Simple Clutch Mod

Sorry, but that is incorrect. There is an internal port in master cylinders that can get blocked if full travel is not allowed. That is how fluid expansion is compensated for and to allow fluid from the res to refill the system.

This port is noted as the Compensating Port in the pic:


I don't know what the GM design looks like and wouldn't be surprised if it was flawed in the way that it might not be a robust design.

 

serious question for you:

are you verified that there is no bypass or relief valve at the top of the pedal travel likes was mentioned about the GM system? because that could be a concern in certain cases maybe... mmmmaybe..

 

I think the cold weather part goes hand in hand, the clutch pedal moves very slowly off the floor in the cold, if that is a Return Assist Spring then I think it worried guys that the pedal will just sit on the floor in the cold.

 

That is for fluid that's being pressed back into the reservoir through the lines. That will only be blocked if the piston is slightly in its stroke. I can't see how this would be an issue if it's just the weight of the pedal on the piston. As i've said before, I've done this on previous vehicles and never had an issue for tens of thousands of miles.

 

Yes, exactly. You said there was no port in your previous post:

It all depends on the design of the master. I checked yesterday that the piston was at full stroke, so I feel as you do. The Taco master should operate fine without the spring. Folks who try this mod should check this as there have been posts about inconsistent free play settings from the factory.

My guess is that the GM version can't manage that and that doesn't surprise me.

 

I guess I missunderstood the previous post I referred to. My fault.

However, the piston does not seem to be touched. Unless this bypass (which I don't actually know if they use or not as I haven't had to look at it yet and don't plan on it) is in a really stupid position, it'll have no affect on the system. The only thing acting on the rod is the weight of the pedal itself.

The turn over spring I believe was designed purely for comfort and leads to some inconsistent feeling in the pedal. If I lived in a high traffic area, I'd keep it and deal with the inconsistency. However, I don't so that sucker is gone. Generally, I keep engine / transmission stuff unmodified as to keep with the design engineers intended design. Being a engineer myself, it's up to me to determine if there's a reason to change the design as intended. I thought about the options, and proceeded as I'd like. For those wanting to do this mod, think about it yourself and determine if the risk is worth it. Completely up to you what you do..

 

Right on!

My guess is that the GM one is not moving completely due to pedal weight. It might not have an internal spring? Seems like something they would skimp on? It might also be a lighter diaphragm spring on the pressure plate or a lighter lever arm?

The compensation port is internal to the master. I looked around last night just because I was way under there. The Taco master has the line from the res coming in near the top (hard to see) and the pressure fitting to the accumulator and slave are easier to see on the left side.

Engineers have different constraints than users. The beauty is that we can play as we like, for the most part, and make it our own. Your mod does work, I just didn't feel the clutch anymore between the two versions. Just a difference between us even though I usually prefer heavier, more deliberate controls.

 

To lazy to read, or dont know how?

 

?

 

back around to this..

i pulled my return spring this morning. drove half a day without it.

after reading the OP again and removing the spring, it surprised me that the required pedal force is not increased like mentioned originally. at least for me. too back cus i like a heavy feel. strangely, the force is about the same.

I'll know more later after driving in different temps and such, but for now here's my feedback:

pro:
a more linear feel within the engagement range. the spring is not trying to pull the pedal up out of that range so you can get a little more subtle feel going. it's not as big a change as i was expecting but i bet that's relating somewhat to our 100F temps.

con:
the pedal sags a bit, maybe 1/8" in my case, at the very top of travel. that's outside the engagement so there's no issues with it. as someone in here mentioned it can be likely remedied with a light spring just for the tip-in point. not sure but i may consider that myself.

happy 4th y'all..

 

By sag, you are saying that the pedal isn't coming all the way back 100% away from the firewall?
(I have the auto Tacoma, so I can't speak with real authority on this vehicle but) watch out to make sure that the pedal is coming up enough to un-port the relief/vent port. @tonered called it a compensation port on this vehicle so that may be the correct terminology here.

 

Dood, methinks you might be a closet MT enthusiast....not that there's anything wrong with that

 

Ya, I can't imagine that they would provide a spring load to increase pressure on a hydraulic system, because hydraulics is built on pressure physics, of which liquid have none. And because hydro cannot be pressurized, it cannot push the pedal into the 100% return range...it needs assistance. So pre-loaded makes sense. And if @BigWhiteTRD is correct and there is the compensation port, then I think that spring is required...

I don't know what a compensation port does

Edit: tag @tonered ...

 

I'm interested to hear peoples experiences with this. Especially in winter when it get's to be -40 degrees in more northern climates.

 

What you found is interesting. Different than me, but that seems to not be unusual with these trucks for some reason.

The compensation port just allows fluid to flow toward the reservoir, so that when it gets hot, it doesn't push the slave out. If you ever look in a motorcycle brake or clutch master cylinder, you will see a little squirt / fluid disturbance at the very beginning of the stroke. This is the piston in the master moving fluid in the opposite direction before the piston moves past the compensation port. You might even see this in the Taco brake master if some one else pumps the brakes? This is also why you can push the pistons back in the caliper when swapping pads, although I usually crack the bleed nipple on the caliper to get rid of that fluid.

Setting the rest position sometimes get screwed up when m/c folks install new levers. The front brakes will drag, get really hot, the fluid has no place to go other than clamping harder, and then endo. . .

 

Yep I am. My Daily driver, and the spouses daily driver are both manuals, but I got auto Tacoma for our hauler replacement (1st gen taco, which replaced Toyota pickup). She was pissed, didnt want it to be auto.

But i like to have one auto in the family if one of us has a hurt ankle or shoulder its it's easier, and it makes it so less stressful pulling heavy boat trailers out of the steep saltwater ramps without fear, or pulling a tree over, etc. (She is definitely better at backing the trailer into the ramp than me now as she prefers doing it, and I love the looks on people's faces when she nails it. And she doesn't have to listen to me complain about not burning up the clutch when extracting.)

So i think it auto is still the right decision for this vehicle for us. But my next daily driver, (and hers) will be manual, I can hope...

 

Cool, cool.

Anyone know if the 3rd gen clutch accumulator delete has been done yet?

Yes I know there was another thread..

 

Not yet as far as I know. I'm still dragging my feet. Sorry.

The friend that has the flaring tool got a divorce sprung on him. He was actually happy about it after a long slog but has been fixing the house up, moving, and such.

 

Yeah me too lol.

 

Oh snap..

Yep, been there done that. Been getting better every day since! I have my 22 year old son with me and we do lots of projects together while he finishes up school.