No Brake pedal Pressure / Pedal Ratio Set-up Question

I remember the post earlier about brake pedal to push-rod ratio but I think I'm still missing something, here's the story:
'54 Lincoln 4 wheel drum brakes all rebuilt w/ new wheel cylinders, all new brake lines, wilwood proportioning valve, Speed Way master cylinder/vacuum booster kit. Now, we adapted the stock brake pedal mechanism & push rod to the master cylinder, adjusted all 4 star wheels up to a good amt of drag. We also gravity bled for an hour a couple times, Vacuum bled a couple times & old fashioned pump the pedal method over & over. We get good solid squirts of fluid out of all four wheels & no air that we can tell, but there is still no pedal. It never feels like it builds pressure. So I'm thinking about pedal ratios & master cylinders, like the push rod isn't pushing in far enough. Is this what it would be like if that were the case & is there anything I might be missing here?!?!

Thanks
BYC

 

Residual pressure valves? You didn't mention them.
1/2 the time they leave them out of aftermarket or rebuilt master cyls.

 

hhhmmm???? never ran into that before but could be I quess...

 

Get some 2lb. valves and put them in the lines to the front and rear from the master cylinder. 10lb valves for disks. (Did I get that right guys?)
Without them the brakes won't pump up. The fluid just goes right back into the master cyl when you let off the pedal.
They are directional.

 

Post deleted by Barn Yard Chevy

 

thats 10 pounders on the drums(m***ive springs and all),2 pounders on the discs.

 

The proportioning valve should take care of the residual pressure. But if it isn't adjustable then you could have a problem.
Wilwood makes disc brakes not drumbs. I don't recall the proper numbers and I'd have to look it up but you need to keep more residual pressure on a drumb than a disc. So if your set up for discs (getting parts from a company that makes disc brakes) than that very well could be your problem.
Unless of course I'm completely mistaken in which case disreguard everything I just said.

 

I 'm following you beanr. The proportiong valve is an adjustable wilwood we have on the rear brake line to adjust front/rear bias later, But I think the master cylinder might be the problem now (As in not for a 4 wheel drum brake setup)

BYC...

 

Thanks Stealth, I never can remember that one.

Not sure what car this is for, but you can still get a 67 mustang master cyl for all drums at your local parts place. That's one a lot of guys use. I used that one on my Deuce and it worked great. It gives you the dual cyl and bolts up the same as the old fruit jar single cyl 65 mustang. That was for 48 Ford/Buick fronts and 9" ford rears.

 

So....what is your pedal ratio ?

 

You shouldn't need a prop valve for drum drum do ya?

 

That would depend on tire size, contact patch, car rake, Brake sizes front and rear, and other factors. You want the rears to start helping before the fronts lock up but not skid the *** end around. You may or may not need one. Depends on the combination.

My chevelle has drums on all 4 and the braking goes to **** if I jack the rear end too high changing the rake of the car with my HiJackers. The fronts lock up sooner and the rears brake lose when the weight transfers so the *** end starts wanting to come around. With the rear lowered you can panic stop without touching the steering wheel. No other changes than the amount of air in the rear shocks.

 

I had this trouble on the Stude before I subframed it. I ended up finding pedal adjustment for the push rod going into the master cylinder. When I found that, I cranked it up a LOT, then the car couldn't even move, backed it off a bit and worked great. I don't know how you Lincoln is set up, but something to look for anyways.

 

You don't use residual valves with hanging pedals. That's what the Lincoln has right?

 

to late now but what would have worked fine is if you would have gotten a pedal/booster ***embly out of a fox body ford late 70s early 80s mustangs etc. and got the dual chamber master out of the 60s mustang mounted it,and ran the lines directly to the wheels in the normal mannor with out any of that fancy stuff, it probably wouldev worked fine, the residual valves are usualy only needed if the master cyl is below the level of the wcyls.

 

when u change your master cyl. or booster you have to reajust your push rod from the petal to the cyl. push it down and listen till the rood hits the master cyl .its a easy ajust a bolt on a bolt .make sure there is no play between them or u will have no petal. and make sure u dont over ajust it .i usually leave about a 16th of play between the two

 

Hmmmmmmmm. lots of experts but nobody talks about the proper mix o bore sizes.............

