Clutch kits for 3rd gens

Just wondering if anyone has had any experience with M-Pact upgraded clutch kits? Wanting to get a tougher clutch than stock but the cheap price makes me nervous from rockauto… I’ve checked out LC Engineering but being in Canada it would be pretty expensive with the conversion.
Thanks for any input!

https://www.rockauto.com/en/catalog...6,3441741,transmission-manual,clutch+kit,1968

 

Why do you want a tougher clutch?
Besides regularly towing a heavy trailer, which if you do you should probably just upgrade to a full size truck, the stock clutch should last over 100,000 miles

 

Stick to aisin clutch kits.

high torque Id only suggest for a forced induction engine.

Besides being overkill it tends to shorten the life of the plastic clutch pedals.

Fatigue on the leg is awful as well.

 

Not a single clutch I've watched others install has proven good longevity. Meanwhile the stock clutch often has good longevity, except in the case of superchargers. I'd recommend keeping stock. If you are running large heavy tires, regear to help clutch life.

 

yeah stick stock, this is no racing engine. If it wore due to slippage, regear properly so slipping the clutch (quick lead to failure) isn't needed

 

Thanks! I think I will try the aisin.
My throwout bearing went and with my truck at almost 200,000kms I figured I might as well just replace the clutch since we’ll be in there anyway and it’s quite the job. So was thinking the mpact might be better for off roading and stuff with the hi torque discs but wasn’t sure, and didn’t want to put a crappy clutch in.

 

Before you commit to replacing the throwout bearing, have you tried adjusting the freeplay of your clutch pedal to the specification? It could just be chirping from the light contact it will start to make when the freeplay goes away with wear. Unless you hear the noise with a decent amount of pedal pressure your throwout bearing is most likely still fine

 

You can’t do anything at the pedal to help the throw out bearing. Clutch pedal free play is there to ensure the clutch isn’t being disengaged by the master cylinder unintentionally. In other words, the free play at the pedal shouldn’t be being eaten up over time.

Down at the bearing, the bearing spins full time and is held up to the pressure plate by a spring in the master cylinder. As the pressure plate expands from wear, the slave cylinder spring should compress. So it shouldn’t be making light contact.

Sometimes I do wonder if the TOB squeak issues are from a weak spring in the slave no longer holding it up to the pressure plate consistently. In 100% of the cases I’ve watched, the noise goes away as soon as pedal is pressed. So maybe a stiffer spring would have helped. But then maybe that would cause disengagement when it’s not wanted, not sure.

 

I'm gonna have to politely disagree with you,

As your clutch disk wears out the disk gets thinner which will require the pressure plate to move closer to the flywheel to compensate. In turn the fingers of the pressure plate protrude away from the flywheel and to the release bearing. Your release bearing should not be spinning all the time.

When a new clutch is installed there is more play at the pedal vs. A worn clutch. Most people skip this step but with the exception of Fords which have a "self adjusting" pressure plate which compensates for that wear automatically, adjusting your clutch pedal freeplay is a maintenance item on pretty much every vehicle I know. Some older vehicles performed the adjustment by lifting the clutch pedal beyond it's stop.

Toyota's as far as i've seen and as far back as I know has had the adjustment performed by loosening the 12mm nut on the master cylinder rod and counter holding with a 14mm. I believe the spec is around 1/4"-3/8" play. If i'm not mistaken that spec is not just in the service manual but also the owners manual

 

The release bearing does spin all the time. That is how Toyota designed it. It prevents skipping of the bearing rollers every time it's pressed in and trying to get up to speed. You are correct that the pressure plate fingers protrude more...that is why the bearing and release fork compress the spring in the slave cylinder more over time. The slave cylinder still maintains that spring pressure on the fork to keep the bearing spinning all the time.

The engagement point can change as the clutch wears, but free play does not. Free play is the free play of the pedal itself...play of the pedal being free before it starts to operate the hydraulics via the master cylinder pushrod. That is to ensure that the pedal is not putting any pressure on the hydraulics at rest. It should not change as time goes on. Engagement of the clutch will change as time goes on, as the clutch disc wears and bites at a different point in the pedal travel.

 

BMWs often have self-aligning/adjusting clutches, too.

 

ahh gotcha, and I would do the same too!

