Front Disc Brake Tutorial

I don't know about the residual valve, (I don't have one, thought they were only if your master is low) but I know I never would have got my 4 wheel discs bled without a pressure bleeder.

 

thanks, i'll try that tomorrow

 

not sure how to even get a pressurer bleeder on there,I have one but the master cylinder is on the frame below the brake pedal under the floor

 

Right. Mine is on the firewall, and I made a plate with an air chuck that can be clamped on the top of the MC. I mean, theoretically, if you can get the lid off the MC, you should be able to get a plate on it. Just theorizing..

 

yeah, i can make a plate i guess, cant be that hard compared to all the work i just did...thanks

 

before i try and pressure bleed the brake lines, im going to add the inline 10 lb residual valve inline and remove whatever is in the master cylinder,is this a good idea? I tried bleeding them manually again yesterday with no change in the way they work, i have to pump the brake pedal once before the brakes will grab, they work well once they grab but have to pump it every time....am i wasting my time with this MC ? the calipers on the dana 44 are big, maybe i need a different MC? im wondering if it isnt moving enough fluid ? im using the original MC ,its a 69 cj5 has dual reservoir,I removed the residual valve in the first port closest to the mounting end/where brake rod goes in and added a 2 lb inline residual valve....this feeds the front discs

 

Maybe I missed it but, did you ever manually adjust the rear brakes before trying to bleed them?

 

I have a ‘69 also with stock MC, converted to front disks. Like you have done, I used the rear chamber for the front brakes with the residual pressure valve removed from the MC and a 2lb willwood inline. For the front chamber (rear brakes), I left the stock residual valve in the MC. I’m using the stock 10” rear drums and Suzuki/Geo front disks. I don’t know if you different brakes are the cause of your issue or not but my first thoughts would be, have you bench bled the master (it can be done while still mounted in the vehicle), is the MC push rod adjusted correctly with pedal return spring in place and as previously posted, are the rear drums properly adjusted. Good luck.

Tim

 

yes i did, i had them tight then backed them off just a little

 

I didnt bench bleed the MC, it was working fine when i had the other axles in it, with 11" drum brakes on both axles..maybe i let it go dry when i was re doing the brake lines? ..I wouldnt think I would have to readjust the MC push rod since i didnt change the MC ?

 

Are you using organic pads? I had 2 issues at first. No pedal and hard to stop. Organic pads helped stop, bleeding with the method I mentioned took care of the spongy pedal

 

doubt they are organic pads, I ordered pads, shoes,wheel cylinders all from one place, i think Amazon for the wagoneer axles....I tried your way of bleeding the calipers, no change..I get that other pads may stop it better but it is fine once i pump the pedal once....im just going to make a plate and try the pressure bleeder , i really wonder if the MC just isnt pushing enough fluid for the calipers, they are the size of the ones on my full size chevy pickup its a 72

 

I came to the conclusion that the MC couldn't push the air out while bleeding by pedal. But once I got it, they worked fine. Here is my crude bleed plate. I used an angle fitting with the saddle over it, so I could C-clamp it over the fitting to the cylinder. I used some rubber to create a seal underneath. I used about 20 lbs air to move the bubbles out, it goes fast so watch the fluid level.

 

I started making a plate for mine this afternoon, making it out of 1/4" plate, i cant use the clamp on one i have,,,the MC is right up against the frame underneath...mine will use the one bolt where the lid bolts on..you probably arent familiar with that MC..ill put a piece of rubber also...thanks....ill let everyone know if pressure bleeding worked or not, may not get it done tomorrow, will have to wait until monday to do it most likely...life gets in the way,lol....good job on the plate you made

 

That is the master cylinder I'm switching to. Stepped bore replacing a single 7/8" bore. The smaller 7/8 bore was fine with k10 calipers on all 4 corners I'm just going to a redundant system with proportioning at the master cylinder. I Don't think this is a volume issue since I'm running a worse scenario. Gotta be something new in the system or air or something dumb that got damaged in the swap.

 

Had problems bleeding my brakes. 2 things I did that solved my problem

Take the brake lines off and install some short lines and run them back into the MC reservoir . Pump the brake pedal and this will bench bleed the MC, much easier than clamping the MC in a vise.

Get some speed bleeders, install them. Get a gallon of brake fluid and start bleeding. I put a small hose on the bleeder and ran it to a jug to collect the fluid. With the speed bleeders you do all this with one person.

 

well I disconnected the brake lines at the master cylinder today, used the plastic lines/bench bleeding kit had my son push the pedal slowly down and back up a bunch of times ,got some air out, did this until we didnt get any air out for several times....then went to each wheel, bled them , got no air, I put wheels back on and no change ,,,i still have to push the pedal twice to get good brakes....I pulled the wheels off, pressure bled the system ,since i got the plate finished today....still no change .....I dont know what to try next...I took the drivers side caliper off the rotor,used some steel for a spacer, had my son push the brake pedal, the piston only moves a little bit ,when he pushes the pedal down twice it moves a little more....sure seems like the MC isnt moving enough fluid when pushing on the pedal....I have the same size calipers that are on my 3/4 ton 72 chevy truck....

 

I did the bleeding of the MC today, (bench bleeding) then did a pressure bleed...no change...this is frustrating!!!!!

 

What are you using for a stop light switch and how are the flex lines? Are your caliper brackets bent?

 

Just a thought from the “ignorance is bliss” camp. I’ve been researching this topic a bit having just converted to front discs, just haven’t got this far due to rain every weekend.

The point of the residual pressure valve is to keep a little bit of pressure in the calipers since they use more fluid to move than a wheel cylinder right?

I didn’t go back to re read your whole thread but I think you used a 2# residual valve?
Could you use a bit heavier valve to assuage the “2 stage” pedal, 3 or 4-5#?
I really don’t know, just spitballing.