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Looks like it's time for an update, finally - busy week unfortunately.
I did indeed end up swapping transmission this past Saturday, and in general most things went pretty smoothly. The new transmission shifts far nicer and seems to have less drivetrain slop than my last one, although it's not perfect. Unless it had been replaced at some point it's got 200k+ miles on it, and that's showing up with some bearing noise, namely the input shaft. Now, the input shaft has far less slop than my old transmission, although some is still present. Regardless, the vibration issue in 4th has almost completely gone away and now only happens on rare occasions and to a lesser degree - I think it was the combination of the bad pilot bearing and sloppy input shaft causing the clutch plate to not center after shifting. Speaking of the pilot bearing, the new one is flawless; too bad my transmission now makes noise, oh well. I also replaced the transmission front cover gasket that GSLSEforme suggested, so hopefully no leaks will be in my future.
But now then, that's nothing clutch related... and well, the swap changed absolutely nothing. There was no damage to the t/o bearing support on either transmission and the bearing itself seemed fine. I did notice something interesting though. The Mazda bearing I ordered was not nearly the same as the ones I've gotten in the exede kits. They both fit fine, it's just interesting how different they look. Here's a couple pictures for reference:
Interesting eh?
So anyway, I also took a look at the clutch disk, flywheel, and pressure plate and noticed some interesting things, namely that there is very little wear on the disk. In fact, from how much slipping I've been doing (unintentionally), I would have thought the bell housing would be full of debris, but there was absolutely nothing. The other interesting bit is that the pressure plate shows uneven wear (photos below). I'm not too well versed in diagnosing such things, but that seems a bit odd to me. When I swapped engines (and at the same time replaced the clutch) I had the flywheel resurfaced at NAPA. I'd like to think that they did it properly, although I don't really know a good way to check that. I've also been having a hard time finding the step height spec for the 81-82 flywheel which is what I have. Could the pressure plate and/or disk be faulty - again, not really sure how to tell.
Just to reiterate, when my clutch feels like there is no resistance for the first half of the travel the slave is moving the correct distance. I have checked again and there is still no fluid leakage (although there's something else I'll talk about in a second), and so I still find it hard to believe that the hydraulics are at fault - unless it's internally bypassing in which case why would the slave be moving correctly? As I've mentioned before, during the 'until halfway down no pressure' gig, when I depress the clutch to where I begin to feel pressure (about halfway down, as just mentioned) the engine idle changes. At a cold start it sometimes changes by as much as 400 rpm, and the clutch is not disengaged at this point (I can tell by the bearing noise). To me this seems like the only possibility left is that I have a faulty pressure plate or disk that is somehow flexing, or getting caught, or something - is that even possible? Perhaps the flywheel was resurfaced unevenly? Is there a sure fire way to check that? The fork is fine, its spring is perfect, the pivot shows no damage, and the slave has not punched through the fork. Whatever the issue is, it has to be something that is affected by the engine running or not (as mentioned in one of my previous posts) and has to be something that can change (as sometimes my clutch feels perfect, but most times it feels messed up).
I also redid the clutch hardline so as to remove the loop. That turned out good, and while I was at it, I also pulled apart the slave - I should have done the master as well but didn't. Well what would you know - metal! There was some metallic residue in the slave cylinder, and it was beyond the fluid side of the seal so it's probably from poor cleaning during manufacturing - or at least that's my thought. So I cleaned that out and re-bled it - turns out the fluid still goes dark. Maybe there's some of that in the master as well, not exactly confidence inspiring. Regardless however, the hydraulics are doing their job, even if something still is causing the fluid to go dark. For the time being, I am going to assume that my clutch slippage is not due to them, mostly as there are other symptoms that are not hydraulic related. Here's a photo of the gunk I found:
So, that was a long post. Anyone see anything suspect? I don't exactly know what to look for here, but that pressure plates wear pattern seems a bit off. Anyway, thanks for the help and advice thus far.
With the difference in thickness of the throw out bearing, this tells me that the clutch wasn't engaging enough, hence, the lack of wear. Just my thought.
-You did replace input shaft seal along with gasket? You reinstalled clutch and p plate pictured?
-Dial indicator placed on machined surface clutch disc rides on and turn engine by hand and record runout in several positions radially,same for stepped area on flywheel. Straightedge on machined area and slide smallest feeler gauge that'll fit under in several places around flywheel and do same for stepped area.
Do same for clutch surface of pressure plate. There is a strange pattern(chatter marks)on both the pressure plate and the disc that suggests at least one of the three is not true/flat. Maybe it's the light on disc but for a newly machined flywheel/new clutch/p plate,the disc is not evenly worn as in not being fully 100% clamped. It should show even contact but definitely appears to have low spots that haven't touched flywheel.Are all bolts/threads integrity good that retain p plate to flywheel? Are springs tight in clutch hub? I have been able to determine clutch hub/lining runout by chucking clutch hub in my motorcycle tire balancer and spinning and using dial indicator on.
-Black death is degrading seals in clutch hydraulics,nothing else causes that.
Specifically, the height of the Throwout Bearing from where the Clutch Fork actuates it to the FACE of the Throwout Bearing that impacts the fingers on the Clutch Cover are causing the Clutch Disk to never be fully disengaged. That's also what could be causing the uneven wear on the outside edge of your Clutch Disk, as the fingers are never fully released to allow the spring weight to settle evenly across the face of the Clutch Disk. I'd also think this would affect your idle speed issues, as there will always be drag on the transmission with the Clutch never fully disengaged. Test this by sitting on a flat, level surface, push in the clutch and leave the trans in 1st or Reverse - if the car tends to move, it supports my belief.
