Drifting rex

iTrader: (17)

Just lately my car has been making a Rattling/Grinding noise in the clutch area. It only makes the noise when the clutch pedal is pushed in. It sounds like a Throw out bearing, but the owner before me has already replaced the pressure plate, Pilot shaft bearing, clutch disk, and Throw out bearing in 94'. It never was really that loud untill just lately I changed the transmission fluid to try and fix it and now it is pretty loud. I put in the regular transmission fluid SAE 90. Do I already need a new TOB or did I just not put good enough transmission fluid?

Drifting rex

iTrader: (17)

Could somebody please help me?

Rx-7Doctor

iTrader: (13)

Sounds like pilot bearing or fron main countershaft bearing which is common. If the trans is in neutral without the pedal pushed in is it nosiy?. Rx7doctor

Drifting rex

iTrader: (17)

It doesn't make any noise untill the clutch pedal is pushed in, it doesn't matter if it's in gear or not and it's funny cause it just started to get really loud all of a sudden.
Thanks for the help!

LongDuck

Be prepared that it's going to get really quiet all of a sudden!

When the pilot bearing goes out, it usually hand-grenades inside the eccentric shaft; this is what's causing all the noise that you're hearing right now. As the tiny pieces of that little roller bearing get beaten around in there, they will inevitably get thrown out against the pilot bearing seal and tear up this seal until it's gone. When that happens, the little pieces fall out into the clutch assembly; making your grinding problem go away if you wait long enough. The grinding stops because the pilot bearing parts get jammed between the input shaft of the tranny and the eccentric shaft, bonding the engine and tranny together making shifts almost impossible, and causing your engine to idle strangely. Pretty soon, you won't be able to engage 1st gear or reverse from a dead stop.

I don't recommend waiting for that.

You should save up some money and get a Clutch Kit from a major manufacturer (stock Mazda parts are A-OK). When you have a free weekend, remove the tranny, remove the clutch pressure plate and disk, grab a flashlight and see what's left of your pilot bearing. A good Clutch Kit will include the pilot bearing, TOB, clutch disk, and pressure plate. These should be changed when needed, but 10-year old bearings aren't the most reliable sort...

The reason why the noise only occurs when you push the clutch in is that the tranny is then stopped, the engine is still turning, and all rotational energy is focused on the pilot bushing which aligns your tranny input shaft to the center of the eccentric shaft on the engine. When the clutch is out (tranny in gear or not), the rotation difference between the tranny and engine is ZERO. They are spinning together, and the pilot bearing is stopped. Push the clutch in and the tranny is stopped and the engine is spinning - putting strain on the pilot bearing.

This is the root cause of this problem. I know because I've had it, fixed it, and can help you to do the same.

Getting the little pilot bearing parts (the cage) out of the eccentric shaft is the pain, but now that you know what the part is, it's just a matter of helping you through the process. Does this make sense?

Drifting rex

iTrader: (17)

Strangely today the noise was alot quieter and once I took it around for a spin I couldn't hear anything and it still shifted fine? Is this what yours did LongDuck? Yes it makes sense, but where on the eccentric shaft is the pilot bearing and is it farily easy to replace all this,because I have never worked on a transmission before, but I do understand how they work.

Here's all little background info on the car:

The car had carb problems and that is why the owner was selling it. He has kept the car in his garage for about three years from now, because it wouldn't run. I got the car from him and got it running and I have just started driving it. He pretty much had the whole clutch assembly replaced (Along with the pilot bearing) in 94', drove it for about 5 years and then let it sit in his garage. The car only has 118,000 miles on it right now, so how long are these bearings supposed to last?

Thanks for all the help

EDIT: I have been waiting a long time to get it running and now that I do the transmission decides to screw over and it makes me really mad! I have really been wanting to drive it and then it breaks, I guess I better get used to it because that is what I get for buying an old car.

LongDuck

These transmissions will run without pilot bearings in place, but for high rpm operation and for smoothness during standing starts, that pilot bearing keeps the clutch disk centered in the pressure plate and flywheel and prevents vibration from the transmission getting power from the engine. The pilot bearing is in the aft most section of the eccentric shaft - the same section of eccentric shaft that mounts the flywheel. The pilot bearing is inside of the eccentric shaft in a blind hole, and oftentimes the PB must be ground to pieces to get the outter cage out.

