hydro assist steering problem

[Goatman]

I'm trying to get to the bottom of a problem with the steering on the buggy. It works fine until the steering gets worked hard, then as it heats up it gradually quits working. It may be as simple as having another bad pump, but......

I'm wondering what parts you guys with hydro assist are using, and what, if any, problems you've overcome. I currently have a stock steering gear, PSC TC pump with the stock resevoir, a Rocklogic 1.5" ram, and a large cooler.

 

[Lincoln]

It's the coolant sensor.

 

[Goatman]

It's the coolant sensor.

You mean it doesn't sense enough coolant? :moon:

 

[vetteboy]

As long as you've got the cooler in there, I'm not sure what the problem would be.

I finally got my rig rolling today and worked the hydro assist pretty hard, and the only thing I noticed was that it was slow. Like, when I turned it at a reasonable rate I had more than enough assist, but if I tried to crank it lock-to-lock it would lag a little bit. So I think I'll be modding my pump for more flow.

Have you done any mods to the pump? I'm running a stock pump to the stock steering box (drilled and tapped), with the 1.5" x 8" ram commonly used. I don't have a 'cooler' per se but I plumbed in a hydraulic filter for more overall system volume. The only thing I can think of in your case is that the fluid thins out when it gets warm, and the pump looses efficiency because of it, which means more effort.

So you're saying that as you work it more, the power assist gradually fades out? Like, eventually the steering requires more and more effort for the same amount of movement? Kind of a weird experience, IMO.

 

[brent]

richard, I don't have a cooler, and have had no problems, I did have to drill out the outlet to the pump so at lower rpm I could turn, and even now in low rpm I tend to oversteer the ram, a little patience or rpm cures that.

I'm running the stock box, pump and same ram.

 

[xj4moab]

I have the same problem with the Cherokee. The only difference in my set up to yours is I am running a stock XJ pump.

 

[Goatman]

I even have the smaller 4.5" pulley which helps the lower rpm effort, works nicely. My yellow XJ is slightly slow at low rpm, so it's going to get the 4.5" pulley.

My pump is a brand new PSC pump, which is supposed to be worked for better performance. It's possible that the pump just isn't up to snuff. The other rig has an AGR stock style pump and stock reservoir with a 1.5" ram and a Tommy Lee steering gear, and it works just like it's supposed to. On this one, I'm getting comments that I need a higher capacity pump and a larger remote reservoir. I just don't want to keep chasing this, as it's already the second pump (1st PSC pump), so wondering what's working for you guys. I don't mind putting a little more into it, but I don't want to put a lot more into it or I'll just go full hydro........which I don't have the funds to do right now.

 

[nhrocker]

Probably a stupid thought on my part, but how's your high pressure hose doing? Could it be slowly collapsing or kinking as it warms up? That could kill your turning power.

 

[jmop]

I haven't been able to work mine hard in a while, but I'm running the stock pump modded for more flow and a 2" bore ram. It is a little slow a times but I've never had it quit working.

How long does it take before it quits working? Is that on the trails or will it do it on the road. I would think there is something wrong with the pump.

What type of power steering fluid are you using. I went to that Vavloline symthetic and I would highly recomend it.

 

[Goatman]

It works good indefinitely if it doesn't get worked hard......which is weird. If I run down a trail fast where I'm working the wheel quickly, or if I'm on an obstacle where the manuevering is tight so I'm turning a lot, it will virtually loose the power assist.

I can change to synthetic, but I don't want to do that if I'm just going to be tearing it apart again. It's looking like this pump needs to go back to PSC. I'm kinda wondering what there might be that could cause one system to have numerous pump problems while another system just bolts up and works like it's supposed to. Other than real bad luck.

 

[Captain Ron]

You've still got along way to go Richard. I'll briefly outline the steps for you.

1. Replace pump. (You've already done this step...)

2. Drain fluid, Bleed.

3. Replace pump.

4. Drain burnt fluid, be extra vigilant bleeding system.

5. Replace pump.

6. Drain burnt fluid, Overfill just slightly.

7. Clean up mess from blown resevoir cap. Replace pump, drain... you get the idea.

8. By now, you be making every other trail, but you'll only be able to turn right.

9. Remove steering box. Dissasemble spool valve. Call local scrap guy to come pick up all the metal shavings removed from spool valve. Go get a rebuild kit. Hone bore to remove 1/16" gouges from metal shavings. Look in disgust at the destroyed seals you put on because the spool valve is beyond repair. Reassemble, because you did this the night before a run.

