CLUTCH SLIP AFTER REPLACEMENT

[C130]

Hey everybody, long time Lurker. All the info here is invaluable, I hope to contribute more in the future
So here goes, 84 SR5 4WD ive been bringing back from the dead. Previous owner neglected for 20 years. Unbelievable compression is still great. So clutch needed to be changed. It was my first time and it was less than fun. Had the flywheel machined all seals and bearings replaced AISIN clutch (CKT-010) KOYO bearings I think. Wrestled the somnbish back into her home and torqued to spec.
So I finally get to test drive and I'm experiencing slip at high RPMs....womp womp womp. Followed the freeplay adjustment procedure and verified the arm on the bell housing isn't applying pressure on the plate. I really don't want to have to remove this $%&&%$ thing again.
So questions
1. Could they have machined the flywheel surface too much so that the clutch pressure plate wouldn't apply enough pressure?

2. It is fine to 3K rpms but slips with more throttle, could it be breaking in for the 500 advertised miles? Reason I ask is that ive found almost everyone else has no slip during break in

3. Potential fluid or grease on disk or plate or flywheel...Used minimal amounts of lube on the points required in the FSM. I'm thinking bad thoughts like drilling a plug hole out on top of the bell housing and dousing the thing with two cans of brake cleaner...

Any and all ideas and opinions would be much appreciated! First post so sorry if I'm noobin

[Petros]

when they machine the flywheel they are supposed to take off the same amount where the cover bolts on as the friction surface, so that should not change (unless they messed this up). if all the linkage and adjustments are correct, seems contamination is more likely. look for a rear mail seal or a transmission input shaft seal leaking. unfortunately if you have an oil leak, the trans has to come out again.

Usually only the rear main seal will fail with age, the transmission input shaft usually holds up well (not as hot as the back of the engine), but they too can fail. If you put in a new rear main, it is possible it was not installed properly and it is leaking.

If it is one time contamination, it will usually eventually stop slipping. sometimes it develops a shutter if it has contamination. Though if that happened you can usually keep driving it for a while, but eventually the shudder will cause the plate to fall apart (I have had that happen, so do not ignore it for too long).

The other possibility is the clutch disk is not compatible with the clutch pressure plate assembly, though if you bought a full Asin kit, that seems unlikely. If that is the case, unfortunately the clutch has to come out again.

Those are all the reasons I can think that would casue slipping of the clutch. do all the checking and testing before you take it apart just to make sure it is not something that can be corrected without removing the transmission.

You might drive it for a bit and see if it goes away, or gets worse. If you do have to pull the trans again, it will go a lot faster the second time, but it is still a big job. My clutch is marginal and I am debating replacing it in my cold garage, or waiting until the spring. likely if I have to dive in deep snow, it will finish off the clutch and I will need to get towned home. Either way, it is a big job and I have all the correct tools and have done it on a Tercel4wd six or seven times.

[xirdneh]

if the rear main is leaking oil should run down from the top of the tranny
wipe top of tranny/bell housing down (above and just behind axle location) and drive it a while then check
i have only had one rear main leak out of 12 plus tercels and it was not the seal but the gasket between block and seal holder plate that disintigrated
have never had a tranny input shaft seal that leaked, they get hard and brittle but still hold the gear oil back
but if you did not replace it and removed the input shaft for easier tranny install it could have gotten banged up
i assume you had a kit and replaced the pressure plate
if all that checks out i would be going with petros on how they machined the flywheel

[teranfirbt]

I've had every clutch slip to some extent until I gave it a good break in. Much like brakes, you actually need to run it hard for a short period of time to get the friction material embedded into the pressure plate and flywheel, then it will work much better. The drive it easy method is pretty much backward for break in (like most things on cars that need to be broken in...)

My general procedure for clutch break in is to run it at full throttle in 3rd gear, allowing it to slip, for ~3 seconds. This will get the material hot and start transferring friction material.

Once you've got about 3 seconds of heat into it, let off the throttle and drive easy in the same gear to allow the clutch to cool a bit.

After ~20 seconds, throttle up again and see if the clutch slips. If it does, allow it for another 3 seconds, then throttle off.

Repeat 5 times, then drive for a good 5 minutes without shifting. At this point, the clutch should be good to go, no more slipping. If the clutch stops slipping before your 5 repeats are done, I would use the clutch pedal to make it slip.

Don't let it slip for more than 3 seconds each time! Excessive slipping will cause the clutch to overheat and glaze over.

