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power steering ??? GM 500 series box

Posted By: moparx

power steering ??? GM 500 series box - 12/12/20 07:29 PM

a buddy is having issues with a 500 series power box in his car.
it has 5 1/2 degrees positive caster, 1 1/2 degrees negative camber, and 1/8" toe in.
the box is new and has a good feel to it, however, he is constantly steering it, like it has no caster on center.
you can make a slight correction [right or left] to stay in your lane, but it seems to keep [slightly] slowly correcting, then it's the opposite correction, then rinse and repeat.
i have driven this car on all kinds of road surfaces, and this gets old pretty fast.
we did a quick pressure test on the pump and it puts out over 1200psi.
could this be a too high of a pressure, or too much fluid flow problem, or a bad box ?
you would think with this much caster it should go straight as a string. shruggy
we have not tried to cut back the pump pressure yet, or tried different alignment specs.
he claims the control arms are against the mounting surface[es], so therefore no shims can be removed to take out any camber.
i would think if a shim was placed in the front mounting points, caster would increase and camber would decrease.
maybe a little more toe in would help ?
all parts are new, and there is no play in anything.
this is just a street car with a conversion to power steering from a manual box, but is a baffling problem for us.
we have, for over 50yrs, converted other cars to power steering, and this is a first for us.
hopefully, you guys can help !
Thanks In Advance guys ! bow
beer
Posted By: moparx

Re: power steering ??? GM 500 series box - 12/14/20 05:38 PM

anyone ? shruggy
beer
Posted By: topside

Re: power steering ??? GM 500 series box - 12/15/20 12:19 AM

Can you try driving it without the pump connected ?
To prove the alignment is right.
I'll assume RF & LF caster differ slightly to accommodate road crown.
Ran about +5.5 caster (tubular upper arms) & just under -1 camber on my 512 Duster (manual steering, which was fine) and it had no issues.
I hate chasing the steering when driving.
I'm thinking that if the pressure's too high, that's what's happening: constantly adjusting input.
Another thing to try is operate the steering wheel 1-handed at the bottom, as light a touch as possible, to make sure it's not a driver-input issue.
But yeah, if I had to guess, maybe too much PSI; but that's only a guess.
Posted By: moparx

Re: power steering ??? GM 500 series box - 12/15/20 05:50 PM

thanks for the reply. up
yes, the right and left caster has a tiny difference for road crown.
one thing we haven't done yet is drive it without the pump belt.
if we get a day before it snows much, we will try it. if not, it will be in the spring.
beer
Posted By: ruderunner

Re: power steering ??? GM 500 series box - 12/18/20 11:54 PM

Is the thrust adjustment too tight on the box? There should be a little backlash in the sector shaft when the box is at the center of it's travel. Note, the box itself needs to be centered, not the wheel or any of the linkage.

If the box is too tight (preloaded) it will want to force the sector shaft away from center.

Drop the center link, cycle the box lock to lock and find center. Check for backlash.

I've seen too many people try to overadjust a steering box in an effort to fix a different problem.
Posted By: moparx

Re: power steering ??? GM 500 series box - 12/19/20 06:42 PM

the backlash was one of the first things we tried. [the box is/was new when it was installed]
we backed it off 5 turns and there was no difference.
the manufacturer of the box stated the box was built to be tight on center.
i should also mention this is the first time we installed a 500 box. the other conversions we did [on GM stuff] used the 600/605 style box[es].
how many turns should it take to notice any play ?
on any boxes ever adjusted, unless they were totally shot, 2 or 3 turns usually tightened them up. i would think 5 turns looser would be noticeable ? shruggy
beer
Posted By: ruderunner

Re: power steering ??? GM 500 series box - 12/20/20 12:57 PM

Wow, you backed off 5 turns? That's quite a lot. After backing off, did you smack the sector shaft to reseat the thrust button?

Did you go back to the previous setting? You might be too loose now.

Either way, I'd recheck the thrust and see what you have. Note, I don't know any actual spec for it, I just go by feel. You want just enough to feel the backlash.

Edit, I've also run into cheap parts like tie rods and ball joints the have very high internal friction. This creates a phenomenon called memory steer but that doesn't seem to fit your description of the problem.
Posted By: moparx

Re: power steering ??? GM 500 series box - 12/20/20 08:17 PM

i can't remember if the shaft got smacked or not. usually, we have to tighten the lash, not loosen it.
anyway, it's back to where it was.
lots of snow here, so we have the time now to come up with ideas to try. we are fresh out.
the vendor we got the box from says this is the first he has heard of anything like what we are experiencing with this box, but i'm sure this has been "said" before with aftermarket parts.
any other ideas to float ?
it may come down to something stupid on our part [not that THAT hasn't happened before laugh2] but this thing is really kicking out azz[es] !
it would help if we could hear bad noises, but we have been under and over this thing so many times, and nothing stands out.
thanks for your input on this. bow
beer
Posted By: Twostick

Re: power steering ??? GM 500 series box - 12/21/20 04:22 PM

Isn't an 1/8" a lot of toe? Too much toe would make it a pain to drive too, yes?

