Dead Clutch

[Iain T]

I've never driven another Triumph 6 pot so can't gauge the feel of the clutch pedal and clutch engagement but I have no real 'bite' in the clutch pedal feel. It's been the same in the 3 years since I bought the car.

I have changed the slave cylinder, clutch plate and cover but it still has a dead feel. Very occasionally the clutch will engage then bite which is very odd, as though the hydraulics are momentarily stopping full engagement but it's not screaming or making a noise. The only thing I haven't replaced is the master cylinder (about 10-12 years old), could this be the weak link? 

Suggestions please and if I want to replace where to go! Price isn't an issue I just want a good quality part that fits and does to job. The new slave cylinder also looks pretty rough, again who makes quality replacements? 

Iain 

[johny]

Is the MC standard size or been changed to a bigger bore as I think that would make it more on-off...

[Colin Lindsay]

Is there a return spring on the pedal? If it's missing or slack then the only resistance is from the hydraulics themselves, which may explain the slow return but also the lack of real feel.

[Iain T]

14 hours ago, johny said:

Is the MC standard size or been changed to a bigger bore as I think that would make it more on-off...

Johny, I don't know as the PO had the car refurbished. It says County on the side. 

The fluid is only 9 months old and looks murky, I'll suck some out and take a closer look. 

Iain 

[Pete Lewis]

master cyl with poor recuperation will have a poor feel , and if the pedal doesnt fully return due to stiff pivots then again it upsets the release load and recuperation there must be a bit of slack in the pushrod . foot off

fitting a cloil clutch disc will destroy feel and make the diaphragm fingers too low as these discs  are thicker

some silly dimensions for next time the box is out

flywheel face to finger tips with a 7.1mm disc /gauge  pad  is 48.77mm

give the disc a firm  nip in a vice its 7.36 /6.86mm thick 

a coil disc will be 8.5mm or more 

Pete

[Iain T]

24 minutes ago, Pete Lewis said:

master cyl with poor recuperation will have a poor feel ,

I don't think it's very well, I'm going to check on the return spring. The pivot looks brand new. 

I can see what is supposed to be Girling and TRW MC for sale, anyone have a preference? 

[Pete Lewis]

by pivot i mean the pedal spindle  these are tucked out the way and often seize the spindle has a D flat to prevent rotation in the pedal bracket

ive seen them wear tis to a full round , its hang up by a sky hook glasses upside down good torch sort of job

a easy feel of the pushrod slack/float  is lift the nasty balkhead gaitor and give it a rattle 

TRW seem to give a 3 yr warranty 

https://www.trwaftermarket.com/en/passenger-cars-and-lcv/actuation-systems/clutch-cylinder/

Pete

[Iain T]

34 minutes ago, Pete Lewis said:

easy feel of the pushrod slack/float  is lift the nasty balkhead gaitor and give it a rattle 

There is a spring although it has little to no tension in the static state. It does look a bit cruddy up there but I can't feel any real problem with the pivot. To be sure I would have to dismantle and check. Both clutch and brake gaitors are stiff and I'm unable to fit correctly to the bulkhead. The pivot connection to the MC looks perfect. The pedal returns ok. The only thing that seems non standard (the one with the car and the one I purchased) is the slave size, I fitted a 7/8" not the 1" as I like a harder pedal. 

I want to do preventative maintenance as a duff MC is not something I can sort out if it fails! 

Iain 

[Peter Truman]

It's not damp from brake fluid up there on the pedal and support so the rust is presumably from an old brake master cylinder leak.

There's no actual locking of the brake M/C piston and the push rod/ brake pedal, so the pedal can return to the off position when the brakes are released being spring aided but the master cylinder piston could be slow to respond or suffer from stiction, ie the piston and dome end of the push rod can separate.

Oops meant CLUTCH not brake same mechanism

[johny]

Its the clutch so should have the full force of the diaphragm pushing the fluid back and keeping the MC piston in contact with its push rod. If anything is sticking in the system I think it will tend to stop the clutch from engaging properly....

[Iain T]

I've finished twiddlin wiv me carbs, tefon sprayed the creaking poly bushes and the Spal fan and temperature controls are working fine so I need to find something to get my hands dirty! 

I've ordered a TRW GMC205 m/c from David Manners for £53 incl postage which should arrive on Wednesday. I certainly don't want to take the gearbox out as I've already taken the engine/box out three times in three years! 

Iain 

[johny]

Hope that does the trick because I find my clutch one of the best things on the car even compared with a modern. It has a smooth, fairly light operation and a progressive, easily controlled bite point... 

[Iain T]

7 minutes ago, johny said:

easily controlled bite point...

Mine needs a new set of dentures! 

Iain 

[Iain T]

On 13/06/2021 at 17:26, johny said:

Hope that does the trick because I find my clutch one of the best things on the car even compared with a modern

Fitted the new m/c, lots of black gunge in the bottom of the old one. Operates OK when driving up and down the car park but can't go for a blast 'cos the Siemens man hasn't arrived to fix the dishwasher! 

First impression is it feels the same but at least it's one off the worry list. 

Iain 

[dougbgt6]

On 13/06/2021 at 16:31, Iain T said:

sprayed the creaking poly bushes

Mine squeaked for about 200 miles, but it stoped in the end.

Doug 

[DVD3500]

Course it did because you arrive at your destination... 😄

 

[Iain T]

1 hour ago, dougbgt6 said:

Mine squeaked for about 200 miles, but it stoped in the end.

I love a bit of lub.......