orion84gsl

iTrader: (5)

You should definitely check the spindle to see if it's still straight. I have no idea how to measure them to figure it out, and even the slightest bend could cause serious vibration. Worth it to have a look.

81WideMariah

iTrader: (8)

Agreed, a bent spindle would cause vibration, but wouldn't it vibrate even going straight? Also, I should note that the car didn't have this issue before the turbo build, respeed swap, etc.

The brakes, rotors, bearings, spindles, outer tie rods (have less than 5k miles), shocks (koni's), LCA's are all the same. I installed new ball joints, and had my buddy tig weld them in.

I am now running Diamond Racing wheels, but they were road force balanced and I saw the read out when they were done.... I set the toe myself, it's about 1/16" in.

I can actually jack the front end of the car up and wiggle the driver's side wheel slightly if I grab the wheel at 3 and 9 o'clock, almost like there is play in the rack itself.

rwatson5651

iTrader: (5)

I am no expert but I do know that there is an adjustment for the preload on the rack. I bought a 15 to 1 rack to replace the 20 to 1 that came with the unit and it had very noticeble play like you describe so I loosened the big nut and tightened, ever so slightly the small nut in the center and adjusted out the play. I had my wife turn the steering wheel back and forth and let me know when it began to get harder to turn, and then backed the nut off just a little and them locked it back down. Play gone. I felt like I was messing with something that maybe I shouldn't be messing with, but it took the play out of my rack. BTW I love my 15 to 1 rack, much less steering effort especially with my big tires. If yours has free play it could cause the vibration.

2 cents....

Whisper

The play is most likely not in the rack, but in the tie-rod adapters. The threads on those don't mate very tightly with the threads in the outer tie-rods, so I've had about half a thread of play. You can remove the play by screwing the adapters all the way into the outer tie-rods, but I think that kind of removes your ability to easily adjust toe for alignment.

I drove with that stuff tightened, and I think I had more vibration. Now that I have a tiny bit of play, the vibration isn't as bad... Hmm. And yes, it seems like vibration happens more when the wheel isn't perfectly centered...like when I'm changing lanes or going around a bend.

I also have weird crunches and pops coming from suspension when turning the wheel hard during parallel parking, or simply when jacking up the front end. Don't think it has much to do with turning the wheel and more to do with suspension geometry changing with weight transfer - something cracks and pops as a result of it. I took it all apart, I couldn't find any looseness or wear on anything. It looks perfectly good. I'm taking it to the pros next week, maybe they can sort it out.

81WideMariah

iTrader: (8)

That is exactly what it feels like.... very similar feeling I had with one of my old steering boxes that had too much slop. There is a vague feeling on center and the vibration slightly off center. With the old box, I adjusted it and it was much improved. I should also note that the vibration is most pronounced between 60-70 mph, and clears up quite a bit above 70 mph. Almost as if there is more load on the rack, taking up the slack.The same way it would when loading up the suspension in a corner. Oh, and I also agree the 15:1 rack feels amazing, one of the best things I've ever done to my car. I'm going to Google Fox body mustang rack adjustment and see what I come up with.

Whisper

Still haven't figured this shimmy out. It's been more than a year now. Dammit.

Some new questions.

1) Is it possible to warp a rotor and hub during bearing race install? Just a little bit, but enough for the whole assembly to be sitting crooked on the spindle, so that it wobbles side to side a small amount?

2) Guys at the shop I took it to suggested that maybe the wheels aren't centered on the hubs. It's true the new brake disk hubs are a tiny bit smaller than the old ones. Maybe by a few thou. But it still vibrates with the old rotors and both stock wheels and Panasports, something it hasn't done before. Is there any merit to the hub-centric idea? I mean the Panasports I got are hub-centric for my specific model. How much play should there be between the wheel and the hub center? Is a couple thou enough to cause a vibration?

I kind of want to find someone with GSL-SE in Seattle, one that doesn't vibrate, and throw their front brakes and wheels onto my car just to test it. Posted a thread on this in the NW forum, and will pay cash money.

https://www.rx7club.com/nw-rx-7-forum-33/any-seattle-gsl-se-willing-lend-me-front-rotors-wheels-day-ill-pay-you-1002521/

Whisper

Another possibility I thought of. Could I have bent my studs slightly when swapping them over from one rotor to another? Could that cause vibration? I've been looking at them and I can't really tell if they're straight or not.

