Clutch... pulling my hair out.

[exigent]

First off hello everyone as this is my first post. I have a 98 2.5 5spd. Clutch grenaded on me the other day. The "hub" inside the disc stripped out while driving 45mph about 1 minute after the last shift... neat huh? When i say stripped I mean the splines are fine... the hub itself broke loose from the rest of the disc. I only include these details for later reference.

Now... this is not my first clutch replacement however I am stumped. Replaced clutch disc, pressure plate, pilot bearing(NOTE: which had no pins left in it what-so-ever), slave cyl, and TOB. Flywheel is nice and clean (clutch didn't wear out remember) and everything "looks" okay. Bled the system (WHAT A PAIN) and got good travel and release. I jump in start the engine in neutral with the clutch in and attempt to shift to first... NOPE. So I think I didn't bleed it well enough... so I bleed it about 30 more times... Still not able to shift from idle. If I start it in first I can drive and shift just fine. Clutch operates nicely, releases for upshifts okay and downshifts with a bit of effort. Drove around 2 mi to see if pilot bearing would "burn in" and no... it DID get a little better but no where near right.

Soooo.... tonight I pull the trans back out and find something odd. The hub of the clutch disc has rubbed against the very end of the slave cylinder. I don't mean a scuff either it has melted about 1/16" of the slave cylinder off. There is still a safe amount of plastic left to hold the retention ring in place but I don't get how this even happened. I triple checked the slave cylinder to make sure it was seated correctly. I measured the height of the old slave vs. the new to make sure it wasn't simply taller. I can't figure a way that the clutch disc should ever be able to touch the slave cylinder but it has and Im lost.



1. When I first pulled the trans the "guts" of the old pilot bearing were gone. I found a couple of pins in the back of the crankshaft but nothing was holding the input shaft from rolling all around. If I try to move the input shaft side to side it moves A LOT. About 1/4" either direction. I have no experience with this trans is this normal or is this what happens when you have no pilot bushing for 30,000+ miles. Trans is out and open rite now... should I replace the bearings on the input shaft? Please advise.


2. How the HECK does the disc hit the slave cylinder! #$%#$%# I assume the slave cylinder was pressing the disc against the flywheel causing my no shift problem.... BUT WHY!!?!?!?!?? The slave cylinder properly seated is in a very specific location a certain distance from the flywheel. The disc is pinched directly against the flywheel.... under what circumstances could they bind? The Aluminum "shim" is in place between the engine and transmission. Is there a reason I would need a thicker shim?

Oh and the disc can ONLY be installed one way... No... i didn't install it backwards.

 

[MAKG]

I hate to say it, but it REALLY sounds like the disk is installed backwards. Or else it was just the wrong disk or slave cylinder.

1/4 inch of play in the input shaft seems excessive.

 

[gotmudd]

not true you CAN install disk BOTH WAYS only one way will allow proper shifting, i agree with MAKG, you probably got that sucker in backasswards, been where you're at. and yes since you are apart you should replace your bearings

First off hello everyone as this is my first post. I have a 98 2.5 5spd. Clutch grenaded on me the other day. The "hub" inside the disc stripped out while driving 45mph about 1 minute after the last shift... neat huh? When i say stripped I mean the splines are fine... the hub itself broke loose from the rest of the disc. I only include these details for later reference.

Now... this is not my first clutch replacement however I am stumped. Replaced clutch disc, pressure plate, pilot bearing(NOTE: which had no pins left in it what-so-ever), slave cyl, and TOB. Flywheel is nice and clean (clutch didn't wear out remember) and everything "looks" okay. Bled the system (WHAT A PAIN) and got good travel and release. I jump in start the engine in neutral with the clutch in and attempt to shift to first... NOPE. So I think I didn't bleed it well enough... so I bleed it about 30 more times... Still not able to shift from idle. If I start it in first I can drive and shift just fine. Clutch operates nicely, releases for upshifts okay and downshifts with a bit of effort. Drove around 2 mi to see if pilot bearing would "burn in" and no... it DID get a little better but no where near right.

Soooo.... tonight I pull the trans back out and find something odd. The hub of the clutch disc has rubbed against the very end of the slave cylinder. I don't mean a scuff either it has melted about 1/16" of the slave cylinder off. There is still a safe amount of plastic left to hold the retention ring in place but I don't get how this even happened. I triple checked the slave cylinder to make sure it was seated correctly. I measured the height of the old slave vs. the new to make sure it wasn't simply taller. I can't figure a way that the clutch disc should ever be able to touch the slave cylinder but it has and Im lost.



1. When I first pulled the trans the "guts" of the old pilot bearing were gone. I found a couple of pins in the back of the crankshaft but nothing was holding the input shaft from rolling all around. If I try to move the input shaft side to side it moves A LOT. About 1/4" either direction. I have no experience with this trans is this normal or is this what happens when you have no pilot bushing for 30,000+ miles. Trans is out and open rite now... should I replace the bearings on the input shaft? Please advise.


2. How the HECK does the disc hit the slave cylinder! #$%#$%# I assume the slave cylinder was pressing the disc against the flywheel causing my no shift problem.... BUT WHY!!?!?!?!?? The slave cylinder properly seated is in a very specific location a certain distance from the flywheel. The disc is pinched directly against the flywheel.... under what circumstances could they bind? The Aluminum "shim" is in place between the engine and transmission. Is there a reason I would need a thicker shim?

Oh and the disc can ONLY be installed one way... No... i didn't install it backwards.

