Projects Brake issue

Guys - I have a '63 Studebaker Lark that I 'upgraded' to front discs (rear drum internals rebuilt) and a dual Raybestos MC36237, as suggested by the disc conversion company. Was having an awful time trying to bleed the system, so I switched to a Dorman M97934 master and added a 2-lb check valve for the calipers. This is a firewall mounted M/C, by the way.

That gave me a pedal, but it's not reliable. Took the car around the block and had to pump the brake to get stopped. I have done dozens of brakes on lots of cars in my 72 years, including disc conversions, successfully. This has me stumped.

I bought a proportioning valve, hoping if I add it to the system - with or without the #2 check valve, I might get a firm brake. I know I'm grasping at straws, at this point and need your input. Can I use both of these? My thought is to use the check valve immediately out of the M/C, going into the brass valve's front brake in port. Overkill? Thanks so much in advance, and I'll save you the keystrokes; I'm a moron!

 

Let me guess? GM style Callipers?

you shouldn't need any check valve for a firewall mounted M/C

 

GM metric quick take-up calipers?

 

That's what I am guessing! [aka Low drag callipers]
These brake conversion kits usually have these ,and the vendors stick their head in the sand [being just a component supplier]

A mid 80's S10 stepped bore M/C is an easy remedy [or swapping out the callipers]

 

That's the Jeep master, is it a Turners kit?. I have one on my girls '60 Lark wagon. It has a lower then drum pedal but firm, with a under the floor master and a manual prop valve. No need for res valves when the master is higher then the calipers.

 

Unless the rear brakes need one.

 

All drums need them, either in the master or inline. That brings up a good point, make sure there's a 10lb res valve to the rear or the new master has one inside for the rear. I'm assuming the rear brakes are stock Studebaker.

 

You need a 10lb reserve pressure valve for the rear drum brakes, if it is not in the master cylinder. Also make sure the drum brakes are adjusted correctly.

 

It is a Turner kit: https://turnerbrake.com/collections/car-kits
He recently changed from a GM setup to a Chrysler caliper and it's been a pain from the get go.
With my firewall M/C his instructions don't say anything about a rear check valve - but I'll try it!
Might also try the S10 stepped bore before I give up and go back to drums all 'round.
Many thanks for the tips, Fellers!

 

Would this be a stepped bore type?

 

Double down on the rear shoe adjustment. I'll make them a tad tight to get the bleeding done, then back them off to normal.

Look for wasted-motion in the pedal link to the master, there should be no slop.

 

just a thought, have you tried a long gravity bleed for the entire system?

 

Check the master with a paperclip into the tube seat, very gently push inside the hole. If you feel a little spring back then it has a residual valve in it. If it doesn't you need one inline (red 10lb to the rear) and I recommend SSBC valves, the ones in your picture tend to leak.


So do you have the new Chrysler caliper or the GM (S10 4x4 if I remember correctly)?.

 

If you have the GM calipers here's a thread about them and is why I most likely have a low pedal in mine.

https://www.jalopyjournal.com/forum/threads/gm-metric-low-drag-calipers-fixed.1202460/

 

^^^^^ Remember that thread very well.