Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[feeutfo]

Should add, on re reading, I haven't mentioned the extra stiffness approaching full lock on bith sides disappeared as we drove off at slow speed around the close to test It further.

As if the problem was building up with aggressive use of lock, but drive sensibly and the problem whent away.


I shall have to try and find a big empty car park and try turning circles left then right etc. see what happens.

[Kevin Wood]

I shall have to try and find a big empty car park and try turning circles left then right etc. see what happens.

Yep, you can test the LSD at the same time, and lose some more release agent from those tyres. 

I would be interested how it feels when turned lock to lock with the front wheels off the ground, both engine on and off.

On checking Opel oem the pipes are feed/return between pas pump and box/box to reservoir.

Odd they should be at ambient, and the reservoir be so warm to the touch.

Engine had been stopped for a few minutes. I'm guessing they had already cooled off. We should have fired it up again to double check. There must be flow through them, or the system wouldn't work at all.

[2woody]

will 0103 on the box be a date code ?

I have on occasion been able to get the PAS fluid to boil if the steering box is mal-adjusted (too tight on the damper usually)

isn't it approaching the time where you should just change the box and pump anyway, to save any more wasted effort ?

[feeutfo]

Time...? No I don't think so. Identifying the exact fault seems more important to me, esp when it comes to wasting effort. Tbh.

All I've done so far is change the relay.

Pump and box I'd expect two see out 150k normally. And change to what? New parts? Anything available will be older from a breakers.

[Andy H]

Should add, on re reading, I haven't mentioned the extra stiffness approaching full lock on bith sides disappeared as we drove off at slow speed around the close to test It further.

As if the problem was building up with aggressive use of lock, but drive sensibly and the problem whent away.


I shall have to try and find a big empty car park and try turning circles left then right etc. see what happens.

Hot oil is less viscous than cold oil so it makes sense that the available pressure drops off as the oil heats up.

There are so many possible ways in which you could be losing pressure that I can't see how you can positively identify the problem without stripping down the pump & steering box

[feeutfo]

Given the pressure relief valve is operating, as Kev says, there doesn't appear to be a problem with lack of pressure.

Must admit I'm a little suprised at the pile and change this and that approach.

[Andy H]

So......
Pump believed to be good
Relief valve believed to be good
Servotronic relay probably OK
Servotronic valve probably OK

how about
piston seal?
Shuttle valve?

Have you considered using a stethoscope to try and identify where the shushing noise emanates from?

[feeutfo]

Why do we think the servo tronic valve is ok?

Piston seal? Shuttle valve? Where are they?

There is whirring noise from the pas pump when the relief valve opens. There is a suction noise coming from the breather hole in the pas reservoir cap when the pressure is released...Ie as the pressure is taken off/released from full lock.

Both noises where quite audible, and repeated on Kevs car. So considered normal I guess...?

[feeutfo]

Ps. Intend to play around with this tomorrow.

Test the lock to lock stiffness and try and see what aggravates that.
When it occurs jack the wheels immediately and see if the stiffness is still there.
When jacked remove the heat shield to box, if I can, and see where this bloody solenoid is, and see of it can be removed, filter cleared or whatever etc.

[Andy H]

Why do we think the servo tronic valve is ok?

Piston seal? Shuttle valve? Where are they?

There is whirring noise from the pas pump when the relief valve opens. There is a suction noise coming from the breather hole in the pas reservoir cap when the pressure is released...Ie as the pressure is taken off/released from full lock.

Both noises where quite audible, and repeated on Kevs car. So considered normal I guess...?

There is a big piston that drives a rack to turn the output shaft. When I rebuilt the power steering box on my Range Rover it had a piston seal that looked like big plastic piston ring. I wasn't sure if it was made of Nylon or PTFE

l don't know if I got the name right for the control valve I am fairly certain that I have seen it called a shuttle valve somewhere

[Andy H]

Spool valve..............

[TheBoy]

Time...? No I don't think so. Identifying the exact fault seems more important to me, esp when it comes to wasting effort. Tbh.

Once you have ruled out problems in steering system beyond the box, you are running low on options .  That leaves pump or box

Pump and box I'd expect two see out 150k normally. And change to what? New parts? Anything available will be older from a breakers.

Never really heard of boxes needing replacing, so assume they are normally good for the life of the car. MV6 is on 189k, no apparent issues with steering, aside from the PAS pump being replaced 2 or 3 years ago (usual low speed lack of assistance)


Thinking aloud, not sure if its been done, worth loosening the damper signifiacantly, in case thats causing stiffness in it - enough to cause hydraulic pressure to be too high?

[feeutfo]

Yes that's next job after writing this.

After another test drive...
On a quiet. Business park, driving as slowly as tick over would allow, turning from lock to lock as quickly as possibles from side to side and trying to turn as hard as possible, caused no real change in stiffness. Although it is stiffer than a normal car as we know. Pas reservoir was roughly the same temp to touch as on Kevs drive, but the pipes behind the bumper where equally warm.

Pulling up to an uphill junction with full lock, and the car not creaping as the hill is holding the car stationary, provides a noticeable increase in stiffness almost exactly as it showed approaching Kevs drive. That being almost too heavy to turn in the last 90degrees of steering wheel rotation.

Now, allowing the car to roll back while turning the steering back and forth in the last 90degrees of steering wheel travel with car in neutral, to allow the revs to rise to about 3000rpm on the throttle, showed a marked improvement, the steering was much lighter. But still showed an increased stiffness in the last 90 degrees of travel.

Thinking change pump.
There may be other issues as well, but the increase in rpm on lock with no engine load does make the steering lighter. The last 90 is stiffer anyway on a normal pas car is it not? Due to the.... Now how the hell am I going to explane this in words ...the end of the travel of the outside ball joint works on a radious. So the easiest point of travel will be with wheel straight ahead like so
 wheel|_______|wheel
But as the lock is reached in the last 90 degrees of steering wheel travel like so
 wheel/______/wheel
the outer ball joint is travelling forward at the end of it's radious

So it WILL get stiffer at the end of travel near full lock. Add in a reduction of say 30% assitance and the last 90 becomes very stiff indeed.

Does that make sense.

Edit to alter the upside ball joint to outside ball joint. Bloody crapple.

[Andy H]

Time...? No I don't think so. Identifying the exact fault seems more important to me, esp when it comes to wasting effort. Tbh.

Once you have ruled out problems in steering system beyond the box, you are running low on options .  That leaves pump or box

Pump and box I'd expect two see out 150k normally. And change to what? New parts? Anything available will be older from a breakers.

Never really heard of boxes needing replacing, so assume they are normally good for the life of the car. MV6 is on 189k, no apparent issues with steering, aside from the PAS pump being replaced 2 or 3 years ago (usual low speed lack of assistance)


Thinking aloud, not sure if its been done, worth loosening the damper signifiacantly, in case thats causing stiffness in it - enough to cause hydraulic pressure to be too high?

Damper?
There should be two adjustments on the steering box
1. adjusts the height of the sector arm to take out the free play between the worm and roller
2. adjusts a pad that holds the rack on the piston in engagement with the gear teeth on the sector arm/output shaft.
If either of these are too tight they will cause the box to bind.

[feeutfo]

Damper loosened. Good half turn. Eeeeyerchh not nice to drive at all, loose and unresponsive dead ahead. But crucially no different lock to lock. Re adjusted to where it was. Can't see a problem there...