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Holden 5 litre power steering pump
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Hello
Lately the old power steering in my VB seems odd, tight spots and sometimes a bit vague. I've had the original rack changed over many years ago but not the pump.
I think the pump is the original unit when built so probably needs replacing. I'm not experienced enough to rebuild it.
So the question is, are the Holden V8 power steering pumps same in VB to VT series I? |
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Originally Posted by: SLENUT  Hello
Lately the old power steering in my VB seems odd, tight spots and sometimes a bit vague. I've had the original rack changed over many years ago but not the pump.
I think the pump is the original unit when built so probably needs replacing. I'm not experienced enough to rebuild it.
So the question is, are the Holden V8 power steering pumps same in VB to VT series I? Damo... yes .. and no! the seal kits are all the same (says my memory) if you want to do a repair (which you don't*) and the pumps themselves (saginaw style) are the same pretty much as HQ Holden on (yes, really!) apart from the hose attachments and the varied mounting brackets (due to being mounted on both sides thru the various V8s engines used) but.. and this tricks most, at about the time of VK series II, GMH went to a METRIC high pressure hose thread (where the flexible high pressure screws in). Previously it was IMPERIAL (like the Holdens) back to your post... 'vague' steering? I would start with the rack first and get that tested. If the valves in the rack spool are worn or not doing their thing, you will get vague steering. Also get the pump output tested ... *ps.. don't blame you not wanting to do a repair! they are a many parted thingy (bit of a prick to work on too)  Edited by user 2 years ago
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As Smitty2 has said the p/st pump varied quite a bit over the years, even though the basic internals remained essentially unchanged.
The biggest change occurred in 1980 (early VC/WB) when they changed to metric threads, for both mounting holes & the high pressure fitting. The high pressure outlet also changed from an inverted flare to an o-ring style at this time.
For Holdens the easiest way to pick an imperial pump from a metric pump is the shape of the reservoir housing. The metric pumps have a "ham can" shape while the older pumps have the skinny neck style.
In summary, the pump which fits directly to the VB V8 is the older skinny neck pump, which dates back to HQ V8. Metric ones with fit if you change the mounting bolts & the high pressure hose, but be wary on VN-VT pumps, there are variations in the pulley offset.
Having said that, the pump itself has very little to do with steering feel, your symptoms sound like the rack valve needs an over haul. Just buy an exchange remanufactured rack from a reputable supplier.
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I was told by a hydraulic place that hydraulic pumps either work or they don’t, being a gear pump, however they look like they use vanes. I would put money on the rack being worn out. Edited by user 2 years ago
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The rack is lucky to have 1000kms on it, was replaced 15ish years ago.
Now, I've jacked the front up so no weight on the front wheels, to do some tests. Should the power steering fluid drop when motor running and turning lock to lock? Cause the fluid never dropped at all. |
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I’ll take a punt and say it shouldn’t drop. It’s only moving a piston, so the same amount goes in as comes out the other side. If it was working a single acting ram like on a tip truck, then the level would drop as the ram extended. I am happy to be wrong though as hydraulic systems can be more complex than that.
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Originally Posted by: SLENUT The rack is lucky to have 1000kms on it, was replaced 15ish years ago.
Now, I've jacked the front up so no weight on the front wheels, to do some tests. Should the power steering fluid drop when motor running and turning lock to lock? Cause the fluid never dropped at all. Damo.. NO, the oil level remains unmoving if the whole system is correctly full and has no air in it (there is a bleed procedure to remove air ) remember the pump is not moving more fluid (it cannot unless there is a leak) but is moving fluid at high pressure to the rack and back. and being ATF, the fluid itself does not expand in use. |
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Originally Posted by: wbute I’ll take a punt and say it shouldn’t drop. It’s only moving a piston, so the same amount goes in as comes out the other side. If it was working a single acting ram like on a tip truck, then the level would drop as the ram extended. I am happy to be wrong though as hydraulic systems can be more complex than that. unlike the early Holden system which used an external piston/ram to assist the steering rods to move (simpler and cheaper than assisting the steering box that was used) the Commodore system is rack and pinion.... with an incoming steering shaft (that comes from the steering wheel) which is easy to make it to turn either way (left or right) by pushing/assisting the turn movement with high pressure oil fed into valves in the 'spool' housing the steering input shaft AS WELL AS assisting an internal piston... see pic for best detail on this  |
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Yes many ways to do it. Old 80 series chamberlain tractors (and probably most machines) use an orbital valve on the steering wheel with no mechanical connection to the steering at all.
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Holden 5 litre power steering pump
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