Clutch problems ....

[Wyn]

Shoulda left it be I know, but these things are sent ta try us

Having just changed my noisy T5 (3rd gear) gearbox it seems I’ve gone from bad to worse.
I originally thought the clutch was also on its way out as it was becoming harder n harder to engage a gear at standstill n it was esp bad at selecting reverse without unwanted grinding of gears (tho it never slipped as such) Anyway I fitted a brand new clutch at the same time as changing the box, but now I cant select any gears unless I turn the engine off. (unless i ram it in)
Its recently had a slave cyl as the old one seemed to be weeping so I cant see that being at fault n the master cyl is also a resent addition.
Odd thing is, if I start the car in gear it seems that the clutch works AND bites where you might expect it.
Crawling underneath I can “just” spin the release bearing, so I assume it’s preload is correct? I can also see the clutch cover fingers move as the pedal is depressed but obv something isn’t right still.

Just an idea, could it be that fluid is leaky back into the master cyl as its deffo not leaking into the car, hence losing clutch pressure? (Heat issue?)
I’m running out of ideas fast

Anyone?

 

[Zed2k]

Have you tried the spigot bearing which sits inside the flywheel this supports the input shaft, I once had a Sierra showing the very same thing and it was this bearing binding up and locking the flywheel and gearbox together. Worth checking.

Nick

 

[Wyn]

Nick
I don’t understand? Is it not just a plain support bush?
Does the box input shaft not spin at the same speed as the crank?

Should the shaft spin independent of it when depressed?

 

[Zed2k]

This is a support bush yes and the input shaft spins at the same speed as the crank when you take up drive but when you put your foot on the clutch the clutch should free the input shaft and flywheel allowing the input shaft to slow down/ stop and then allowing gearchanges if this bush breaks up usually a roller needle type it looks the two at times giving the same impression as a faulty clutch unit or release mechanism. This maynot be the case but, it's worth a look while you're in there and if you have any doubts just change it anyway.can be a bit of an Ar*e to change though
Hope this helps.

 

[Wyn]

Cheers for the advice. I tried running the car up in 4th with the clutch depressed (wheels stationary) but things still didn’t improve so I tried rebleeding a few times n that didn’t work either.
So after wasting most of the day looking for the cure it I think ive eventually found my mishtake

With the bearing preload removed the clutch fingers on the new cover seem almost straight, yet the fingers on the ol unit protrude by some amount. Still not 100 sure yet but as I didn’t use the supplied bearing with the new kit (another story) it looks like that bearing is longer then the org one. I think that will allow more throw
Does that sound right or am I missing something?
Gearbox out again is all I can do

 

[zbloke]

The fingers on the clutch pressure plate will stick up a little until you install it and torque the retaining bolts down, if you have an old flywheel to hand you could always bolt the old driven plate and pressure plate to it and you'll see what I mean,

You could be onto something with the release bearing, can you get an assistant to press the clutch pedal down while you check the travel of the slave cylinder pushrod, if its moved as far as it can within the slave cylinder and the clutch will not clear then something else is too short, lets hope its the release bearing

Tim

 

[Zed2k]

I think you could have tracked down the problem with there being 2 lengths of release bearing carrier as you didn't use the new one supplied did you check to see if they were the same length as I have heard of this problem before. I think the short carrier goes with the raised finger clutch and the long one with flat type clutch cover, to keep the through right.
Nick

 

[Nigel Brook]

I think you could have tracked down the problem with there being 2 lengths of release bearing carrier as you didn't use the new one supplied did you check to see if they were the same length as I have heard of this problem before. I think the short carrier goes with the raised finger clutch and the long one with flat type clutch cover, to keep the through right.
Nick

Are we talking T5 to Chimera engine or Z transmission?

 

[Wyn]

Cheers
Cars using cossie/tvr T5 5spd
Tim You are right, the fingers do compress/decompress as I noticed when I removed the lot again this morning.

http://img.photobucket.com/albums/070

Theory no 2 now is the above bearing is what’s amiss? The supplied bearing in the kit doesn’t actually fit the tvr box (to small dia to fit over the carrier part) that’s why I had to use the old bearing. I can only guess they’ve supplied the wrong bearing or have their data wrong? Measuring the new bearing it seems to come up as 3mm longer from where the arm operates on, giving more throw.
I’m not sure tho that would be enough to cure the prob?