They usually last quite a while, but if they were installed incorrectly (without proper lube, or just jammed into place), then they will quickly wear out and cause the symptoms that you're describing. If your tranny is suddenly getting quieter, it could be that the bearing is grinding itself into smaller and smaller pieces, then the dust is no longer posing a friction source to your tranny input shaft.

You're still going to want to replace that bearing, if for no other reason than to avoid potential clutch problems or input shaft problems from the bearing not there.

It looks like this;

and also needs the PB seal:


Cheap parts at about $20 for the 2 of them, but they are there for a reason.

GyroJon

Ok, well you described my tranny now, so what does it indicate when the tranny makes noise when in neutral w/o pedal pushed in?

shadowlife25

You guys really need to get the FSM. It covers all this in detail and has good pictures to show you as well. It was the best $90. dollars I ever spent on my car.

shadowlife25

That's Factory Service Manual.

Drifting rex

iTrader: (17)

Long Duck, am I going to need a special tool or press to get it out or put it in? Is it possible to take the flywheel off from under the car? I found a Timken bearing at autozone for $10 is that a good enough bearing?

Thanks alot Long Duck for helping me get my car runing right!

LongDuck

You don't remove the flywheel to change the PB. The PB is easily accessible with the tranny out and the clutch pressure plate and clutch disk removed. From there, you'll need a special tool to remove the bad PB, and you can use a standard long-body socket to install the new one.

Here are some pics to show the puller that's the easiest method to removing a PB:

This is just a slide hammer with a head attachment that fits inside the PB and then tightens down to grab the back edge and pull it out with just a few whacks. They are normally a total PITA to get out, and sometimes require grinding by Dremel if you don't have the right tools. The part that sticks is the outter cage for the roller bearing race that through heat and time manages to stick itself to the inside of the eccentric shaft.

Once you get the PB out, installation of the new one (and the rubber seal) is very simple. Grab some penetrating oil and squirt a bit into the end of the eccentric shaft where it goes. This provides a little lube so it inserts more easily. Find a long-body socket that's the same diameter as the PB, and gently tap the new bearing into place - DO NOT USE A LOT OF FORCE, or you will damage the new bearing that you're installing and it will fail quickly. Tap it gently on all sides of the socket to ensure that it's going in straight, and then use a heavyweight bearing grease on your finger to fully lube the rollers. Install the rubber seal to keep the grease on the bearing, and then reassemble the clutch components with your replacements.

At this point, I'd suggest a new TOB, clutch disk and pressure plate, just because you're going to have it all apart anyway. If you've got the cash, this is time and money well spent that you won't have to tear it apart in 6 months or a year to do the clutch. Clutch is my LEAST FAVORITE work to do on the '7'. Mostly because I always seem to be alone and using the 'bear-hug' technique of tranny removal and reinstallation.

Reply back with any questions and I'd be happy to help out (with information!),

Drifting rex

iTrader: (17)

I got the PB from Oreily's, but they said the didn't have the seal to go along with it! I don't really have the money to replace the whole clutch assembly right now I pretty broke. I have one question: Does the clutch assembly come out with the transmission or does it stay on the eccentric shaft when the tranny is removed? I like that, the 'bear-hug' technique.

LongDuck

The clutch stays on the engine when you remove the tranny. The PB should be replaced with the seal, the seal keeps the grease inside. Without the seal, your PB will fail prematurely.

I would beg, borrow, or steal enough money to get the clutch parts that you need, otherwise you're going to be kicking yourself in the *** for not doing it all at once. This is a reliability issue.

To each their own. The seal is only about $5 from Mazdatrix, and they ship quickly,

Drifting rex

iTrader: (17)

I was looking through my haynes and I was wondering what you used to center the clutch?
BTW, I think my dad might buy some of the parts for me(I'm only 16). If not, what would be the most important part to replace? Thanks

Elysian

a clutch alignment tool of course... can get one from any auto parts store, whether u want to get one specifically for a 7, or a universal one if u plan on working on more than just 7's... i got a universal one, it was like 20 bux

Drifting rex

iTrader: (17)

Hey, LongDuck could you help me one more time. Does it matter which side of the PB seal goes toward the flywheel? Do you know which one of the pictures is the side that goes toward the flywheel?

