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TR6 TR6 Clutch Problem

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GOYN

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Hello, I am a newby TR6 owner having just purchased a '76 TR6 a few weeks ago. The car has undergone an extensive restoration and has been mostly mechanically rebuilt by the appropriate Triumph experts. I understand that the master and slave clutch cylinders are new.

After about an hour of driving yesterday, I came to a stop sign and depressed the clutch pedal. There was no resistance whatsoever and the pedal went straight to the floor. The clutch had been functioning well up until this point. I managed to nurse it into gear and drove about another 15 miles before finding an appropriate place to stop. Still no resistance in the pedal. I stopped the car and had a look around, expecting to see some leaking fluid. I also checked and functioned the pedal, thinking that it had perhaps become disconnected from the Master cylinder piston. Everything looked normal, so I put the top up and was getting on the phone with AAA for the ride home. I decided to give the clutch one more push and lo and behold RESISTANCE! The normal function seemed to return and I was able to drive the rest of the way home, not without some anxiety.

While I could certainly understand if a seal had gone bad in the master or slave resulting in a loss of hydraulic pressure which might explain the lack of resistance, I am baffled by the fact that whatever problem caused the resistance loss initially seemingly corrected itself after about 10 minutes at rest.

I am no mechanic and will be taking the car in. However, any thoughts to point me in the right direction would be greatly appreciated!
 
Welcome to the forum GOYN, I'm sure you'll get many suggestions back from the TR6 folks on the forum.
 
This is just a wild guess... have you checked the return spring on the slave cylinder push rod? Maybe it's possible that the push rod was not fully retracted. Again, just a guess...
Welcome to the BCF!
 
I cannot think of a hydraulic scenario where a pedal would have no resistance one minute and then work again. I would start by looking under the dash at where the clevis and pushrod attach to the top of the clutch pedal.
 
I have had the same thing happen to me in years past. Seal in MC is bypassing for whatever reason. Install a new seal kit and/or an new MC if that one looks suspicious. There are some new MC's out there that are not the best quality.

Marv
 
Thank you all very much for your suggestions. I did check the connection between the pushrod and pedal on the roadside (about all I knew to do at the time) and it seems properly attached. The MC that is installed is a TRF part and of good quality, I would hope. However, it sounds like the MC is the place to start and probably the most simple to replace.

Thank you all again for your warm welcome and I will post an update once the solution is found!

George
 
GOYN said:
The MC that is installed is a TRF part and of good quality, I would hope. However, it sounds like the MC is the place to start and probably the most simple to replace.
George
Click to expand...

My 1-year-old TRF master only lasted a year and failed 1,500 miles from home. Thanks to some friends in Calgary it was replaced and we have been able to continue on our trip. Looks like we will reach 6,000 miles by the time we get back home in Wisconsin. (Thanks Dave and Barbara)

That was the second TRF master in two years.
 

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Well, I almost hate to mention what I think it is, but better you consider all the possibilities. I also have never seen a hydrolic issue that fixes itself by cooling down. TR6's are know for the pin in the clutch shaft to shear (item #9 here https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=32782#top). Once it shears, it doesn't fix itself, but might engage or disengage randomly with the broken bits. When it doesn't 'catch', the pedal would have no resistance. When it 'catches', it would function as normal. But don't expect it to fix itself or get better... -hopefully it's something else.

Welcome to the wonderful world of TRs, and the best place to find out weird things about them. Have you joined the local Triumph club? Someone there can tell you the best local shop able to remove the transmission and replace the pin.

Jer
 
My thought as well, Jer, but like you, hated to mention it... :eeek:
 
TexasKnucklehead said:
Have you joined the local Triumph club? Someone there can tell you the best local shop able to remove the transmission and replace the pin.

Jer
Click to expand...

The broken taper pin also ran through my my as I read the symptoms. If it is the problem and you remove the tranny to fix it, it would be best to add some insurance by drilling the fork and shaft for an additional bolt.

You can see the taper bolt safety wired to the fork. That's the one that breaks. The other bolt going through the fork and shaft is the addition.
 

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I think its funny that they wired the pin in place thinking it would vibrate loose and fall out, but they never condsidered it would break

Hondo
 
hondo402000 said:
I think its funny that they wired the pin in place thinking it would vibrate loose and fall out, but they never condsidered it would break
Click to expand...

Makes perfect sense to me, for two separate reasons:

1) Back then, the normal "maximum lifetime" of a car was only 10 years or so; and really all the car makers worried about was getting them past the warranty period without any failures. Anything that broke after the warranty was just extra income for the dealers.

2) I would almost bet money that the original design for that joint would not break even after 40 years of service; but someone altered the design to make it easier to manufacture. All it would take to make it last forever would be for the hole in the fork to be smaller, so the pin would hit the side of the hole before reaching its fatigue limit. Undoubtedly some bean counter came along and decided the hole could be the same size as the tap drill for the threads, eliminating an extra machining operation. The larger hole allows the pin to flex enough that, given enough cycles, it breaks.
 

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every manufacture at least now, only wants things to last one day past warranty and they could give a crap about it lasting . I sell high end equipment to power companies and I never call on engineering companies because they always buy the cheapist crap they can get as long as they meet the specification,

I sell to the end user, who has to fix the crap they got

sorry for the rant, but I would think it took more time to wire the bolt in place than it would take to have machined it right but I kind of doubt someone thought that hard about saving a dime, maybe just poor thought about the design

Hondo
 
You may be right, but you'd be surprised at the things car makers do to save a penny. There were a lot of production changes in the TR3 that had no purpose other than to reduce cost (like eliminating the fuel shutoff before the sediment bowl, or changing the door hinges from brass to steel).

Some years ago, a friend of mine designed a circuit for Ford. They had lots of restrictions to keep costs down, like it had to be a single layer board, and phenolic rather than fiberglass. Then they made him redo the entire design, in order to save less than $.01 per unit, by using a lower grade capacitor.

And whatever we may think of the cars, those engineers at Standard weren't dumb. Then (as now), most of the really stupid decisions (like all of the castings in a TR2 had to be common with some other car) were made by management.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] Then (as now), most of the really stupid decisions (like all of the castings in a TR2 had to be common with some other car) were made by management.[/QUOTE]

I fully agree Randall. And it is not just the car business. Wait until the health care act fully kicks in and watch the shortcuts that are going to be taken to save money from all sides.

I refer to it as the "Dilbert" syndrome. Followers of that strip will understand my comparison.
 
I'm a big fan of Dilbert (Wally is my hero), but the healthcare act is a bit too close to politics, so I won't say any more about that here.
 
TR3driver said:
I'm a big fan of Dilbert (Wally is my hero), but the healthcare act is a bit too close to politics, so I won't say any more about that here.
Click to expand...

:iagree: and thanks, Randall.

:cheers:
Mickey
 
Hmmm... some possibilities that do not sound good.

Perhaps I should have mentioned this earlier, but the car also has the HVDA Toyota transmission conversion kit and Toyota transmission. The conversion has fewer than 5k miles, so I am hoping that should rule out issues with the clutch itself. It appears to have a hydraulic thrust bearing, which I guess also rules out slave cylinder issues. I have emailed HVDA requesting the documentation on the conversion.

I am disappointed to hear that the TRF master cylinders have not been successful. I have been buying TRF parts simply because the previous owner relied upon them. Of the big three TR parts vendors, who is the best? Does anyone have any opinions on the best replacement MC?

Thanks again for your help.
 
Friend of mine with the hydraulic release bearing on his TR6 had it fail couple years ago. After it fails the inside the bell housing design doesn't seem quite so clever. Greg
 
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