niburu

iTrader: (1)

After doing all the bushings and ALL the boots my shifter definitely doesn't feel sloppy but the 2nd to 3rd shift stillfeels vague.
I wish that I could get the 7 to shift as well as my 90 Miata, that car never misses a gear.

scrip7

iTrader: (6)

It could very well be the bottom ball bushing. I know for a fact that an s5 shifter has tons of play in the shift shaft hole when the nylon bushing is missing. That's why I removed the play by making my own bushing. Also check to see if the centering spring is missing. It's not enough to replace just the upper ball bushings and springs and the groove bushing. All of the bushings have a role to play and they all work together to give you the right shift feel.

Jpk3200

Yes I still have the spring. Is this going to get in my way while I try to replace the bottom bushing?

Here might be a stupid question, but here I go. Why does the spring only have one side to it? As it stands right now, when I pop my shifter in, the spring is lying to the left of the end of the shifter, resulting in a much stronger return to neutral when coming from 5th or reverse compared to when it comes from 1st or 2nd.

Is the shifter actually supposed to somehow fit in between here?



Seems like it would be a pain to get that ball slid in there if that's the case. Unfortunately some things have been broken, ghetto rigged/half-assed from the previous owner of the car, and I don't know how it's supposed to look

clokker

iTrader: (2)

Because your tranny has TWO return springs.
The second one is not visible/ accessible from the shifter hole, that's all.

You've got the visible one aligned correctly.

Jpk3200

Thanks clokker. I learn something new every day.

Maybe sometime after the Clemson game today, I'll have a look and see what I can do about making that bottom bushing. I'm waiting for the groove bushing to come in.

scrip7

iTrader: (6)

You'll find yourself moving the spring over to one side with a narrow pick or scribe while you insert the bottom ball/bushing. It's not difficult, just makes you want to grab another beer afterward.

Houpty GT

I took the suggestion and made my own lower shift bushing for the small ball on the shifter. I used an elbow for copper pipe for AC refrigerent lines that cost me $2 and change. I bought it at a specialty home supply store. I could not find anything at Lowes or Ace hardware. There was some PVC pipe but I do not think it would hold up to the oil. I know it will fail when exposed to anti-freeze.

I had to do some rigging because the copper piece was not an exact fit so would still have left the shifter with some play. I cut the wall of an aluminum can. I shimmed one piece all the way around the outside of the copper. I put it in after I put the copper pipe in. It was difficult to get in with the spring having to be held back at the same time. I also used a piece of aluminum folded over to make it double thick on the inside of the copper pipe. I am not happy with the aluminum on the inside because it seems like too much of a rigging job but it took out a good bit of that last bit of play. There is only the smallest bit of play left. I am going to see if I can find a better alternative to the aluminum being used on the inside. I may try to make my own bushing out of brass if I can find a good OD or I may get some thin brass to shim on the inside.

I also used the Mr.Gasket shift boot which saved me about $50 versus the Mazda part. I did not have a drill on hand to modify the metal plate that came with the boot so I cut the old rubber boot to seal around the outside.

The photo of the copper pipe is after I cut the end I used off. I had to cut it a little shorter after that.

Here are some really good links. I think with the following links andthis thread combined, this thread would make a good candidate for the archives since there is no info in ther for the bushings.

There first link is a good write up and the second link is Mazdatrix version. The 3rd link has a trail of links in it that can bring you to the write-up on the MR.Gasket shift boot.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/diy-shifter-bushings-637191/
http://www.mazdatrix.com/faq/shiftbsh.htm
https://www.rx7club.com/showthread.p...hlight=shifter

Jpk3200

^ very good info.

I have just a few questions on this...

1. So basically, to find the right fit for the bottom ball of the shifter, you just inserted the ball into different sized pipes to make the tightest fit possible? Is there such a thing as too tight? Also, the purpose of the aluminum on the outside of the pipe is to make up for the slightly smaller diameter of the pipe resting inside the larger diameter of the hole, correct?

