Master Cylinder ???

Just completed the disk brake conversion on the front of my 48 CJ2A. I still am having trouble with solid brade pedal. I have read all the post I can on the set-up. Yes I have the caliper installed bleeder up, 2psi residule valve installed, new napa master cylinder, new brake lines and I still have to pump the brakes and still can't get them to lock up. rear brake pads new, new rear wheel cylinders, new rear brake lines. Do I need a better , bigger master cylinder or am I missing something else? What other master cylinders are you guys using?

 

Which mastercylinder are you using? I have the same problem. I thought about changing to a different mastercylinder. Some of the post on this site use a mastercylinder with equal size chambers in the mastercylinder, and some use one that has two different size chambers. Which one works the best?

 

Are the rears adjusted up correctly? Out of adjustment shoes can cause a seeming soft pedal. I am a little confused, you say you have pads on the rear which are for disc but then you say you have new wheel cylinders? I'm guessing you mean new shoes in the rear....

 

Did you bleed the Master Cylinder before bleeding the individual brake lines? Skipping this step has caused many a brake system to feel "mushy" and needing pumped up.

I have solved many a "mushy brake pedal" issue with this small, overlooked step.

 

Yes, I am sorry new shoes on the back used stock rear set up for now would like to convert to Dana 44 and rear disks later. I even have tried plugging off the rear brake line at the Y infront of the master cylinder, still soft. Stupid question? How do you just bleed the master cylinder. I have replaced/rebuilt several MC over the years and always bled air off at the wheels and no issues. The master cylinder I used was a stock replacement single piston, single resivor from Napa for a 48 CJ2A, I have heard of others using an aftermarket wilwood setup, Just trying to keep cost down, but will do what's needed for good, safe brakes.

 

The master cylinder can be bled right on the bench before installation. Put er in a vise, fill the res and place a finger over the output port (acts as a check valve to prevent air into the cylinder during actuation). slowly actuate pump the with screwdriver or anything convenient till you get good fluid out of the port (if youpump it fast you will have brake fluid all over yer work bench and self, go s-l-o-w and keep a rag under yer paddies to catch the running fluid). This bleeding can be done after install also, just do it before you connect brake lines.

Theoretically master cylinder air should bleed out thru the system by bleeding wheel cylinders/calipers (farthest wheel from MC to the closest), but sometimes you are stuck with the mushy pedal if the MC bleed is skipped. My take is that while bleeding WC's, it is stopped as soon as the air appears to have been removed from the cylinders instead of flowing another goodly amount of fluid to get all air out of the lines. Brake fluid is cheap, flow plenty to ensure all air is out.

Hope this helps

 

Try bleeding the mc first then try bleeding at the wheels as suggested. If that doesn't work I'd suspect a bad mc. I'm still running stock mc in the '59 cj5 with 4'wheel discs with no proble
S and nice firm pedal.