 

[grnrngr]

Hard to say if the input shaft wobble destroyed the pilot bearing or a defective pilot bearing allowed the input shaft to develop a wobble, but it's a safe bet that's what destroyed your clutch. Did it make a whining noise when it was running? I'd pull and replace the input shaft bearing and prolly wouldn't hurt to replace the slave cylinder. Good luck...

 

[Will]

I think the tranny is wasted. Whatever the input shaft is connect to (front cluster?) is probably whipped. That's what mine was like when it died--you could move the input shaft around like a gearshift lever. My replacement tranny wasn't like that.

 

[thegoat4]

The common progression of this kind of failure:
Pilot bearing goes out and burns the tip off the input shaft
Input shaft begins to walk around
Clutch disc's center breaks out

Drain your transmission oil and check for metal. If it's ok, the transmission is ok. Input shafts can have a good bit of wobble and still work fine. But if the tip of the input shaft is not a good fit in the pilot bearing, you will need to replace the input shaft.

 

[exigent]

Thank you for the replys

Here's an update. First I checked to see if I installed the clutch disc bassackwards. NO. If I lay the disc on the flywheel it lays down nice and flush with the entire surface of the flywheel. If I try to put in on the other way it will not even come close, the center hub holds the disc about 1/4 away from the flywheel. At least with this particular clutch it cannot be installed backwards. I know what side touched the slave cyl because that side of the clutch disk is polished from the contact. So that theory is no good guys... I had it in correctly.

I got to looking at the input shaft and thegoat4 got it right. The pilot bearing failed at some point and the input shaft ground against what was left of the bearing. It machined two nice clean slots into the end of the input shaft (front and back lip of bearing). At first I assumed it was supposed to have those slots but after looking into this it appears the end of the input shaft should be smooth.

SO... I still have no idea why the disc contacted the slave. In the mean time I tore down the transmission. It's really stupid that you have to tear the entire thing down to replace the input shaft bearings. I realize the front section can be replaced but to get into the rear you need to pull the entire assembly.

SO.... I get the thing apart finally and find that the innermost bearing is where the slop is. The output shaft side is the "male" side and the input shaft is the "female" side. They roll against one another on roller bearings in a little cage. The surface of the male side is heavily scared from all the slop. The female side seems to be okay but I need to replace the input shaft anyway... now though it seems I basically need a new transmission(rebuild anyways) as the price of the parts is fairly close to a rebuild. I have a press to do the job but I dont have about 3 other special tools needed to pop the bearings off... It seems I'm rather stuck at this point.

I read something about flywheel shims... what purpose would those have? Im going to pull the flywheel tonight and see if it's shimmed. That would certainly explain the contact.... phew...

Just a side note... the rest of the trans is in remarkably good shape... its a shame really. Im guessing it was replaced at some point. Do you feel it is worth it to replace the output shaft and the input shaft? Along with whatever bearings get ruined on the way out? Im open to opinions. I can get a rebuilt m5od locally for $750.

 

[MAKG]

Make or modify a puller. Sometimes you can rent bearing pullers, but they need to be DEEP to pull off transmission bearings. With a light transmission assembly, you can often play games with (thick) shims, a bearing splitter, and the press to get the stuff out.

FYI, virtually every transmission requires significant surgery to replace an input bearing, and complete disassembly to change the roller bearing.

 

[rboyer]

I actually have a trans that came off of a 2.5 that i'd sell to you if you're looking for one. I think I robbed the shifter bushings out of it a little while ago but you could either use yours or I could dig some up. If you're interested i'll sell it to you for 350 shipped to your door.

 

[exigent]

Thanks for the info

I already ordered all the parts i need so im set for that. Ill grab some pics for to post to help others in thanks for your help. I've looked into bearing pullers and such and it seems I can wing it. Im only worried about installing the last bearing onto the mainshaft in the rear. Special tools shows a tube to press the bearing on. I was able to beat the old one off with the method described on this site. Im considering using a peice of steel pipe cut to length and a bolt/washer to press that bearing on. Anyone try this method? Id use a high grade bolt of course. It seems this is basically what the special tool does.

Any other thoughts on why the clutch disc contacted the slave cylinder? I have a least 5 days before I try to put the trans back in... Id like to have something sorted out for that problem.

 

[MAKG]

If you can rig a steel pipe and bolt, that's great. Fire away.

I've been known to just beat on a steel pipe with a sledgehammer. Or, IF it's feasible, put the pipe (with a large flat piece of steel on top) and the whole transmission into a press. A bolt puller is MUCH better than beating, as it is far easier to control.

 

[thegoat4]

Get you a fry daddy or small crock pot. Cook that last bearing until nice and toasty, drop it over the shaft and quickly tap it into place with a long punch.

 

[Jspafford]

Get you a fry daddy or small crock pot. Cook that last bearing until nice and toasty, drop it over the shaft and quickly tap it into place with a long punch.

Make sure to put new oil into the deep fry before the next batch of fries...

Nothing worse than bearing grease in your fries.

 

[rboyer]

Yeah heat helps alot as long as you don't get too excessive. Actually when I reassemble smaller 2 stroke ATV motors I put the crankshaft and bearings in the freezer for a few hours, heat the cases then stick the bearings in. Then heat the bearings that are in the cases and put the cold crankshaft into the bearings. Usually doing it that way I almost get away without having to use the shop press. You would be surprised what a difference a little heat can make.

 

[MAKG]

No need for a "fry daddy" or whatever. Stick the bearing in the oven to 400 deg or so. If you're FAST, you can slide it on. But as soon as the bearing contacts steel, it's going to cool and shrink.

Some people will tell you to freeze the transmission, but it makes a LOT less difference (freezing is only some 50 deg or so difference ; cooking the bearing is over 300 deg).