Clutch hydraulic system

[iceminion]

Ok, this is on my 91GVR4.

Freshly rebuilt trans from TRE.

New Fidenza aluminum flywheel.

Competition clutch Stage 4 using included TOB.

Shimmed the fork, would not be comfortable shimming it any further.

visually inspected the fork, seems fine, never seen a bent one...not quite sure what to look for.

blead the system quite a bit, pretty sure this is not the problem

Clutch release point is 1" off the carpet.

I replaced the master cylinder with a new DSM master cylinder.

the only other question in the system is the slave cylinder, so I am just going to replace it, see what happens.

Slave cylinder sizes:
Stock GVR4 - 7/8"s (Big)
AWD DSM - 13/16"s (medium)
FWD DSM - 3/4"s (small)

I am leaning toward getting the FWD slave cylinder.
Reasoning - Smaller space to fill, more travel, better release point!

Why are the extended clutch rods so popular if they are not needed?
Right on TRE's website, he says "DO NOT USE THE EXTENDED ROD"

When I installed the master cylinder, I was very critical of the clutch pedal assy. I made absolutely sure that there was absolutely no play compared to the pedal and the master cylinder.

Help? please?

[Kracka]

Use the slave cylinder you are supposed to use (GVR4). If the clutch system is bled properly there is no "space to fill" since it is already full of hydraulic fluid with does not compress (hence why the clutch fork moves). What problem are you trying to fix? Do you not like the clutch engaging 1" off the floor? Depending on how heavy the PP is that may be the best you can get. The extended rod, like shimming the ball, is a band-aid that temporarily solves an existing problem. Ideally, you should have replaced both the ball and fork while the tranny was off, and with a heavy clutch new master/slave cylinders are needed.

[JET]

You also likely have play in the pedal assembly, this can cause the same issue. There is a VFAQ on it I believe. A few have done it on here also. I am pretty sure Peter did and maybe Brandon.

[iceminion]

JET - My last line in my (long) post said I checked for play....unless I am doing it wrong, my assembly feels OK

Kracka- Questions answered in order listed:

use the GVR slave? I dont think so, I have a DSM Master now...so i would assume that I would need a dsm slave.

the problem I am trying to fix? um, the clutch engagement point should be about half was through the throw....not at the floor.

the PP is not that heavy, I would say its about as heavy as my ACT2100, for sure its lighter then my 2600....I have also removed the clutch fluid restricter in the slave cylinder.

The clutch does not fully release, its hard to go into gear, im sure its not good for my transmission.

the ball is new, and the fork looked fine, WHAT DOES A FAILED FORK LOOK LIKE?

[iceminion]

so.....can anyone think of a reason NOT to buy the FWD slave? displacement is smaller, so the same volume of fluid will make the clutch release point better?

remember if this was an all stock car then this would use all stock parts....but we are no longer in Kansas anymore...

[Kracka]

If you've already replaced the master, replace the slave and see if that helps.

[iceminion]

agreed! now, which one!

(anyone use a FWD slave on an AWD car?)

[JET]

Going to the smaller slave will make the pedal pressure higher, since you don't have the mechanical advantage. It will dissengange the clutch quicker, but give you a smaller dissengangement window. I don't see why the all DSM system would not work.

[Kracka]

Are AWD and FWD slaves even interchangeable? I think I remember getting a FWD slave for my AWD and it would not work.

[Kevin 1G Drummer]

I believe the way the FWD slave mounts to the tranny is different. I'm not 100% positive about that, so don't quote me on that.

[Kracka]

Originally Posted by Kevin_1G_Drummer

I believe the way the FWD slave mounts to the tranny is different. I'm not 100% positive about that, so don't quote me on that.

I am pretty sure you are right b/c I remember that being my problem. Just buy a new AWD slave cylinder to keep thing quick and easy; I highly doubt the small differences in size will make a difference.

[iceminion]

Turns out you guys were correct!

The only way to use the FWD slave cylinder is to run new metal brake line....which I am not willing to do now.

Here is a picture of the FWD(yellow cap) vs. AWD (blue cap)

[Andrew7dg]

This may sound like the dumbest question but this is what happened when I put my ACT2600 in, engagement point was close to the ground of the car, but it was an easy fix...

you did adjust the rod connecting the petal to the master cylinder right?..

From what I understand people buy the extended rod so that they don't have to adjust the clutch or it will adjust the clutch for them, however it is easy to adjust it right at the petal.

Anyway I am just starting with the most simplest things first.
This worked for my GSX anyway
I say stay with the stock vr4 system because that system should work. I have never seen anything that said swapping master cylinders and slave cylinders to make clutches work...

[dragonforce]

Most likely you have worn out pedal assembly. To check, first you can depress the clutch pedal all way down. Second release the pedal. Third try pulling the pedal up with your hand or foot. Your pedal is worn out if you can feel any movement.
You can fix this by adjusting the rod (temp fix). replace the whole pedal assembly. The best way to fix is to weld the end of pedal rod. I've done few of these.

[iceminion]

Thank you Andrew for your suggestion, and yes, it is adjusted all the way out, anymore and the u-shaped nut would fall off the end.

dragonforce - on post #1 and #4 I said that I checked for play, but thank you for the write-up...I did it a different way, I got upside down, stuck my head where your toes go, and wiggled the pedal with one hand and looked at the other side of the assembly with a flashlight, about .5mm of play due to the peg diameter vs. hole diameter.

[JET]

Originally Posted by dragonforce

Most likely you have worn out pedal assembly. To check, first you can depress the clutch pedal all way down. Second release the pedal. Third try pulling the pedal up with your hand or foot. Your pedal is worn out if you can feel any movement.
You can fix this by adjusting the rod (temp fix). replace the whole pedal assembly. The best way to fix is to weld the end of pedal rod. I've done few of these.

To do it this way you need to adjust the upper switch up so the pedal is not hitting it also.

[iceminion]

Ok, im going to just start over and add dot 5 fluid with new mitsu GVR4 parts. (master/slave)

[Kracka]

Use dot 3 or 4 fluid, not 5!

[JET]

Yep, Dot 4 only. Ford Blue Dot is good stuff and cheap. Valvoline synthetic is decent too.

[Kracka]

For the clutch it really shouldn't matter since it won't be seeing much heat.