Whisper

Ok, so Jhereg let me try his front rotors and wheels, and it still vibrated, so I guess we can rule out brakes, bearings, races, wheels and tires. Plot thickens. This leaves us with the entire rest of the car. Ffffffffffffffffffffffuuuuuuu

Anyway, one thing I'm still seeing is that my gearstick vibrates up and down in sync with the wheel shake, and sometimes when the wheel is smooth the stick vibrates more and when the wheel is shaking hard the stick is pretty steady. I can also sometimes feel it through the seat and I see my hood vibrate a bit as well sometimes. It's something under the hood, or even something in the back and transferred forward with a driveshaft.

xXGslseSleeperXx

this is pretty wierd do keep us updated on whats goin on but just a random suggestion , sterring rack bushings?

Whisper

Steering rack bushings what? I mean yeah, they're there and pretty tight as far as I can tell.

xXGslseSleeperXx

sorry didnt read second page, my bad but the poping u say when turning happend to my gslse when i replaced the struts n didnt tighten down to top nut on the strut tight enuf( and i used a 300ftlb nuematic air wrench i loosened it off n then put all little grease on the threads and let it have it with the air wrench n worked( my strut shaft was spinningf on the top when iwould turn the wheel) also maybe time to change motor mounts? i know i had minor vibrations at speeds but cuz my engine waz shakin around on hard turns n when i replaces the mount it was damn solid!

xXGslseSleeperXx

yeah that was a stupid suggestion i just sayed cuz on my truck that happend cuz they were worn( my se doesnt have a rack yet) n steering felt loose n when i would slow down whith the wheel in the same possition it would pull like i was turning the wheel in more, also couldnt align it cut the rack kept movin. this is deffinately wierd!

xXGslseSleeperXx

sounds like a pain in the *** but if you have the old worm gear box n parts around maybe try to re install them and see if it goes away but id save that for a lat resort. a few friends of mine have the re speed rack on their fb's n ive never heard them say anything about issues the rack but maybe a one in a million chance

Twilightoptics

iTrader: (1)

If the shifter moves up and down considerably, your trans mount is toast. I've seem some strange issues arise from bad transmission mounts in many cars over the years. I'm surprised energy suspension doesn't make a poly mount for our cars, I'd love to have one.

ray green

iTrader: (14)

I tried to read this whole thread buy may have missed it.

Have you renewed your idler arm? This is a common source of front end play and vibration that can be hard to spot even with the car up on jacks. I did one recently that didn't look that bad on the car but after removal it was obvious the bushings were toast.

The Moog unit, with ball joints, is a cost effective upgrade (check RockAuto), will last much longer than the stock unit that uses the bushings.

Whoops, never mind, I see in the first sentence you have a respeed rack and pinion installed.

dream36realms

iTrader: (4)

im just adding that I need a solution for this as well. I have the entire respeed suspension, braking, and steering systems as well. For me the shimmy only happens at 50mph+ or left hand turns. if I pull the wheel right it eliminates the problem but then I am steering right, lol.

Anyway I havent narrowed it down yet and wondered if you found a solution. If I cant figure this out, I will just get rid of my respeed components and go with a s tock second gen steering system.

85turbo12a

I too have just started driving my Respeed conversion steering and i have the same exact issue, to detail mine, its similar in almost every way, the vibe is severe but it comes and goes at highway speed, sometimes its silky smooth, other times beats you to death.

i just put a set of nitto neo gen 205/50/15 on the front, and all the ball joints and tie rod ends are new etc etc, its all new, the rack is solid mounted to the Xmember due to my space constraints of my build, and i have solid motor mounts and a poly trans mount.

the only mechanical anomaly i can find is if you grab the tire at the top while car is on the ground and pull in/out there is slop like a wheel bearing is bad, but its not in the bearing, and there is ZERO side to side play in the rack/tie rod assembly, its like the strut insert is blown out and not supporting side loads...but in my case, they are not old at all, maybe 6k miles, and the car exhibited no vibe before the steering conversion, not all of a sudden its there. oh and that play is on both sides, identical, not like 1 went bad and other is fine type of thing, something has changed....

so at risk of ruining my alignment im going to start taking things apart and try to find out how and why i have that side play, other than that, im at a loss, because everything is either new, rebuilt or not very old.

i think we need a whole forum for discussing the problems of the rack conversion, installing it was a pain and i had to remake some of the parts as they were not right, and now i have this issue, which it seems i am not alone.

