correct me if i'm wrong

[Stuart]

I've read a lot of stories that the 944T brakes do overbrake at the front and at the rear there is nothing happening. Can this be overcome by bolting bigger brakes to the rear(callipers with bigger cylinders)?????

[MattKab]

Hi Stu, yes you could alter the brake biasing by changing caliper$.

Please share these stories about bias issues.

No issue if you use '86 only calipers on the front with a constant bore m/c.

Using (as we can easily in our case ( 4wdb 4pot) disc radius, pad area/profile and pad friction are constant) hydraulic leverage ratio's,

I get '86 951 36and34mm front and 30and28 rear, with a 3/4" m/c biased 1.45 to the front.

The same combo using the '87 and on, 951 40and36mm front calipers gives rise to a bias of 1.72 to the front.

The latter later calipers with the 24/19mm split bore m/c gives a bias of 1.1 to the front. This m/c with the '86 calipers give a no no bias of 1.08 to the rear.

Remember wheel speed must be considered, if you have dissimilar sized tyres front and back. Even in this simplified model. :silly:

Calculations on word doc if queried. Please share any discrepancies. (get ur numbers out)

Matt

[Alex]

The story was that people were over braking with the rear because they used the 944 M/C and connected it the wrong way. The front circuit is in the back of that M/C.

Also, even with it connected the right way you should use a proportioning valve.

Alex

[paul_f]

I have single pot 1985 944 brakes all round on my bus, with a stepped master cylinder that apparently came off the same car (though it was nearly new), should I not be using a stepped master cylinder with these brakes. What effect would not using a stepped master cylinder have.

I find my bus does tend to nose dive under heavy braking which can get scary as the back end gets light.

Paul

[paul_f]

Oh and Alex, which master cylinder has the front circuit on the back of it???

Paul

[Alex]

The 944M/c is reversed from the bug one.

Alex

[paul_f]

Ah so the right way round for a bus as the master cylinder points the other way!

The 23mm side goes to the front brakes

Paul

[MattKab]

yes, 24mm

[paul_f]

Oh yeah, 24mm!

What would happen if I fitted a MC with 24mm to both front and rear brakes???

Cheers
Paul

[DORIGTT]

Paul,

I would imagine that unless you had a proportioning valve set up properly, you would have too much brake force applied to the rear which would cause the rear to lock before the front. Some racers like it that way in certain circumstances, but I think a more balanced with the bias toward the front would be safer for the masses of lemmings out driving our highways and bi-ways.

Kevin J Hale