Sudden loss of power steering....then back again?

[ChrisHGTV]

Morning, learned collective of the forum, wonder if you can help?

On my way out to get some softener salt i drove through a shallow puddle that was obscuring a small speed bump. It was just before a junction so i was going slow anyway, maybe 10mph but it was enough to give a slight jolt. Certainly ive hit pot holes that have been way more severe! But then suddenly the steering went very heavy (and actually required a lot more steering angle to turn - i guess this is due to the the variable rate?). I was literally 300m from home so thought id limp back, then after about 10 seconds i thought i heard a motor buzzing noise and the power steering gradually came back. Now it seems fine. I checked for any obvious leaks and all looks good, the fluid level is on the min mark for cold which im assuming is ok, as id only driven about 400m each way.

My concern is what could cause it? I thought maybe the slight jolt caused a connection issue, or the fact both sides of the car would have received a slight jolt could the fluid cavitate which caused an intermittent loss of power?

Any ideas? Is there a particular fuse/relay/connection i could check?

Many thanks!

 

[whitenemesis]

Water on the drive belt? Causing a slip and loss of assistance?

 

[ChrisHGTV]

Water on the drive belt? Causing a slip and loss of assistance?

Could be i guess, good idea thanks. The puddle wasn't really deep but i guess if it splashed up. But then i think the undertray would likely prevent that? I'll have another look to see if the belt could have been in the line of fire. When i was looking for leaks i could see some evidence of water but there wasn't a lot.

 

[OneForTheRoad]

Wet abs sensor ?

 

[Petrol Pete]

How old is the car , how many miles and has the PAS fluid ever been replaced. ?

 

[ChrisHGTV]

How old is the car , how many miles and has the PAS fluid ever been replaced. ?

It's a 2011 E250, 109k miles. Im not sure about the power steering fluid replacement but it's got a full history. When is it due on these? I can then check for invoices, i have all the paperwork for all the services. Thanks!

 

[Bellow]

Water on the drive belt? Causing a slip and loss of assistance?

That, and the belt being cold and stiff on such a short journey would be my guess.

 

[BTB 500]

Water on the drive belt? Causing a slip and loss of assistance?

That would be my guess - I've had it happen to me in the past.

 

[ChrisHGTV]

Thanks all for the suggestions - puts my mind at rest somewhat! Cheers!

 

[190]

May not be applicable to your car but some Blue Efficiency models have a clutch to disengage drive to the power steering pump when the wheels are straight ahead. I don't know if the clutch can be affected by water but another possibility to consider.

 

[Bellow]

deleted

 

[Petrol Pete]

At ten years old and 100K plus mileage if you cant find PAS fluid change history get it done . Can't say if thats your problem but it's worth doing . My PAS only has just over a litre capacity, lot of work for a litre of fluid to do for over 10 years. It's an often overlooked bit of cheap maintenance. New/refurb steering racks are not so cheap.

 

[Trickythemerc]

I changed my PAS fluid at 110K and the the difference in colour between the old and new CHF was enough to convince me it was a job worth doing.

 

[ChrisHGTV]

I changed my PAS fluid at 110K and the the difference in colour between the old and new CHF was enough to convince me it was a job worth doing.

I'll check - i did have a look and the fluid actually looks nice and clear/clean so maybe it has been done. Will check all the invoices though to be sure. I did some investigating and seems a lot of folk recommend the turkey baster method and change the fluid a couple of times to mostly flush out the old with new. I might give that a go - i quite like doing things on the car that are within my capabilities and that method sounds easy enough!

 

[grober]

If the PAS fluid was at minimum air may have drawn momentarily into the system----the system has now self bled?

 

[Trickythemerc]

I'll check - i did have a look and the fluid actually looks nice and clear/clean so maybe it has been done. Will check all the invoices though to be sure. I did some investigating and seems a lot of folk recommend the turkey baster method and change the fluid a couple of times to mostly flush out the old with new. I might give that a go - i quite like doing things on the car that are within my capabilities and that method sounds easy enough!

That is how I did it, saves a lot of messing about. I used a litre and a half of Pentosin CHF and did it over two days to get the system well flushed.

 

[ChrisHGTV]

If the PAS fluid was at minimum air may have drawn momentarily into the system----the system has now self bled?

I wondered that when i saw the level was close to the bottom of the little dipstick but then when i checked closely it seemed pretty much at the correct level and there's a tiny difference between min and max when cold . I'll check again when it's light and i can see better. Is there any downside to having a little more in there? There seems a significant difference in the required level between hot and cold so guess it must expand quite a bit. I don't want it to blow any seals or anything if i put in an extra squirt.

 

[ChrisHGTV]

That is how I did it, saves a lot of messing about. I used a litre and a half of Pentosin CHF and did it over two days to get the system well flushed.

Sounds like a plan! Will be a nice diversion from the lawnmower restoration as well!

 

[Petrol Pete]

I did the 'turkey baster' method (but used a BIG syringe from an equine/vet supplier) It took me 3 litres of the genuine MB (green in mine) stuff to get it perfectly clear , which worked out a bit pricey £ but got the job done . The fluid in mine was rank.

Some models have a filter screen built in to the header tank . changing the filter means changing the tank .