wheel felt as though it completly jammed up, and i had to use rather excessive force to continue moving the steering wheel while taking off (going forwards)...
Im going to get the castor and wheel alignment/balance done this weekend if funds permit...
Will update when i have some information

 

[Muzza_NZ]

Jack the front up off the ground and see if it turns freely without any contact with the ground. We had too much static friction with a steering box in the RX7 and it felt like it was jamming up (what was more noticeable though was the lack of self centering ability). This shouldn't happen with a rack and pinion though...

 

[cjsupra90]

Something i thought i should add as it just adds to the confusion.. Well for my head anyway.. Not sure if this supports the Scrub Radius or not, but when i pulled out of a parking spot last night (reversed out) and put it in first, while still rolling back and tried to take off, the steering wheel felt as though it completly jammed up, and i had to use rather excessive force to continue moving the steering wheel while taking off (going forwards)...
Im going to get the castor and wheel alignment/balance done this weekend if funds permit...
Will update when i have some information

This is sounding more and more like a control valve issue.

 

[361UZ]

Jack the front up off the ground and see if it turns freely without any contact with the ground. We had too much static friction with a steering box in the RX7 and it felt like it was jamming up (what was more noticeable though was the lack of self centering ability). This shouldn't happen with a rack and pinion though...

...Or the pinion lash (free play) is adjusted up too tight. But I wouldn't imagine there would be any need to adjust this when doing a swap.
The 1uZ wasn't dropped on the rack during the swap was it?
But for my money, as Muzza said, jack it up and see if it's binding at any point during a full lock to lock test. Do it with power on and off. Look far any spot where the steering gets heavy, then light. For a R&P system it should feel smooth all the way, and require a fairly constant force on the steering wheel.
If you find nothing, then a full wheel alignment should sort it.

 

[LXS-180]

Not sure if lextreme is the best place to be asking this about a nissan rack... but what is involved with the control valve? How do i adjust it if i need to? Not sure if the engine was dropped on the rack or not... But the guy who put the engine in, isnt a clutz... so im sure we can cross that option out...

I will jack the car up this weekend and try a few things out..

Thanx alot guys! Really appreciate this!! :hail:

 

[cjsupra90]

The directional control system (i.e. pressure control valve) is internal in the rack. It is not adjustable that I am aware of. Its technically correct name is a rotary valve. If that turns out to be your problem, my suggestion is to replace the rack unless you have the knowledge to rebuild it youself....

 

[cjsupra90]

Here is actually a pretty good brief explaination of how it works. Its basic but still gives you a good idea. It starts about mid way down the page.

Enjoy......
http://auto.howstuffworks.com/steering4.htm

 

[LXS-180]

yet another update of information....

Still havnt had the chance to get under the car and have a proper play, but last night while driving the car around a parking lot, i had to jump on the brakes because as i was turning around a corner, i had the steering completly LOCK up on me.. when i say lock i mean, its as though sumone or sumthing grabbed the steering wheel and wouldnt let go... it was at very low speeds around 10Km/h and i had to give it quite a hefty yank to resume normal steering...

I might also add that i did stiffen the front sway bar (Adjustable 22mm), and put in an adjustable whiteline 22mm rear swaybar yesterday (rear bar was stock)...

 

[Peewee]

I've noticed my Hilux's steering gets VERY heavy whenever I get on the brakes.
I'd say its just something to do with the steering box set up.

 

[LXS-180]

Found the problem... and funnily enough, it was nothing anyone had mentioned... After getting under the car this morning with a light to see whats going on, i noticed the engine mounts are pretty much completly destroyed... the old S13 mounts i combined with my custom engine mounts werent up to it with the 1UZ in... Cause the mounts are pretty much gone, the engine has dropped, and the exhaust manifold is hitting the steering column... Hence the 'grabbing' feeling while im turning...

Engine mounts for sale anyone?? Cheers for the help guys..