i lost power steering around a corner,, a bit hairy.

Submitted: Thursday, Jul 24, 2014 at 17:54
ThreadID: 108863 Views:1613 Replies:5 FollowUps:6
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G'day all

I'm down in Mildura at the moment and temporarily lost power steering for about 10 seconds going around a corner.

This is the second time it has happened.

First time in Southern highlands about 7k ago.

It seem to be fixed by draining 1.5 ltr of 'oil' and putting new oil in.

It's a Dmax 7/11 manual single cab diesel.

Isuzu Mildura think it has more to do with either the 'rack' or pump.

Me,, I would not have a clue. I am taking it back tomorrow morning for a better look at it.

The not so funny part is we are on our way to Medowie tomorrow afternoon and need to be there Sunday afternoon.

Has anyone experienced this failure?
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Reply By: Ross M - Thursday, Jul 24, 2014 at 19:42

Thursday, Jul 24, 2014 at 19:42
G'da Boo Boo

The pump is gear driven so drive to it shouldn't be a problem.
The reservoir has two hoses to it, both near the bottom, one above the other.

The upper19mm dia hose is the supply to pump (feed line) and is rubber hose nearly all the way, the last bit which runs near the LHS of the crank pulley is steel.
That hose should have absolutely no kinks in it as the full dia will be required for pump flow when actually turning the steering and flow rate has to be sufficient so the flow is not impeded.

It may be necessary to carefully check that hose by removal.
If it is squashed, twisted slightly or kinked or even internally restricted by delamination of the inner lining, the vane pump will not be able to supply pressure as pump action will stop if that vital flow isn't possible.

The bottom line into the reservoir is "return oil" from the rack. That should not be a problem.
There is a possibility the rack's steering shaft valve may refuse to open and allow the flow of pressure oil to the rack. That could be because of some particle contamination in the valve system.

Best to have the lower hose, ie, smaller one on reservoir, removed from reservoir (plug the lower hole) and all fluid fed into the reservoir caught (into a bucket) as it leaves the system as the steering is operated from side to side, ie lock to lock, with the engine running.
That will cause flow pressure as the wheels are made to turn side to side.

That should completely flush the system and clean all fluid from inside the rack, pump,lines and reservoir.

I hope the dealer can perform that for you. It is not hard to do.

So either rack steering directional valve or hose restriction is a probability. Can't see how the pump is going to be go and stop.

Mine is same month same year.

Cheers
Ross M
AnswerID: 536530

Follow Up By: Member - Boo Boo (NSW) - Thursday, Jul 24, 2014 at 20:43

Thursday, Jul 24, 2014 at 20:43
G'day Ross

I will mention your info if they don't suggest that the hoses etc may be the problem.

The mechanic also agrees that it the pump is unlikely to be the problem.

Your suggestions make sense to a non mechanic with a bit of general knowledge.

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FollowupID: 820679

Reply By: Member - mechpete - Thursday, Jul 24, 2014 at 20:17

Thursday, Jul 24, 2014 at 20:17
boo boo

hi
I have struck the problem on 2 occasions in the past 1 with GMC3500
an 1 time with a Mercedes Benz ambulance . with the GMC when hot you could turn the wheel suddenly an actually beat the power assistance , the benz was a pump down on pressure
cheers mechpete
AnswerID: 536531

Follow Up By: Member - Boo Boo (NSW) - Thursday, Jul 24, 2014 at 20:46

Thursday, Jul 24, 2014 at 20:46
Pete

I was hoping it might be that simple, but I was going very slow and turning the wheel very slowly.

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FollowupID: 820680

Reply By: Erad - Friday, Jul 25, 2014 at 09:31

Friday, Jul 25, 2014 at 09:31
I don't like the sound of your problem. A different issue, but still P steering related...

A few years ago, I was doing a driver training course with the Aust Federal Police. During a classroom session, I asked "Which is better - Power Steering on not?". I was expecting the answer Power steering because it is normally less turns lock to lock. The instructor said "No! When you need the power assistance most, it goes out to lunch." A few hours later, we were out on the course in a standard VP Commodore, and pushing it a lot harder than I would ever consider on the road. The tail broke away and in chasing it to opposite lock, the Power steering did indeed go out to lunch - right when I needed it.

Similar thing with the brakes. I had assumed that with 4 wheel discs, the braking would be unbeatable. Wrong! and I am not talking about simply locking up the wheels. Two successive applications of the brakes under really severe braking and the pedal was on the floor as the brake fluid boiled in the calipers. Again, this was driving way beyong what I would do under normal road conditions, but say towing a heavy load down a long hill without changing down a few gears, I could easily see the situation where the brake fluid boiled. Even more so when you consider that most people do not change their brake fluid very often and it absorbs mositure, dramatically lowering the boiling point.

