I have a 31 ford sedan with a 350/350 and drums all around. The front brakes are from an F1 and the rear is a Dana 44. I’m using a corvette style master cylinder with a booster mounted under the dash with a 90* bracket. I have 10 lb residual valves but I don’t think I need them bc the master is the highest point in the system. Should I leave them out or just put them in bc it wouldn’t hurt and I already have them?
If you had discs the heighth of the M/C would keep fluid in the pucks. With drum brakes the springs will force the fluid out of the wheel cylinders. When you step on the pedal you will have to displace that volumn again. Use the residual valves. If the rear locks up first you might need an adjustable proportioning valve also. Or you can cut a couple of inches off the brake shoes until you have balance.
I always use residual valves in any style system. I feel they help quicken braking action by taking up any slack in the hydraulics.
They aren’t necessary in your application but if everything is working well sometimes it’s better to let sleeping dogs lie.
Residuals were used and needed on all vintage drum brakes up to about the middle '70s when they were replaced with cup expanders. Their purpose is to prevent air from entering past the wheel cylinder cups during fast brake release caused by the strong shoe return springs, regardless of master cylinder location. If you have vintage drums, you should have a residual "check" valve at the end of a stock production single system master bore, or individual valves behind dual drum master tube seats. The use of masters without any internal residuals will perform better with external inline production or aftermarket 10# valves. Modern conventional disc brakes never needed or used residuals because master cylinders were all firewall mounted before discs became regular production in the '60s. The one exception is master cylinder location below disc calipers, where an aftermarket 2# residual will prevent caliper drain back.
Thanks for all of the info!!! - I have a 60's style master, but new, with a booster. - Then 12" or so of line going to a residual for each line. - Then one line (with the larger master port size) goes from the residual to a T and splits between the wheels, which are a drum set up from an F1. - The other line (from the smaller matter port size) goes from the residual to a proportioning valve, which is mounted closer to the rear, then to the wheels, which is a Dana 44. I'm not sure what that originally came from but it has 3:31 gears. - I think the general setup should work, but I won't know 1) if I have the correct bore size for the master and wheel cylinders, 2) the correct size line, and 3) all with the correct pivot ratio. I guess I'll see how well it works when I get it moving, which I'm hoping will be before it gets too cold to work outside where I keep it.
I appreciate the wisdom I find here. This is my first build from scratch so there's a big learning curve
Good fight?! Watching with a bucket of popcorn?!? With drama like this, I feel like I'm listening to my wife while she's watching Desperate Housewives!! I thought this was America, if you don't like what you see/read, instead of complaining...change the channel and don't watch/read!! (how was that? ) Anyway, I don't post much, but I read everything. I like to learn and I like to talk about cars, but my family is sick of listening to me. Any response I can get when I do post is another tidbit of wisdom, another point of view, or a confirmation I'm on the right track. Brakes and steering are two things I'm afraid to get wrong.
... uh ... That's FOOD FIGHT Short eyeballs? Not bad for the average moe-ron. Maybe that is why the wifee watches that crap, hoping you will go away. I get a big kick out of reading H.A.M.Bone BRAKE THEORY (subject to constant change and wild a$$ guessing). If you understood braking, you might get a kick out of it too ... How was that!?! No use being one if you can't act like one, right?
I have never used residual valves my 1932 ford combinations. Original pedals = mastercylinder under floor Brakes are Old 37-> Lincoln bendix or later 1939-> Ford. Works fine !!! A
I guess some will just keep all their knowledge and wisdom to themselves, and not share with anyone, even though they feel they know how to do it properly. They just want to show you their new ball, then take it home without you playing with it. Mercy what an ass.
Let me see if I can figure this one out ... I am not much with anyone wanting to play with 'my ball', except of course ANN-MARGRET. I don't make claim of having 'knowledge and wisdom', but I do know common sense. And THANX! for the complement of my posterior.
Well let’s sum up your replies in this thread. Not in order, but just a summation, shall we? So you posted as if someone who had replied had no clue, but you know how to quote a reply, so no one knows who you are referring to. So then, or abouts, you belittle a thread by a member who is not even in this thread. Nor did you explain the inaccuracy of either. Then the OP of the thread can see where it’s going, try’s to diffuse it, yet you then hammer on him. I think that about sums it up. The lovely thing is in just a few seconds, I’ll never see a pst, reply, etc of yours again. I’ll skip the video I was going to put up, but you’d enjoy it.
Reply directed to no one individual - If you (or the individual I am referring to) cannot figure out why I use that signature, then you have serious comprehension problems. I am not 'belittling'. I am only trying to draw attention to the disinformation posted here. Somebody is going to be seriously injured one day reading this tripe. He (and others like him) are the reason all this disinformation keeps going. A poster comes here seeking TECH help and receives only GOD knows what OLD WIVES. Here is what is most likely going to happen one day - CLICK HERE - I also see you finally found the IGNORE FEATURE here. THANK YOU!
OK, let me try it this way - Below is an excerpt from a well known auto repair/theory website - Now this statement is shared all over the inner-screen. Is it correct information or not? Now, the correct description of a how a caliper piston is applied and retracts - Now I am aware that most will not read but it describes why I use the SIGNATURE I do. I have not seen one poster that has called out his post. In reality, most here will believe it.
Every single piston master cylinder I ever had apart had a check valve to hold pressure in the lines when the brakes weren't applied. On drum brake dual master cylinders there are check valves behind the brass seat for the brake lines in the outlets of the master cylinders. Disk brake master cylinders do not have those check valves. Those check valves in the dual master cylinders tend to work well with firewall mounted master cylinders but my experience says that they are not strong enough for under the floor mounted master cylinders. They work if you drive the vehicle on a regular basis and it never sits more than a couple of days between being driven but my personal experience is that those check valve springs do not have the strength to maintain pressure on the lines for extended periods of times and if you let the vehicle sit for weeks at a time you will have mushy brakes because air has leaked in past the cups in the wheel cylinders.
The Jalopy Journal
