front seat gear swap (Broken Seat/Missing Cap Issue, pt. 2)

[nakman]

A few of you have been bugging me about these, and tonight I have some good news for you. The long awaited seat gear appears to have been successfully reproduced..


start by removing your seat

take off the front plastic panel

then remove the 4 5mm allen bolts.

[nakman]

Here's what the FSM has to say.. (check back when you reassemble, to verify torque of those 2 shaft nuts)

[nakman]

To take off the shaft bolts, hold the shaft with a vice grip. Remove the little plastic the rear supports, then unscrew the gear housing. When you remove the shafts from the slides of the seat, do your best not to allow the thing to twist at all, and thus change position. It's important that both sides are at the same position, in relation to each other, or it's going to try to push your seat crooked and probably not work too well.

[nakman]

Notice how there's a thick rubber washer on the "inside" of the shaft, and a thin one on the "outside," against the little panel you just took off. I'm not sure if this matters, but suspect you could swap them down the road if you wanted to wear a different part of the gear.

To remove it, jack it off using a deep socket, or similar tube-like object. the 18mm I grabbed seemed to do the job well.

[nakman]

Notice how there are three little indents (in the picture in the post above) in the side of the stock gear, where the thing has been staked in place. When removing, I pressed it so that I didn't make those stakes pass over the knurls of the shaft. Actually I don't know if that matters, but it felt worth mentioning at the time. To get it to budge (didn't want to shatter a perfectly good gear) I heated up the shaft with propane, actually aimed the flame at the vice mostly then let that heat the shaft. At about the time the gear started to look like it was about to melt, I was able to press it off with moderate force.

I cut a small chamfer in the new gear with a utility knife, to help it get started. I'll put this chamfer into the CAD file for future parts, so don't worry about that step.

[nakman]

To press it on you can use a smaller socket if you want, and actually that will help create a stop when it smacks against the raised knurled portion of the shaft. Once on, I deburred the little chips the knurls made with a utility knife. You can see by the material removed how well engaged the knurls of the shaft must be with the new gear.

Then it's just bolt it all back up, I put the rubber washers in the same orientation as how they came out, and put a mess of grease around the new gear teeth.

[nakman]

Picture of all the the parts you removed, and most of the tools. Really not that much to it, I did all the bolts finger tight, then went around and put a wrench on them.. remember not to over torque those shaft nuts.

Also if you haven't done the white cap, you may as well install that now since the seat is right in front of you. This is the passenger seat, if you hadn't guessed that already, a perfectly working passenger seat I might ad. Tonight I swapped out both the white cap, and the gear, with ones that I have made.

[nakman]

Once back in the truck, set it in place and plug in the power first, then test it a couple times just to make sure it works. Mine took a couple times going front & back before it kicked into its groove, not sure what was up so I removed it and loosened the white cap a little (something that made the DS work a little better). Put it back in and it was better, so I bolted it up.

Remember when you're installing any seat, get all 4 started before you tighten anything, otherwise it takes twice as long as it needs to. total time start to finish was about 1 hour. To test it, I sat in the seat and lifted my feat, then rode the seat forwards all the way and back all the way about 10x. After the first couple it seemed to run a little smoother, maybe they needed a little break-in period or something. That's probably the most that seat has had to move in 5 years though, usually it's just a little tweak here and there, often with months of no adjustment. So really not sure how long these will last, but if they're not abused I suspect they should last a long time.

I've got a couple test subjects who will be receiving their gears in the next couple days. I look forward to them posting up their results, and at that time will decide if these are for sale as-is, or if further development is required. But for now, I'm pretty satisfied and actually pretty psyched this all works.

ok, on with the comments..

[sdnative]

Great job! Waiting patiently for a set.

[fjfar80]

Question...and if I am way off base...just let me know. Looking at the pictures it looks like this would be a part that you could combine...in other words make it one part or a shaft with the gear...all of one piece of metal. Is there any reason that this would not work...is it necessary for the gear to be plastic? Just my non-engineer thoughts on it.

[nakman]

Originally Posted by fjfar80

Question...and if I am way off base...just let me know. Looking at the pictures it looks like this would be a part that you could combine...in other words make it one part or a shaft with the gear...all of one piece of metal. Is there any reason that this would not work...is it necessary for the gear to be plastic? Just my non-engineer thoughts on it.

You asking why did Toyota do it this way? IMO biggest reason is cost, that would be a lot of material to remove. You'd have to start with about a 1.125" stainless bar then hob the gear teeth then drill & broach the ID then turn down the ends... Costs a lot more than machining just the smaller piece of metal, then slamming a plastic gear onto it.

Also you could argue for wanting to create the weak point in the system.. so by stripping these gears everyone's motors have been spared, which likely cost a lot more than a little plastic gear. (break a Warn hub & save a ring & pinion any day).


Or if you're asking why I made these out of plastic well that's easy, my life is plastics.

[fjfar80]

Nakman -

Thanks for the info. I was actually looking at it from an original design point. I see what you mean, but it looks like that if you had the time and cash a solid piece might be a good substitute.

Cheers.

[cruiserdan]

Originally Posted by nakman

any day).


Or if you're asking why I made these out of plastic well that's easy, my life is plastics.

Sure, you'll make these goofy little bastards but you won't make my end caps...