Boo Boo - maybe your Power Steering fluid is stuffed. Is it dirty (burnt)? If so, maybe the pressure relief valve on the pump needs checking.
AnswerID: 536549

Follow Up By: Member - Boo Boo (NSW) - Friday, Jul 25, 2014 at 12:23

Friday, Jul 25, 2014 at 12:23
Well, after a several phone calls I got some answers.

Because I am now out of warranty, even thought the problem was addressed by Isuzu Tamworth at 100425 km ( They did not quibble about the 425km), I have to pay the repair cost, then make a claim to Isuzu.

If the claim is accepted I will still have to pay the labour cost.

The repair cost is around $1000 and the labour content is about 1.5 hrs.

Hopefully Isuzu come to the part as the pump is obviously around $850.

The Mildura dealer says he has seen a pump fail before.
It appears that a vane in the pump maybe sticking every now and then.

Dealers at Tamworth and Heatherbrae appear to agree.

The car is booked in at Heatherbrae on Monday morning.

I will give an update after the pump is replaced. Hopefully they can say for certain that was the problem when they look at the old pump.

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FollowupID: 820722

Follow Up By: Member - Frank P (NSW) - Friday, Jul 25, 2014 at 23:21

Friday, Jul 25, 2014 at 23:21
"but say towing a heavy load down a long hill without changing down a few gears, I could easily see the situation where the brake fluid boiled."

This should never be the case, but how many times have you followed someone down a long steep grade and the brake lights NEVER go off? Then you smell them. And some of them are towing.

Pulled up to help a bloke in a Pajero towing a pop-top who seemed too be stuck in the middle of the road at Leatherbarrel Creek on the Alpine way in the NSW Snowies. He had smoke coming from behind his wheels and you could smell the brakes. Asked him if he was OK and he said yeah, but the brakes were failing. Told him to pull into the campground, wait half an hour to let everything cool down and then use third or second or even first gear going down the steep grades and minimise use of the brakes.

"But it's an automatic" he said. So we had a little lesson on the spot.

I think there should be a special towing endorsement on your ordinary licence, regardless of weight or size towed, issued only after successful completion of theory and demonstration of skills.

Cheers
FrankP

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Follow Up By: The Bantam - Saturday, Jul 26, 2014 at 12:32

Saturday, Jul 26, 2014 at 12:32
I'm a bit sceptical about brake fluid boiling.

I have sat at rally controlls in the middle of the forest and seen car after car come in with disks glowing red or orange.

The most likley reason for brake fade is the pads overheating....and standard pads, just like drum linings are very much prone to brake fade.

The american engineered cars ( ford / holden ect) have been less inclined to have high temp pads from standard because they consider their customers want a soft brake pedal so they install soft pads and lingings....and if you are taliking about factory Fords and Holdens.....their brake systems are not wonderfull..so don't use them as an example.

Its very true that many vehicles have disk brakes on the rear..not because it gives a better result but because it is a sales point.

The biggest issue with rear disks, is the piss poor hand brake.

All that said..let me tell you a properly engineered and maintained 4 wheel disk brake system will piss all over a disk drum system in every situation.


As for power steering....yeh back to the ford and holden problem......cheap scates that didn't spec a big enough power steer pump......they didn't spec a big enough oil pump in the sump either.

Both 4 wheel disks and power steeing are used in competition motor vehicles with little incident.

who wants to go back to armstrong steering.......

I grew up in fast rearwheel drive 4 cylinder cars and none of them had power steering.... and none realy needed it...but they all weighed in well under the tonne.

see how you go driving a 3.5 tonne 4wd without power steering, particularly off road.

Anybody driven a stock 40 series lately.

cheers
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FollowupID: 820803

Follow Up By: Member - Phil G (SA) - Wednesday, Jul 30, 2014 at 22:55

Wednesday, Jul 30, 2014 at 22:55
It might not be the brake fluid boiling - more likely the water in the brake fluid is boiling.
Brake fluid is another item that seems to get ticked off..... but not actually changed every 2 years like it should.
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FollowupID: 821121

Reply By: Ross M - Friday, Jul 25, 2014 at 20:44

Friday, Jul 25, 2014 at 20:44
Boo Boo
If it is a sticking vane I would a small amount of Nulon Auto trans additive.
It is Teflon of course and will make the pump and all steering related internals last longer.

I wonder who the person at the dealers is, who can ID a intermittent sticking vane.
An examination with a strong magnifying glass "may" reveal a problem.
AnswerID: 536606

Reply By: Slow one - Saturday, Jul 26, 2014 at 13:41

Saturday, Jul 26, 2014 at 13:41
Boo Boo,
Good to see Isuzu are going to help out, I know it would be a little disconcerting to have the power steering go at speed and by what one person said, it is lucky you weren't driving a Ford or Holden as then the brakes would probably failed as well. LOL.

It is always good to see a manufacturer backing their product, even when it is slightly out of warranty.

Hope all is fixed quickly and at minimum cost.
AnswerID: 536629

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