Advice asked on defective clutch throwout bearing

With a few thousand miles maximum on my car since new clutch, pressure plate and throwout bearing (Borg and Beck), I started to hear a funny sound when letting out the clutch.

I just had the car up on a hoist at a well respected British car repair shop and the graphite part of the throwout bearing is loose. I could rotate it with a long screwdriver put through the bell housing access hole.

Other than the intermittent noise, the clutch works fine with no juddering.

The local shop says that the noise is probably the most noise it will make and that it could last up to 30,000 miles. On the other hand, they said the graphite could fragment one day which means metal on metal and the clutch would have to be redone.

I ask your thoughts

Dennis 69 OTS

Hi Dennis,
Sure sorry to hear that this has happened to you, I had heard that there were some defective clutch sets out there and I wonder if this was their failure mode?
If it were me I would replace it just because I can see myself getting stranded in Hiko Jct, Nevada or some other place equally scenic. I have a hard time imagining your carbon ring lasting 30K miles but I’m sure no expert.
Cheers,
Lynn

That seriously sucks. I do suspect it will fail, and especially soon if the break wasn’t clean. Suppose a mound of carbon or bonding exists and it rotates so that force is applied non uniformly. It will eventually shatter. It’s up to you whether you want to wait until failure occurs. It might last a week or a year or a decade, who knows? I certainly wouldn’t be going on long trips though.

I don’t see that it makes much difference whether you end up needing a while new clutch or just a TO. The cost difference is negligible compared to the labor.

If this was my problem, I would consider disconnecting the linkage so you can get to the bond area, blow it clean and then use a long syringe to inject some gorilla glue, then apply pressure to the fork so it seats as the glue sets. You have nothing to loose.

I think the steel portion has a recess into which the donut sits. If one were to slacken the linkage to try and create an air gap into which to inject glue (or for any other reason) I think the donut would fall out of place, and that would be game over.

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Judging from this picture I think you are correct. And the one in the picture has what appears to be a screw going in the side. To help keep the bearing donut in place?

Annotation 2020-05-20 163012

I asked the shop about trying to drill a hole in it and then either inject glue or try pin it in.

They said that the drill would likely shatter the graphite when it reached it.

I like the glue idea but access is horrendous and if that could be solved, then what type of glue would grip graphite?

Dennis

https://www.final-materials.com/gb/132-high-temperature-graphite-adhesive

Probably the only place you could snake it might be around the inner edge of the ring bridging the carbon and metal. Since it’s behind the clutch even if some accidentally got on the shaft splines it shouldn’t be a big issue, unless it was so much that it glued the shaft to the bearing.

I think the only possibilty is to drill a hole on the metal part that houses the graphite and inject the glue, then press clutch while curing.
It says cure at 120 degrees C. (My question is how!! ) Could this fry the transmission input shaft seal?
Dennis

By the way. Thanks to all for suggestions. I love this forum.
Dennis

I misread the spec and only saw the high temperature application spec.
There is one that cures at room temp!
Dennis

I’m not sure that your mechanic is correct about a drill breaking up the graphite. So long as it is a very sharp bit and it’s done slowly I’d hope it wouldn’t shatter. You wouldn’t need a particularly big hole, 1/8" maybe. Then glue in a soft steel rod. Does your mechanic have a junk one you can experiment on? If not then someone here does.

First, if the carbon block has come loose and is spinning, the inside of the metal cut is going to be filthy with powdered carbon. I don’t see adhesive sticking to that.

Second, this came out of my E and there is no way to assume this carbon block will survive spinning for very long. It doesn’t mount to a single flat surface.

Boo. That’s crap.

Graphite is pretty brittle stuff from my experience with making brushes to refurb motors and generators.

The glue idea probably has no particular downside if you can actually get glue behind the graphite ring.

Without trying to upset you we book clutch replacement for about 20 hours labour plus parts on a 6 cylinder E Type. Is there any way you can get the supplier to come to the party?

I hate to say it Dennis, but I think you might be looking at a TO bearing replacement. I’d be wary of any repair working or lasting long.

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Back in the '80’s when I was a poor college kid who could barely afford any car I was at the very limit of the clutch free play adjustment on my high mileage Vega. It is cable activated not hydraulic. At the time I could not afford it monetarily or to have the car off the road for a few days while I figured out how to replace it. I extended the life of the clutch by several months by only using the clutch when I had to come to a complete stop. I got pretty good at shifting without the clutch and had to break myself of the habit after I replaced the clutch. Can you do this well with an E ? I have not tried it but remember in Dennis Jenkinson’s book that he nursed his E home to the UK from France by doing this after his clutch blew one night. He had to shut off and then put in 1st and start again in gear when he had to come to complete stop. Just a thought if you don’t want to dig into it now and want to risk it.

David
68 E-type FHC

I have shifted mine without the clutch but it is very hard on the synchromesh rings.

My clutch slave cylinder packed up and all the fluid came out at a stop light.

I turned off the engine, put the car in gear and turned the starter key. The engine started and the car moved and I got home by shifting without the clutch.

Basically to shift you pull it out of gear and hold it with a little pressure against the gear you want to go into. When the gear is synchronized, the resistance to pushing it into gear drops and it pops into gear. But this wears the synchros. I would not advise to do it except the day before you pull your transmission for a rebuild job!

Dennis 69 OTS

I am thinking that I may try the glue fix
Here is the process and I welcome your comments

  1. I will see if it is possible to can get a drill bit to drill into the throwout bearing metal. Maybe a special carbide something is needed

If Yes

  1. Drill a hole into the metal holder of the throwout bearing arm but not the graphite

  2. Blow into hole with lots of compressed air to clear out dust. Rotate graphite bearing while doing this

  3. Blow brakeclean into hole and then dry with compressed air (First test that brakeclean does not degrade graphite)

  4. With graphite bearing loose, inject some graphite glue, then rotate graphite bearing a bit and inject more glue and repeat a few times. This will spread glue around circumference

  5. Then keep pressure on clutch throwout bearing while glue cures

Dennis 69 OTS

Dennis, what does this intermittent noise sound like exactly? What made you think there was a problem?