[corsair23]

Dude,

You ARE the master of plastic fabrication!! So how long till you can fabricate FZJ80 body parts out of plastic - Just think of how much faster we could make it to Moab with plastic hoods, fenders, doors, etc

[yarborg]

I finally got around to taking my gear box apart; thanks for the photo walkthrough they are so important for us newbs. I certainly need a new one, two actually. Here is a photo of mine. I am going to replace them both if you will make them. I hope I can get the plastic piece on the metal gear.

At first I didn't think it looked stripped. I was expecting the whole thing to be ground to bits. But just the center is worn down and inside the remaining grooves there is bits of plastic meal along with the yellow grease. What kind of grease should I use when putting this back together?

Thanks!

[nakman]

Originally Posted by yarborg

I finally got around to taking my gear box apart; thanks for the photo walkthrough they are so important for us newbs. I certainly need a new one, two actually. Here is a photo of mine. I am going to replace them both if you will make them. I hope I can get the plastic piece on the metal gear.

At first I didn't think it looked stripped. I was expecting the whole thing to be ground to bits. But just the center is worn down and inside the remaining grooves there is bits of plastic meal along with the yellow grease. What kind of grease should I use when putting this back together?

Thanks!

Cool glad the pictures helped, and hopefully I'll have some positive feedback this week from my unbiased "test subject" on the gear's success, then yes I will have these available for sale. could be as soon as this week.

what kind of grease? I dunno, whatever you have left over from your axle service is probably fine. I used some wheel bearing stuff... there's probably one out there better for plastics, but I don't know what.


edit: and that gear should come off fine if you have some deep sockets and a vice, as shown above. Blow off the heat if you want, who cares if it cracks that gear is already jacked. I'd only use the heat if you wanted to save the gear for some reason, or if the gear just won't budge.

[Clutchee]

Thanks Tim for saving us all TONS of money replacing large, costly parts!

PS...hurry up & start selling these

[concretejungle]

awesome Nak!! my end plug screw thingys are holding up really well.

[LCflyer]

I'll need a couple of the gear pieces when they are available. Mine look just like the pictures above. Nakman...are they ready to sell yet?

[tbo_cruiser]

Originally Posted by LCflyer

I'll need a couple of the gear pieces when they are available. Mine look just like the pictures above. Nakman...are they ready to sell yet?

I would take 2 pairs. Let us know when they are ready.

[nakman]

I've got a "test gear" with the guy who donated the one I copied. I am still waiting for his feedback, mainly because it would be completely unbiased. But I haven't heard from him, will try to send another PM to shake that loose.

But we did a 4-day wheeling trip this past weekend, so I was able to test mine out. It works fine, many adjustments were made to the seat position over the course of the trip. However I noticed more backlash in the seat than I have on my driver's side, like the seat will shift front-back a little bit. It was most noticeable when wheeling, going from uphill to downhill, you'd feel a little shift in the seat. Of course my wife didn't notice at all when I was driving, but I picked up on it.

One thing I didn't do was measure the gear before installing, but it's possible it ran a little small. If so, I can easily scale it up, by whatever factor I want. I still think it's best to err on the small side though just to minimize any binding, but am honestly not sure on that one. If it's too loose then we risk stripping that worm gear, and that would be an even tougher one to draw in CAD, I'd rather not go there. I've got an extra one at work and will measure it tomorrow to see for sure.

But worst case is these should at a minimum restore function to a non-functioning seat, for those of you with stripped gears. Best case is I can tweak it a little to get it a little closer to stock performance. So give me another week or so, hopefully by then I'll have more feedback and if not what the hell let's just run some anyway.. you guys have been super patient and I'm sure if they suck we can work out something fair for a refund.

[yarborg]

I noticed the seat shifting thing as well. However, my gear is now out completely and I assumed it was that. Maybe it has something to do with the seat on the tracks or something? Anyhow, we are waiting paitently. Thanks for being willing to do this.

[vasellers]

Great, great thread. I need a pair of those myself, driver's side seat just broke!!

[nakman]

Success!! special thanks to ScottBx for the design feedback.. I tested out the "2nd gen" seat gear tonight, and it works really well. What changed was an increase in the gear angle, from 10° to 13°, as well as a small leading edge ID to help get the press fit started. My seat is running really smoothly now, much better than it was with the 1st gen gear in there.

Also I realized all the backlash I was experiencing was likely some loose bolts, I must have forgotten to tighten the brackets that ride on the lead screw shafts and connect them to the glides of the seat, because both sides were very loose. blame that one on the installer.

I had the "1st gen" installed for just over a month, and around 800 miles. The seat still functioned well, despite having some loose hardware . Below is a picture of the inside of the 1st gen gear that I removed, where you can see the indentations created by the knurls of the shaft you press into this. Second pic is all three gears compared, and how you can see the difference in gear pitch- note how the 2nd gen gear pitch most closely resembles the stock gear.

[nakman]

Cost of these is going to be a little more than those little white caps, so we're looking at 2 for $20 for these, shipped. I'm going to do a run of 10 sets (20 total), and will sell those to basically the first 10 guys who send me paypal, you can get my address from the white cap thread. In fact, no need to post up that you'll take 'em, just send me your money and I'll post up when I run out... or send me a PM if you want to confirm first. After this, we'll take it over to for sale.. but in the interest of tech I'm sure you first few guys will want to post up your feedback. And of course, if they don't work for you I'll give you your money back.

[sdnative]

Paypal sent

Thanks Tim!