master cylinder help, which is front?

[veltex]

hey any brake guys, on a disc brake master (Raymold 2539075) the rounded type w/two hold down bails, which compartment is for the front discs? the rear compartment is larger, and the fitting coming out of the front one is larger, I am assuming the front is for the discs, let me know how yours is hooked up

[gonebad2]

Front of master cylinder is for the front brakes.

[Longhorn Man]

That makes NO sence on his master cylinder then, if the rear resivour is bigger, then it is made for the disc brakes.
The drums have a mechanical adjustment, which makes it so when the shoes are thick and new, it uses abut the same amount of fluid as when it the shoes are worn down....the discs however, hav no mechanical adjustment, and takes all adjustment with the brake fluid. (This is why you have to bress the piston back in and force the fluid back into the master when you chaing pads)

[Dean]

I'm pretty sure the 4x4s are opposite also.

[MOTHERTRUCKERS]

3/16" line for front disc brake 1/4" line for rear drums.

[veltex]

thats the thing, I said 2wd when purchased, and have been to every parts store in the valley trying to get the right fittings (reducers) to get the rear half to 1/4 and the front half to 3/16, the threads on the master cylinder are quite a bit to large, and made every store bring out a 71 c20 2wd to try the fittings, they were all the same as the one I got. I notice some masters have the same size compartments, mine looks like it should but with the cap off the rear one is noticably larger, it almost runs part of the way under the front compartment. Are there any residual pressure differences between the back and front compartments?

[rage'nrat638]

you are trying to plumb it to the pro-valve and not stright to the brake lines to the master right?

[Stout72]

They are opposite on my K20, i.e. large rear reservoir = front discs. Didn't know there was a difference between 2x and 4x trucks WRT the master cylinder. The tubes cross when they go into the prop valve, so then front end of prop valve= front discs. I believe Longhorn Man is correct as to the why.

Let the fittings be your guide.

[MOTHERTRUCKERS]

The rear fluid compartment runs under the front fluid compartment???? Maybe the fittings are metric? What is that master cylinder for?

[photoglg]

I just installed power front disks on my truck a few weeks ago. My master cyclinder chambers are the same size, but the fitting to the combination valve are different sizes. I hade to get a stepup and a stepdown fittings

[photoglg]

Got this out of me class book on brakes

[veltex]

my damn provider wont let me get in to post photos, but my master is just like "photoglg", I am preped to go either way, stock pro valve or wilwood adjustable, the master looks like same size compartments until you pull the lid, then you can tell the rear is larger. However the larger fitting size is on the front compartment? So if I use the stock pro valve they cross? If I use the stock pro valve should I hook it up a certain way, and if I use the wilwood which way? I will post photos of the master later tonight if I can, and also another master on my 55 that has large compartment in front that is plummed to the front discs, then to rear thru wilwood adjustable.

[veltex]

here is the master I need to use, and the installed one on another rig.

[veltex]

hey photogl are your master chambers really the same size when you take off the lid and look inside?

[photoglg]

Yes they are the same size, I will take a pic then I get back from Santa Maria after the truck show today

[veltex]

will my new master cyl. have different risidual pressure in each compartment? is there any way to test this? that would tell me which one is for the discs

[veltex]

ttt