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1994 NAS D90 Portofino ST #4
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Discussion Starter · #1 ·
I'm totally at a loss and so is my mechanic regarding some issues that I'm having with my clutch. Here's the work that's been completed thus far...

  • Installed a new master and slave cylinder
  • Installed a new clutch kit, pressure plate, and resurfaced the flywheel
  • Installed a new pitch fork and push rod
  • Installed a new clutch fluid line
  • Installed another new slave cylinder
  • Repeatedly bled the clutch (the clutch has pressure and it feels great)

The primary issue is that the clutch isn't being released and unable to effectively shift when the vehicle is on, which was why it was brought in for service. When the ignition is turned halfway, the gears shift normally and it feel great. The fork is moving properly and master and slave are working, but I can't shift from gear to gear. My vehicle has been in the shop for almost a month. Frustrated doesn't begin to describe how I'm feeling. Any guidance or suggestions would be greatly appreciated.

Thank you!
 

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Mendicant
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8,483 Posts
I've got a similar problem that is a bit inscrutable. My bite point is so low to the floor that if I don't jam it all the way down then the gear change is sticky and difficult.

I used:
New LOF master
New stainless hardline
New soft line
New OEM slave
New operating rod (being careful to order the correct length)
New fulcrum bracket
New fork from Britrest
New HD clutch and throwout bearing from LOF
Resurfaced flywheel

I've bled the hell out of this thing with vacuum, gravity, old-school pump method, using a broad to hold the pedal down overnight, etc. Probably ran 2 bottles of fluid through it.

I wrote to LOF and they recommend not installing their master until a clutch has about 3k miles on it, so my next step is just to wait to see if things improve over the next few months of driving.
 

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Premium Member
1994 NAS D90 Portofino ST #4
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521 Posts
Discussion Starter · #4 ·
Stupid question, did y'all adjust the pedal correctly?
Double checking all those measurements on the pedal and pushrod again...

  • 140mm from the base of the pedal to the floor (without mats) at the base
  • adjusting the pushrod on the master cylinder to make sure there's 1.5mm of free play between the rod and master cylinder
  • 6mm of free movement on the pedal pad before it engages tension on the slave cylinder
  • bleeding the line again

Hoping that works! I'll keep you posted.

Thanks you!
 

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6,514 Posts
I have the same issue as above, same exact setup as JIm. I even removed the slave and blocked the piston from moving and bled it in a vertical position. My bite with a LOF master and OEM slave /2.8TGV HD clutch kit is near the floor and it a bitch to shift. Im actually thinking about adding a small extension to the pushrod to see if that helps. there is essentially no pedal adjustment in the later style clutch tower . @JimC you dont happen to have a pushrod handy do you ? could you give me a the diameter of the rod?

i also have a stumpy r380 trans setup
 

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pushrod lengths:

FRC3417: ~91mm early stuff up to lt77
FTC5199 ~100mm 300tdi and td5
FTC3912: ??? R380 TDI also
 

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655 Posts
Just FYI guys, I changed to the GM Master Cylinder from SeriesDefender. It's a dream to shift and way more stable than OEM. Not sure of LOF, but theirs is still aluminum, which in my book is still crap. Cast iron is where it's at.
 

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Stupid question, did y'all adjust the pedal correctly?
Yes, try adjusting. Had to adjust my LOF quite a bit, after installation. Free play (amount of travel from top of pedal to feeling resistance when applying pressure) was five inches at first, adjusted to just slightly below 2" and drives/shifts great.
 

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What release bearing are you using?
In Matts case, if you have a stumpy you have to use the release bearing unique to the stumpy that Ashcroft sells.
There could be other suppliers, but I just use the ones that come from Ashcroft because they come with the stumpy's we get from them.
The release bearing from the R380 out of the 300TDI "off the shelf: clutch kit will not work properly because it is for the long belhousing R380.

I can't explain why, but in the past have had similar issues as the ones you guys are experiencing and experimented with welding an ever so slight extension onto the end of the clutch rod to make it slightly longer.
Since I rarely throw anything away, have noticed several different length push rods, but never took the time to measure and document which rod came from which specific application.
Always surmised that if the rod were slightly longer, could always compensate for the release bearing resting off the pressure plate within the overall petal adjustment and if I couldn't then it was time to shorten the added length.
In a few cases over the years, extending the length of the clutch rod was the only thing that obtained a properly functioning clutch.
Sorry for not being able to explain why, but hope this post will help you guys out.
Please don't get angry at me if you try this extending and it doesn't work.
For me it was a last resort.
 

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I had an epiphany this morning. It will be way easier to just add some shims inside of the slave cylinder instead of making the pushrod longer. Testable by just maybe throw in some washers in there, figuring out what height you need and then making a spacer or shim.

I'm at the point where I know my clutch is fully bled 100%. No chance that there's any air in it. I have the newer style pedal box and lof master. Even with the pedal adjustment to the point where I get maximum travel from the master I still bite very close to the floor.

The downside to all of this would be that the slave extension pushes the clutch fork so far that it contacts the back of the transmission bell housing. If it's not releasing though at that point I've got other issues.
 

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Yes. The shims will achieve the same thing.
You didn't mention the release bearing in your setup, could it be the issue?
 

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huh? I’m not picking up what you’re putting down...
my idea to fix the clutch engagement on trucks like ours that it just seems impossible is instead of making the clutch push rod longer inside of the transmission but to add shims inside of the cup of the slave. It essentially makes the same thing happen is that the pushing arm that would push the clutch fork physically longer.
 

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Mendicant
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Yeah, I just haven’t busted one open and can’t envision the procedure. What’s the bet that there is a crap batch of cylinders out there that are slightly different?
 

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It will likely work as long as the shims don't scrape and score the inside walls of the slave cylinder.
The end of the piston in the slave cylinder is concave, so it may be difficult to accomplish, but certainly not impossible.
It will alter the dynamics from mechanical with the longer rod to hydraulics based on the fluid travel from the master to the slave cylinder with the rod extended by the shims.
In other words you're shifting the modification from making the rod longer to making the piston in the slave cylinder longer.
The only caveat is being sure the fluid with the one petal stroke will give you the required movement of the slave cylinder piston.
 
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