 

I agree that the pedal friction point will get higher as the disk wears, I still disagree that the release bearing is supposed to spin all the time. The spring in the slave cylinder is there to maintain tension on the piston but not to compensate for pressure plate wear. As the slave cylinder compresses due to the wear in the components the fluid gets forced back up into the master cylinder. Keep in mind that fluid does not compress. In turn that will also force the master cylinder piston back until it reaches the stop of the pedal once the freeplay is eaten up. After that you'll start possibly having the issue of the clutch not fully engaging. That's a far off point though.

 

I don't really know what to tell ya. Toyota has the bearing spinning from the factory. Take off the inspection cover on your bellhousing and you will see it. The slave cylinder spring keeps the piston outward and the pushrod against the fork and does so all the way to the point where the fork pushes the bearing into the pressure plate fingers.

The master cylinder stroke should be the same all the time, or in other words, the clutch wear that forces the fingers outward should not do anything to the pedal height or free play. You install the master cylinder into the pedal assembly with the rod fully extended at rest. You adjust the clevis to be slightly loose from the backside of the pedal which is where the free play comes from, and is to ensure the pedal is never acting on the hydraulics at rest. If the slave cylinder volume lessens over time as the piston is pushed back from the extended pressure plate fingers, that volume should go up to the reservoir. Meanwhile, the spring is increasing its force on the TOB over time due to the extended fingers.

Since you install the MC with the pushrod already extended fully at rest, the pushrod should not extend out as time goes on and the slave cylinder volume lessens. That should go up to the reservoir, causing levels to rise. Which on a Sport is unnoticeable because the fluid comes from the brake reservoir and will be overall unnoticed since the brakes are pulling the fluid level lower as the calipers hold more fluid over time when pads go down. On an OR or Pro with the separate fluid reservoir, the fluid could eventually go too high. But it's very slight.

If the slave cylinder volume decreasing over time did eat up the free play, that would be a problem for FJ owners with the metal pedal, because that clevis style doesn't allow for much free play since it uses a clevis pin. Actually, the FJ clevis is plastic and has a somewhat slotted clevis attachment, but the metal clevis on the land cruisers from overseas have a simple hole that allows for very little free play. If the free play was eaten up over time, eventually the clutch pedal height limit switch would start to push on the clutch hydraulics, which would be a problem. It would happen on the Tacoma and FJ too, but it would happen a lot sooner with the low tolerances of the metal clevis hole.

 

This post by Jeff Lange is helpful in explaining it all.

 

So I did take a read through Jeff's post along with yours and it contains alot of info. I agree that following my explanation leads to possible contact of the clutch stop/switch. I've only honestly found that to be the case with aftermarket clutch disks and only when they are pretty well worn to the point of replacement anyways. I also agree that the pedal height doesn't change over time as the pedal stop is set and nothing will change that on it's own and, I also agree that the clutch fluid level is opposite to brakes in that the level can slightly rise over time as the disk wheres thinner and all the other jazz happens.

Some throwout bearings are made to be in constant contact, I believe the chevy Caviler was like that but, as far as i've seen so far those setups have a spec of 0mm to maybe 5mm of freeplay at the pedal where as other setups where the bearing doesn't spin all the time usually has a spec of more than 0mm. This could very well be an exception to that in Toyota wanting pedal play to ensure the pedal is not exerting external force on the system as you said.

Maybe this clutch master cylinder is also an exception but, the one's i've busted open also have had a chamber behind the piston which is full of fluid but at atmospheric pressure not pressurized by the pedal to allow for a quick refill of fluid as the pedal is released incase the pedal is depressed again in a hurry. The cup seal of the piston deforms to allow for that fluid bypass when the pedal is released. The slave cylinder is not like that with the additional chamber behind the piston. When you adjust the rod freeplay, you're slightly pulling the rod away from the master cylinder piston.

I've never seen a Land cruiser or FJ setup before so I can't comment tons on that specifically so i'll take your word on those setups. To be honest i'm still not sold on that because with every vehicle i've owned so far except for the Fords but including this truck, the freeplay has diminished over time and only once on my old Corolla did I get any sort of chirp. After adjusting back in my freeplay though the noise went away. Pedal height specifically i've only had to play with if someone else was already in there or the stop/switch was replaced