Hydraulic Steering or Pump

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23 Aug 2018 15:09 #1 by alanj
alanj created the topic: Hydraulic Steering or Pump
Hello all,

I took the OKA out for a drive earlier and noticed a vibrating sound coming from what I think may be the steering box or hydraulic pump.

There are earlier posts that seem to point at a few different issues.

Is this a common issue?

Has anyone out there had a similar issue recently?

The noise only occurs when I turn the steering wheel. It doesn't seem to restrict its driving and even seems goes away after a couple of minutes.

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23 Aug 2018 16:35 #2 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Hydraulic Steering or Pump
Alan check the fluid level it may just be low and the pump is getting air instead of fluid. there have been issues with the steering boxes on earlier trucks but most have been changed.

OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.

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25 Aug 2018 12:48 - 25 Aug 2018 13:02 #3 by mort
mort replied the topic: Hydraulic Steering or Pump
Hi Alan,
There was a posting some time ago, I had a whine which appeared to come from my steering box and there was some ideas that it was the box or maybe the regulating valve but before I could do anything another mechanic who I had asked was quite firm that it was my hydrulic pump and all I needed to do was replace the vanes which should only cost about a few hundred $, a few people I know had a similar issue including 1 x OKA owner so I did find I could get the part from overseas at I think say $75 and the install was very easy and the noise went away.
You may have the same issue I can get the part for you and anyone else that may need and if it isnt worn now it will eventually.
Martyn
P.S. I just found the past post and it is under the heading.
Hydraulic pump for power steering
It looks like it cost me $150. Maybe I spend so much on the Oka I was quoting the price that I give my wife.

Martyn
Last Edit: 25 Aug 2018 13:02 by mort.

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25 Aug 2018 14:44 #4 by alanj
alanj replied the topic: Hydraulic Steering or Pump
Hi Martyn and Peter, thanks for that. I checked all oil levels when I first got the Oka home. The hydraulic oil level is fine thankfully (or not).

So what is the function of the vanes? How and why do they cause the vibration.?

Alan.

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26 Aug 2018 07:46 #5 by mort
mort replied the topic: Hydraulic Steering or Pump
Hi Alan,
The easiest way to explain is step by step with photo's and remember I am no expert on this and only learn as I go along but the mechanic who told me what the problem was had more knowledge and ended up was correct.

This photo is of the pump showing the 3 sections and the 1 in the middle next to the blue is what I had to replace.
dont bother removing the whole pump as it is too difficult and not needed.

This is the back showing the 4 bolts to remove that hold the 3 sections together.



These 3 photo's are the back the centre and the front that remains bolted to the engine.
So you can see the middle has an oval hole and the centre spins this allows the vanes to move in and out which pumps the hydraulic oil at pressure its very simple really.

this photo shows the vanes and holder seperate.
The problem is that that the vanes are spinning and always rubbing on the housing which will cause one or both to wear which you could say so there is plenty of space and material before it becomes a problem.
What I found is that on the inside wall of the oval hole was ripples in simple tearms much like corrugations so the vanes were bouncing which was causing the pump to loose pressure so this may be the whine or it could have been the pressure valve which is basiclly a ball with a spring and was the lower pressure causing the ball to bounce/vibrate I dont know except the mechanic said the steering box will not make the noise.
Martyn
The following user(s) said Thank You: Rick Whitworth, Holmz

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26 Aug 2018 07:55 #6 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Hydraulic Steering or Pump
Great explanation Martyn you took the pics I didn't ;-))
Remember too that the hydraulic pumps aren't engine specific in that most are an SAE mount and the drive gear is usually engine specific so any pump with the correct mount will fit that engine as long as a drive gear is available to suit which is quite often as the pumps usually have the same size shafts.

OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.

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26 Aug 2018 18:35 #7 by alanj
alanj replied the topic: Hydraulic Steering or Pump
Excellent, thanks for that. I suppose if the vanes are not sealing properly then that could also cause the pressure valve to shudder.

I am yet to get under to inspect closer but it does point toward one of the items above. Is the pressure valve easy to come by? It may be worth replacing both if that is the case.

Your thoughts?

Alan.

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27 Aug 2018 05:20 #8 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Hydraulic Steering or Pump
Alan most Oka parts are off the shelf from some other vehicle so my usual habit is if I don't know or can't find the origin is to take said part to a specialist for that part. In this case a hydraulics place, the bloke that looked at my secondhand pump I had to fit the 6bt pulled it apart on the counter, looked all over the innards and put it back together saying it was good to go as he did it.
A good car parts place that has been around in the 80's and 90's when the Oka was born, they usually take one look at it and say "from a XXXX YYYYYYY"
The other source of info is a truck wrecker for the heavier stuff especially one who has been around for a similar period.

OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.
The following user(s) said Thank You: alanj

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28 Aug 2018 16:57 #9 by mort
mort replied the topic: Hydraulic Steering or Pump
Hi Peter,
I am not really into photography however I did consider a few selfies to enhance the experience for the general public but in the end decided that my stunning good looks would over shadow the topic so your left with second best.
Martyn

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28 Aug 2018 17:05 #10 by mort
mort replied the topic: Hydraulic Steering or Pump
Hi Alan,
In the end I didnt replace the pressure valve, I did find the agent in Perth but they wanted some stupid price and so I started looking overseas and that was as far as I got because the replacement of the vanes fixed the issue so maybe just do one at a time and see what the result is otherwise you could spend time and money replacing everything and in the end not knowing what really was the problem.
Martyn

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11 Nov 2018 16:04 #11 by mort
mort replied the topic: Hydraulic Steering or Pump
Hi All,
I have been asked if I can get a set of vanes for the hydrulic pump from the source overseas so no problems the confirmed price is $120.00 so while ordering if anyone else wants a set I can order at the same time.
Martyn

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24 Apr 2020 17:53 #12 by Daktari
Daktari replied the topic: Hydraulic Steering or Pump
Hey Martyn I do hope this finds you well. I have been researching an issue I am having with my Oka currently ... just replaced water pump and fuel injection pump ... had the hydraulic pump removed during the process. Now all back together and engine running sweetly but have no power steering or power assist on the brakes ... seems to point to hydraulic pump issue. Fluid level is good. Can't seem to find info on pump, or ?bleeding it (as we had the pump off?) although didn't 'break' the system at any point.

What's your thoughts? Should I be looking to overhaul the hydraulic pump?

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24 Apr 2020 18:15 #13 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Hydraulic Steering or Pump
Alan sometimes for unknown reasons power steer systems can be a real bugger to bleed.
When I fitted the 6bt I just filled it with fluid, started it up and it bled itself virtually.
I did have the front wheels off the floor and wound the steering lock to lock a half a dozen times and also applied and released the brakes at the same time, you will need an assistant to constantly check the fluid level and don't use either the steering or the brakes while the assistant has the lid off the reservoir, it comes out like a geyser as the air pushes out especially early in the process.
Nothing like bleeding the previous vehicle an ex-USAF Humvee which took hundreds of lock to lock operation and brake applications to get the air out.
The pumps when empty will quite often not suck the fluid through so you may have to fill the pump before installation and even leave the return line off the pump until fluid comes out.

OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.

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25 Apr 2020 08:38 - 25 Apr 2020 08:41 #14 by mort
mort replied the topic: Hydraulic Steering or Pump
Hi Daktari,
Peter is right the pump is not a sucker or more its not a self primer but a pusher so it needs to have fluid in the pump to work.
If your pump was fine before you removed it then it will be ok after installing and if you have fluid in the tank then you have an air lock.
When removing the pump the system drained and the pump is higher than the tank so unable to drain from tank and fill the hose and pump.
The easiest way is to remove the hose from the steering box and hold as low as you can to allow the fluid to drain and in turn removing the air, once the fluid starts to flow lift hose up so you dont loose too much oil then connect.
Once you have fluid in the pump it will work and dispel any air left but dont rev the engine at first as the pump is dry and needs the fluid to lubricate this includes the steering once fluid pumping then as Peter said operate your steering and brakes then smile.
Martyn
Last Edit: 25 Apr 2020 08:41 by mort.

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25 Apr 2020 09:06 #15 by Daktari
Daktari replied the topic: Hydraulic Steering or Pump
Many thanks Peter :-) I shall examine further.
Bruce

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25 Apr 2020 19:04 #16 by Daktari
Daktari replied the topic: Hydraulic Steering or Pump
Thanks so much Martyn for your input. After pondering the presenting symptoms, I checked in with my comrade who guided me through the injection pump overhaul to ask if he had disconnected any of the lines in to the hydraulic pump when we were moving it aside to access the injection pump ... he indeed had removed a line and placed a small red cap in the line to prevent loss...
So after removing the line and passing a wire through in an attempt to recover the cap, it ended up being lodged in the junction / flow diverter and was easily removed. Rookie mistake ;-) Good lesson learned.
So I drained the system, changed the filter, and then topped up the tank, it self primed and we are now riding sweet.
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