1uz hydraulic fan pump specifications

**Hodgey** · 15-03-2013, 09:34 PM

Hey all,

Firstly, I am sorry to bring this up again as I know it has come up a few times, but I am struggling to figure out what is going on.
Im currently in the final stages of putting a 1uz into a 77 HX kingswood and have found this forum to be extremely helpful in answering questions I have had about the 1uz so far. Im hoping you can also help me with using the hydraulic cooling fan pump to run the power steering box as I have no room for the factory power steering pump. I have been trying to replicate what was explained in this post.

http://www.toymods.org.au/forums/tec...-steering.html

I have opted for the jaycar controller method. I have built the controller and it varies voltage between 0-12V, I have also tested this on the pump and it does vary flow. My question, however, is in regards to the pressure supply by this pump. When I connect everything up, my steering is ridiculously heavy. Im wondering what other peoples experience with this is?

Because of the heavy steering I began researching a bit more and found 70's style power steering pumps produce around 700-900psi (google tells me) and then newer type rack and pinion pumps produce in excess of 1250 psi. This hydraulic pump however, only generates about 171-358 psi (refer to the attached). This is from an engine manual I got off a friend (I assume it from Lextreme or similar).

So how have people done this so far? is 360 psi enough to run a power steering system because at the moment my steering is very heavy. Have people modified the pump so how to increase the pressure (not just reduce the flow)? Any help would be great as I would quite like to make this system work (everything is already hooked up so it would be good if i didn't need to redo everything). if you have successfully done this (either methods listed in the above thread), please let me know

**petergoudie** · 16-03-2013, 12:06 AM

When reading your post my initial thought was whether a fan motor/pump has enough power for what you want. It might be worthwhile using a photo-tachometer to see what rpm it is getting up to. It might just not be capable of rotating fast enough for what you want to do.

**Jaemus** · 19-03-2013, 12:30 PM

A quick, probably ill-considered thought is that you might be able to dissasemble the pump and remove or modify whatever mechanism it has for regulating the pressure (probably there's a port you can drill out or something) and thus increase the pressure. In combination with this you could also drive the pump with a smaller pulley to increase the speed. But, this could possibly take the pump well beyond its rated performance and damage it / cause leaks etc.

What might be much smarter is to see if you can remove the hydro pump entirely and fit a proper P/S pump in its place. They are pretty small usually, so it should be possible with a bit of bracket fabrication etc. The 1UZ belt self tensioning system should make this easier.

**Hodgey** · 19-03-2013, 02:29 PM

Thanks for the replays guys, highly appreciated.

Jaemus, I was thinking about pulling the pump apart, but with out any sort of testing equiprment (pressure gauge I guess would be all I need) I would just be stabbing in the dark. I think this pump is not quite going to work. Im so confused as to how it worked for the guys in the above link?

I think I will change the pump to an idler and use an mr2 pump for simplicity of mounting. I would need to do a lot of research into power steering pumps to find one to fit into the same space as the cooling pump. The electric ones I think would be much simpler.

Thanks again guys

**ian** · 19-03-2013, 02:50 PM

you might find that you wont need power steering, as the toyota v8 weighs a little less than a holden six

**Jaemus** · 22-03-2013, 12:15 PM

Yeah MR2 pump is the time-honoured solution when there's uncertainty about fitting a belt driven one

And yeah depending on how fat your front tyres are and if you can get a manual rack with a decent ratio, you might be able to get away with unpowered. I presume power steering was an option on the HX and thus there will be manual racks available at the wreckers or something

**AndyTTR** · 19-05-2013, 10:31 PM

Hodgey! I can't remember if I already asked this, but why not just use a 1UZ power steering pump? These things are turning up all the time at pick-a-part / Centre Rd. lately.