Power Steering Noise (or maybe something else?)

[SELfor50]

Hey All,

This problem actually occured the first day after the transplant, and then thinking it would be solved by swapping back to the old power steering pump (possible issue with seals in the new one after sitting for so long) I hadn't posted it yet.

But problem is still there. Hasn't actually occured for about 3-4 days now, so 'may' be gone but not sure. Maybe you can help me shed some light.


Firstly, I need to confirm that it is actually the power steering.

A whiny high pitched noise is present after prolonged driving and what appears to be a higher temp. On cooler nights it does also appear but not as much and only after a longer driving session.
It seems to be louder when turning a corner and is felt through the steering wheel. And louder again when turning if the throttle is pressed at the time.

I'll try and get a video of it, but maybe it's somethig someone has already experienced.

My feel is that it's air within the power steering line somewhere, but I thought these systems manual bled?! If not, where can I bleed it to ensure there is no air?

The noise (when present) seems to be from the steering box area and a little noise from the pump. And from within the car, it is definitely directly in front of the drivers position and almost sends a vibration through to the footwell (mainly where you rest your left foot on the stop in drivers seat).


I'm 90% confident that it's the power steering lines / pump / steering box, but due to the transplant, just want to make sure it's nothing else as well.

Any assistance appreciated.

Cam.

 

[John S]

The type of noise you are describing can come from air in the system, but it should disappear after driving it around a number of corners if the oil level is correct.

The only time that the noise does not go away (in my experience) is when the oil level is too low, so it may be worthwhile topping the reservoir up and driving around a number of corners to help the bleeding process.

 

[WGB]

If the fluid level is right "on the borderline" the pump will make a squealing noise when cold which goes away when warm.

If there is air it will make noise for a day or two until totally clear.

Genuine M-B power steering fluid is supposed to be quieter than auto trans fluid usually used.

Belts can make a noise - especially if they are pre-used and bottoming in the V.

There is a posting on another board on this noise and it turned out to be the rubber hoses disintegrating - the noise disappeared with a flush of the hoses.

The commonest problems with ex-storage hydraulics seems to be the rubber shaft seals being torn on inital startup as they are dry and sometimes sticking to the shaft - but that causes leaks rather than nosies.

I would top up the reservoir and drive carefully for a while and see what happens while checking for other causes of possible noise.

Bill

 

[BenzBoy]

and a little vaseline on the drive face of the V belts will help eliminate them from the equation. Don't try it on a toothed belt.
Regards,
Benz-Boy

 

[SELfor50]

Thanks guys, i'm 'pretty' confident it's air in the power steering.. only weird thing was the vibration through the floor.. but I'm guessing that's cause of the hot air in the power steering lines. It's definitely temp/prolonged driving related. It never happened on the first couple days till it got warm or was driven for a while.

Belts could be a possible cause, but it would be weird that it's accented on turning. I might pull out the vas anyway and just steer clear of the toothed belts.

Bill, I always drive carefully.

Cheers,
Cam.

 

[TJ 450]

Yep, you can get a vibration if there is air in the system. It has to do with the pressures involved and the fact that there are what appear, relatively speaking, to be voids in the fluid. The pressure difference results in shock waves propagating through the lines.

Tim

 

[Styria]

It looks as though the problem has gone away - am I correct in assuming this ? Generally Cam, the self bleeding system is very effective and responds quickly. I normally jack up the front, and turn the wheel from side to side without the engine running. It doesn't do much, but it just 'gets the eye focused' - so to speak. Then simply start the car, repeat turning process, switch off engine, and check the fluid level - you also need to wait for the oil to stop frothing.

The high pitched noise - could come from the pump for the PAS, or even the pump for the suspension system - I guess that one you can eliminate. Right ? The knocking noise is a strange one - I must admit that I've not experienced that situation, but doubt if it'd come from air in the system. Could the engine down pipe be touching the body anywhere ? Anyway, have been following your efforts with a great deal of interest. Regards Styria

 

[SELfor50]

I think it might have gone away.. Haven't really done any extended driving this week so far (since it occured last time). Just short trips to and from work. There's no real "knocking", it was more just that there was a vibration through the floor well. But as stated, I think that if the hoses have air and pressurised, could definitely make this noise. Sorta like a kettle boiling on crack. hahah...

Don't think it would be downpipe, there was slight touching previously but we re-jigged it on re-install to fit it better.. and if it was touching - it would be more of an end of the world sound rather than a high pitched noise.

 

[SEL_69L]

I used to be quite familiar with the noise that you describe, when I originally acquired my 6.9. I have had three cars now that have all made their own distinctive noise when on hard left or hard right. The solution to the problem is to always make sure that the power steering fluid reservoir is filled.

With one of the other cars I had, the problem started because one of the hoses from the steering pump ruptured. The hose was replaced, and the noise almost completely dissipated. I suspect that in this case, there may have been some slight damage to the pump, but it continued to function for another ten years after that.

 

[SELfor50]

I's weird.. swapped the pump, same noise.

Happened again pretty bad last night, but only after a lot of smoke billowed from the rear wheel arches. So, post 'revving' analysis is.
The car was sitting at about 5000rpms for about 15seconds, and the noise appeared straight after and was amplified on turning the wheel.. sorta like a whining / grinding sound.
I'll check it on Friday when I pick the car up and try some vas on the fan belts, and double check fluids etc. It seems to be something related to higher / more revolutions of the system. Doesn't appear to be from extensive steering or temp related cause it appeared straight after and I hadn't done any turning of the steering wheel.