It's normal to smell a little burning clutch, this is really the volatiles in the clutch binder burning off and is completely normal.

If this doesn't solve your slipping problem, you'll need to start investigating a deeper issue.

[marlinh]

Hmmm...Teran, I have never heard of that procedure. Just did a google search and so far everyone says drive it easy to break it in.

When you installed the clutch did you clean the pressure plate and flywheel with brake clean? The pressure plate usually has a coating on it to prevent rust. If that wasn't cleaned off, maybe that is why it's slipping.

[rer233]

Disc installed backwards??

[teranfirbt]

Not surprising, it's gotta be done carefully. It's one of those things where if a little is good, a lot will glaze the hell out of the clutch and ruin it. I've done it to the last 3 clutches I've installed, all are smooth and felt exactly like it did when new after 25k miles (none have more miles yet).

Disk won't install backward without running the hub into the flywheel bolts before touching the flywheel surface.

[Petros]

I would suggest checking that the linkage is not too tight, and than drive it for a week or so and see if the problem goes away. If it has a layer of contamination it should wear it off soon enough, or brake-in on its own.

Just do not push it if you know it will slip.

do you have a tach on your Tercel? If not install an aftermarket one, it will better allow you to determine if it is indeed slipping at high speed when the RPM goes up without the speed increasing.

[xirdneh]

i have never experienced clutch slippage after replacing clutch/pressure plate on any of the tercels i have messed with
the only probelm i have ever had was a bad pressure plate (new) that would not allow tranny to shift in the lower gears

[Jonymoto]

Same here, and I've replaced 3 on my 32 yr T4 and I didn't even follow a break in procedure.

[C130]

Thanks for all of your responses
Update:
If I put the hammer down it doesn't have the hesitation. I replaced the cap and rotor and fuel filter too. Got a bit better.
First gear is fine but second gear and up has a bit of hesitation under medium throttle application.
My tach is fully functional and has no indication of slip. Ive also downshifted and rev matched from 5th to 4th with zero indication of slip at about 3500-4k rpm's.
I don't think I remembered to clean off the clutch, pressure plate and machined flywheel. The flywheel was machined entirely as well, not just the step. Shouldn't this improve over time regardless?
Install was a bear and at one point the input shaft was resting on the pressure plate splines. Could that have damaged it? Visual inspection of the splines didn't indicate any damage or bends...hardly an accurate way to check but eyeballs were all I had.
I'm not sure about the fluid issue, my trans seals leak and are next on my list. I may have overserviced the trans while it was out too. More gear oil is better than less right. I can get a boroscope from work and there is just enough clearance from the bell housing dust cover to get in there. Ill try it out next week at work.
I'm wondering if I may have a fuel delivery issue. My bowl sight gauge is at three quarter so a rebuild is due. I have the kit, just waiting til I finish renovating my bathroom to get started.
And if the dizzy is worn could that cause the bogging? I'm just confused because first gear is pretty seamless so if Its fuel wouldn't the issue be throughout the gear range?
And dizzy because it got a bit better with a new cap and rotor. I'm also pretty sure the Vac Advance is disconnected(3AC)...
Maybe I can get a video uploaded soon with the symptoms. Thanks a lot fellas, love this thing more and more as the days go on, happy shes back on the road. Surely would have seen the scrap yard if I hadn't found it in time.

[Petros]

check your mechanical advance in the distributor, they get sticky or rusty and do not advance will have weak acceleration.

it does not sound like your clutch is the problem. you will not fix the clutch by installing new cap and rotor. I would look elsewhere for the problem.

I usually hang the trans off the input shaft in the clutch to get it it installed, if careful that should not be a problem. if you got the trans spline shaft into the clutch and bolted up, it will work fine. If there was enough damage to cause an issue you would not have got it together and running I suspect.

[C130]

Good call petros, Ill pop the dizzy open again this week. I think I saw a procedure on here for freeing up the linkage. I'm starting to feel relieved the clutch is slowly moving out of the picture. That was a bear of a job. Still going to borescope the bell housing for fluid contamination I think.

[C130]

Follow up,
Clutch is good, strong engagement. Think it was fuel or my dizzy lube. Not sure which one because I did them both before I tested her out. What a relief. Also ended up changing out the carb with a National reman for 170$. Performed the adjustments as per the FSM and the car is way more responsive. No vac advance though. The idle mixture adjustment was pretty confusing too.