Pulling my hair out

348tripower · July 15, 2011, 12:08:49 PM

I am still messing with the power steering rack on the Stude. This thing truns harder to the left than the right. I have bled the pump out so there is no more squealing coming out of it. I did remove one of the lines from the steering sector to the end of the rack to rebend it before I installed it. I am wondering if there is air in there causing the problem. It never seems to react the same when I drive it. It is a 1989 center steer rack. Any ideas?
thanks,
Don

wayne petty · July 15, 2011, 01:58:14 PM

this is more of a question for a steering rack rebuilder...

but i would take a big guess as

1. Dirt or debris in the spool valve.....

2. bad seals between sections of the spool valve...

3. twisted beyond center torsion bar that controls the spool valve...

4. bad piston seal ...

1 description... the spool valves allow pressure to both sides of the piston.. then shut off /reduce flow to one side allowing the other side to push the piston to recenter the spool valve when turning input stops...
this pressure on both sides of the rack piston keep pot holes from yanking the steering wheel out of your hands...

2. description.. the spool valve seals can be damaged during installation.. causing a one way taper to be cut in the square edged teflon seal.. allowing leakage one way..... the spool valve case bore could also be worn or have grooves worn in it ...

3 description... torsion bar in the spool valve recenters the spool valve when there is no steering input.. i know its designed to not be able to be bent beyond a certain point where it takes a set.. but sometimes when steering a car without the pressure to assist will put a twist in the torsion bar or spring... so its NOT totally centered..

4. description... like the spool valve there is a seal on the piston .. these can be damaged during installation.. causing it to seal better in one direction than the other..

rack rebuilders i have been in work the rack back and forth on their bench.. without a load /drag on the rod ends... they just watch flow and pressure... do you have any local rebuilders where you can have them test it for proper pressures and flow...

i have several independent rack rebuilders near me...

lee enginnering out in sun valley ca...

and a small father son shop down on pico blvd.. one thing.. if you decide to send your rack in... be sure to attach a tag that says the BENT tube is for clearance .. or the rebuilder will look at that and put a straight one in its place...

hope this helps...

348tripower · July 15, 2011, 02:48:21 PM

Wayne,
This acts as if the center position is changing. I unhooked everything yesterday, centered the rack and started over. Seemed better this morning but screwed up now. Like turning the car to the left centers the rack. This is a 2 3/4 to 3 turn rack. could I be turning it too far and screwing it up?
Don

wayne petty · July 15, 2011, 03:20:35 PM

Quote from: "348tripower"Wayne,
This acts as if the center position is changing. I unhooked everything yesterday, centered the rack and started over. Seemed better this morning but screwed up now. Like turning the car to the left centers the rack. This is a 2 3/4 to 3 turn rack. could I be turning it too far and screwing it up?
Don

i am taking that this is one of the GM style racks where the inner tie rod ends are bolted to the front...

i have a question... how hard would it be for you to remove one of the inner tie rod end bolts... to examine the back of the case... there have been problems when the spacers between the bushing center and the rack fall out.. letting the end of the bolt drag inside the housing tearing it up...

bolts 37 in this image... the spacers /washers between are not shown.. as they were in early applications of this style of rack

http://www.compnine.com/largeimg/911008GM06-126.gif

i will have to look at a blow up diagram of the rack.. see if there are any stops that could have been left out... i have seen the end not properly seated and the wire ring and end cap blown out..

you might also contact this shop... they might be able to help
http://lee-powersteering.com/contact-us.htm

post if its a GM rack.. and what model if you can... i will look around for more info...

when you mention that the center changes...

can you have somebody steer it from stop to stop with the front wheels on the ground.. while you look.. make sure the rack is NOT slipping back and forth in its brackets/ mount rings....

348tripower · July 15, 2011, 03:42:29 PM

Spacers are there. The rack can't move because it has an integral mount. Wondering if I could mess it up if it wasn't centered by turning to far one way at the start of this mess.

wayne petty · July 15, 2011, 03:57:27 PM

if its harder in one direction than the other...

its internal to the rack...

if it does not want to stay centered...

348tripower · July 15, 2011, 04:45:41 PM

It stays centered. Just acts as if it isn't due to the feel in the wheel.

348tripower · July 15, 2011, 04:59:08 PM

Also,
Would the Cavalier have a stop on the spindle or would the stop be in the rack? Maybe this is loading up too much at the ends and screwing up the internals. I have never checked to see if the Stude front end will turn past the rack limit. ?

wayne petty · July 15, 2011, 05:17:37 PM

internal i would imagine.. it should have enough push to bend most cavalier strut arms..

there is NOT any recentering device.. in a rack and pinion.. that is accomplished by CASTER in the front wheel alignment.. so the steering recenters as with caster dialed into the settings.. the king pins are laying backward.. so the wheels tend to recenter..

perhaps you have not enough caster..

have you any turn table plates to test the steering ability..

or 2 pieces of sheet metal under each wheel with a layer of grease between and the parking brake set tight or both rear wheels properly chocked so the front does not slide around.. this reduces friction to see if the suspension is binding..

http://www.cdxetextbook.com/steersusp/wheelsTires/alignFund/caster.html

here is another with video links..

http://www.quicktrickalignment.com/index.php?p=1_6_Alignment-101

wayne petty · July 15, 2011, 05:38:54 PM

with the kingpin centerline laying toward the back at top . when you turn the steering wheel to the right.. the right wheel do to the angle has to lift the car slightly to fold under.. when you release the wheel the angle it will want both sides to equalize..

it will want to drop to the lowest that equals on both sides...

so both wheels are pushing equally ... hopefully centering the steering.. if both tires have even tread and your camber settings are within reason..

now.. if you have a LOT more caster on one side.. it might be harder to steer in that direction..

do you have an level area... 0 bubble..

you can if you don't have a wheel alignment gauge.. and with the greased metal plates and the brakes locked.. cut some 20 degree triangles so you can verify how much you are turning each time..

turn the wheel out 20 degrees.. stick your level against the tire.. see how far its out.. if you have a angle indicator that will work also.. 0 the angle indicator.. or figure out how much angle there is in your level..

now.. turn the wheel 20 degrees in.. check again.. measure without zeroing your device a second time.. the difference is your caster angle..

wheel alignment gauges can be had from circle track suppliers for under 50 bucks..

hf used to have turn tables.. nice once with x and y motion also for about 100 bucks a pair.. i will have to call them see if any more are coming in from overseas..

lazy susan's can be used.. but suspensions move in and out when turning.. so it takes multiple directions.. to free up the suspension..

one could create trapped plates... with ball bearings in a punched or drilled separator plate..