cav master cylinder and servo

[simonm]

i no its prob been asked a million times but cant find what i want to no has any body fitted one of these to there nova and if so have you got any pics of it fitted im using 288mm brakes and rear discs and want the best set up for the least amount of travel in the pedal but dont really like the feel of a pedal box for road use

[mowgli]

astra mk2 gte m/c & servo was a popular mod back in the day. i believe the cav one is different.

you need to get 3/20 valves on it or the rear end will lock up.

[conza123]

you can fit them as ive seen one fitted but dont how m8

[simonm]

ive seen one fitted alrite so it can be done just looking for a little info on how to the astra one i believe still has the 4 ports on im looking for 2 as ive already made new lines and split it at the rear and for the fronts i also have a tilton bias adjuster so should be no probs there

[mowgli]

is it a bias valve?

you can blank out ports easily enough, any decent hydraulic shop can sell the bits.

i'm more worried that trying to run both fronts off one side of a stock m/cyl will simply be too much for it...

the factory setup runs one circuit for the lh front & rh rear, and the other circuit to the rh front & lh rear, each side puts the lions share of the fluid to the front & its diagonally opposite rear gets very little. and the rear disc braked setup needs even less than the original nova drums, which causes the lockups..

[simonm]

I have a good idea how it all runs and the cav gsi turbo had abs so only had a 2 port cylinder that was split at the abs unit hence my reason for fitting one it's the cylinder that came from the factory with those front and rear calipers so should have no problem stopping a nova and the bias valve is definitly a bias valve had it fitted to one before and worked very well Just really looking for info on fitting it to see what other people have done

[simonm]

So been to the scrappy today managed to find an astra mk3 sitting in the corner so whipped the servo and cylinder off it it has a 4 port cylinder so as I already had a master cylinder from a cav turbo with 2 ports I swapped them around it bolts rite on the nova mount and just need to fettle up a push rod to suit the nova brake beam so all looks good so far should have fairly responsive sharp brakes will get it all fitted up over the next few days and get some pics in my old project tread

[craig green]

Test this offroad for gods sake!

[simonm]

Once alls on and tight where can it go have seen it done before and worked quite well no reason for it not to really as it's the original cylinder for the calipers just using different pipes seems a better plan than most using a standard nova cylinders and having a pedal near hitting the floor if you ask me that should be only used off road if used at all

[craig green]

But you are messing with the mechanical actuation between the pedal (bar) & the back the servo. get this wrong & the brakes could lock on or not operate properly.
Though I do see the need for enlarging the std master cylinder I have always had a good pedal with the 20mm MC even with rear discs & 288's.

[simonm]

Yea I agree but once done properly and strong it will work fine I'll get a better go at it later in the week maybe even rosejoint it and yes it will be tested and retested before actually hitting the road I'm not one for taking chances and just want it to be as best it can be for what it is if it doesn't work or if it feels dangerous I'll just have to switch to a pedal box but my lazy leg just likes the thoughts of a servo

[Benn]

Iirc Fitting the Cav one you need to cut and weld the bar on the back as it's in a different place to the Nova linkage.

[simonm]

Yea the cav one has a fork on it and an m10 thread so I may be able to use a Rose joint screwed on to slip in to the nova beam it may be a little long but no peons to shorten it but will still be stronger that little fork that it comes with

[simonm]

Right so got at this yesterday cav cylinder fits perfect to the astra servo which also bolts right on to the nova mount. The actuating pushrod is different so ran a die down the shaft a little further trimmed it off and screwed an m10 connecting nut got an m10 rosejoint trimmed that back a small bit and screwed it in till it butted against the push rid and gave it a good squeeze looks really strong and better than the original cav folded plate job so as is it all fits quite nicely and can't see any reason why it won't work and work safely pics to follow a little later

[Benn]

Pics will be good.

[simonm]

This is the original one for the nova decent looking rod

http://i961.photobucket.com/albums/ae95/simonm5360/AC7055B9-95B8-4036-AE19-17EA077AE35A-689-00000125D7659A66.jpg

This is the cav one it's a fairly weak looking effort to which only uses a 10mm pin to connect it

http://i961.photobucket.com/albums/ae95/simonm5360/A47F3851-DCF4-40EC-99E3-14920397E880-689-00000125D0878CE3.jpg

This is what I've done looks strong and can't see how there would be any probs with it if any one has any input just let me no

http://i961.photobucket.com/albums/ae95/simonm5360/32600DC8-E76C-4669-917B-38355829B0A1-689-00000125DFDB378B.jpg

This is a rough pic of it sitting in it's place only it was dark and taking pics with my phone excuse the poor quality

http://i961.photobucket.com/albums/ae95/simonm5360/4D42023A-DDA3-4241-930F-4978C3E093E0-689-00000125C13FA917.jpg

Thanks for looking

[Benn]

That looks good. Was it all the same length then? Thought the Cav one stuck thru alot more...

[simonm]

Yea apart from the threaded roy part it's all the very same so once that's trimmed down it's the exact same I'll finishe fitting it later in the week and get the pipe work connected and see how it feels from there

[Benn]

Oh, nice work.