Art, great to hear that this is working nicely for you. I'm glad you did the slave/release bearing too. It is so tempting not to, save a few hundred bucks but so often it is false economy not to.

Now you have the peace of mind and satisfaction of having it set up right!

 

How often is the slave/release bearing and slave cylinder replaced?

Every clutch change or are after a certain mileage?

 

If you go to the dealer they would probably replace the bearing/cylinder (it is all one unit) every time they do a clutch. It is good shop practise and if you look at the total cost of clutch replacement, the incremental amount to change things like the release bearing, crank oil seal etc. are usually worth it. If you stick with the original bearing and it needs replacement before the clutch goes, then you're looking at 10+ hours of labour to change it and then suddenly it doesn't seem like such a good idea to skimp!

 

what has been the major failure in the clutch ? the clutch disc coming apart? that sounds like it should be a recall item if the rivets come out of a perfectly good clutch disc. again...... aston design team.... another group to be fired.

 

This is just conjecture so I wouldn't take it to the bank. The disc coming apart appears from what I can tell, to have been a limited bad run of parts from a supplier. You can hardly blame the design team for that. And to the best of my knowledge anyone who has had this type of failure has had the parts replaced (normally clutch is a wear & tear item.)

Generally speaking, I think it can be said that the clutch CAN be made to last a reasonable amount of miles, but that it doesn't stand up to much abuse and that the life can be shortened quite quickly if you're not careful.

Certainly there's been enough demand for up-rated items that we've sold a fair number of the twin plate units as an upgrade.

 

What does the clutch disc (probably from Valeo) coming apart have to do with the Aston design team?

 

The design team designs and sources parts for the entire car. you wouldn't use parts that were not tested and solid. Valeo makes decent stuff.
clutches, if driven correctly, can last 100k miles , with no issues, even with a lot of track use.
AM uses the granzano transmission, why wouldn't they use proven clutch parts from Sachs or someone with a great track record? again, clutch discs shouldn't come apart.

 

With so much of a problem in this area, you would think they would narrow down the date codes of the problem discs and do a recall. the design team is absolutely responsible for this. they often time, choose the part supplier and configure their clutch design. (even though it might be a copy of what is already been done. ours looks a little like the ford mustang design)
the clutch disc itself, is not a wear item, if driven correctly. the pressure plate is just a set of springs , and T/0 bearing will wear, but it should last a good long time if normal care is used.
The rivets popping out on the clutch disc is a clear defective design and poor choice, especially for a car with the power it has, and the quality it has in other areas.

 

Hey Art,

How does the engagement compare to stock?

 

The Valeo clutch on my Esprit also came apart at the rivets. I don't think you can blame the design team for a supplier having a bad batch.

 

if its a weak design, absolutely. And did the bad batch hit every aston ever made? If so, maybe the design team didn't do enough testing , which would be their fault as well. the design team is integrally involved in sourcing components, especially in a company with a relatively small production output. (compared to the big boys). If IM on the design team and selecting clutch parts, im looking at proven durability and performance. if its a new design, im designing it to be both as well. you over build everything, within limits, so that there is no weak link on something as simple as the clutch disc. I know why these things are wearing out, due to the performance clutch, with soft grabby compounds, but high pressure plate force to accommodate the high HP car. that's user error. but , falling apart clutch discs is a bad design. They should wear out before they fall apart. the only accepatable defect in my book should be clutch disc material delamination, or T/O bearing failure. bearings can be bad from the start (very few), and poor bonding can happen, but not common. and, for the rivets to fail on so many of the production run, points to AM in neglect to not have a recall on the clutch lots with this problem. no way should a clutch have an issue at pre 25k miles. I race a 450hp Porsche hard, and over 8 seasons, the stock clutch still had the part numbers showing on the surface of the clutch discs. (sachs).
that's 50k of street and racing miles. a short time later the throwout bearing failed. 3 years later, still using those discs with no issues.

 

I'm not sure you understand the realities of working for one of these companies. You over-engineer a part and then the bean-counters come and force you to change it for something less costly.

As an interesting anecdote:
Legend has it that Henry Ford sent a team of engineers to salvage yards to analyze the parts of their cars that had been wrecked. He wanted to know which parts had survived well and still looked new. He then had the design team re-engineer those parts to a lesser specification since his belief was that parts that were over-engineered were just a waste of profit.

Back to the clutch: suppliers also have other suppliers. It's possible that a company like Valeo gets a bad batch of rivets and several cars experience clutch failure. And for this you want Aston to issue a recall? You don't even know how many cars had clutches that failed for this reason. In reality t might not be that many. The internet tends to magnify problems. At worst case you would issue a service bulletin if you notice a repetitive issue, not a recall.

Clutch failure from misuse is much more likely than from faulty components. So the appropriate thing to do is to handle this on a case-by-case basis and if the failure was indeed due to a faulty component, then cover the repair under warranty. This is exactly what Aston did. Expecting them to replace every clutch under some sort of non-safety related recall is silly.

 

007, the engagement is a bit better, softer than stock.... However, when we took the old slave cylinder out, the bearing was wobbly and somewhat rough. So with the new disc and new bearing/slave I think it feels as it was supposed to feel. Since my clutch was original and had 55000 miles on it, I think the bearing was just getting hung up a bit upon engagement and thus the hard pedal feel. Now it is nice and smooth and the engagement is VERY predictable.

A word of note too on the stock clutch. Interestingly enough, after working on many Japanese high HP cars over the years, I ALWAYS avoided "Valeo" brand clutch components. Especially their discs...... Almost every one I replaced, which is probably in the range of 40-50, the rivets were either broken, or failing in a catastrophic fashion. Daikin clutches makes many OEM jap manufacturer clutches and had ALWAYS had positive results using them, while avoiding Valeo clutches through personal experience. Seeing that the factory clutch is a Valeo unit, I was not surprised that the disc was worn and glazed but luckily I replaced it at the first sign of slippage, thus avoiding damage to the pressure plate friction surface and the flywheel.

 

Awesome, thanks for the heads up! Did you resurface pressure plate or just reused with no problems?

 

disc being worn or glazed is not a valeo problem, that is a user issue. there should be very little wear if the clutch has been used correctly. its a high friction surface clutch material, with a high clamping force pressure plate. This is a formula for disaster in the clutch wear dept., so its very unforgiving for mis-use. totally separate to rivets falling apart