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Brakes plumbed backwards?

janschutz

janschutz

Corn Hauler
I think my brakes are plumbed backwards. I have power disk brakes on my 68. I removed the bad after market Master cylinder which had two large bowls. I had an original MC that I put on, it's large bowl in in the back. I did not change the MC to distribution block lines.

As I bleed the rear brakes, my wife pumped and refilled the bowl.

When I was done with the back, I noticed the rear bowl was low and asked which bowl was emptying, she said the rear.

Is it going to effect the braking with the large bowl to the rear brakes or do I need to re-plumb the lines?
 
As long as you have enough fluid in either bowl to fulfill the volume demand of the brakes it won't matter. That is provided it is proportioned correctly. Which it evidently is as you have been driving it that way.
 
tried to bleed the fronts but nothing came out, guess I will try re-plumbing tomorrow after I get some brake line. At least the pedal is firm which confirms that is what was bad.
 
I took the front brake line off and was not able to push any fluid out of the MC front bowl. I guess this MC is bad also. This has really been a brake job from heck.
 
Did you bench bleed the master cylinder before installing it in the car? If not you will be attempting to bleed the brakes without success for the remainder of your natural life. If you didn't get some fittings that match the line connections, either with hose barbs or on bendable lines, connect and bend them back into the bowls. Fill the bowls 2/3rds of the way, using a large Phillips or other suitable rod slowly push the piston in and out until the bubbles stop. I've found that lightly tapping the master with a hammer breaks loose some air bubbles that maybe sticking in the bore or to the pistons. Once complete, plug the connection fittings, cap the master and install it in the car. Then bleed at the wheels, it is said that starting at the right rear and working your way towards the left front as last makes it easier.
 
I always thought that the rear bowl is for the front brakes and the front bowl is for the rear brakes.
And thereby ,it matters how it is connected !!!
When you depress the brake pedal , the front brakes should be first applied with pressure before the rear does !!!
Otherwise you could be in danger when applying brakes during cornering.The rear would lock and the tail would brake out !!!
JMHO
 
B67FSTB said:
I always thought that the rear bowl is for the front brakes and the front bowl is for the rear brakes.
And thereby ,it matters how it is connected !!!
When you depress the brake pedal , the front brakes should be first applied with pressure before the rear does !!!
Otherwise you could be in danger when applying brakes during cornering.The rear would lock and the tail would brake out !!!
JMHO
Click to expand...

I don't think it matters, as the pedal s pushed the entire piston assembly in the master cylinder moves, not the rear and then the front as you stated. However, I just looked at the instructions for the Wilwood master cylinder I have in mine and it states this,

Connect one of the primary outlet ports (A) to the brakes at the end of the vehicle with the greatest total effective piston bore area.
On most vehicles, this will be the front brake line (see note next page).

Connect one of the secondary outlet ports (B) to the brakes at the end of the vehicle with the lesser total effective piston bore
area. On most vehicles, this will be the rear brake line (see note next page).

Outlet port A being located on front of thew master cylinder, the bowls on it are the same size.
 
Typically, the greater fluid volume would be in the front brakes, as stated above. This is why one bowl is traditionally larger than the other. Once the lines and calipers have been "filled" and primed not much fluid is needed to flow to actuate the brakes. And yes from all I have ever encountered and read the full brake "system" is equally actuated as the pedal is depressed. A separate control (i.e. proportioning valve) is used to develop the bias front to rear. So you can get away with using either bowl although its likely best to stick the "norm".
 
This brake jobs issues just will not stop. Took the MC back to the parts house, and they ordered in a new one. Said it would be there yesterday, was not, came in today. Open the box and it is the wrong one. Looks like one for manual brakes with the plunger installed that you can not remove.

I feel like throwing something (maybe a fit).
 
Finally I have good brakes. Replace all the rubber lines, still an issue, firmer pedal but the fronts are still dragging. Got a new booster but did not install. Order a new distribution block and proportioning vale. Installed that tonight, SUCCESS!

No leaks, good pedal, no dragging on the front. I am a happy camper. Needed this car to drive to Houston on Friday. Need to outrun my Brother in law and his Camaro.
 
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