Re: Brake Hose Diagram

Posted by Craig Hendrickson On 2015/6/28 12:33:08

HH56: Thanks for posting that diagram.

This is currently relevent to me because I am re-engineering the brakes on my Panther. As some will recall, it is a 4 wheel disc setup with modern booster (MPB 7IN dual diaphram) and disc/disc MC (1979 Pontiac Trans Am WS6).

Here's something to ponder: In the stock Packard setup, one has 0.200IN steel brake line entirely though out. This means that the MC (usually BTV) is outputing into that line which is about 0.144ID (0.028 tubing wall thickness). The maximum flow rate at this ID is 1.25GPM (according to info on the web). This flow is then split into front and rear lines. Each is then further split at each wheel. So the maximum flow rate to any one wheel is 1.25GPM/4 = 0.313GPM. By example, this is obviously acceptable for a mid-1950s drum/drum arrangement, but it causes one to wonder about a disc/drum or disc/disc conversion wherein the caliper piston probably needs more fluid to actuate than a drum wheel cylinder.

On my 1955 Pat, which I converted to disc/drum, I used the stock brake lines, but since I have a dual MC, it has double the stock flow rate and it works fine. But OTOH, I don't usually abuse or stress the brakes on it. My Panther will be a different story. On it, I decided to use 1/4OD (0.250IN) lines from the dual MC outlets to each splitter block (front/rear) which then have 0.200OD lines from their output to the calipers. It is then obvious that this will provide quadruple the flow capability compared to the stock Packard lines.

Craig