LongDuck

Flat side goes toward the bearing. The beveled side is to help guide the tranny input shaft as you reinstall the transmission.

Helps to have the tranny alignment jig, too. This is a dark blue piece of plastic that centers the clutch disk to the eccentric shaft.

Fast enough for you?

Drifting rex

iTrader: (17)

Yes, that was very fast! I ended up getting all new clutch parts and I'm just now starting the job.(Took me awhile to get all the parts)I also got one of those clutch center tools.

bliffle

I would definitely get an OEM PB from Mazdatrix, and probably the whole clutch set. They also have a custom PB remover that works pretty good (I've been told). Some guys just grind down a standard slide-hammer gripper from the tool rental place. I've used a Dreml on some other cars PB.

Another way to pop a PB out is to get a mandrel or piece of rod stock same diameter as the pilot shaft, fill the PB hole with heavy chassis grease and bang that mandrel hard with a lead hammer. Often the hydraulic pressure drives the PB out.

B

LongDuck

It's good that you're doing clutch and pressure plate (and TOB) at the same time. Removing the tranny just to do the PB would be wasted effort to find out that you have a worn clutch disk or noisy TOB a few months down the road.

Let us know if you need any help with stuff along the way - getting the PB out of there is the hard part. If you've already accomplished that, you're most of the way there,

Drifting rex

iTrader: (17)

Hey Long Duck, it's me again.
I'm having some problems, I got the job done and got everything back together. I started the car and it ran fine, just like before (no excessive shaking from transmission), but when I tried to push in the clutch to put it in gear, the clutch wouldn't release. I'm very sure I put the clutch disk and pressure plate in right. My uncle was helping me and he suggested we check the clutch release cylinder, so we took it back out and bled it. It had some air bubbles in it, but after we bled it, the end of it would extend without doing anything to it. After it extended, we bled it again and it had air bubbles in it again, maybe more than before. We figured that it had an air leak in the cylinder and the air was compressing and didn't have enough pressure to release the clutch. I got a new clutch release cylinder, but I haven't gotten it in the car yet. Do you know what the problem might be? Thanks for all the help!


BTW: When I was replacing the Pilot Bearing I saw no evidence of the PB seal that would've been in there from the last job! I think the mechanic was either too lazy to put a new one in or just didn't think he needed one or something. Also, how tightly does the PB fit in the hole and if you stick your finger in there should it spin freely?

LongDuck

Well, in regard to the clutch not dis-engaging, that sounds like you've correctly diagnosed this as either the clutch Slave Cylinder or Master Cylinder, or both. Usually, if you have to replace or rebuild one of these, it's due time to do the other as well - having new parts in the slave will quickly lead to a blown master, which suddenly became your weakest link in the system.

On the PB, some mechanics don't bother to put the seal in, or even to replace the PB in some cases. The PB is friction fit into the eccentric shaft, so it will be a very tight fit, usually requiring the special tool to remove it. When you stick your finger in there, you're likely feeling the rollers on the inside of the bearing spinning around; not the bearing race itself.

HTH, and glad you got it this far,

Drifting rex

iTrader: (17)

I put the new slave cylinder on and the problem didn't change
It still won't go into gear and I still only have a little bit of clutch pressure. I can see the fork(coming out of the transmission) moving back and forth when the clutch pedal is pushed in and out, but I'm not sure if it is pushing the pressure plate out far enoguh to disengage the clutch disk. Did I maybe put the pressure plate in wrong? I'm confused and frustrated!

LongDuck

Re-bleed the clutch slave cylinder and then look at it to see if you've got enough travel to operate the clutch TOB. This isn't really a problematic part when you do the clutch, so I'm somewhat confused about what the cause could be.

Have another go at bleeding the system and then let us know what you find. In some cases, the Master Cylinder is also leaking along the inside of the firewall under the carpet and you'll be losing fluid pressure out of there. Have a close look at the hydraulics of it before you start tearing the tranny out again. HTH,