Me thinks i'll have to get a video uploaded after I pick the car up.

 

[Styria]

Hi SELfor50, puzzling alright - tell me, why did you hold it at 5000 for 15 seconds, and also why is it blowing smoke from 'the rear wheel arches' ? Are you not yet satisfied with the way the car is running, or the engine ?

The gearbox - is it your original box, or is it one that came with the package deal ? I seem to recall that you had some problems with the box with flaring, not changing properly etc. Is it an Australian box with the auxiliary pump, and in the course of the transplant, did you guys carry out not so much modification, but changes ? You know, did you do away with certain fittings and/or pipes ? Don't be surprised if the problem is in that area. I know oof one 6.9 that, when pushed hard in the low gear, or if 1st gear was selected manually, the drive train (I think the box) came up with some quite significant noises and howls. Just drawing from some of my experience. Regards Styria

 

[SELfor50]

The rpm test was part of a stationary Italian tune up.

Very interesting what you say about the gearbox.. when the noise is apparent, I can't exactly rule it out from being from the area around the bell housing / torque converter.. so will investigate further there. I just assumed it was around the steering box.

Gearbox was part of the package deal, and as you pointed out to me yesterday - I can assume it's a Euro gearbox also.

Cam.

 

[SELfor50]

Thanks for your help Styria, you were pretty close..

It's not power steering at all.

It's the Gearbox. 99.9% confirmed. It's only when it's hot (atf fluid getting thinner) and only between about 500-2000rpm's.. disappears after that.

Sitting idle after a lengthy drive, the sound is there.. then when you tap the accellerator, it gets noisier between the above rev ranges.
I put my head under the car and it's from around the torque converter.

It seemed like power steering cause of the area it sounds like when in the car. But now it also confirms the vibration that's felt in the footwell when it appears (thought that was caused from the steering box previously).

Next step will be to remove the gearbox, swap torque converters.. and see how we go.

 

[Styria]

Hi SELfor50, don't rush into removing the box at this stage. First of all, I would remove the gearbox sump and also change the filter. You could also, no you should also, remove the valve body and either clean that in petrol or, better still, refit the valve body from the old box - if you've still got it. I tend to think your problem is in the valve body.

You could, and again should, remove the Allen headed drain plug from the torque converter to drain out any oil although, having said that, removal of the valve body will drain just about all of the oil. Also pay close attention to the two seals for the connecting tubes beween valve body and the central casing carrier. Good luck with the job. Oh, BTW, removal of the valve body will also enable you to pressure test the three bands - look for about 4mm between release and application of the bands #2 and #1 - i.e. rear and middle. #3 has a different clearance rate. Regards Styria

 

[TJ 450]

Yikes, if the noise is from the trans, then that is a concern. It sounds like the front pump to me, but the valve body is always a good place to start as per Styria's post. If you do it, take a note of the amount of debris trapped in the valve body maze.

I would quadruple check the plumbing in case something has been mixed up or is blocked in the cooler loop.

Tim

 

[SELfor50]

Ok.. will try a few of those things first. Will definitely be looking for debris within the valvebody.

Will also check all the plumbing. I'm pretty confident it's done right, but will do good to get it on a hoist and then go back over everything. Probably didn't spend enough time double checking all the gearbox connections etc, mainly due to wanting to get on the road.

Engine's been running warm too, but that's 99.9% due to the viscous hub - which is very stiff. new one of those coming next week.
So, with the fan running like that - it's probably not helping the trans cooler too much.

Cam.

 

[BAR]

If your viscous coupling for the fan has gone: then the clutch will be 'locked' and the fan will be running all the time.

This will result in a lot of noise coming front the fan and may be why you get vibration. When mine was 'locked' it really made a nasty almost ginding noise above 1,700 RPM (right at motorway speeds).

When replacing the assembly, be careful to ensure that the power steering hoses are retightened: at the pump (you need to loosen the mounting bolts on the pump to release tension on the fan belts). Styria can talk you through what's required and then you can replace the viscous clutch. He supplied mine when I relaced it a year ago. Need to remove the fan shroud at the same time to get the fan off the car.

Not a big job, all done within 45 mins.

 

[SELfor50]

Thanks Bar, i'm actually already waiting for a viscous coupling to be delivered. Should arrive this week.

Will install it when I receive it. I'm pretty certain the noise is from the Gearbox. could be a slight amount of noise from the fan / belts. But the fan clutch / coupling certainly isn't locked on - it does spin free still just very slowly.

The gearbox i'm pretty confident is where the issue lies. haven't driven long enough over the past week to experience it, and will be attending to it when I find sometime in the coming week or so.

Cheers,
Cam.

 

[SELfor50]

Ok.. so I was pretty sure it was from the Gearbox, but either the gearbox has sorted itself out - OR - all the air in the power steering is finally gone.

I'd been driving around sedately and only on short trips until I was going to get around to swapping the gearbox or at least getting it on the hoist to investigate further - and then it never came back. Though, the power steering fluid had gone down a bit and no longer looked like strawberry jam. So the post analysis is that i'm guessing it was the power steering lines / air in them after all. If not, then I'm sticking with that theory until it comes back..and touch wood the issue doesn't rear it's ugly head again.

 

[Styria]

Him Cam, thanks for the update. Nice to know that matters appear tp have settled down as well as they appear to be. Good stuff, and kind throw of the dice. Regards Styria