 

[Wyn]

Nope, scratch that
The whole lot is wrong

Further investigation reveals the added bearing length wouldn’t make up for the diffo in the two clutches now anyway
After bolting the old clutch back up you can see the fingers are still proud by approx 4-5mm

http://img.photobucket.com/albums/0703/900ss/Zed/wrong2.jpg
http://img.photobucket.com/albums/0703/900ss/Zed/wrong1.jpg

Now look at the new clutch n you can see the fingers are now recessed by atleast the same amount.

http://img.photobucket.com/albums/0703/900ss/Zed/wrong3.jpg

Not that I understand why one cover should pull down much more then the other, as off the car they seem to measure the same
Looks like the clutch kit must be all wrong after all.

 

[Yokohama]

I have encountered this problem many times. The car has problems going into almost any gear and can only go into gear when turned off. It turns out to be one of two things. As stated above, it can be the clutch slave, or TWO, it can be the clutch master! The clutch master in many cars is easy to rebuild, so I would suggest getting a rebuild kit and saving yourself some money. Just be sure to clean the cylinder and pre-lube the kit internals with brake fluid before you put it all together.

 

[Nigel Brook]

Further to Yokohama's post, have you got enough stroke in your Z master cylinder to feed enough fluid to your T5 slave cylinder?

 

[Wyn]

I'm waiting for another kit to arrive. This time i'm told it's coming via TVR, so it should fit lol. The other kit was obv wrong.

Btw, Car uses matching master and slave cylinders from the TVR
Master cyl is a straight swap, apart from the hyd line out.

 

[Nigel Brook]

Btw, Car uses matching master and slave cylinders from the TVR
Master cyl is a straight swap, apart from the hyd line out.[/quote]

OK, but are you getting enough stroke on the pedal to properly activate the slave cyl?

 

[Wyn]

The honest answer is “I don’t know”
At least not until I have it all back together.
I can’t see that I wouldn’t be tho.
I’ve adjusted the “pedal to rod” free play to zero and have adjusted the org pedal stop point to increase its stroke (large hammer lol)
As this pic shows, there’s not a lot in it, esp as I believe I've gained all that by adjustments.

 

[Nigel Brook]

Yes, they certainly look compatable. Mind you, it would be worth checking it out by having someone pushing the pedal down whilst you watch the amount of travel on the slave cylinder.

 

[Wyn]

Easier said then done as the slave cyl push rod operates inside the box

Update to admit…… defeat so far

All back together at last and guess what … its still not much better lol
So far it’s had …
Brand new clutch kit twice
New spigot bearing fitted 2nd time around
3 diffo slave cyls
New 5.1 fluid
And finally a rebuild master cylinder last night
All parts are matching TVR so it can’t be a mismatch of parts
Only thing left must be the pedal throw
Today I again adjusted the free play to add slight preload, yet still it’s the same

What I can’t understand is that when I do engage a gear… how the clutch doesn’t bite till at least "a third or more of pedal movement is released" Like letting the clutch up is fine!
Surely it cant work one way and not the other …..
I’m now thinking of adding more throw on the pedal rod, but I don’t want to end up with a clutch that ends up releasing with the pedal in the air

 

[Nigel Brook]

Back to basics on this one.
Is the first motion shaft on the gearbox [cossie isn't it?] the same as a TVR one? and is the bellhousing compatible with the box?
What bore size is the master cylinder? I'd be tempted to go up one size to give more fluid into your slave cylinder.
Final thought for the minute, whilst cylinders etc may be compatible the clutch pedal itself is unlikely to be. The pivot is going to have a different measurement from the pushrod I'd have thought, which which will have an effect on the stroke maybe?

 

[Wyn]

Many thanks go to Nigel for all the info/encouragement on what to try next

... and others as well

At last, we have clutch

........ I think

Seems that some serious bleeding and zero + preload on the M/C piston has cured it

It’s either that or that fact I’ve put some miles onto it now. Seems that after a few evenings out test-driving

the clutch atlast is working as I want. Today after a 20mile blast n sitting in traffic to warm it right up I can at last select reverse without any crunching of gears.
I feel happy right now lol

Till next time

 

[Nigel Brook]

Glad to be of assistance. It's nice to know there is a member who appreciates help