Pedal Box Confusion

[Guest whiz]

Well guys I managed to get a bulk head panel fabricated to take away the sloping bulkhead to make it vertical the guy made a great job, just gave him a cardboard template & he turned it into a stainless steel thing of beauty. its now fitted into the car so there I was standing looking at the pedal box thinking how the hell am I going to get the clutch to work with the cable. As the only part to fit the cable to would make the cable be pushed not pulled. I was thinking about all manners of pivot point configurations so as the cable could be pulled. finally I phoned comp brake to ask for a schematic so I could fit it properly. turns out that the pedal is the wrong one fitted to the box, which is for a hydraulic clutch set up. so i will hopefully have the right one shortly. one question I do need to ask tho which cylinder serves the front brakes the 0.7 or the .625?

 

Andy

[Guest mcramsay]

i think the 0.625 is for the front, the smaller bore will give a higher pressure, 0.7 for the back, that means you will naturally get more brake force going to the front calipers, which will help stop the rear locking up.

 

i believe that is correct, but knowing me it will be the wrong way around, hopefully some one will back me up in a minute!

[Guest Alan_builder]

This is a question we can't answer at the moment.

Why, the answer depends on what the front and rear cylinder sizes are!

[sj-bradley]

Assuming the front and rear calipers are the same size for now.

 

A smaller bore would move LESS fluid than the larger bore for the same amount of travel so there would be a smaller movement of the cylinders attached to that one (assume rear cylinders) so less pressure.

Large Bore - more fluid - more movement on slave cylinders (if they are the same size) so more pressure on the pads.

 

Simon.

[Guest ickle]

My guess still stands and it is a guess

 

Smaller to the front

Larger to rear

 

Smaller means less fluid more pressure

Larger means more fluid less pressure

 

Am I wrong ?

 

Stuart

[sj-bradley]

Thinking about it that way, you might be right.

 

Is this a bias bar that you're talking about ?

 

I think if you have discs all round that the pads will have to move the same amount of distance to the discs (usually) so the mechanical advantage of the smaller piston would as you say give a higher pressure. It would have to move further than the larger bore cylinder.

 

I stand corrected.

 

Simon.

[Longboarder]

Smaller cylinder exerts more pressure but moves less volume so with sierra calipers it usually feeds the fronts. Life was easier when balance bars allowed some fine tuning. Now need to be locked off.

 

Nigel

[Guest whiz]

Hi guys hanks for the replies . I should maybe have stated that I'm running an old cortina set up. vented discs at the front and drums at the rear there will be a biased bar fitted with the new pedals.

Andy

[sj-bradley]

Hi,

 

You do know that the bias bar will need to be welded into a fixed position for the IVA?

Adjustable ones aren't allowed.

 

Simon.

[Guest whiz]

Hi Simon the car is already on the road I've had to change my pedals due me changing from a pinto to a zetec,

cheers

Andy