2. Did you use something like a string to hold back the spring while inserting the bushing + aluminum?

3. What tool(s) did you use for cutting the pipe? Hopefully nothing really fancy since I don't have access to good tools right now.

Houpty GT

I am glad you appreciate the info. The problem is there are so many threads that do not answer the full question.

The tighter the fit the better as long as the lower ball is able to move freely. The ball is also going to be submerged in gear oil once you fill it back up so there will be some lubrication.

I did not have anything to measure the diameter of the hole so I found that the large end of a 1/2" Craftman ratchet extension just fit in the shifter housing. I took the extension and the shifter with me to find a pipe that with the same outer diameter as the extension and let the shifter ball fit inside.

That is exactly what the aluminum is for. Any play in the bushing will be felt greater at the shift ****.

I used a pick to hold the spring out of the way and it was a pain. I think the spring may have bent a little because I think it may not push back on the shifter as much but the shifter is so much tighter now it is would be hard to tell.

I would recommend a hack saw to cut the pipe. I only had my Dremel tool on hand so it made the job harder than necessary.

My philosophy: Good tools are worth there price in time and aggrivation. Never buy cheap tools and borrow what you do not need much. If people can share their tools, then everyone the community is wealthier. A penny saved is a penny earned. Buying chinese is like throwing your money in the trash can.

I attached an image of the empty housing.

Jpk3200

Update:

I just made my own out of some leftover PVC pipe. It turned out to be a perfect fit!

The diameter of the bottom shifter ball is ~ 18mm.
The diameter of the housing that the ball sits in is ~22mm.
The depth of the housing is ~ 16mm

The shifter is much much tighter now, and the driving experience is that much better.

Thanks for everyone who gave their input. Seems like a lot of threads don't mention the bottom bushing, and this one has more complete approach to correcting the shifter bushing problem.

Houpty GT

I found that PVC pipe that fit well also but I did not think it would have a long life in the transmission. I found 2 reasons which would also suggest it is a poor choice for a material. I read that heat has a negative affect on the PVC by causing certain components of its make up to volatize(evaporate). This probally explains why the PVC pipe I mentioned in an earlier post failed after a couple months of beingi used a a heater core bypass. Chemical reactivity to the coolant is also possible. It also seems that PVC is not overly inert to organic or oil chemicals. "Special "Oil Resistant" (PVC-OR) grades of PVC are also available that possess a high resistance to oil and other organic hydrocarbon attack."

Copper and aluminum cans may not be the very best mateial for use(I doubt nylon is either since it does not seem to be capable of lasting even 15 years) but I would recommend using something other than PVC.

My brother has picked up jewelery making as a hobby and has mentioned casting my own from brass. I have cast lead before but I may look into this further.

Jpk3200

Yeah I don't think it will hold up for an extended period of time. However, it is a temporary (and much welcomed) fix until I can find something better. I couldn't find anything really close to a match with a piece of brass or copper.

I will keep looking for a better alternative. In the meantime, I guess I cut me off another piece of the pipe every so often.

Force Fed

Finding a brass sleeve that fits it would seem to be a better, longer lasting solution.

Edit: Oops, didn't notice how old this thread was, I got all caught up in reading it

Houpty GT

I have some updates:
After 2 years and 20,000 miles the aluminum I used to shim the inside of the copper pipe has broken.

I purchased the mazda part but I do not know of anyway to remove the plastic sleeve with out likely breaking it. . I do not consider removing the transmission an acceptable option to replacing the entire metal piece.

The Mr. Gasket shift boot did not hold up to the heat or oily environment. It became hard and cracked open. I do not recommend this modification since it did not even last 2 years.

I plan to see if I can machine some brass into a sleeve that will work perfectly. This is something that I will have to do at work. I am also going to buy the Mazda middle shift boot.