Kevin
Posted By: moparx

Re: power steering ??? GM 500 series box - 12/21/20 05:04 PM

1/8" is a pretty common number for a front steer application.
the factory specs for this application are 1/16 to 3/16" toe in.
toe out really causes problems, especially in turns on a street only ride.
countless times we have just used string to set the toe, plus use a carpenter's level for the camber [and let the caster fall wherever] and not had the steering act like this thing does.
beer
Posted By: Twostick

Re: power steering ??? GM 500 series box - 12/21/20 05:12 PM

What kind of car is it?

Kevin
Posted By: moparx

Re: power steering ??? GM 500 series box - 12/21/20 08:04 PM

i didn't mention it before because this is a Mopar board, and this car is a 58 impala custom.
a while back, i asked about this on the general forum, and didn't get much response. [although i did get a couple of ideas. THANKS to those guys !]
so i figured i might get some ideas here, since handling is appropriate to everything.

i don't want to run afoul of any rules, but this thing is taxing our minds.

it HAS to be SOMETHING causing this symptom, but we haven't been able to pin point the cause.
this is a very nice car, and not a slopped/slammed together p.o.s.
previously, this car had air bags, but those proved problematic with the controls, so that setup was removed and the factory springs/arms/bushings setup re-installed.
the car also had this problem with the bag setup, everything is new now, so the only thing left from the bag setup is the 500 box, the pump/pulley arrangement, and the steering column/ shaft hookup to the box.
the car had the factory manual steering box with the bags, and we converted it to the 500 series power box at that time because it was hard to steer with a 14" diameter wheel.
however, with the manual box, it DID go down the road without having to correct the input all the time. we do not know what the alignment specs were at that time [with the manual box]

since the power box conversion, we have had this car on the alignment rack twice, and it does the same thing.
i will attach the last printout from the rack. maybe something can be seen we are missing.

there has been NO hacking or butchering done to the chassis, and from all our measuring, the chassis is factory straight.
beer

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Posted By: Sniper

Re: power steering ??? GM 500 series box - 12/21/20 08:37 PM

Well, the massive toe out it had wasn't helping. Did the new alignment help at all?

I'm thinking you may need more toe, assuming of course there isn't any hard parts issues. Did you look at the rear suspension and make sure it's not an issue?
Posted By: Twostick

Re: power steering ??? GM 500 series box - 12/22/20 05:42 AM

What happens if you jack up both wheels clear of the ground and start it? Does the steering wheel stay put or does it wander off by itself?

If you are say making a left or right turn at an intersection and just let go of the wheel, will it come back to center on its own? With that much caster it should fly back. Stock spec is like 1 deg. If it won't come back, I'd check for a seized balljoint or joints.

1/8 toe is supposed to be the max for radials if that's what it's running. Bias calls for up to 1/4".

Those have a trailing arm coil suspension, yes? Grasping here but make sure none of the bushings are worn out. They don't drive nice if they steer from both ends.

Nice car by the way. Had a chance to buy a 58 348 tripower like that in triple black complete with continental almost 30 years ago. Everything original except the diamond tuck interior and the TH350. Prepped and ready for paint with enough NOS trim to do the entire car with at least another complete set for spares. $5000.

Passed in favor of a 59 Edsel wagon... realcrazy

Kevin
Posted By: ruderunner

Re: power steering ??? GM 500 series box - 12/22/20 10:00 AM

Just for clarification, the car was still bagged when converted to ps?

Ps drove bad from day one?

Eliminating bagged suspension made no difference?

If so that puts the problem squarely on the ps swap.

That means the problem is between the center link and the nuts behind the wheel. Literally. Which brings up the possibility of a bound up center link or steering column.

If you drop the tie rods from the center link, see if it travels smoothly from lock to lock, then try the steering wheel from lock to lock. Engine off for the first test, then Engine running. Note I don't expect the actual power assist to be the problem.
Posted By: moparx

Re: power steering ??? GM 500 series box - 12/22/20 07:03 PM

348 4spd, and it runs like a top. since we got the car going, it has had a nagging valve cover leak, due to the cover being a casting and slightly porous in the one corner. and now, this power box issue.

anyway, back to the story.

the car went down the road as it SHOULD when we got it going with the bagged suspension and the manual box it came with.
we then converted to power steering. got the car aligned [that was the sheet posted above, so the before toe specs were out] and hit the road.
as with all projects, we chased some "new car blues", but after a while, it became apparent the bagged suspension just wasn't going to cut it. the controller had troubles we couldn't get right, plus the compressor wouldn't keep the system at a constant pressure. my buddy wasn't happy with it at all, and this was a very well known, 5K kit.
during this time it became apparent the car had this "wandering" condition, requiring a constant input to keep it going straight. not a lot mind you, just a constant little correction [back and forth] all the time. i really can't truly classify this as a wondering condition we are all familiar with in the basic sense, but i don't know what else to call it.