10. Whola! You can turn left now. Turning right is overrated.

11. Wait 2-3 weeks to get new steering box. Install.

12. Replace pump.

13. Drain burnt... You know this part.

14. Now that it works, don't open the hood.



Richard, check the steering box. It sounds like the 2 center seals on the spool valve are bleeding as the viscosity drops with heat.

--ron

 

[Goatman]

So, now I wonder is it easy enough to rebuild the steering box myself, or worth it to send it down to Tommy Lee? Who's rebuilt their own steering box? I see rebuild kits are cheap.

I also wonder if my new pump is already bad. I see that I need to flush the system and replace all the fluid, clean out the ram, etc.

New (rebuilt) steering box, and on the third pump.........

 

[jmop]

I've rebuilt a couple of steering boxes. It is pritty easy. A press helps but there really arn't any special tools required.

 

[Lincoln]

Have you talked to PSC or Tommy yet? My thoughts are it's either fluid or the box. Wasn't it kind of acting like this before you changed the pump last?

Mine actually seems to work better when it's warmed up. I'm running the P pump and I think the pulley is a little on the big side. Low idle turns are fine unless you drive to move it quickly then it seems to lock up. Anything above and idle works perfect. No cooler but PSC told me I should put one on. I'm running the high dollar GM fluid in the cold weather formula.

 

[Captain Ron]

The one thing I have not had to do is play with the ram. The great thing about the spool valve is that it traps just about everything. If something does get past the last outer seals, you can "bounce" the steering off the stops. The pressure rise will push anything thru the valve short of Boulder Colorado. Anything that gets thru the valve at that point will not be big enough to stay in the ram, even being the low point.

As I suggested, rebuilding the spool valve is not such a great idea. The bore has to be better than 125 rms finish, not something you can do with the average hone. Being overbore doesn't help the seals either. Most places sleeve the bore right from the git go.

On the valve itself, one tiny little nick in the seal grooves and your history. Even with tiny diamond files, it's next to impossible to fix unless your very lucky. On the surface of the valve, you may be able to knock down the high spots, but the surface finish requirement is even higher. Why, because those tought little hi temp viton seals do not stretch very much at all, and if it snaggs on something while feeding it over the first, second, and third grovves, it's history.

My system finaly started to work together after figuring everything out individually, then replacing the pump and box together, and making sure it did not suck air the first time under power. Bleed, bleed, and bleed again if in any kind of doubt.

Of course the final thing was the pump groaning. It was doing it for a few runs. In adhearance to step #14, it went away on it's own, and has worked ever since.



--ron

--PS: If you do rebuild the valve, leave to old seals on it if you can, or get a sacrificial set. Leave the outers in place and cut the inside one you want to do out, slide the new seals over the outers, you'll be less likely to nick or twist the little suckers this way.

 

[jmop]

If the bore is bad on the box why even bother rebuilding it? Last box I pulled out of a yard was like $10 or something. Pull it apart and if it isn't bad, drill n tap, replace seals and reasemble.

I didn't have any problems getting the seals on the spool valve. They were a bugger to make sure they didn't twist but not imposible.

 

[Goatman]

Hmmm.......I would love to go cheap, but more importantly I want it to work right when it goes back together. I kind of hate the cost of sending the whole thing to Tommy Lee, but I am confident that if they get the pump, box, and ram that it will work when I get it back.

Damn. I want the steering to work on the buggy, and I have some money set aside for a new turbo housing and 4 position chip for the truck..........truck or buggy....truck or buggy.

Another problem is that if I have to spend $5-600 yet on making the steering work, I'm halfway to full hydraulic.

 

[uglydog]

go with psc 4.5 zero offset pulley and get a hd sterring box and run royal purple fluid[no trany fluid per psc ,see web page tech artical] should take care of problem

 

[Goatman]

I decided my next step is to add more cooler, since heat is obviously part of the problem, and use synthetic fluid. I got a few quarts of Red Line. I already have a 4.5" pulley, which is one reason the system works perfectly before it gets worked real hard. I am most likely going to get a new steering gear, built for hydro assist rather than a stock gear that's been ported. I'll see how it works next weekend with the new fluid and increased cooling, then get another gear if it still has a problem. Then, if it still has a problem, I'll send the pump back to PSC for a another one.

 

[VegasAnthony]

richard, I don't have a cooler, and have had no problems, I did have to drill out the outlet to the pump so at lower rpm I could turn, and even now in low rpm I tend to oversteer the ram, a little patience or rpm cures that.

I'm running the stock box, pump and same ram.

sorry to Hijack richard but im putting a new pump and a 4.5" pulley this week and need to know about this


well how does one do this?