Ah yes CaptainQ. One person’s simple can often be another persons “impossible”

 

Totally agree !!

 

The continuous rating of the Astra pump is about 12 amps at 12 volts and 60 amp
peak if you try to turn the wheels against a kerb. The average amperes
during turning is about 25 amps.

Here is a Rolls Royce plug & play solution built for you. All you have to do is wire it in circuit with the pump & mount the control conveniently. Insulate board & stick under dash with Velcro. Very robust. Price reasonable.


$17.49

 

That's fantastic Glyn - just the ticket ! Thank you for that information - I'm placing my order today. I'll make a small aluminium box to contain it and, as you suggest, mount under the dash. I like the fact that I'll be able to
play with the settings to achieve a comfortable assistance. Thanks again !!

 

If you mount it in a box drill some holes in it to allow the heat sinks to dissipate heat. Insulate the board from the box in case it accidentally touches the car's chassis. Plastic screws, nuts & standoffs at the 4 mounting holes.

Hope you have an alternator or uprated generator fitted.

 

Thanks Glyn, will do. Yes, I upgraded to an alternator some time ago.

 

I was going to leave this until you did the job but on reflection decided to cover it now. We can always discuss later.

This unit has an on/off switch on the control knob. If you want to leave it at a standard setting (& thus switched on) then ideally you need to wire it's power supply from the battery via the ignition switch. I doubt the ignition switch would be happy with a 60 amp peak draw. Thus you should wire a 60A 12v solenoid/relay in line with the power supply from the battery so that the ignition switch is only used to switch the solenoid (low current draw)

Alternatively you could disconnect the switching wires from the potentiometer (control knob) & connect them to the ignition switch. Then the board is handling the high current and you don't need a relay.

Your choice. Switch it on at the knob & set when you start the car. Or have it come on when you switch on the ignition with the key.

I'm trying to cover all bases. Retrofitting non standard items to classic cars can have their potential pitfalls. I want to make sure you never run your battery flat.

 

Will you supply who your sourcing from and the part number Please? I really like this solution even though I haven't tested my system yet, ;_))

 

$17.49 ~ click on Amazon link.

 

Thanks again Glyn. I think the second option is probably the best. I've ordered the board from the States - in the meantime I'm going to start installing the box, hoses, idler etc next week (got the made-up hose eventually last week - they made a good job of it in the end). The outlet on the box for the low pressure hose is bigger than the nozzle on the pump so I've got to install a reducer adaptor to join the two different sized low pressure hoses
together. Shan't get rid of all my standard non-pas fittings for a while though, just in case ..... lol !

 

Yes if it were me I would go the second option but we all have our preferences. As this Astra pump conversion seems quite common I'm hoping you have no issues. But it is something I have never done. Wise to hang onto your old rig in the unlikely chance of issues.

 

Thanks again Glyn - I'll keep everyone posted on the eventual progress (the 'box of tricks' won't arrive until mid-end August anyway).

 

Hello all. Well after a few electrical uncertainties I finally got the pump installed and connected up so now all that is reqd is the lower steering column which should be here next week - at least its in the country!. I was speaking to the chap that I got the kit from about limiting the pressure and mentioned it had come up on this thread. He was of the opinion that altering the voltage might do damage to the unit but, as he said, he's a mechanical engineer not an electrical engineer but it might be worth checking how these motors react if they are run at less than optimum voltage. So his way of limiting the pressure is to physically change the size of a hole within the unit such that there is less flow. He then said I wouldnt have to worry about it as he had already done it on that unit . As a consequence I dont have any more info at the moment than that.

 

Controlling the voltage to a DC motor won't damage it. It's done all the time on modern cars with Air Conditioning electric fans as an example. The A/C controller varies the DC condenser fan speed continuously as required. Over voltage/current draw is all that will damage them. Physical throttling of the pump supply will make the pump motor draw more current & run hotter. Should not be an issue if he has not drastically cut flow & thus raised pressure.

 

i must admit I couldnt see why lower voltage would cause damage to the pump. The only other i noticed is that it is possible that the pump actually doesnt operate at lower voltages. When i connected it up yesterday it seemed to take a few revs before it started to wind up - basically until the alternator light on the dash went out. If this is the case the using the variable resistor type setup to lower the voltage might not be as successful as initially hoped. Will be interesting to find out. Cheers

 

Latest update. The pump is connected up and is working. The lower steering column is now in place. I started the car, raised the rpm and lo and behold the power steering works! Not sure why I felt surprised but i was.
HOWEVER, the steering box now has a leak. This is the box that i had pressure tested and had no leaks. I have done some looking around and the leak is not coming from the shaft or at the hydraulic connections. Turns out one of the nuts is missing from the top plate and leak is coming from that. I really dont know how I missed this but there you go. I can get to the bolts position with the unit in the car thank goodness - just have to find one.

 

The missing nut is the one to the lower right of the top plate as you look at this photo.

 

OK, nut found and attached. A question for the group. Is it possible to adjust the power steering box in the same way that a non power steering box can be adjusted ie if there is a bit too much slack when turning is it possible to adjust that slack by changing the number of shims under the adjusting nut on the top of the unit or is that adjusting nut for some other purpose.?

 

Hello CaptainQ. Did you get your power steering up and running using the electronics Glyn pictured? If so did the idea of lowering the voltage work to give slightly more road feel?

 

The DC motor controller works by pulse width modulation. Effectively it switches the supply on and off so the voltage jumps between zero and 12 volts (nominal). It switches at a sufficiently high frequency that the motor speed and current stay constant. If the controller is a good design and matches the demand of the motor, both it and the motor should be extremely reliable. Still, it's probably best to avoid overloading the motor or controller by allowing a high load-zero speed condition for more than a few seconds. My guess is that would never arise in a pas system with a suitable pressure relief valve. Zero speed-negligable load is fine.