Psc steering and shock setting

kpig

kpig

Member
Someone, please explain this. I've had the PSC hydro assist on my JK for the last year along with a Prorock 44 with Prosteer ball joints. About 3 months ago after a trip to Hot Springs OHV, the steering became very twitchy on the highway. Since then, I have called PSC for advice and began troubleshooting by replacing anything that had any excess play. Still twitchy and wandering over 65 mph. I had the alignment checked. Caster at 5.7 degrees (pinion is still ok at 4.3 degrees). Toe was a bit high at 3/8", so adjusted to 1/16". Today, I remembered that prior to that trip I had the Fox shocks set on 3 or 4 of the 7 compression settings. The shocks have been at full compression 7 of 7 since then. I would think that the higher compression setting would overcome the twitchyness and darting on every road imperfection. Well, I lowered the compression setting back to 3, and voila, tracks straight and no more twitchyness all the way up to 80mph. What the heck? Someone please explain how the heck a simple shock setting can cause such grief.


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The shock is so stiff that it isn't allowing the axle to travel. So your basically bouncing over the road rather than floating over it if that makes sense
 
Makes sense. I'm just a bit shocked (pun intended) that it would make that big of a difference. I'm a bit concerned because I am planning on the DTD, but I don't want the twitchyness to come back having two shocks at each corner. Thanks for the reply.


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kpig said:
Makes sense. I'm just a bit shocked (pun intended) that it would make that big of a difference. I'm a bit concerned because I am planning on the DTD, but I don't want the twitchyness to come back having two shocks at each corner. Thanks for the reply.


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Click to expand...

I wouldn't be concerned with that set up. It's way more adjustable than your current set up so you can really dial in the ride with different spring rates, compression and rebound rates and so on. Tons of combinations to be had
 
kpig said:
Someone, please explain this. I've had the PSC hydro assist on my JK for the last year along with a Prorock 44 with Prosteer ball joints. About 3 months ago after a trip to Hot Springs OHV, the steering became very twitchy on the highway. Since then, I have called PSC for advice and began troubleshooting by replacing anything that had any excess play. Still twitchy and wandering over 65 mph. I had the alignment checked. Caster at 5.7 degrees (pinion is still ok at 4.3 degrees). Toe was a bit high at 3/8", so adjusted to 1/16". Today, I remembered that prior to that trip I had the Fox shocks set on 3 or 4 of the 7 compression settings. The shocks have been at full compression 7 of 7 since then. I would think that the higher compression setting would overcome the twitchyness and darting on every road imperfection. Well, I lowered the compression setting back to 3, and voila, tracks straight and no more twitchyness all the way up to 80mph. What the heck? Someone please explain how the heck a simple shock setting can cause such grief.


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Click to expand...

I have a PR44, PSC ram assist, Dynatrac PRO Steers and Rancho 9000's - I can set the rancho's at their stiffest setting when traveling and will hit 80+ mph without the wandering you're describing - I don't purposely take that speed but sometimes I have a good tailwind ;

What's your tire pressure set at? I put mine to 37 when traveling, 32 around town - 37's BFG KO2

When I 1st had the PR44 installed, the shop put too much caster in it and i was getting wandering, I took it closer to 4* and no issues since.

Also check your PSC fluid level to make sure you don't have a leak or an air bubble but I'd put my money on the caster

The lower level on the shocks may actually have been masking the problem all along
 
Have you checked your unit bearings? More or less that's something that I find can play and with my PR44 I had to replace them twice last year and it help tremendously with this issued (I'm running your same set up).

Also check the usual: track bar torque and ends, drag link torque and ends, tie rod torque and ends....
 
jeeeep said:
I have a PR44, PSC ram assist, Dynatrac PRO Steers and Rancho 9000's - I can set the rancho's at their stiffest setting when traveling and will hit 80+ mph without the wandering you're describing - I don't purposely take that speed but sometimes I have a good tailwind ;

What's your tire pressure set at? I put mine to 37 when traveling, 32 around town - 37's BFG KO2

When I 1st had the PR44 installed, the shop put too much caster in it and i was getting wandering, I took it closer to 4* and no issues since.

Also check your PSC fluid level to make sure you don't have a leak or an air bubble but I'd put my money on the caster

The lower level on the shocks may actually have been masking the problem all along
Click to expand...

I've been running anywhere from 24 to 32 psi with minimal effect.

I'll try decreasing the caster a bit too.

I've checked and re bled the system soooo many times. Can't find any leaks.

Thanks for the suggestions.


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tgoss said:
Have you checked your unit bearings? More or less that's something that I find can play and with my PR44 I had to replace them twice last year and it help tremendously with this issued (I'm running your same set up).

Also check the usual: track bar torque and ends, drag link torque and ends, tie rod torque and ends....
Click to expand...

The unit bearings are the only thing I haven't changed out. I checked them but can't detect any discernible play. Other than pulling on the hub is there another way to see if they are bad. The alignment showed 0 degrees camber on both sides.


