Power Steering Weak

I'm on to the next and hopefully last issue on my son's truck. The power steering doesn't seem to give any boost at all, especially noticeable at low speed. Driving at speed seems relatively normal but probably a bit stiff. Definitely seems to have a slow ratio. I don't hear any significant whining noises from the pump or rack. No leaks underneath. I've done a little research and first suspect is the filter in the reservoir is clogged up. I don't want to start throwing parts at it so will flush the fluid out and remove and clean the reservoir. I'm sure it could use a flush and then will go from there. What is the best way to flush? Saw a video where he ran the motor and dumped the return into a bucket, or can it be done but manually running the rack back and forth with front end jacked up? And should I clean the reservoir filter before or after flushing?

Any ideas on other areas to look? I'm surprised that so little boost could be caused by that filter. Are the steering racks on these suspect and how do you tell? 170k miles.

 

Usually if the reservoir screen is clogged causing slow fluid movement, the pump will squeal. Having said that, I'm willing to bet the screen is clogged regardless because of how many miles you have on it. I suggest you jack the front up and manually turn the wheel to flush it with the vehicle off. You'll be surprised how fast it flows. I don't see how you can fill it fast enough with the engine on. Make sure that you are constantly topping it off. It is best to have someone inside turning the wheel while one person watches and refills the res. I would personally flush first and then do the screen. The debris is not likely to move since it's already clogged up. Make sure to buy a replacement oring for the reservoir. Reusing the old one is a crap shoot.

 

Finally getting back to work on the truck. I did a flush manually with wheels in the air and wife turning the wheel back and forth while I topped it off. Went through two quarts, which seemed to be plenty to get to clean fluid on the return. Then drained it down a bit and pulled the reservoir to clean the filter. I removed the top by making a tool and bending the tabs back. It wasn't real difficult, you just have to be a little careful so you don't damage anything. I didn't go as far as to pull the filter part out because I had good enough access. I used brake cleaner and then my ultra-sonic tanks with some Simple Green and blew it out with compressed air. The filter screen was pretty clogged and there was nasty buildup in the bottom. Got it all out and put it back in with the original o-ring and fingers crossed, it didn't leak. I lubed the o-ring and pump before install to help it.

Result...inconclusive. It's marginally better but not there yet. During the test drive last night, the boost seemed to start working better and I ran the rack end to end at least two dozen times. Made sure to top it off to correct level. When I got back to the driveway, the boost was there and the wheel would turn smoothly lock to lock with truck parked. Wasn't over boosted but a significant improvement. When I just went out to try it this morning, it was back to being stiff and notchy while parked almost like it was before.I let it warm up a bit and it's a little better but still a bit stiff at low speed. No noises from the pump. I'll let it go for a few days and revisit it. I hate changing parts blindly and I'm not sure if it's a pressure problem from the pump, or something bleeding by in the rack. There are no leaks underneath.

 

Any signs of fluid collecting in the rack boots?

 

I don't think so. They look pretty dry but I haven't tried to look inside or overly close. Hoses look good, but due to age should probably be replaced.
My son doesn't complain about it, but it just nags at me that it might not be right. I would rather not get into the rack if I can avoid it. A pump seal kit is $10-$15 which wouldn't be the end of the world but I don't think it would correct a low pressure output issue but I would see how the pump surfaces look. From reading, the aftermarket and rebuilt pumps seem pretty sketch and hit or miss on lasting.

It has 265/75-16 tires on it so I'm sure that I should expect a little more steering effort but I don't know how much. I have the original wheels with some worn out Blizzaks on them, maybe I should get them down and see how they feel mounted up.

 

You're correct in thinking something is wrong if the steering effort is high. My Tacoma is on 35s and the stock pump puts out enough pressure to turn them without much effort.

Is the level of effort the same both left and right?

If the high pressure lines look OK You could have a weak pump or the rack could be bypassing inside.

 

You say it felt 'notchy'. How does the intermediate shaft u-joint look? Between the firewall and the steering rack.

 

I would try rebuilding it. When they go bad they usually get noisy and weak. Maybe yours is bad in such a way that it’s only weak. Where are you finding rebuild kits for $10-15? Best I’ve seen for OEM kits is $40 https://www.toyotapartsdeal.com/oem/toyota~gasket~kit~power~steering~pump~04446-04010.html

 

That looks fine. When I say notchy it seems to turn a few degrees, load up, and then get a little easier before repeating. The shaft and U-joint were good last time I was underneath.

RockAuto has three or four choices for gasket/o-ring kits in that price range. I'm sure they are more expensive at the dealer, and it looks like that kit may have a couple pieces the RA one doesn't but I don't know if you can trust the crappy pics and descriptions Toyota puts out.
https://www.rockauto.com/en/catalog...87,steering,power+steering+pump+seal+kit,7407