 

Tman.....Exactly ! Quite a few elaborate answers but they totally ignore the basics.

 

Root,
Probably don't need one but when you lower one you can adjust the bias so that you have more brakes in the back.
The theory goes that a vehicle with a lower center of gravity doesn't lien as much on the front wheels so you can make better use of the rears without locking them up.
Given that most of the rides we would be caught in (aside from the g***er bunch) we could all make use of different proportioning without going to a major brake upgrade (four pistons caliper or outragiuosly large rotors?)and end up with better brakes.
Probably not needed but...
I have never used a wilwood setup (too cheap i guess ) but if I recall I think that they have check valves built in. Just thought I'd throw that in.
as far as cylinder size I guess the ***umption would be that the later master (upgrade to speedway power unit?) would have a larger piston than the original. That should (once again in theory) give you more pedal not less. Right?
so that brings us back to the balance bar on the brake pedal setup.
Of course all this brings us back to the fact that the brake system is comprised of pieces that aren't necessarily matched to one another. That brings us back to the use of a proportionaing valve as a possible way to adjust for the differences, or not.
Now all that said, back to the theory on the lowered stance and the vehicle liening on its front wheels. If said vehicle has much rake (already liening toward the front or back) then you go right back to the problem of a major weight shift toward the front wheels (when the brakes are applied). In which case you would want less brake in the back so as to keep the back wheels from locking up.
That should muddy up the waters a little
The ol' man always said if ya can't dazzle 'em with brilliance then baffel 'em with bul.....t.
Once again if I'm not right then totally disreguard everything I just said.

 

When you say no pedal..that means the pedal goes to the floor to me. The pedal ratio or the w/cyl size will have no effect on that. You may not get adequate stopping power but you will get a pedal. ***uming you don't have 3" of toe play that the others have mentioned.

No pedal means... air in the system, lack of adjustment or the m/cyl seals are leaking internally. (fluid byp***ing the seals)

Vise grips or brake hose clamps can locate the problem. Lightly pinch off the 3 rubber hoses. Still no pedal? it's probably in the m/cyl. Make some plugs for the lines out of s**** tubing. Still no pedal? replace the m/cyl.

M/cyl check out ok? open each clamp 1 at a time and test. When you lose the pedal...bingo. That is where the problem is.

4 wheel drum brakes can have a ***ulative affect with the adjustment. A little bit off in the front. A liitle bit in the rear and you get a low pedal.

 

Thanks for all the good input here guys, Got a couple Ideas of things to check again! Nothin like another set of eyes & a fresh mind to get things in prospective. Tommy, your exactly right about testing the master cylinder by plugging it off. I've been suspecting that the cups aren't sealing, so I'm gonna use your test.
I also agree Phat Rat that residuals usually aren't used unless the master cylinder is low, (it is a hanging pedal setup) but I just wanted to be sure.
Also Speedy I'm going to check my pushrod depth. Hearing your explination of adjusting makes perfect scense to me & I never did do it to that extent.

Thanks guys I'll let you know
Viva La HAMB!
BYC

 

I was reading this old tread 'cause I have a similar problem on my 31 coupe. Everything is new ( residual valves installed) but I had no pedal if not pumped continuously. Then reading this tread I have tryed to adjust master cylinder pushrod. But I am not able to find the right measure: too much wheels don't move easy, too less no pedal.

 

With the pedal fully released, you only want about a 1/16th" (.060" or 1 1/2 mm) push rod clearance with a manual non-powered master cylinder.
With a vacuum-boosted system, the normal booster push rod to master clearance is .030"-.040", or about 1 mm., checked with full vacuum (engine running).

 

@lb for disc 10 lb drum.

 

When i built my electric circuit, a positive cable accidentally has hit the brake line and burned the flex line. I bleeded with new oil all the circuit and installed a new line but from then it did not work right; Is it possible the it damaged the residual valve too?

 

I had a problem with a Speedway MC,and got a new one from NAPA think it was 79 Mustang with disk brakes.I now have brakes.

 

If the flex line got hot enough to burn, it's possible other brake system components could be damaged, including residuals and master/wheel cylinder cups.

 

I'll check residuals; MC is new and WCs do not leak... Thanks