Brake problem

[sallens]

I have a ford pop with jaguar rear end and vauxhall viva front end with viva brakes up front......
I have just done a front brake conversion , changing the viva brakes for xr3i front calipers keeping the backs the same.
I have an under floor servo and girling master cylinder attached with 2 out lets ::front brakes/ back brakes
the master cylinder has these numbers on:- 8697 DR1O78
a strap round the cylinder... 60 40 875



the reservoir has these numbers on girling
64676942 04 G
FR1

MY PROBLEM IS I HAVE BLEED THE BRAKES ...THEN I BLEED THE BRAKES..THEN I BLEED THE BRAKES BY THE USE OF A EeZIBLEED , i have put 2 litres of brake fluid through and no air bubbles comming out ,, the pedal still goes all the way to the floor and i can still turn the front wheels while my boy puts his foot on the brake pedal.
has any one got any ideas on how to get the brakes to work....


STEVE........

[inchhigh]

Had the same problem years ago with a mini and in the end I had put left calliper on the right side and right on the left just make sure you have them on the correct sides

[kapri]

Sounds like you are short of fluid volume to pump though and operate the brakes. XR calipers are about 6mm larger bore than Viva from memory (54 as opposed to 48mm diameter)

I presume the brakes were working before ? Any idea of what m/c it is , or are there any markings on the cylinder like 18 or 19 or 21 ?

[sallens]

the only marking are on the mc are at top of page
the caliper size is 60mm and yes they were fine before...

steve...

[mygasser]

although the piston is bigger there is only 1, the viva calipers had 2.

[kapri]

Doesn't work that way Neil as the other side of caliper has to slide towards it to work so effectively the one piston moves double the distance a one piston n a double piston unit would. Plus it takes about 150-190 extra line pressure just to make the caliper slid eon its posts. There is no technical superiority to a floating caliper just a cost advantage to the car maker

[kapri]

the only marking are on the mc are at top of page
the caliper size is 60mm and yes they were fine before...

steve...

60mmm bore is huge compared to a Viva then! You will need a minimum of 7/8ths ( 22.2mm ) master cylinder to make that system work. If they are actually 60mm then you need to be looking at 15/16ths with between 4:1 and 6:1 pedal ratio dependent on servo diameter used.

Sounds like you had a 3/4 or possibly 13/16ths mc before.

[mygasser]

Doesn't work that way Neil as the other side of caliper has to slide towards it to work so effectively the one piston moves double the distance a one piston n a double piston unit would. Plus it takes about 150-190 extra line pressure just to make the caliper slid eon its posts. There is no technical superiority to a floating caliper just a cost advantage to the car maker

makes sense kev

[chrisvs]

Your MC may be a Marina item, also fitted to LRs, the 64676942 number is listed on Paddock Spares site with a part number of 569671:

569671 | Brake Master Cylinder. Dual Line Servo. No. stamped is 64676942

Found this article about MCs for converting brake master cylinders on Marinas, most of it covers single line MCs but right at the end of the article it lists dual line MCs and shows the 569671 as having a bore size of 7/8" and also shows a couple of alternatives with larger bore sizes:

New Page 1

Hope this helps

[kapri]

Nice research Chris