anyway, the car was then converted back to the original spring setup. at that time, the front suspension got tube control arms, new tierods, new bushings, new idler arm, and a rebuild kit for the center link. the rear suspension received new bushings in the control arms, and the lower arms were boxed. the upper control arm on this year only, is a giant wishbone connected to the chassis at both sides in the front, and a very large bushing attaching this piece to a cast boss on the top of the rear end housing. in 59, [and lasting to 64] this was changed to a pair of upper control arms.
the car was re-aligned [sheet posted now] and back on the road we went.
car rides better, handles better, but still has that constantly needed correction when on center.

so the only thing staying the same is the box. aside from replacing the bushings, ball joints etc just because.

yes, the car was bagged when converted to power steering.
the car drove like described from day one.
eliminating the bags made no difference [except in ride and handling]

yes, i can believe there are "nuts behind the wheel" ! laugh2

we definitely need to get the car in the air and tear it apart.
i believe we will start with seeing how smooth it is with the engine off, then with it running, put a slight input from a straight ahead position to see if it takes off on it's own. [as twostick suggested] will do this first at an idle, then at 2500rpm or so. then it's unhook one thing at a time to see if there is any binding anywhere in the system.

a couple things i haven't mentioned [if it really matters]. first, this car has an "X" frame, not really known for being stiff [think "flexy flier"] 2nd, when this was converted over to the power box, we removed the front sway bar because the pulley added to drive the power pump took up the space where the sway bar was, and we never put the bar back. third, we have no idea what pulley sizes are to be used with this box [currently a 6 3/4" crank pulley and a 4 1/2" pump pulley] and the vendor we got the box from has been no help with this, so we are flying blind here.

we REALLY appreciate you guys helping out a couple of old geezers with this issue ! bow
beer

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Posted By: Twostick

Re: power steering ??? GM 500 series box - 12/22/20 08:39 PM

I've read that these cars were prone to bump steer. With aftermarket tubular control arms etc it might be an idea if possible to track toe and camber change through its range of motion. If the geometry of the tubular arms is different than the stock ones, it might make a somewhat minor issue into something much more noticeable.

How good is the guy running the alignment machine? Lots of potential for error there too.

Kevin
Posted By: moparx

Re: power steering ??? GM 500 series box - 12/22/20 09:31 PM

you may have a point about bump steer. that was neither thought of, or checked.
i have a dual gauge toe plate i used to check that when i designed and built the front suspension for my 33 dodge humpback panel truck [the ENDLESS project grin] i'll have to dig that out and check the toe curve as well as the camber curve.
i should also point out the reason we went to tube control arms was the original arms were modified for the bagged suspension.
however, both suspensions have the same characteristic symptom.
i thought about the guy running the machine as well. however, this shop has been around for at least 70yrs [and maybe longer], and it has a stellar reputation when working with all types of modified rides as well as heavy trucks.
still more ideas you bring to the table for us to try, and we THANK you ! up
beer
Posted By: ruderunner

Re: power steering ??? GM 500 series box - 12/23/20 01:25 PM

Rebuildable center link end? Didn't those cars would have that. Are you sure you didn't crank the end cap in too tight and bind up the socket?

Maybe back the cap off a notch or two and see what happens.

Edit, you should be able to visually check the preload on the center link end. Rock the steering wheel back and forth with the front tires on the ground. The stud should move slightly in the socket as the springs compress and take up the slack. No play indicates the springs are in coil bind and too tight. This could be exacerbated by a worn ball that isn't perfectly round anymore.
Posted By: moparx

Re: power steering ??? GM 500 series box - 12/23/20 05:09 PM

this thing does have the rebuildable center link, and there is no play in it, so you may be on to something there !
it certainly is worth a try.
beer
Posted By: ruderunner

Re: power steering ??? GM 500 series box - 04/28/21 09:07 AM

Bump. Sounds like you're back to it.
Posted By: moparx

Re: power steering ??? GM 500 series box - 04/28/21 03:46 PM

yes. thanks for the bump ! up
i have a flow valve coming for the type 2 pump that is supposed to cut the flow from 3gpm to 2gpm. however, i got a covid notice saying delivery of that valve "may be delayed".
anyway, the car is on stands at the moment, changing rear gears from 3:36 to 3:08. waiting on a crush sleeve for that setup.
beer
Posted By: ruderunner

Re: power steering ??? GM 500 series box - 04/28/21 04:18 PM

Yeah, saw you asking questions elsewhere. So what vehicles use a 500 series box? Can you get a used on to swap in and try?
Posted By: moparx

Re: power steering ??? GM 500 series box - 04/28/21 05:11 PM

Originally Posted by ruderunner
Yeah, saw you asking questions elsewhere. So what vehicles use a 500 series box? Can you get a used on to swap in and try?


that's a good question. i'm not sure this isn't just a performance part made to fit different applications.
it is a 14:1 ratio, and the steering wheel is 14" in diameter. the tires are 215-70R-14 if that makes any difference. the tires are new, and yes, this thing did the same constantly-correcting thing with the old, funny wearing tires that was on it before.
beer
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