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Discussion Starter #1
Racejunk getting some more love. About 90% done with converting the steering rack over to manual, but having issues.

Need to replace this stupid plastic plug sealing up the pinion retainer bolt on the bottom of this '05 steering rack. The tabs sheared off it when I tried to remove it, so I had to chip it out to get the pinion out.

Anyone ever taken one out or have any resources to find out the thread and pitch of the plug hole, or a plug lying around? if i have to ill slowly melt out the rest of the plastic and start gauging it, but I'm hoping I'm not in uncharted territory. In that same respect anyone have or know of a manual somewhere on these first gen racks? I was going to retorque to Miata rack specs since i have them, but if I can get the OEM specs I'd be happy.



Thanks all!
 

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Uncharted territory, don't know what you were attempting.

To go without P/S folks usually just loop a hose to connect inlet/outlet lines at the rack IIRC.
 

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Discussion Starter #3
This is done relatively frequently by the miata folks from the sounds. Involves eliminating the added effort of pushing seals, air and extra fluid through the rack from the looped line method, then welding up the pinion to eliminate the few degrees of slop it leaves without pressue. If no one else has done it maybe I'll make a rough how-to if I can find this plug, not for the faint of heart though lol
 

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Discussion Starter #4
Got all setup to turn my own then happened to be digging through my NPT bin and found a 3/4 NPT plug that if I turn down threads a hair should work nicely. Rack back together just need to torque. Will update the race car thread soon!
 

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NPT doesn't seal for spit when used with straight threads unless retapped and you have zero depth room for that......................any number of freeze plugs could fit that hole.

The thread is commonly one off metric and hard to find much less a plug. I used to rebuild racks. NPT will only match like for one maybe two threads then go off, it commonly looks like it fits then doesn't. BTDT with many NPT to metric comparisons on various parts.

How does that one establish preload that prevents rattle at the steering wheel? Commonly that is done with variable shims that cap holds in place.

You cannot eliminate the internal breathing that has to occur from side to side movement, it's impossible. And you have to have at least some fluid to lube the bushings or they tear up.
 

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Discussion Starter #6
Hey amc! Well that's good to know, I had assumed it was metric, close to m26-m28, but the measurements I took of it didn't correspond well with any thread charts I could find. I was going to just turn up another threaded plug on the lathe originally, so maybe I'll do that still. It's 18 tpi, and I've got the min and mag dims, so wont take long.

As far as preload on the shaft, I had wondered about it, but no shims were present under the cap and the cap as far as i could tell was only bearing against the bearing outer race which was a press fit to begin with so I don't know :shrug: I have another rack I will try to dissect the cap on and see if the inside of the cover is bearing against the end of the shaft.

For the side to side internal breathing its pretty straightforward to stop, just remove the central seal/bushing, nothing is pumping then. The boots will still be retained on the outside with their crossover tube, but internally no pumping action will be taking place anymore
 

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Discussion Starter #7
Re-reading again, amc are you talking about the preload on the pinion itself at the base of the pinion or the preload assembly that presses the steering shaft against the pinion?
 

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Hey Xyclone, I have a 2000 zx3 Lemons race car with deleted power steering, it is a bear to turn in the pits, and tiring on the track after extended stints.(up to 2 hrs per driver) Wondering where I could get more info on rack mods to make it steer easier. Did you just wing it or did you follow instructs from somebody that has already been there? Any help would be greatly appreciated!
 

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Discussion Starter #9
Hey faux

If you search depower steering rack on google, a number of miata sites will come up. The basic ops are the same, but tools needed in some cases are different so I made my own. Still haven't rolled with it yet, so jury is out on how much easier it will be versus looped lines but only one way to find out. Still need to diet another rack and see what this plug is dping as I have reset the preload on the pinion to rack, but see no provisions for the pinion itself, we shall see
 

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Thanks for the response, I found numerous deletes for miatas, ford probe, and multiple others. I plan on having at my spare rack after this racing season. Should be a good improvement over what I have, although its livable as it is. For this year, a slightly larger steering wheel than I have on there; 13" to 13 3/4. Cheers
 

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Discussion Starter #11
Good deal, if it works I'll throw up how I did it and feel free to give 'er hell! Maybe we will race sometime! On day two down here at NJMP after a super wet day yesterday in a tail happy e36
 

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Awesome stuff! Next week my Back To The Future themed Focus will be tearing it up at Thunderhill's 5 mile track. The FauxLorean is a gas to drive! With recent improvements, it's been even better than I hoped for. Hope Tom and I can finalize the tune for the race... If you want to talk Lemons and setting up your car let me know. [email protected] Lou
 

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Reviving an old thread, curious if you got this done and if the steering effort was reduced, Xyclone?
 

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Discussion Starter #14
Yep! Went through the motions and ended up make it my own cap. It did seem to reduce the effort and so far it's going on two years strong of hard racing without issue! Now it's not by any means "easy" to steer, but I don't have issues. My other jelly armed drivers do but they have been going to the gym 😉 I have considered putting power steering back on, but if I did it would be an electric pump or I have an electric column out if a fiesta that I may experiment with
 
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