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Discussion Starter #1
Greetings, all.

I need some guidance following problems arising from my replacement of the steering rack on my 08 Sienna.

After replacing the rack, which was exceedingly tedious due to really difficult bolt, nut, and steering line access angles, I refilled the reservoir with the required fluid, bled the system (10 full swings left to right), checked for leaks, and all seemed well...until the test drive

The steering "groans" in either direction. The steering geometry, which I expected to me slightly off until I got it aligned, is way beyond "a little off." I made only a short, slow trip around the block in my neighborhood with the traction control alarm going off every few feet. It almost seems like the steering wheel wants to "home" itself about 120 degrees out of phase.

The steering wheel was secured during the replacement and was not touched. The intermediate shaft slid onto the input shaft during reassembly without issue. The vehicle was pointed straight ahead when jacked up and the replacement rack installed. Aside from the really frustrating bolt access, the replacement itself was seemingly very direct. I don't know what I might have done wrong, but clearly something isn't right. Waaaay "not right."

I bought a new, OEM Toyota rack and it matched the original perfectly, both with a "JTEKT" sticker. Transferring the tie rods was a little tough, but only due to stuck jam nuts. I counted the threads/turns when moving the tie rod ends and ensured they were moved to the correct sides.

I just don't know what's wrong, or where to start looking. I see no leaks. I plan to repeat the bleed procedure, as I suspect a lot of air was introduced while the lines were disconnected. Could the air have actually damaged the pump during the refill/bleed process? I'd normally associate steering groaning with a bad pump, but the pump operated normally prior to the replacement.

I'm out of ideas. I'm no expert, but I think I followed the steps I laid out properly. I can't think of what I've done wrong. Wouldn't the input shaft of a new rack be centered by default when manufactured? The steering shaft was in the same position when installed on the new rack and the pinch bolt tightened and secured properly. My OBD2 tool does support zero-angle adjustment for a Sienna of my model year ('08), but I don't think the zero-angle setting will fix this issue. This seems like a basic but serious mechanical issue, like impaired fluid flow (?). I suppose a failed pump is possible, but it was OK going in.

I'm open to any ideas. I really don't want to have to start over, and hope I haven't damaged the brand new rack.☹

Any suggestions or ideas are welcome and appreciated. Thanks in advance.

David
 

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Thats tuff situation.. I imagined yu have seen all the youtube videos on these .. But if yu haven't, heres one that is excellent, hes got excellent camera angels, fully detailed and have watched most his videos..it's not 08 yr but would think its almost same procedure.


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Discussion Starter #3
I've watched his video and he does a great job, but I have found some key differences between mine and his; the P/S line nuts on mine are 18mm, not 17mm; those lines weren't accessible as directly from the front driver side as they were on his. I was surprised to encounter as many differences as I had.

Spoke with a friend who is a big-time car guy and he doesn't think it's a damaged rack issue; he thinks it's a simple alignment or geometry issue that is solvable. He wants me to take off the tires and end rods and redo the bleed process. I hope that'll fix it, but that's purely a first-shot attempt. We're not at all sure what's up. The replacement went as planned.

I am hoping at this point it's primarily a fluid issue in the rack. Don't know yet. Still hoping anyone here might have other insights. Thanks for taking the time to reply!
 

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Are you sure the level is ok?? Don't just look at the side of the reservoir. Pop the lid off and look inside. These reservoirs can get stained and look like they are at the proper level. The pump will bled out the air just by running it up and turning back and forth.
 

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Discussion Starter #5
Thanks, 3Wheeler. I still note the fluid level is low. I also have been thinking about the reassembly phase, and recalled that I had to disconnect the stabilizer bar link so it could be moved and allow the rack to be removed. The wheels meandered everywhere. When I put it all back, I didn't ensure the wheels were pointing straight ahead. As soon as I get home, I'm jacking it up, pulling the tie rods off, recentering the steering wheel, and pointing the wheels straight. Once that's done, I'll put the tie rods back and re-bleed the fluid level. I believe I may have effectively reinstalled the thing crooked. Rookie mistake if that proves to be the solution. Will advise hopefully just a bit later today.
 

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Well I finally got this (mostly) solved!!!

It turns out there were two issues. First, I had not sufficiently refilled the system with fluid. That solved the "groaning* problem. But the " grinding problem was something entirely different.

I brought my son along for a test ride and some new/fresh ears. As we drove slowly down the road, he pointed out something - I could make slow turns just fine, but the "grinding" sounded like brakes. Then, it dawned on me , just as my son said "Hey, dad, are you sure this isn't the computer just going nuts with all this new rack info and thinking the car is gonna destroy itself??" And that's precisely what it was doing; as the traction system went off, it was assuming a serious steering/control problem, and turned on the ABS if the vehicle speed exceeded a particular threshold.

The solution? Erase the learned zero-angle sensor and yaw data via an OBD tool. I happen to have a diag cable and Techstream software, did the reset, and the problem is solved. I think there are two pins on the OBD DLC you can short in a repeated cycle for a few seconds to do the same thing wihout a cable or special software. Bottom line, no more stability issues. My steering wheel is still about 20 degrees off, but I can probably fix that with a judicious reattachment of the intermediate shaft to the rack input gear. With the steering wheel cockeyed, the car otherwise handles like silk and my repair effort has been a success.

Thanks everyone!
 

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Discussion Starter #7
Hi all. I made a video of my Sienna steering rack repair that I thought I would share with this group. This condenses my 3-plus day project into a single video. It was a great learning experience!!

 
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