Chris,
I too have experienced this problem. Here are some issues I've dealt with:
1) Assuming the fluid level is correct, the system is properly bled, and there
are no leaks.
2) Measure the lateral movement of the slave cylinder push rod as a function
of full pedal movement. This should be about 5/8 of an inch. Note that the
slave cylinder push rod should be in the center hole of the clutch shaft.
If the travel is not ~ 5/8 " then:
3) Inspect the hole in the pedal into which the master cylinder push rode
connects. If this is ovalled out then it is likely that you are not developing
enough travel at the input to the hydraulic system. For this case you have two
options: 1) remove the pedal, brazen over the hole, and redrill a new hole;
or 2) fashion an adjustable master cylinder push rod. I have implemented the
latter with much success.
4) Check the condition of the plastic hose segment (between master and slave
cylinders). I have heard of this expanding under certain conditions (namely a
cheap replacement part which has weakened with age and heat). This can be
measured with a micrometer as you depress the clutch, but if you suspect this
hose it is easier to just replace it.
5) Make sure both the master and slave cylinders are working properly (may
need to dismantle them to check the conditions of the rubber, piston, and bore.
At this point you have either found a problem which has returned you travel to
~5/8 " or had sufficient travel to start with. The problem is inside the
clutch.
6) Check for a broken taper pin. -- replace
7) Check for excessively worn clutch fork pins. -- replace
8) Check for excessive wear on the contact surface of the release bearing. --
replace
9) Check for an excessively worn groove into the finger springs of the
pressure plate (the point at which the release bearing makes contact) --
replace entire clutch
10) Check thickness of the drive disk ( I have experienced fraying of
disintegration causing the disk to "swell" -- lesson learned is not to buy
cheap clutch parts! ) -- replace entire clutch
At this point you have either found the problem or your really frustrated.
11) Check for excessive crank shaft end float. -- see thread on thrust
washers
Hope this helps. I think the most likely problems are 1) the ovalled hole in
the pedal, or 2) generally worn clutch parts (release bearing/pressure
plate/driven disk).
Mike Morelli
76 TR6 (daily driver)
Houston, TX
morelli@mickey.jsc.nasa.gov
> Date: Fri, 18 Apr 1997 21:22:18 +0800
> From: Chris and Kathy <caz@net1.nw.com.au>
> Subject: HELP! I can't change gears on my TR6
>
> To one and all!
>
> I jumped into my TR6 this afternoon after a long drive in the morning, and
> found that it was progressivly harder to change gears. By the time I got to
> my destination, I could not put the car into 1st. In the end I had to get
> home by driving in 3rd Gear (that is starting and stopping in 3rd). If I
> trurned the ignition off the gears would engage perfectly, however when the
> engine was on I could not change the gears. On contacting and explaining to
> the mechanic that I use my predicament (via phone), he seemed to think that
> I had blown a "master seal". He then suggested that I fill the oil reserve
> for the clutch. I have done this but it has not seemed to do anything. Oh
> when I have the car in gear with my foot on the clutch, the car appears to
> crawl along. It almost seems that the clutch is burnt out.
>
> I'm taking the car in next week to the mechanic, but to satisfy my mind can
> anyone suggest what it may be?
>
> All the best.
>
>
> Chris
> Perth, Western Australia
>
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