Toy power steering pump upgrade.
Not mine...
Reposted with permission from the op on the old place...
#1 · May 29, 2015
Disclaimer #1 - I just did this tonight so it has not actually been tested, I don't see any reason why it would not help but I wont be able to test it until I get the rest of my full hydro setup done which will be about a month.
Disclaimer #2 Yes I know TC pumps are cheap and easy...but polishing this turd is cheaper and easier and I am curious how far I can push a Toy pump. Plus I have a motor swap planned in the fairly near future and I can go with a different pump at that time if this does not work out.
What is stage 3 you ask? well stage 1 and 2 are the higher pressure and output flow mods that are already documented here. The problem with the output flow mod is it results in pump noise for a lot of people who do it. This is most likely being caused by lack of sufficient flow into the pump. Just for fun and because I had an extra pump that was no good laying around I took it apart to see if there were any restriction or areas where flow could be improved on the intake side of things. Here is what I found.
ID of hose from reservoir .630
ID of hose barb on intake fitting .540
neck down area of hose barb .420
Leg of intake fitting that goes into pump .390
vertical passage in pump .390
horizontal passage in pump .466
I think we can all see where the problem is. A quick look at some hose selection charts show that the 5/8" hose should be getting the job done assuming these pumps are putting out no more than about 3GPM with the flow mod. The problem is the restrictions in the pump and fitting. The one thing that cannot be changed is the size of the horizontal passage, there is not enough meat to drill it out any bigger so our limiting factor is .466". Lets take a look at what opening up the small passages to .466 does to our flow
passage size---area in sq in
.390-----------.12
.466-----------.17
This does not sound like much until you do the math and realize that it is a 42% increase in flow!!
Luckily Toyota built just enough material into the tight areas to drill them all out to .466 or 15/32 which is actually .4688 but it is close enough.
This mod requires completely disassembling your pump which is actually not as scary as it sounds. Follow along and I will walk you through it, and give detailed instructions on how to do the other two mods.
EDIT: I started thinking about how bad of an idea it is to put this thing back together with 30 year old o-rings..Turns out a seal kit is only $17 from Oreily so I guess I will be taking this thing back apart again and doing it right. I will post up the part number latter today when I get it.
#2 · May 29, 2015
#1 Needles to say you will have to remove your pump from your truck. On it you will find 30 years worth of built up crap. Clean it off!! Cleanliness is vital to this project. When you think it is clean, clean it some more, make sure you get all the nooks and crannies.
#2 Mark the two halves so you can put them back together in the correct orientation, don't be a dumbass like me and use a paint pen, we will be washing parts down with brake clean latter and guess what happens to paint when you hit it with brake clean

use a punch to make some permanent marks.
#3 Remove the four bolts that hold the two halves of the pump together. You can do this without removing the pulley if you have the right tools, which in this case is this little adapter that allows you to turn a socket with a closed end wrench. The bolts are very tight and they are locktighted in. The casting is too close to two of the bolts to crack them with a box end and you will probably round off the heads with an open end. A socket is the right tool for the job but there is not enough room for a ratchet with the pulley on. I cant remember where I got these but it harbor freight sells something similar
3 Piece Square Drive Socket Caps
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#3 · May 29, 2015
#4 With all of the bolts out flip the pump over so the pulley is down and give it a light tap on the bench to make sure the right parts are loose. lift the back half off (pic 1) and you should have what is shown in the second pic. Leave the front half of the pump assembled as shown and set it aside somewhere clean and away from your work area.
#5 Take note of the orientation of the shiny bit in the back half of the pump (pic 3), you can't really mark it so look for some small detail and take a picture or make a note of where it is in relation to one of the fittings. You don't have to get it back in exact but it needs to be fairly close. Next take the back half of the pump and slam it down on a smooth hard surface with the open side down. It might take a few hard hits but eventually the round part and a short spring will fall out (pic 4). Put the round thingy and the spring in your clean place where you parked the front half of of the pump.
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#4 · May 29, 2015
#6 Remove the high pressure fitting (pic 1), make sure you don't loose the o-ring (pic 2)
#7 Remove the plunger and spring that are under the high pressure fitting (I failed to get a pic but you will see it), if it won't come out that side you can take it out the other side after step #8
#8 On the other side of the pump is a small cap held in with a snap ring, push the cap in about 1/4" then remove the snap ring, push the cap out the snap ring side of the pump (pic 3)
#9 Remove the inlet fitting by taking out the retaining bolt and working the fitting out of the pump. (pic 4)
Set all parts other than the back half of the pump body and the inlet fitting in your clean place
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