Power steering bleeding

[mjb]

I've just replaced my high pressure PAS pipe, syringed out all the old (dark brown/orange) PAS fluid, filled up with new PAS fluid, and tried - unsuccessfully - to bleed the system.

I couldn't figure out how to get at the pipe connection to the rack so I replaced the pipe section between the pump and the front side of the subframe

The car's front end is still off the ground (about 6" between wheels and floor), there's no visible leakage, and the fluid level is just above the 'max' line after the engine's been running. The PAS pump pulley is turning without noise. I have turned the wheel many, many times left to right with the engine both off and on.

With the engine off, turning away from centre too quickly causes the fluid level in the reservoir to overflow. I can see this while turning the wheel and reducing the speed so it stays just shy of overflowing shows it bubbling. Stopping movement or steering towards centre shows the level drop to above max. 50+ left-right turns (both fast and slow) and no change.

With the engine on, it doesn't overflow. There is however a violent shaking on the steering wheel and road wheels when the steering wheel's turned. Looking into the reservoir shows fluid is being pumped around at a fair rate.


Any idea what's wrong?

[steve_earwig]

No idea, but it does sound like there's air still in it. I think if the level falls when the engine starts then this is the air being compressed. Not sure what the trick is, apart from leave it overnight, do the lock to lock thing again. Good luck!

[teamster1975]

That's really weird. I did exactly the same job on Saturday, ditched all the old fluid, fitted replacement high pressure pipe, refilled, lock to lock several times with ignition off, top up, lock to lock again with engine running, top up to correct level and all is fine.
I wonder whether it'd be worth dumping the fluid again and refilling? When I drained mine off I disconnected the HP pipe from the pump & the union that sits on the subframe below the steering box, I didn't need to syringe the reservoir out as it pretty much all drained out.

[Welly]

Might simply be because the front end is raised from the floor?

[teamster1975]

Might simply be because the front end is raised from the floor?

Sounds plausible, if that's the case Matt may swear a bit!
I must be honest mine was back on the deck when I refilled it.

[mjb]

Might simply be because the front end is raised from the floor?

Sounds plausible, if that's the case Matt may swear a bit!

"bit"?

I must be honest mine was back on the deck when I refilled it.

I thought about that, but I've currently got a stack of pulled muscles in my neck/shoulders, so that wouldn't be much fun, especially the following morning... Guess I could drop the car by a good few inches though...

[Welly]

Well knowing how 'awkward' the 406 can be about venting the coolant system I wouldn't be surpised about the level thing here.

[mjb]

I thought the pas reservoir looked quite sensible though - suck in through the bottom and spit out at the top

Mind you.... it spits out at the front of the top (partly above fluid level when jacked high), and now you've got me thinking about it, it probably sucks in from there too when the pump's not turning. That would definitely explain it!

[Welly]

I thought the pas reservoir looked quite sensible though - suck in through the bottom and spit out at the top

Mind you.... it spits out at the front of the top (partly above fluid level when jacked high), and now you've got me thinking about it, it probably sucks in from there too when the pump's not turning. That would definitely explain it!

I bet you can't wait to get home now

[teamster1975]

Waiting in anticipation Matt!

[mjb]

Dropped it onto the lowest my axle stands would go so the wheels were about 1/4" off the floor, filled the reservoir to 1/2" from the brim, and lo and behold all the air came out!!!

However, the shaking's still there when turning with the wheels off the floor. Drop the car and the vibration's gone Horribly light steering now though

Does anyone else's PAS vibrate when the car's in the air, or could it be to do with the fact the rear section of the HP pipe looks like it should be attached to something (there's a bracket thing) but ain't (and from the cleanliness of the bracket, has never been )



CRAP! Someone remind me to plug in my reverse light switch! I noticed the wire dangling while under there, so it can't have been working since the last clutch change!

[steve_earwig]

I remember my D8's wheels doing the hokey-cokey when they changed that pipe. I think Mika just carried on bleeding and it went.

[teamster1975]

Maybe that happens when there's no resistance on the wheels Matt? I don't know, I've never tried the steering with the front jacked up. Glad it's sorted anyhow.

Plug in your reverse light switch!!!!

[mjb]

I'm hoping it's that too, or maybe the vibration's always there just dampened by the weight on the wheels...

[poddack]

Flushed mine the other week, just took off the top reservoir pipe, attached another to it, ran the engine and bled the system into a bucket, re fitted it and filled up with new.
Slow lock to lock a few times with the engine running and check/top up, no problems.