Pilot bushing

[Skid]

I remember reading here that the common problem of getting false neutrals when shifting to 3rd can be solved with a MazdaComp pilot bushing. From a search through the parts catalogue on their website I'm not sure which part it is that's being recomended for a 12A stock tranny. More specifics? TIA.

[lee graser]

The early model rx7 trans(79-80) has a shifter mounted "in" the body of the trans---81 and up the much shorter lever is "remote mounted.

the 79-80 shifter has a pilot "bushing" in the ball tip--these wear and present problems--possibly what you are experiencing--the little cup like bushing comes in aluminium (competition) and nylon (stock)----new nylon bushings work fine for a long time---the one experience that I have (indirectly) had with the aluminium bushing was less than 100% satisfying---we went back to the nylon and replaced it once or twice a year.--minimal cost and easy to access.----problem solved.

[GEO46]

If I'm not mistaken, Skid is refering to the Pilot bushing that the input shaft of the tranny fits into at the back of the E-Shaft.

Sorry skid, haven't looked at what Mazda comp has to offer, so can't help there.

[Skid]

Yes, as GEO46 states, I believe its something at the clutch/tranny interface. Is it the bushing the clutch fork on the tranny moves in/out or is it something buried in the clutch itself?

[lateapex911]

The pilot bushing, also known as a pilot bearing, is, I believe, a needle bearing, that fits INSIDE the center of the back of the eccentric shaft. Then, the nose of the transmission input shaft slides into the bearing. It's obvious purpose is to keep the input shaft concentric with the e shaft, and its known to fail over time, especially if there has been water infiltration.

It can affect shift quality, and will usually tip you off by making a rattling noise when the clutch is depressed but disapears when the clutch is engaged.

Good luck and grease it well, and you'll never have to go there again!

(the other bearing that you refer to is the "throwout" bearing...ALWAYS replace it when you're in there!)
------------------
Jake Gulick
ITA 57 RX-7
New England Region
[email protected]

[This message has been edited by lateapex911 (edited August 30, 2002).]

[Karl Bocchieri]

The pilot bushing is the bushing that holds the input shaft of the transmission in alignment with the encentric shaft. The standard one is just a solid bushing or metal sleeve. The motorsports one is a roller bushing, which reduces friction, and is suposed to enable you to shift faster.
Never used it, don't know if it works, but most real racecars use them.

[ddewhurst]

Some added info on the transmission shaft input shaft pilot bearing. My race car is the 1985 RX-7 base model "S" & it's original pilot bearing was a needle bearing. Replaced it when a new clutch went in. It's a real female thing to get out. Sorry ladys. Tried a Snap-on needle bearing puller in a couple different configurations & that didn't work. Next I mangled the
%@#$ out of the bearing with a hammer & chisel trying to split the %@#$ing thing. Finaly I used a hand air grinder with a long grinding tool to split the thing so that I could pull the %@#$ing mangled needle bearing out.

I am open to listning to an improved removeal process.......

Have Fun

David

[lateapex911]

Ahhhhhh....I feel for you David! Been there! Some can be a tricky wicket!

Must be very careful not to bung up the E shaft hole!

Here's a trick that worked for me. Flodd it with brake cleaner to degreas it, get a grinder, and grind off the plating on the cage of the bearing. Fab up a plate that will fit over (across the bearing) drill a small hole in the middle and stick a machine screw through it and tack weld it in place. Now using the protruding bolt/screw, place the plate over the bearing and tack weld it to the bearing. Don't touch the e-shaft! OK, get your slide hammer and start pulling!

(Depending on your slide hammer configuration, you may not have to weld in the screw/bolt....a simple hole may do the trick.)

Takes 10 minutes to set up, but only 2 minutes to pull it!

------------------
Jake Gulick
ITA 57 RX-7
New England Region
[email protected]

[Karl Bocchieri]

Boys, this is a place where the correct tool will save you hours of hell. Mazdamotorsports part # 0000-09-0105
Mazda part # 4912-85-071

Mazdatrix also sells one for about $100

Before you put the new one in, clean the hole of any rust or grit and lube it up with some synthetic grease. It will come out with much less trouble next time.

[MK]

This works well most of the time:

Pack the pilot bushing/bearing 3/4 full with grease(no air pockets). Find a bolt/shaft with an OD a hair smaller then the ID of the bearing. The closer the fit the better. Center the bolt in the bushing and whomp with hammer. The grease will not compress and will usually push out the bearing. You don't know how cool this is until you've done it.

[lateapex911]

I bet it's especially cool when a buddy of yours is standing in line with the E shat...in the line of fire!

You may fire when ready, Gridley!

------------------
Jake Gulick
ITA 57 RX-7
New England Region
[email protected]