Clutch Failure (or not ?) ???

[Don]

This is what happened: The clutch appeared to be fine and oporating as usual. Then I noticed that the clutch started engagine with the pedal closer to the floor each time I changed gears. After about 10 shifts, a hard spot developed in the pedal travel. Because I was in traffic and needed to change gears, I pushed through this hard spot, but heard a "snap" when I did so. After this point the clutch would not RELEASE. An inspection of the slave cylender showed that the slave had gone to the end of its travel in the cylender. I expected to find that the actuating rod had punched a hole through the clutch lever, but it is fine.

What could have happened? Has this happened to anybody else? [?]

[Marko]

hmm,

check the hydraulics for leaking

clutch fork bent? one of those studs (or metal squares on the fork) actuating the clutch fork bent, broke, wore out their slot on the clutch bearing, clutch springs broke/bent,

if the hydraulics are fine then youre in for a gearbox removal [xx(]

my condolences

[Hasbeen]

Don, I have not experienced it, so I don't know what it feels like,
BUT, there is a design fault in the clutch release leaver, [clutch
fork] or what ever it's called in your part of the world.

The leaver is a bit weak, & the pivot point, [bolt] it rotates on
wears its way into, then pushes through the leaver.

I have had the gearbox out of 3 TR7s, each with a bit over
100,000Km on the clock, & each of their release levers had been
repaired, & strengthened, due to this problem.

Unfortunately I doubt you can check this, without pulling the box
out, but if it can be, someone here will tell you.

Hasbeen

[Marko]

anyone solved the problem?

like welding a patch of stainless steel inside ( is harder and stronger ) , greasing the pivot point with some copper based ( or ceramic based, something with crude lubricant inside) grease ?

or that "newer" fork that has those bends to unscrew the bolts behind it is better?

[Don]

New information:

I now have the engine/trans out of the car, and have separated the bell housing from the block. The fork/ball and throwout bearing look fine. I can see grease on the input shaft splines where the clutch normally rides. The tips of the clutch springs are only 5/8ths of an inch from the clutch disc. Also, the springs appear to be parralel to the clutch disc. Other clutch springs I have seen have a conical (convex) shape. Is this normal for a triumph clutch? It appears that there is not enough travel in the slave cylendar rod and clutch fork lever to depress the springs.

[Jolyon39]

Look at the plastic, hydraulic hose from the clutch master cylinder to the slave cylinder. Apparently these soften and expand under pressure when they get too old. This leads to less fluid reaching the slave cylinder and therefore less travel in the rod. This could be one of a couple of contributors to your problem.

Jolyon

[saabfast]

Is the system still full of fluid? The lowering of the biting point can occur as the master cylinder runs out of fluid, normally caused by failure of the M/C seals. This often shows itself by a trickle down the rod inside the car dripping onto the carpet. If the piston seal or bore is very bad in the M/C I think it can stick and turn 'inside out' so to speak. While the box is out try the operation of the clutch to see if the slave moves full throw.
As above, if the old plastic connection pipe is still installed replacement with an Aeroquip type flex pipe is recommended.

Alan
Saab 9000 Stg 1
Saab 9000 2.3 FPT Auto
'81 TR7 DHC

[Hasbeen]

Don, that doesn't sound like the clutch gear I know. Probably just
my slow old brain. Any chance you could post a photo?

Marco, one of mine had been reinforced with a large patch of weld,
on both sides, & the pivot remachined. This appeared to be something
hard, like stellite. Beautiful work, & would have to be done by an
expert welder, to avoid embrittlement.

The other 2 had washers, 1 welded on the back face, & one brazed in
on the front, pivot face. Both were roughly done, but had worked. I
don't know how long they had worked.

Hasbeen

[jclay (RIP 2018)]

Proper Clutch assembly:



From Beans:



jclay

[url="http://web.mac.com/jclaythompson/iWeb/Site/Welcome.html"]My Triumph Site[/url], [url="http://web.mac.com/jclaythompson/iWeb/Technical/Intro.html"]Technical Stuff[/url], [url="http://homepage.mac.com/WebObjects/FileSharing.woa/53/wo/HJMTK8gsojtwKleP.1/0.2.1.2.26.31.97.0.35.0.1.1.1?user=jclaythompson&fpath=Triumph_Articles&templatefn=FileSharing4.html"]Download Page[/url]

[Don]

Well,

I can't get photos to post to this site, but, if you follow this link:

http://s967.photobucket.com/albums/ae160/dgregg65/

the images I tried to post can be viewed. Jclay, thanks for your images. Does pressure plate look excessively flat to you? Note that the push rod is nearly into the bell housing, leaving very little travel left in the clutch fork movement. How much movement should there be when the clutch is actuated?

Still puzzled,

Don

[busheytrader]

<font size="2"><blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Marko</i>

anyone solved the problem?

like welding a patch of stainless steel inside ( is harder and stronger ) , greasing the pivot point with some copper based ( or ceramic based, something with crude lubricant inside) grease ?

or that "newer" fork that has those bends to unscrew the bolts behind it is better?
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote"></font id="size2">

The pivot pin wore through the clutch fork on mine (no evidence of any grease or lube on the interface) prompting my V8 conversion[:D] The clutch pedal went all the way down, came back up again and became solid.

When I rebuilt the clutch, a thick blob of copper grease was applied to the pivot pin and socket on the new clutch fork with the excess wiped away. I reckoned this would reduce the wear and hopefully not pick up too much friction plate dust. 18 years later and the clutch action is still smoother than the original, although it's covered far fewer miles since.

I've heard of others applying a bead of weld behind the pressing / socket of the clutch arm to give it extra strength although I reckoned a bit of lube was necessary to stop it wearing out in the first place.

Adam





TR7 V8 DHC Jaguar Solent Blue. 9.35cr Range Rover V8, Holley 390cfm, JWR Dual Port, 214 Cam, Lumention, Tubular Manifolds, Single Pipe Exh, 3.08 Rear, 200lb Spax & PolyBushes, Anti- Dive, Capri Vented Discs & Calipers, Braided Hoses, 4 Speed Rear Cylinders, Uprated Master Cylinder & Servo, AT 5 Spokes and Cruise Lights. No Door Stickers. Mine since July 1986, V8 from 1991

[saabfast]

The pushrod looks reasonably normal, it only sticks out about 3/4" from the engine backplate from recollection. The slave cylinder projects into the bell housing making the piston travel more effective. Do you have pictures of the fork in the bell housing?

Alan
Saab 9000 Stg 1
Saab 9000 2.3 FPT Auto
'81 TR7 DHC

[Beans]

Indeed check the clutch fork and the hydraulic system.
Also check flexible hose they have a tendency to expand with age and when hot.

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