# MR2 Power Steering Pump?



## gemmuj (Feb 22, 2008)

Hiya guys,

I am looking to connect a MR2 Power steering pump to my ev's rack. Does anyone know exactly how I connect the MR2 pump to the rack? eg, which pipes connect where, lol? also, does anyone know which electrical connections connect where, lol. I'm so crap at some parts of this?

Thanks guys

Muj


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## electricmini (Oct 21, 2008)

First off, I'm assuming you've got a mk2 MR2 pump. If it has a
round metal body, with a funny rubber cover on one end, and no
built-in fluid tank, it's probably the mk2.

I'm also assuming your EV had power steering before you started
converting it...

If you have a mk3 type, bravo you're in luck - there's a guide
here on this forum. I wish I'd been able to find one of those pumps,
would be a much neater installation.


Ok, if it's the mk2 MR2 pump....

You need to find the thick heavy hose that goes from your car's
power steering pump (belt driven off the engine) to the rack.
This pipe will be very thick reinforced hose, as it has to withstand
pressurised fluid at around 1000 psi inside.

This is where you connect the MR2 pump's outlet. The outlet is a
female threaded port in the side of the cast iron bit, that's on the
end of the pump. Unless you're very lucky and it fits straight in, you'll
need to get a new hose assembly made up by a specialist -
- the pressure's far too high for anything home-built to stand up to it.

I got mine made by my local Pirtek centre in Cardiff, I just measured
how long I wanted the pipe, and took the MR2 pump and the banjo
bolt which holds the old hose into the rack with me. They identified the
fittings and made the hose right there & then.

It's just not worth trying to cobble something together, my new hose
only cost 30 quid, and your steering depends on it (and therefore
the safety of your EV and everyone near/in it)


The low-pressure fluid feed to the pump (basically just gravity feed
from the fluid canister) is a shiny pipe coming out at an angle, about
2 inches long. This hose is 5/8 inch inside diameter, I got some from
http://www.thinkauto.com/acatalog/On_line_shop_100R6_multi_purpose_hoses_131.html


Depending on what fluid your car uses, you'll probably need a special
grade of hose. The Supra uses ATF (auto gearbox fluid) for the power
steering, and ATF will kill many types of rubber (makes them go hard
and crack). Look for hose of type 100R6, again thinkauto have this in
various sizes, along with lots of useful bits like hose fittings & clips

As for the electrics, the pump runs from 12 volts, has two thick wires,
and several thin ones. I left the thin ones in their connector as they don't do much,
and I cut off the thick wires' connector as I didn't have the mating half that'd plug into it.
I then crimped on some heavy-duty lugs, bolted them to new longer
wires (10 mm2 area) and insulated the connections with several layers
of heatshrink. These wires need to be really thick, or the pump will
slow down & stall on full lock as thin wires would restrict how much power it could draw

To switch the pump on & off, you'll need a high-power relay or contactor.
Albright do a new "baby" contactor which is perfect for this, it's cheap and
can handle the 70 amps the pump could pull at full whack,
have a look at
http://www.thetoolboxshop.com/sw60-...-solenoid-contactor-continuous-80a-6947-p.asp

They also stock other Albright contactors, and nice big fuses
(Littelfuse "Mega" series) which are perfect for protecting the pump circuit, so a very useful place.

Hope this helps, I can post more details of my setup later
(just got it running tonight)

Richard
supra conversion project - now a real, working EV !!


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