Failed transmission removal. What did I miss?

[Nukeman7]

Legit question here...since the OEM Toyota pressure plate was an AISIN brand, why do you expect the new AISIN part to be sprung any softer? You really need to take a very close look at (or replace) the other auxiliary components which can contribute to a stiff clutch pedal before bolting everything back together again. Did you feel less pedal pressure when you pressed on the clutch pedal to separate the transmission housing?

Also, wire brush and apply a liberal amount of anti-seize paste on the dowel pins when reinstalling the transmission case.

 

[D60]

Throw out bearing does not look great. It’s rusty. But no noise when turning it. It’s a little crusty when turning, but not bad for 180k miles.

View attachment 285532

Sure but how does it travel along the shaft axis? What about the fork?

 

[brages]

A non-self-adjusting clutch (which this appears to be) will get stiffer as it wears... at least that's what I've read.

 

[eljefino]

Legit question here...since the OEM Toyota pressure plate was an AISIN brand, why do you expect the new AISIN part to be sprung any softer? You really need to take a very close look at (or replace) the other auxiliary components which can contribute to a stiff clutch pedal before bolting everything back together again. Did you feel less pedal pressure when you pressed on the clutch pedal to separate the transmission housing?

Also, wire brush and apply a liberal amount of anti-seize paste on the dowel pins when reinstalling the transmission case.

I went through this with two 2002 Camrys. "Something" got really stiff with time on both of them. Replaced one with a Sachs and one with LUK. 1/2 got better, sadly I forget which brand. These aren't old school race clutches; they weren't this way from the factory, and OP is on the right path.

 

[Bailes1992]

Your heavy pedal will be coming from the clutch mechanism and not the clutch itself. Replace it all.

 

[tcp71]

When I bought the Mazda, it had a stiff clutch. It was new to me so I didn't know better. Replacing the clutch with a LUK unit and new bearings made the clutch action much easier. Same Master and Slave cylinder.

 

[Vercingetorix]

Is your clutch helper spring working?

 

[JimPghPA]

Try pressing the clutch about 1/2 way without anything connected to provide return on the master side, just to verify that your not fighting a bad hydraulic hose that has restriction or a rusted slave or master. Hydraulic hoses sometimes expand internally with age and cause restriction.

Ya gots to be careful not to extend the slave more than it normally travels, because if you do, the slave piston might be damaged by traveling on a rusted section of slave cylinder that is never used during normal operation.

 

[Kurtatron]

I test drove an identical Scion with 70k less miles than mine.

The clutch was noticeably lighter. Toyota clutches are not supposed to be stiff. I theorize that the pressure plate has gotten stiffer as it ages also, like cold working metal.

It’s a theory, but I may be wrong. Once I bolt the transmission back together, testing the slave cylinder will be the first thing I do.

 

[Nukeman7]

A non-self-adjusting clutch (which this appears to be) will get stiffer as it wears... at least that's what I've read.

I believe this is actually a misperception of what is really going on. As the clutch and pressure plate wears, the pedal engagement point takes more travel to reach. Hence, the driver perceives it as being stiffer since the worn pp engagement doesn't occur linearly and comes on suddenly at 1/2 to 3/4 pedal travel. Instead of engaging over 90% of the pedal travel path, it only engages during the final 50%-10% of the normal range.

 

[brages]

I believe this is actually a misperception of what is really going on. As the clutch and pressure plate wears, the pedal engagement point takes more travel to reach. Hence, the driver perceives it as being stiffer since the worn pp engagement doesn't occur linearly and comes on suddenly at 1/2 to 3/4 pedal travel. Instead of engaging over 90% of the pedal travel path, it only engages during the final 50%-10% of the normal range.

I think it actually requires more force... here is an article about it, but it's too complicated for me to understand, at least not yet: https://www.schaeffler.com/remoteme...ia_1/downloads_11/2_Self_Adjusting_Clutch.pdf

 

[Nukeman7]

I think it actually requires more force... here is an article about it, but it's too complicated for me to understand, at least not yet: https://www.schaeffler.com/remoteme...ia_1/downloads_11/2_Self_Adjusting_Clutch.pdf

I learned something new today! Thanks for providing the linked info from LUK/Schaeffler.

Hopefully a worn clutch is the root of the OP's problems with an excessively stiff pedal.

 

[JimPghPA]

Here's an idea, as the clutch wears, both of the hydraulic cylinder pistons end up traveling against portions of their cylinders that had not been used for a very long time and may have rust.

Also, if it's not a closed hydraulic system, there's a time limit of how long the hydraulic fluid can protect against moisture entering it and causing corrosion of the pistons and cylinders. It probably should be drained and filled every few years just like brake fluid.

And if it uses brake fluid, Bosch extended service interval 6 ( ESI 6 ) is designed to provide protection for twice as long as standard brake fluid.

If it's not a closed system, given it's age it may be that moisture has become too high of an amount in the fluid and the cylinders are corroded and require replacement.

SOP, most never change a fluid and only think about it after a problem has occurred.

 

[Kurtatron]

For some perspective, I used a bathroom scale to get a rough estimate of clutch pedal forces.

First picture shows what the scale reads at 25lbs.

Second picture shows the highest force reading I got pushing the pedal slowly. If I push the pedal quickly, I get higher peak forces, which makes sense.

But I think the 52lbs is reasonable representation of how hard I might push when driving. Actual force will be a few pounds less when comparing to the 25lb weight.

 

[Kurtatron]

I think it actually requires more force... here is an article about it, but it's too complicated for me to understand, at least not yet: https://www.schaeffler.com/remoteme...ia_1/downloads_11/2_Self_Adjusting_Clutch.pdf

Thanks for this article. I think the photo below clearly shows what’s going on. A thinned out clutch disk means the pressure plate fingers stick out more, meaning more deflection is needed to disengage it. Maybe my clutch disk is worn out?

It is the original clutch on 180k miles after all.

 

[meep]

@Kurtatron - hats off to you sir - this is a big job. I never quite worked up to doing one of these. I hope you find it.

 

[Kurtatron]

Clutch disk wear inspection pictures. By the looks of it, if I ran it much longer, the rivets may have scraped into the flywheel. Hopefully this is the reason the pedal was so stiff.

I’m debating if I want to resurface the flywheel or not. There’s no ridges or indications of scraping. And there was no chattering or slipping before, so it must be fine as it is now. Rear main seal isn’t leaking either. Decisions decisions.

 

[Daroo]

I changed the clutch on my 2008 Yaris 1.4d for the same reason (stiff pedal). I used a Sachs kit, didn’t replace the flywheel, just sanded it down a bit with sandpaper, and didn’t replace the rear main seal because it wasn’t leaking.

Since I changed the clutch, I’ve driven 60,000 kilometers and I’m satisfied, the pedal is much softer

 

[Fabulous50s]

Always resurface the flywheel. Always replace rear main seal, Always replace release bearing. Always clean, inspect, and grease all pivot points on release fork. Anything less is hack work.

Think about 180k miles. Its done its time.

 

[Daroo]

I live in Italy, where most cars have a manual transmission. Usually, the flywheel isn’t resurfaced; it practically never fails if it is not dual mass. Rear main seal replace it if you want peace of mind.
The bearing is included in the kit, so obviously you replace it.