Whisper

It's now been two years. I've given up on this crap for now. I've gone to a number of professional shops and none of them been able to figure it out. I just get the usual speculation: "out of balance rotating assembly or wheels aren't perfectly centered on hubs, otherwise we have no idea". Come spring I'm gonna try swapping the stock rear brakes on as a last ditch attempt. Maybe the vibration is actually in the rear and is somehow transferred to the front through transmission/driveshaft (hence the vibrating shifter). I've had dreams where I figured this out, only to wake up to a disappointing reality.

I donno. I can't even drive the car anymore, because this vibration has loosened my steering column to where I have a bunch of steering play and probably need a new bushing, and now I have other problems to fix as well.

Mazda RX-7 EFINI TYPE

Have you changed your engine and tranny mounts? Also bad driveshafts & U-joints cause some pretty nasty vibrations

Mazda RX-7 EFINI TYPE

If you're seeing slop, pull the wheel off and perform the same test on the hub, the issue should be visible. If it's not, then maybe for one reason or another, depending on your setup, maybe the wheel is not being tightly bolted to the hub.

To be honest though, yours sounds more like a driveshaft or u-joint issue.

dream36realms

iTrader: (4)

I got $20 that says on all these kits it is the RLCA setup that is used. I think the whole design was horrible from the start. I mean you have to remove the whole suspension just to adjust it? that's bs and laziness by design. when I totalled my seven the impact had sheered off the three bolts holding the right rLCA and the plate was wedged in by the frame (where it folded over itself) only after the accident did the car stop the shimmy I described in many threads.

82transam

iTrader: (18)

I had the r/p kit on both my FB's for a while (6000 miles on the one, and about 15,000 on the other) and never could get it setup right. The bushings on those rear control arms were completely shot on both my cars after only a short time, and the control arm bushings weren't too far behind either...

I wish I could be of more help getting your vibration sorted out, but I could never fix the issues I had on mine either and ended up selling both kits - haven't looked back

Mazda RX-7 EFINI TYPE

Well if many ppl with the kit are having issues, maybe it's time to return to stock & see if the vibration disappears.

85turbo12a

i dont have the option to return to stock, i have to find a solution and preferably quickly...DGRR is a month and a half away....and as far as Ujoints concern, no, im 100% sure that is not the cause, i have already been down that road for another reason.

i too think the control arm set up is at the very least insufficient, so ill be looking into something different, perhaps a whole fabricated lower arm or something, all i know is this is for sure not just my car at this point.
its just so odd how the vibe comes and goes, but only does it at high speeds of 60+

i wish i could have and probably should have used the second gen subframe, but i would have had to mod the hell out of it and probably been worse off...

first i need to find out what that strut noise is....and go from there, after that im going to see about maybe beefing up the control arm situation

kinda wish i still had the stock steering arms to put on and try...but alas..i gave them away..

rwatson5651

iTrader: (5)

85 Turbo, I just re-read this thread and I think I may have found your problem.

I had been dealing with this same issue and I thought I had solved the problem by adjusting the play out of the rack, but It came back, or was never completly gone, so I kept looking and I FINALLY found my problem once and for all. It was in the steering shaft where the two shafts slip together and are held by the aluminum rod that acts as a sheer pin. When first installed the aluminum pins held tightly enough so there was no play between the two shafts, but after awhile they loosened, just a tiny amount. The free play was almost impercevable, just a couple thousandths of an inch. When the problem was at its worst I could barely and I mean barely feel the free play when the car was sitting still and I would ever so gently move the wheel back and forth feeling for it. I took the shaft out of the car and found the free play, barely a "click" when I would twist the two shafts in my hands. I put the outside shaft in a large vice, pressed it against the inner shaft as hard as I could to remove the free play and reassembled. All the vibration problems I had been dealing with completly dissappeared. It was like a different car all of a sudden. But....after I drove about two months the problem returned, I took it back apart, installed shims between the two shafts by driving them in tightly between the shafts on the flat sides, and it has fixed my problem, months of driving with no further issues. I hope this helps you find your issue.