Leaking ATF out of power steering gearbox adjustment bolt

[taoofbean]

I just rebuilt this gearbox a month ago. I thought I did a stellar job, having never done one before. All the parts went back together as expected and I tried to be very careful in reassembly as to not damage any of the teflon seals. On the first 2 weeks of test driving no leaks at all. Now it is leaking out of the adjustment bolt at the top and I am really hoping the answer to this leak is to somehow tighten or readjust the adjustment bolt, not take it all apart and tear it down on the bench again to rebuild a second time, but better. When I first noticed it leaking I was able to tighten that top nut (17mm) down tight and hoped that stopped it. It is still leaking after I cranked it down hard so I need to figure something else out before I tear it out and start anew.

I ask here if anyone has experience with this type of leak before I start messing with the adjustment screw and bolt throwing the gearbox lash into disarray while I try to stem the flow of ATF being pushed out the top without taking this all apart again.

Important for context, I also just as part of this rebuilt changed out the power steering pump to the Saginaw so there is more pressure coming into the gearbox than there was before.

 

[Spook50]

Is it a severe leak or is this just buildup from several days' worth of seepage? It looks to me like a seal either got damaged or (though I doubt this is the case) blown by the higher pressure of the Sag pump.

On my 62 what I typically do for adjusting the screw is with the nut loose, turn down the screw until it stops, then loosen it 1/8 to 1/4 of a turn and tighten the nut back down. I doubt this will affect your leakage issue, but it's a shot in the dark to try in case it might be too loosely adjusted.

 

[taoofbean]

It is not a tiny trickle and counts as problematic to severe. It looks like the pressure in the gearbox after an extended drive releases the fluid on stop in my driveway once you get done. That may be why I wasn't seeing anything from little trips around town and needed to do an extended 2-3 hour drive to really bring it home.

 

[CruiserTrash]

It is not a tiny trickle and counts as problematic to severe. It looks like the pressure in the gearbox after an extended drive releases the fluid on stop in my driveway once you get done. That may be why I wasn't seeing anything from little trips around town and needed to do an extended 2-3 hour drive to really bring it home.

Did you replace the washer with the rubber seal that goes under the adjustment nut? Toyota still has them. Might start with that and adjusting the bolt/nut back down like Spook said. I just rebuilt a box too, and that's exactly where the adjustment ended up being correct - about 1/8-1/4 turn out from fully in.

 

[taoofbean]

Yeah I replaced that washer with the new one. I just did the adjustment Spook mentioned, cranked the nut back down hard (hand hard, not impact hammer hard). Will drive it this afternoon for errands and see what happens.

 

[CruiserTrash]

Yeah I replaced that washer with the new one. I just did the adjustment Spook mentioned, cranked the nut back down hard (hand hard, not impact hammer hard). Will drive it this afternoon for errands and see what happens.

The bolt threads into a collar on the top end of the pitman arm. did that collar come loose, so the whole thing is out of adjustment? I can't think of another way that would be leaking.

 

[taoofbean]

By collar, do you mean the cap at the top of the sector shaft? If that is the collar you are talking about, I don't see any oil coming from the cap. It was definitely originating at the adjustment screw. The cap is screwed down tight to torque values, whatever they were. I am a novice in all of this but the way I understand it is that adjustment screw pushes the sector shaft up and down so that the sector gear aligns more tightly or loosely with the worm shaft. The fluid in my example is/was very clearly coming out of the adjustment screw area. The good news is that yesterday I took it for an hour drive after cranking the adjustment screw tight, then backing it off 1/4 if a turn and then cranking the nut down and so far not a drop of a leak. Maybe the adjustment screw was so loose that fluid was working out through the threads? Amazing also how much less sloppy the steering feels now that I adjusted it this way.

 

[Spook50]

By collar, do you mean the cap at the top of the sector shaft? If that is the collar you are talking about, I don't see any oil coming from the cap. It was definitely originating at the adjustment screw. The cap is screwed down tight to torque values, whatever they were. I am a novice in all of this but the way I understand it is that adjustment screw pushes the sector shaft up and down so that the sector gear aligns more tightly or loosely with the worm shaft. The fluid in my example is/was very clearly coming out of the adjustment screw area. The good news is that yesterday I took it for an hour drive after cranking the adjustment screw tight, then backing it off 1/4 if a turn and then cranking the nut down and so far not a drop of a leak. Maybe the adjustment screw was so loose that fluid was working out through the threads? Amazing also how much less sloppy the steering feels now that I adjusted it this way.

