Power brakes- 3/4t & 1/2t

[Ace in the hole]

Is there a reason why a 3/4 t truck has the brakes lines flipped around- rear lines go to front of distribution block and front go to rear of block? Or I guess I should ask does it make a difference?

Reason I ask is I have a 3/4 ton truck and bought 1/2t lines. I can make them work as far as plumbing goes, but doing so hooks the front lines to the front of the distribution block and the rear to the back or the block.

Also, any difference in manual & power master cylinders for drum/drum set up?

[Ace in the hole]

anyone?

[Eichorst69]

http://67-72chevytrucks.com/vboard/s...d.php?t=281185

But I don't know why ???

Rob

[Ace in the hole]

Thanks, but I know 1/2 & 3/4 tons plumb differently, I just wondered if there was a reason.
Also if there is a difference in master cylinders between manual and power on a drum/drum set up. So far I have not found an answer.

[Ace in the hole]

come on, some one has to know

[Longhorn Man]

master cylinder p/n for power and manual are the same.

[Ace in the hole]

thanks longhorn man

now how about if there is a reason for reversing the hook ups-- front brakes go to rear reservoir and back to front reservoir?

[slammed1]

My truck is a 1/2 ton with a 3/4 ton cab with the same mastercylinder and booster but I did mount the booster to the firewall without the extension brackets. here is a picture.


I dont remember having any real issues mounting up my brakes but you can see for yourself the 3/4 ton set up worked fine.

[slammed1]

I can ake a better closer picture if needed,and yes the truck was driven for 3 years with this set up only put together for you smarties!! LOL

The mastercylinder is the type with 4 like sized reservoirs like Vettes came equipped with instead of the smaller rear brake/larger frt brake reservoirs.

[Longhorn Man]

I would not hook it up backwards. can you return the lines?

[Ace in the hole]

I can't return the lines, they are already installed. I was thinking I will either hook them up reversed or take and cut off the flares flip the nuts around and re-flare the ends of the tubes. Just thought I would find out if there was a reason for them being reversed before I go to the trouble of cutting and flaring.

[slammed1]

Ace,I went back outside and looked at mine after I replied,and I will take a picture tomorrow in the light so you can see mine. I used my 1/2 ton lines and hooked them to the 3/4 ton prop valve. On mine the rear line is a larger diameter that feeds the rears and the smaller lines have a "T" at the left motor mount area and both the frt lines are the smaller diameter ones.

[Ace in the hole]

thanks, I'll have to go back out and look at mine too, I was thinking the nuts are different size but the lines are the same size, but I'll double check. Right now the cab is off and they are not hooked to anything so thats why I was thinking of just swapping the nuts around if there is a reason for the lines to be hooked up in a special way.

I thought that the reason for going to a 2 reservoir system is for safety. so if you loose 1 half of your system you could still safely stop. In a drum/drum set up there is no proportioning valve so I would think that the pressure would be the same to both front and back lines (basic hydraulics) and so it should not matter which line goes to which port but I have been known to be wrong before (at least once or twice ). That's why I posted the question.

[Ace in the hole]

Ok, I confirmed that the lines are the same size, just the nuts are different.

[Steelawork'n]

If you have front disc brakes, you need a proportioning valve for that system. The forward lines are also smaller for disk brakes than for drums. And the lines going to the front disks are smaller in diameter than the lines going to the rear. It has to do with the pressure leading into the brake cylinders at the wheels.

[Ace in the hole]

I don't have discs, I have a power drum/drum set up.

[Ace in the hole]

I have searched and searched and can't seem to find an answer to there being a reason for the brake lines being reversed at the distribution block on a 3/4 ton. I will more than likely change the ends around to keep them hooked up the way the factory had them, although I am kicking around trying it the 1/2 ton way just to see how it works.

[Ace in the hole]

ttt

[JMac11]

Hooked mine up with stock lines then bought the conversion lines from Inline Tube, could not tell a difference. I am putting rear disc on soon, wonder how that will work.