So, did you put the new Mazda Throwout Bearing in there? How did it change things, or did it? With a mix of parts in there (*or so it seems), it's hard to diagnose what may be causing the issue, but the difference in Throwout Bearings is odd.
Reread OPs post,he hasn't yet responded to my post about what's in there currently but his post says nothing changed with the new t/o bearing.
Throwout bearing is not the cause,100% certain.Doing 1st clutch job on my SE several years ago after @50 miles had an annoying whine from t/o bearing that came in Exedy kit-not the 1st one i've had like that.Pulled trans and put in Mazda t/o bearing from my stash as seen in pic. Noise gone,no issues. Had to do this with a customers GSL for same reason. Hate having to dive into my stash,but again addresses the quality point difference between oe Mazda and aftermarket parts.
Clutch hydraulics would not be given a pass...presence of metal has distinct possibilityof a cut/nicked seal that would definitely cause some of the symptoms detailed in thread. The engine dropping rpm with clutch disengaged makes me wonder about e shaft end play,think this is replacement engine?
Look closely at wear/chatter marks on pressure plate and clutch disc. Above radial/runout measuements are starting point to figure out what's going on.Has to come back apart... believe is DD,sucks.
Last edited by GSLSEforme; 02-14-20 at 12:31 PM.
Reason: spelling
- First off, the 'taller' t/o bearing is the new Mazda one, so if anything I'd be having the issue of not fully engaging now rather than before. Regardless, it didn't seem to change anything. What I can do, however, is see if the slave is holding the t/o bearing against the pressure plate to find out if that's an issue now, although I don't think it is.
- The input shaft seal and gasket were indeed both replaced. The clutch and pressure plate were also reinstalled (as in the ones in the photos). Only things that have changed are the transmission and t/o bearing (plus the new fork and whatnot from the new transmission).
- The car does not creep when in gear on level ground, never has that I've noticed. The issue I'm describing with the idle speed changing is when in neutral, not in gear. During the times that my clutch feels strange, depressing the clutch about halfway raises the idle on average 150 rpm. The amount it raises is not always consistent (such as on a cold start idling at 1.5k like this morning, depressing the clutch halfway in this scenario raised the idle to ~1.9k). The issue is not full disengagement (as noted previously - and I understand there's a lot of text up there so info does get lost in the mix) but rather full engagement and hence slippage. I have never once had the car begin to stall or creep while in gear at a stand still. This issue (the weird feeling and slippage that is) presents itself while in gear or not, although obviously I can't depress the clutch halfway when in gear to test the idle because I'm moving and at that point the clutch is not yet fully disengaged.
- I agree that there is still an issue with the hydraulics and that if they are not yet damaged and failing, they may soon be due to whatever debris was in there. For now I was 'dismissing' the issue as when depressing the clutch pedal halfway, something is obviously moving in the bell housing (aka clutch slave is not acting completely faulty if at all, yet) because the engine speed changes. To me it seems like the hydraulics aren't what are causing the slipping and idle speed changes, although perhaps they are on occasion causing an additional weird pedal feel. It also would seem to make sense that any fluid being bypassed is not causing a major issue as I've never yet had an issue with clutch disengagement, unless perhaps the hydraulic system is failing to return properly after the clutch is released and causing re-engagement issues.
- It's interesting that you bring up e-shaft end play, as that was something I noticed while doing the clutch. It is... less than desirable, although no worse than the other two engines I have on hand. By guessing I'd say it's somewhere around 1/16" so, yeah, not exactly great. I rebuilt the engine this summer as my first rotary rebuild, so yes it is a replacement engine. There are a few things on the engine I wish I had spent a little more time on, but end play was something I didn't try, or think, to adjust. The engine will need to come back appart at some point here anyway because I'll need to replace some hard seals (they were within spec and hence were reused, but are nearing the end of their life - still decent compression though) and do a little work in the dowel pin oil leak department. It was more of a learning experience than a proper engine rebuild, but so far it seems to be working pretty good - end play omitted that is.
- Next chance I get I will drop the trans and get some numbers on the friction surfaces, although that will likely not be for a couple weeks as you are correct in that this is a daily. It's hard when you have to fix the car you drive everywhere isn't it... Oh well, we'll get this thing sorted out eventually. Thanks everyone for your thoughts and assistance. While I likely won't have a chance to inspect things for a little while, if anyone has anymore thoughts still feel free to share - might as well check everything I can while the trans is down.
Just wanted to wrap up this thread with the final outcome.
It turned out that all these issues were being caused by a crushed thrust bearing. It was my fault, as it occured during my engine rebuild, but I'm certainly glad I caught it before it worsened. Along with the thrust bearing getting squished it also took the bearing plate and thick thrust washer with it (resulting in over 2.0mm of end play, ouch). The bearing plate got so hot that it, in addition to turning color, cracked in two places. I'm more so amazed that I drove, and drove hard, for ten months like this before figuring it out...
As of a couple days ago everything is back together, the end play is well within spec, clutch feels wonderful, and the car drives like a dream (a noisy, rattly dream, but a dream nonetheless). I had truly forgotten how much I loved driving this car. Thank you to everyone who has contributed to this forum. You've enabled me to spare a car from the scrap yard, and now I'm never looking back.
For those among us who find destroyed parts sickly amusing I'll attach a few photos below.
02-13-20, 04:46 PM
Oh well, we'll get this thing sorted out eventually. Thanks everyone for your thoughts and assistance. While I likely won't have a chance to inspect things for a little while, if anyone has anymore thoughts still feel free to share - might as well check everything I can while the trans is down.
