Struggling to get my hyd clutch set up working I don't think im getting a enough travel at the gear box end to fully release the clutch getting approx. 10-15 movement on the arm, Im using a 625 master cylinder.

using a floor mounted peddle box and getting a good amount of push on the master cylinder.

What size master cylinder do you normally use thinking im going to have to go up to a .7.

 

I've been told to use a .70 as smaller don't push enough fluid but that's going with a bmw e30 slave

 

Yer I think that's what i'm gonna have to do, guess I will be taking it all apart again tomorrow

 

I've read others use a smaller one guess it may depend on what slave you use?

 

at .7 I would expect the clutch to be bloody heavy.

I use a metric 14mm ap cylinder an it gives an awesome feel.

 

With the .625 I can push the peddle easily by hand was surprised how light it is, its been a complete wanker to bleed may be give it another go before changing cylinders. how much movement at the clutch fork would you normally look for.

 

Back bleed it with an oil can best way I find to bleed clutches

 

Been using a vacuum bleeder pulled a litre bottle of fluid through 3 times , had to use a tie wrap to pull and hold the slave in as I was getting air trapped in there.

 

I've bleed loads of problem clutches on the road doing Daf aid over the years people can keep there fancy pressure bleeders a simple oil can small tube from the can to the nipple on the slave then pump away till the empty fluid pot is full works spot on

 

Yer reverted to manual bleeding once the fluid was at the slave, very tight on space total twat to get on the nipple and only get an 1/8 of a turn at a time makes it hard to open and close.

 

Sorry I mean back bleeding by pumping fluid into the slave via the oil can and up through the system till the master cylinder pot is full

 

I see, good tip will give that a go.

 

When you put this set up on a 2wd and 4x4 Cosworth,s the size cylinder that I'v all ways used is a .700 and you don't need to bleed it as long as you have put the slave cylinder on right with the hose punting up and the bleed nipple punting down . I'v fitted loads of these kits and never had a problem .

 

I found that with the 0.625 too ended up with a 0.750 in the end the balance is very nice now although it is alittle heavy but I can live with it.

Rich

 

iirc if your using the BMW cylinder then the nipple must point downwards, the bleed drilling must go above the feed internally.

I always use concentric rather than the arm setup, and twin or triple plate clutches, so maybe my advice a little skewed for road use.

 

Have now changed to a 0.7 and I get it in to gear now, bite point is low but car is up on stands stopping the wheels from turning by hand so not a true test really.

 

Ill be using a twin plate clutch but still going to use an external slave for ease of servicing

 

Bit of a thread hijack, but is there any way to alter the biting point? I can alter the height of the clutch pedal fine by adjusting the master cylinder arm, but I find the biting point is right at the end of clutch travel. I assume i need to alter the slave cylinder to change the biting point?

 

No way to adjust hydraulics, the clearance should be set, the leverage needs to be worked out to know how much travel you need.

 

I found I had a really low engage point when I had the 0.625 Master Cylinder fitted so bad at high revs it wouldn't select gears.
Changed to 0.750 and it's perfect now although the pedal does fell alot heavier but definitley something I can live with.

Oddly ebough when I first had it fitted from new it was perfect with no such issues, it only changed when I fitted a new slave cylinder looked identical to the one I took off (it was leaking) but was about 3 years newer.
Perhaps the E30 slave cylinders spurious manufacturers have changed something slighly??

Rich

 

Depends on the cause of the low biting point.

Does your pedal have full/enough/correct amount of travel ?

Is there any slop in the mech before it can actually build hydraulic pressure in the line ?

And are the master/slave suitably sized ?

Solution is straightforward.

Gain more travel, leverage, whatever way you want to describe it, all the same deal. Just achievable in any or all of the areas mentioned above.

For some it will be simple adjustment, others may move mechanical leverage points, others may fit different master/slave combo's to achieve more leverage/travel etc etc

And if your bleed nipples are a ballix to access, just fit a remote nipple to where it is easy to access.

 

are you using the full travel of the master ?

I assume you have an adjuster on your pedal where it pushes on the master ? maximise your travel there for starters as you may have more thrust available that your not using currently

 

I have the Master adjusted up so as soon as you push the peddle you get movement at the slave, if I go any more it will be applying pressure on the cover with out touching the peddle,

You have to push the peddle to the floor to get in gear and the bite seams just off this point , I guess the only way to bring the bite more into the middle of the Peddle travel is going to be by using a .750, I was just a bit worried about over pushing the cover and damaging it.

Will hopefully get the car on the floor this week and try it in anger.

 

So wish i had left mine alone worked perfectly. The centre is not as good IMO. Before you argue I have had both .

 

Internal ones are trouble rod I've herd loads of horror story's about them. External is just easy and works well I deal with that set up a lot at work

 

I started with side push then went to centre push now i'm back to side push, I do prefer the side push and the fact I don't have to the change the centre push bearing every 3 months
Rich

 

I can't comment on all center push set ups but there's a company in Basingstoke call Whitspeed. They built a green wide arch mk2 escort yb'ed.
That's been through 5 now lol they use a saab bearing

 

The pedal-master needs adjusted so there is no slop in the mech.

You cannot pre-apply pressure to the master without risk of pushing it over the fluid supply hole. Do this and when the pedal is released, it may not drain back correctly to the reservoir. If you do, it can trap pressure in the system causing the release bearing to push against the clutch, leading to slippage and other problems.

It'd take a hell of an overpush to damage most covers ( but yes it could happen ). And you'd feel under foot that you're doing this.

 

What don't you like about the centre push ?

 

Love all the people complaining about how poor concentric release is, 90% of production vehicles are fitted with them, they must be crap lol

The fact that people/companies are taking a std production concentric, modifying it for competition clutches and then complaining when they fail or don't feel right.

Makes me laugh.

Ran concentric for years on road cars and competition cars - no issues.

 

I know we've discussed this before Mark but the problem is you need to spend Ł300 on a centre bearing that will cope with a competition clutch.
It's just not cost effective for most people, when the side push works perfectly well.
If I had money no object option then yes i'd probably run centre push and triple plate clutch

Rich

 

I can not see any benerfit at all in a center push they cost more they work no better and if there is an issue it's box out

 

that's what hes saying hes already done steve, hes got no slop left and clutch bite point is on the floor still.

 

how high is your pedal at rest ? im just wondering if your custom pedal is setup right so that its coming high enough to allow enough throw to push the master piston far enough for full thrust ?

 

@Rich,
But you wouldnt begridge spending the Ł300 on the clutch (or a lot more in my case).

@everyone else
I see it as part of the clutch package, and yes they are more efficiant than with an arm as they also press the clutch squarely rather than with a floating bearing affair.

If you need to use a proper clutch then you need to use a proper bearing and release mechanism for it.

If you are using a std derived cover then stick to a std arm. (and a BMW cylinder lol)

 

We will see how they last as mine is having a twin plate an external plus they do push square on the clutch as the bearing moves in the arm lol

 

my r33 and supra ran triple plate clutches with just a small slave on the outside of the box, worked perfectly I don't really see the need for a centre push also a complete pig to get to for repair work.

 

It's already been mentioned but I didn't know if you'd noticed it.. You do have the bleed nipple on the slave facing down wards don't you??

 

The centre push is just as good (if not better) than the side push if its all set up correctly and yes I've had both too but used centre push for both my Escort (twin plate) and my RS500 (single plate type with organic drive plate) and I've never had any issues with either, I also sell loads of centre push kits both here and abroad and don't get any complaints.

 

Dont think i made any complaint about the centre push it works just fine. It was just not worth the cost/effort for no gain.