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Buffy
27-02-2017, 05:51 PM
What size are people using who have converted to hydraulics.
I have a .625 but seem to have too much travel at the pedal end to get a clutch. The only way I can get one is by having the pedal over centre.
It's all bled through and adjusted so would a .75 sort it out?

One step forward and 2 back it seems at the mo 😡

Spacenut
27-02-2017, 09:09 PM
0.625" is about the smallest bore size you can get. And if your slave cylinder bore is significantly larger then yes, I would say that is a possible reason for the clutch not disengaging. If you can get a smaller bore slave cylinder or a larger bore master then I would agree this would change the pedal ratio and increase the clutch lever movement.

Don't worry, it's all part of the learning process - it's taken me 20 years (6 of which were on the road) to figure out that my handbrake leverage ratio was too small, so I couldn't get the handbrake to work efficiently - 11 clicks and it would only just hold, reduce the pad clearance and it would bind all over the place. That's the fun of mixing and (mis)matching parts!

Lauren

Buffy
27-02-2017, 09:22 PM
Thanks Lauren
I think increasing the master cylinder bore may make the clutch slightly heavier to push but that is a small price to pay .

Spacenut
28-02-2017, 09:22 PM
Agreed. And for reference I am using twin 0.625" master cylinders for my front and rear brake circuits, so I have to push both in parallel - it's not that bad.

Dirk
28-02-2017, 10:56 PM
Hi Mark,

Not sure which pedals you got, but mine came with two .7 cylinders and one .625 and my understanding is that the .625 is for the front brakes and the two .7 are for rear and clutch?

Dirk

Buffy
28-02-2017, 11:22 PM
Hi Mark,

Not sure which pedals you got, but mine came with two .7 cylinders and one .625 and my understanding is that the .625 is for the front brakes and the two .7 are for rear and clutch?

Dirk

Bought the compubrake kit which is probably the same.
That does make me think, however its a universal kit and they do not know which slave you would actually be using so it is all down to the master/ slave ratio.

islandman
01-03-2017, 12:35 AM
This is the response from Compubrake I had when I queried the set-up on my scooby nova last year

"Good day DavidRight what we recommend is the following
0.625 front
0.7 rear
0.7 clutch my friend
Also please find set up guide enclosed

Kind regards,

Klint"

Buffy
01-03-2017, 06:47 AM
Think me needs to examine the cylinders again then.
And I had just got a great brake pedal !!

Spacenut
02-03-2017, 08:50 PM
Interesting - so the brake bias is due to the different master cylinder bores... so for an equal pedal force applied to each one, the 0.625" will apply more brake pressure than the 0.7", effectively biasing the braking effort to the front wheels. Very clever.

I assume that this approach is used because brake balance bars are not permitted for BIVA?

Dirk
02-03-2017, 10:42 PM
Interesting - so the brake bias is due to the different master cylinder bores... so for an equal pedal force applied to each one, the 0.625" will apply more brake pressure than the 0.7", effectively biasing the braking effort to the front wheels. Very clever.

I assume that this approach is used because brake balance bars are not permitted for BIVA?

They still come with a balance bar, and I'm not sure that they are not permitted just not happy with them being left adjustable i.e whilst you are driving. I think in the latest's CBS catalogue they say you have to stop them being adjustable once set and have some sticker on them, Ill see if I can dig it out and scan it tomorrow.

Dirk