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I have a new fitting coming from PSC to try to restrict a bit of fluid volume from the pump. With the gearing at 5.38, PSC suggested trying it out to make the ram a bit slower at such high rpms at highway speed.


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I'd be much more likely to start with either loose bolt somewhere or chalk up the difference to tire wear.
 
Update. Pulled the ram after seeing the ram pushing with the slightest steering input before the pitman arm began to move. Basically the ram was trying to steer before the pitman arm began to steer, so they were kind of fighting each other. With the ram removed, everything steers dead straight. I would hate to lose the ram assist.

Would a slowing the flow from the pump slow the ram input a bit, or does the box have to be rebuilt/revalved?

Thanks in advance.
 
kpig said:
Update. Pulled the ram after seeing the ram pushing with the slightest steering input before the pitman arm began to move. Basically the ram was trying to steer before the pitman arm began to steer, so they were kind of fighting each other. With the ram removed, everything steers dead straight. I would hate to lose the ram assist.

Would a slowing the flow from the pump slow the ram input a bit, or does the box have to be rebuilt/revalved?

Thanks in advance.
Click to expand...

Now THAT is interesting. Subscribed. I do not have any insight into the problem but do plan on following this thread so I can see what the deal is when it is uncovered. :eek:
 
try this, with the ram collar on the tie rod loose turn full lock to passenger so the ram is all the way in mark that location then turn full lock driver causing the ram to extend full and mark that location. mark the location on the same side of the collar for each direction


measure between the marks, it should measure the same length as your ram.

find the center between the marks and lock the collar to the center marking see if that gets it in sync with the pitman arm.

There is also a little adjustment in the back of the ram to shorten it a bit, I recall I was having a similar issue when mine was 1st installed because the ram was too long and I was able to adjust it by shortening the ram just slightly.

I'm not home to take pics but will later on .
 
jeeeep said:
try this, with the ram collar on the tie rod loose turn full lock to passenger so the ram is all the way in mark that location then turn full lock driver causing the ram to extend full and mark that location. mark the location on the same side of the collar for each direction


measure between the marks, it should measure the same length as your ram.

find the center between the marks and lock the collar to the center marking see if that gets it in sync with the pitman arm.

There is also a little adjustment in the back of the ram to shorten it a bit, I recall I was having a similar issue when mine was 1st installed because the ram was too long and I was able to adjust it by shortening the ram just slightly.

I'm not home to take pics but will later on .
Click to expand...

I know that at full lock to the right, I only have 1/4" shaft left. I'll have to try your measurement.

With no steering input, nothing moves, but turn the wheel ever so slightly in either direction, the ram pushes out or pulls in on the tie rod before the pitman arm.

Does the ram have to be centered in the middle of its throw? The directions call for it to be bottomed out at full lock, which is what I basically did.

Thanks for the insight.
 
kpig said:
I know that at full lock to the right, I only have 1/4" shaft left. I'll have to try your measurement.

With no steering input, nothing moves, but turn the wheel ever so slightly in either direction, the ram pushes out or pulls in on the tie rod before the pitman arm.

Does the ram have to be centered in the middle of its throw? The directions call for it to be bottomed out at full lock, which is what I basically did.

Thanks for the insight.
Click to expand...

the ram on mine was too long and I was able to shorten it a bit with the nut on the end of the ram tube but still not enough so I used the centering method.

it doesn't completely bottom out at full lock but it travels with the pitman arm movement a lot better. you may need to adjust your steering stop on the driver side after.
 
kpig said:
I know that at full lock to the right, I only have 1/4" shaft left. I'll have to try your measurement.

With no steering input, nothing moves, but turn the wheel ever so slightly in either direction, the ram pushes out or pulls in on the tie rod before the pitman arm.

Does the ram have to be centered in the middle of its throw? The directions call for it to be bottomed out at full lock, which is what I basically did.

Thanks for the insight.
Click to expand...

sorry I told you wrong how to measure for the length of the ram.

You want to use a square or something solid attached next to the pumpkin - this vid will help.

is you use my method using the ram collar it'll measure out wrong. this is the method I used to determine my ram was too long

https://www.youtube.com/watch?v=MF9IsrSVCUo
 
kpig said:
Update. Pulled the ram after seeing the ram pushing with the slightest steering input before the pitman arm began to move. Basically the ram was trying to steer before the pitman arm began to steer, so they were kind of fighting each other. With the ram removed, everything steers dead straight. I would hate to lose the ram assist.

Would a slowing the flow from the pump slow the ram input a bit, or does the box have to be rebuilt/revalved?

Thanks in advance.
Click to expand...

Any update on this? I think I am having the same issue.
 
I'm not certain of the issue you're having, but, the ram will move as soon as the wheel is turned the slightest bit. It will fully extend as soon as you move the wheel from center. It is fighting the steering box at times, assisting the other times.
 
The issue I have seems to be worst over 35 MPH.

Any little steering input results in the ram giving the steering a "push". To correct that push you turn slightly the other way. When you do that it pushes the other way.

So you spend you time looking drunk going down the road.

If you let go of the wheel it does fine. But the next time you need a slight course correction you are back to the pinball mode.
 
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