hydraulics genius needed

[bluebus1987]

I have a non vw steering rack that I have just replaced the pinion seals on. With the rack back on the car the first time the rack would turn and then hydraulicly lock. If it was backed off a bit it would turn and lock again. I came to the conclusion that I had very stupidly transposed the feed pipes to either end of the cylinder ( meant to take a pic before disassembly but didn't). With the pipes reversed ( with the aid of a photo of very similar rack to confirm) fluid thoroughly bled, flow confirmed through the reservoir when pump running etc I am getting no power assistance at all. Have I f===ed it or am I still missing something. I'm not a complete novice at this sort of repair but I'm now completely stumped. I'd give up on this one but have put a lot of hours into the car and I am unwilling to give in if there is a possible solution.
Ta.

[silverbullet]

First off, whats the vehicle? Not meaning to pry but it may have some bearing on matters.
I would be suprised if it were possible to mis-connect the high pressure feed line to the return.

[bluebus1987]

Its the espace mk 2 I was on about.
Yes the lines will fit on both ways to the ports on the pinion housing pretty much perfectly. As you do, I thought there's no way I can mix that up. The way that looked right locked up. Feeling remarkabley stupid and frustrated right now. Fluid pumps through the system when you turn the wheel. I've been waiting over a month for a mounting rubber NLA from Renault from france to refit. Ended up having to get it sent to a friend in the far south of France so he could post it on to me. The cars not worth much at all but its hard to give up on a problem sometimes.
The rack is NSK, similar if not the same as R25. The only things I disturbed are the pipes and the pinion shaft.

[bluebus1987]

It has a nice 80s stylee dash pod with built in boost guage!

[silverbullet]

Have you seen the tech manual pdfs you can download from matrasport.dk?
Listed in the "vault"
http://www.matrasport.dk/Cars/Espace/vault/J63/" onclick="window.open(this.href);return false;

[bluebus1987]

Yeah, been there. Lots of realy interesting information but a big section of the manual is missing including steering. As with the downloaded manual I paid for and probably the hard copy thats in the post. It seems like there is one copy circulating with bits missing.
I'll keep on looking though.

[bluebus1987]

Right. Looks like I was not so stupid to start with. The reference image I was viewing ( clearest image I could find without logos) when I decided to reverse the pipes could well be a reversed picture of a left hand drive rack used to ilustrate a RHD rack. I'm sure life was easier before Google!
So back to square one. Rack off again. Not a simple job.
So the question is now, why was the steering locking when first reinstalled. Supply and return hoses wont interchange as far as I can remember. A rack should surely never lock due to a hydraulic fault or air in the system? Fluid pumps the right way through the reservoir.I dont think its possible for the pinion shaft/valve to be located incorrectly in relation to the other parts. The steering operates nice and smoothly in all other respects, with no tight spots or noises.
As you can tell I'm thinking out loud here.

[silverbullet]

If you have had the pinion shaft/valve assembly apart I would go back to the start.

[bluebus1987]

Yep, I think so.
I'd get a rebuilt rack if I could find one that isn't silly money. then there's the question is the r25 item the same in all respects?
So do you think the pinion/ spool valve / control valve is indexed to something. As far as I understand ( and I am capable of being a bit thick on occasions ) the torsion bar (which I believe it has) controls the the flow of fluid to either end of the cylinder regardless of the position of the infinitely rotating (theoreticaly) valve/pinion assembly. Or am I missing something fundamental.

[silverbullet]

In my limited experience (done more than a few pas steering boxes) the control valve/torsion shaft has to be set up correctly otherwise the flow can be biased to one side at the very least. Some are self-centring, others very very sensitive to adjustment.

[bluebus1987]

I'll take another look at it. Just spent the last couple of hours reading about hydraulic flow control, spool valves, torsion bars,bendix patents.............
When it comes down to it, took it out, put a seal on either end of it and put it back as it was. Read lots of scary stuff about specks of dust ruining whole systems. So as much as I want to continue the learning process, I'll have to call it a day if another session doesn't fix it.

[silverbullet]

Lip seals or o-rings? Is it possible that one got nicked or folded when it was reassembled?

[bluebus1987]

Lip seals, basicly what you'd call an oil seal on either end of the pinion shaft. Its six weeks ago now and getting a little foggy in my memory but I'm pretty sure I disturbed nothing functional and took as much care as I could to keep everything spotless, but it may be worth splitting it again to remind myself. The main problem is being an espace it takes half a day just getting the rack off. Renault/ Matra realy didn't consider repairs other than regular mainainace when designing this thing. And I swear they expect you to drop the engine to get to the upper mounting bolts.Its a very clever design for the time but I'd think hard before having another one. Having dealt with both renault and Peugeot recently It seems the French have taken the policy of only holding spares for current models.

[silverbullet]

Its just possible that one of the spring garters has popped off in assembly, it does happen sometimes but usually causes an immediate fluid leak.
Without an exploded diagram of the rack its pretty hard to know what could have been mis-positioned. My money is on the valve being 90 or 180 degrees out, it is balanced when off-load but the moment it is asked to turn you seem to be getting full pressure on both sides of the ram/rack piston so it locks up.

[bluebus1987]

Cheers for that, Not had a chance to look today as three small boys tend to fast forward your day a bit. Off for half an hour of football before tea in a minute.
I will start at the begining again as soon as I get a chance.
Plenty of racks out there for older renaults that look the same, but the illustrations are so unreliable its too risky to take a punt.
Vws are easy in comparison!