1FZ Power Steering issues

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So my power steering paperclip rusted and it was decided to bypass it. This is what I did

8D57E37D-D453-4E5A-AE19-789CED8216F3.jpeg


now I’ve raised the front filled the reservoir and the wheel turns fine in the air. when the car is on the ground I can’t move the wheel an inch.
somone suggested there’s not enough back pressure in the system after bypassing the paper clip so I put a smaller hose inside the factory one and it made no difference.

anyone please have any ideas?

B6EF451D-EB44-4A4D-813C-C01B8D31FA25.jpeg
 

NLXTACY

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The paperclip is also the lowest point of the power steering hydraulic system and likely prevents cavitation. You’ve now removed that.

Even running a long run of 3/8” hose along the old path is better than what you are doing now.
 
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brettk

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The paperclip was bypassed whenever we bought our 94 for the same reason. Between the pump and the gearbox, it leaked power steering fluid pretty bad. I was told it’s because the fluid was getting too hot and baked the already 25 year old seals. I’d recommend getting a new cooler soon.
 
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The paperclip is also the lowest point of the power steering hydraulic system and likely prevents cavitation. You’ve now removed that.

Even running a long run of 3/8” hose along the old path is better than what you are doing now.
Thanks for the reply. Is it necessary to put some kind of reducer in there to mimic the pressure the paper clip would have provided, in your opinion? Cheers
 
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The paperclip was bypassed whenever we bought our 94 for the same reason. Between the pump and the gearbox, it leaked power steering fluid pretty bad. I was told it’s because the fluid was getting too hot and baked the already 25 year old seals. I’d recommend getting a new cooler soon.
Was yours bypassed the same way as I did mine?
 

brettk

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Was yours bypassed the same way as I did mine?
It’s been 2 years, I can’t remember how exactly, I just know the paperclip was rusted in two and it was bypassed. There can’t be too many ways to bypass it haha. I ended up upgrading the cooler by getting a kit from Joey (@NLXTACY). Looks like he’s out of stock currently though.
 
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It needs to be bled. Turn the steering right and left 10 times each with the tires in the air, and fill with fluid as needed.
I did that. Had the wheels a good 4 inches off the ground with the jack under the diff (suspension fully extended) didn’t seem to make a difference. Although I did have cap on the reservoir could that have prevented a bleed?
 

cvenom96

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Mine was similar after I replaced everything but the reservoir. Cycling it in the air didn't fix it. What I did was once the wheels were back on the ground I yanked the wheel hard to one side and then it seemed to have magically started working. I could see bubbles in the reservoir after that and so I continued cycling 10 times again. Never had an issue afterwards.
 
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fluid temps are too high (guaranteed) and the pump is probably cavitating...higher fluid temps mean you need more NPSH (pressure to feed the pump) or it will starve and cavitate. Oil has a notoriously low vapor pressure so that is almost certainly the problem. You need to cool your fluid or get more pressure behind the pump (not really possible without a pressurized reservoir).
 
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fluid temps are too high (guaranteed) and the pump is probably cavitating...higher fluid temps mean you need more NPSH (pressure to feed the pump) or it will starve and cavitate. Oil has a notoriously low vapor pressure so that is almost certainly the problem. You need to cool your fluid or get more pressure behind the pump (not really possible without a pressurized reservoir).
Thanks for your reply. the wheel won’t turn within 3 seconds of starting the car? Theoretically it should have higher pressure given it’s bypassed the paper clip?
 
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Mine was similar after I replaced everything but the reservoir. Cycling it in the air didn't fix it. What I did was once the wheels were back on the ground I yanked the wheel hard to one side and then it seemed to have magically started working. I could see bubbles in the reservoir after that and so I continued cycling 10 times again. Never had an issue afterwards.
Honestly with both hands and all my eight I cannot turn the wheel an inch?
 
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Thanks for your reply. the wheel won’t turn within 3 seconds of starting the car? Theoretically it should have higher pressure given it’s bypassed the paper clip?
the paper clip is between the steering gear box and the reservoir and I don't think the reservoir is providing any pressure seal for the system so the only pressure behind the pump would be the height of the reservoir feeding the pump.

just to walk through my thoughts:

before the pump you have the reservoir and its at ATM pressure plus the column of fluid to the pump
after the pump you have high pressure line to the steering gearbox
fluid pushes the gear to help steering and then is bled into the paper clip for cooling and is now at return pressures0
fluid cools and then returns to the reservoir.


If the fluid temp aren't high yet, the next things to look at would be the pump veins/seals could be burn up and you aren't moving fluid under load or the internal gear box seals are burnt up and they are allowing fluid to pass through without using up pressure to turn the wheels.
 
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the paper clip is between the steering gear box and the reservoir and I don't think the reservoir is providing any pressure seal for the system so the only pressure behind the pump would be the height of the reservoir feeding the pump.

just to walk through my thoughts:

before the pump you have the reservoir and its at ATM pressure plus the column of fluid to the pump
after the pump you have high pressure line to the steering gearbox
fluid pushes the gear to help steering and then is bled into the paper clip for cooling and is now at return pressures0
fluid cools and then returns to the reservoir.


If the fluid temp aren't high yet, the next things to look at would be the pump veins/seals could be burn up and you aren't moving fluid under load or the internal gear box seals are burnt up and they are allowing fluid to pass through without using up pressure to turn the wheels.
Thanks again.

was working fine the day before but it was just using lots of fluid as it was leaking. I’ve noticed also overnight that the reservoir has emptied and appears to be coming through the connections I made with my bypass.

I intend to get a hose doctor out and create a solid bypass solution and test that but I feel ill need to return to original Oem Configuration and source parts.
 
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get an upgraded cooler instead of the factory unit, it will be way better and get new hosing and clamps to stop any leaking. I wouldn't wheel it without some sort of cooling. I just spent a ton of money on rebuilding my gear box (rebuild kit from Toyota is about $260), new PS pump ($350 - Toyota) and all new hosing. You could end up getting into that stuff if you burn something up and that's way more expensive than the cooler from wits end.

Not sure whats available in Australia...but I'm sure there are options that are similar.
 

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