View attachment 3631590

Sounds like you just might have gotten it. Hopefully that's the case anyway. It was a shot in the dark but definitely worth throwing out there.

How loose was your adjustment screw?

 

[taoofbean]

It was pretty loose, took 3-5 full turns to tighten it down all the way which didn't seem like much when you look at it in the picture above because only 3-4 threads were showing above the nut. But the screw was loose enough that the nut that I was using to tighten down around it kept walking free after I cinched it down after driving so that implies the nut was not able to actually clamp it all together with a wobbly loose adjusting screw.

In my head I think I have a seal incorrectly set inside that sector shaft cap. I don't think there should be any fluid pressure trying to cram its way out of those adjustment screw threads if that sector shaft cap was sealed properly. I am going to pick up a cheaper than OEM set of Gates seals somewhere for 20-30$ bucks and have them on hand in case it pops up again. I will be surprised as heck if just tightening down the adjusting screw and nut fixes this whole thing.

 

[Spook50]

It was pretty loose, took 3-5 full turns to tighten it down all the way which didn't seem like much when you look at it in the picture above because only 3-4 threads were showing above the nut. But the screw was loose enough that the nut that I was using to tighten down around it kept walking free after I cinched it down after driving so that implies the nut was not able to actually clamp it all together with a wobbly loose adjusting screw.

In my head I think I have a seal incorrectly set inside that sector shaft cap. I don't think there should be any fluid pressure trying to cram its way out of those adjustment screw threads if that sector shaft cap was sealed properly. I am going to pick up a cheaper than OEM set of Gates seals somewhere for 20-30$ bucks and have them on hand in case it pops up again. I will be surprised as heck if just tightening down the adjusting screw and nut fixes this whole thing.

Yep that'll definitely do it!

Reminds me, I need to check mine this weekend while I'm neck deep in my Cruiser...

 

[CruiserTrash]

@taoofbean

This is the part I was talking about. How that bolts fits into the top of the sector shaft. There’s a collar with internal and external threads. The collar threads into the sector shaft with the external threads, and the internal threads are for the adjustment bolt. Both available new from Toyota, although mine looked good and I didn’t want to make some specialized tooling to remove & replace everything. Anyway, maybe there’s something loose there?

 

[taoofbean]

Man that picture is so clear. Thank you for posting it. I didn't realize that was a separate part of the sector shaft. It makes me realize I don't actually know what is happening when you adjust the screw. Are you threading the screw both inside of the collar and the housing cap and the adjustment is pulling the sector shaft up or is the screw pushing the sector shaft further from the cap by putting more distance between the two? Because if it is threading in both, then it is just like twisting a bolt through two nuts and they can bind up. The gap between the cap threads and the sector shaft collar threads matters.

In the end as of right now I know I don't have a leak for today after I screwed the adjustment bolt down to the bottom, then backed it off 1/4 turn. I hypothesize that it leaked when loose because the increased pressure of the saginaw pump was forcing fluid past sector shaft seals at the top and out through the adjustment bolt threads. I assume bottoming the adjustment screw tightens the sector shaft by pulling it up towards the cap and bottoms out the threading in the collar. I am comfortable with this being a mystery in the universe for me as long as it doesn't leak.

 

[CruiserTrash]

I stared at it for a while and can’t figure out what the adjustment is doing either. Changing the tooth mesh between the sector shaft and piston? Of those teeth are wide at the top or bottom it could “tighten up” the mesh. I don’t know how that would change a leak, but I’ve heard it does - even prior to this.

FYI, that bolt has a carriage head, almost like a rivet top, that gets captured inside the dual threaded collar piece. That simply makes it stay captured under the collar so it can’t come out. There’s a well cast into the top of the sector shaft that it all sits in, it’s not connected to any fluid path or anything.