I finally figured out why I have so little rear brake... I'm using the m/c from a truck with manual disc/drum so the rears are not getting the needed volume.

What is the OEM application I should look for, bearing in mind I need the O-ring retaining groove?

Saved this from a Dr Diff post

...right, and that's the truck I'm using it from. None of those are 4 wheel disc. The rears are not getting the volume they need from a drum m/c.

I wouold give Cass, a.k.a. Dr Diff a call, give him te specifics of your brake system and see what he says. He's a very knowlegable man.

I have two complete 4 wheel disc conversions, one power & one manual, using his recomended parts set-ups. Both are amazingly balanced, predictable and cost-effective.

I'm curious why you think the rears aren't getting the needed volume? Is the pedal bottoming out?

Unless the MC bore is stepped, the needed volume will be supplied by a longer pedal stroke.

What John said, was wondering that myself as usually they have 2 much bias

i have the wilwood 4 piston on all corners. using 1 1/8 mc. I had to turn down rear brakes with adjustable prop valve. car would not stop as rear was trying to do all of the work. I am thinking of going to the 1 1/32 for more stroke and higher pressure. my current pedal travel is short and it takes a lot of leg to make hard stop. It is all manual setup.

the modern mopar master is set up 70/30 bias---did you bypass the line divider for the rear brake line? you need to for proper funtion-the line divider may be restricting by doing the 70/30 bias over again--- and disc brakes dont need a big volume of fluid to move---the pads are riding on the rotors all the time--they barely move when you hit the petal---and on the other hand drum brakes need alot of fluid to apply the shoes------i am running my 64 with the d150 manual master and 4 wheel disc brakes---works great----on my 71 dodge military truck i run the same master on dana 60 with 4 wheel disc brakes and they work and if you really wanted to we could take the original tiny master from my 64 and run 4 wheel disc brakes off of it--it would take a while to bleed it out because the resevoir is small ---and hey can anybody tell me how wilwood got there start?----bob

I have NO prop valves, either factory or aftermarket. The reason I don't think the back brakes are working is after 200 miles of road racing at 140 mph and probably 100 1/4 mile passes I can still see the factory grind pattern in the rear rotoer, whereas the front rotors are worn about .030" each and at about 80% pad life.

are you using that brass brake line divider?---in the older cars that is the prop and residual valve---when you disc up the rear you bypass it--if you car was a drum brake car you throw it away---or as i read what you are saying you ran all new brake lines front and rear and you used a plain T to split the front brakes-if the line to the rear of the car is still original i would suspect it is obstructed or pinched shut--bob

thought of one more idea---if everthing is new--sometimes guys mix up the brake lines---the front hole in the master goes to the rear brakes----the rear hole goes to the front brakes---bob

Put a pressure gauge in both circuits and see what it says.

Thanks guys, and sorry for such a delay in replying. We've been in a 2 month thrash getting the second car ready for Silver State.

As I stated before, there are NO dividers, prop valves, adjustable whatevers, just m/c feeding lines. Front port to rear brake line, hits a tee on the rear axle and goes to the calipers. Rear port to flex line to line-lock to tee to front calipers. The systems NEVER meet.

Weight bias of the car is 54/46, T-bars were .925, now 1.12.

I will try to get gauges plumbed in and see what's going on up there.