Disc Rear Drum Front

I know it is reversed; but I have a set of 55 Ford, F100 brakes (fresh cut drums, all new hardware and shoes) on same year dropped I beam axle. I then have a 65 T-Bird rear (one of the early 9 inch Fords), which had all frozen drums and hardware; so for three bills, I bought weld-on brackets, metric GM calipers, and Lincoln rims steel 15" to squeeze the Gm calipers under.

My plan is to runthe lines this holiday break. Suggestions? I was thinking 2psi adjustable proportioning valve to the rear calipers and then 10 psi fixed valve to the front drums? Have a GM master, new't know the rear, think it is a rebuilt for a 69 Camaro.

Comments, ideas, experiences, no-nos! Help! Please!
The Pork

 

Oh, also, if I have banjo fittings in the rear on the calipers; when I go to split from the junction block in the center of the pumpkin, how do I hard line to the banjos on the calipers?
Pork

 

Uh What?

good luck with this, most masters are either drum drum, drum disc , or disc disc, and are set up reservoir and piston wise to work this way. Your back wards setup will probably cause some issues .....

 

That's crazy talk... Your fronts need the most breaking power and reversing that could be problematic. I have never heard of anyone doing that...

 

you should be able to recoup some of your $$ that you have in your rebuilt ft drum setup by selling it & put it towards a ft disc kit....like they said most of your braking is up front, ....
I know some racecars have rear only, but if it was a dragster it would have a parachute

 

Probably have some flatspots on those rear tires if you do this.Find some more money and do it right,you do want to be able to stop.

 

What he said....

 

drive around in reverse

 

Comments, ideas, experiences, no-nos! Help! Please!
The Pork[/QUOTE]


Without being derogatory, you don't have a clue on how to build a proper brake system, or how it and certain components work. Some basic vehicle brake ABCs would be mandatory! What production vehicle made so far has anything close to what you think will work??? 2 PSI adjustable prop valve???
This post was a joke, right?

 

I thought I was the only one who had his issue solved!


You are going to kill yourself kid!

 

i have a friend wt a 32 roadster wt disc rear drum front for 25 years ,,not a problem

 

I keep thinking about the characteristics of bicycle coaster brakes, when I imagine that set up. Slam on the brakes, and the rear wants to come around on ya! I've never been around that set up and it seems kinda compromising. Compromise an me don't get along.

 

Are you kidding? That's the response! The factory didn't do it! That's genius! I know for a fact, there is a guy who has this set-up running on the road. In fact, I saw it this summer at the Cruzin-Ride. The guy doing it has a 31 with Ford/Lincoln Factory discs on the rear and Chevy drums off of a 46-48 axle up front? I spoke with the guy, but he was an **** with an at***ude; he did say it was a daily driver - rain permiting.

The sad thing is the guy was a complete tool and I didn't want to ask anymore questions about valves and what not because he was a braggin' know-it-all. I guess I have more of that here. "They didn't do it from the factory that way." Man, that's not only sissy talk, that's just plain non-hotrodder talk. As for driving it backwards- now that's a good one. I chucked out-loud when I read that one.

The Pork
HaAppy Holidays

 

As with most situations like this, there's always someone who can dig up a contratictory example. But what do we know of this friends 25 years no problem? That's up for interpretation.

 

As most have said, the balance is going to be off, front to rear. You cant do much to increase the front, so you're going to have to reduce the rear.
Overall this will hurt the total....
However, you can put in an adjustable proportioning valve in the line going to the rear, to take away some of the line pressure.If this isnt enough, cut come of the brake material off the pads, leave the metal part alone.
Make sure you hook up the master cylinder the way it was intended, one side for disc, one for drums.
I think speedway sells banjo fittings to inverted flare. I've seen them somewhere.
Do your testing in an empty parking lot, that way if the *** end tries to p*** the front you can gather it back up without hitting anything.
It may be possible to find bigger wheel cylinders for the front drums, but I cant help you with part numbers....find a good parts guy and do some digging.
Good luck

 

I think part of the problem would be that drums are self-energizing and discs aren't. The primary shoe contacts the drum and jams the secondary with a good amount of mechanical advantage. None of that on discs.
Maybe this would work if you used brake valves to correct the discrepancy, but I honestly think you'd be spending time and money crutching the system when you could build a kick*** brake setup for little more. Just my opinion.

 

In a panic stop you are going to snap the back around the front before you know what you hit.
I would defiantly not do it.

 

I think it could be done successfully, but would require a working knowledge of, at the minimum, hydraulic system principles and brakes systems in general. Armed with that, you might be able to figure out the necessary combination of parts to keep rear brake (discs) at a low enough clamping pressure to avoid the rear brakes locking up.

But it seems time and money would be better spent by either fitting the rear axle with drum brakes, which it aparently had, or putting generous sized discs on the front. the 2# and 10# valves you refer to are Residual Pressure Valves.....not proportioning valves. They do two totally different functions.

You are correct in that just because it wasn't offered by the "factory" doesn't mean it can't be done. However.......stop and consider WHY it was never done from the factory. Their is a clue in that fact.

Ray

 

You couldn't rebuild drum brakes for under $300?? I can find a 9" complete on craigslist right now for half.
http://kansascity.craigslist.org/pts/2096254669.html

 

Think what will happen in a panic stop.

 

zerk and Hnstray are right you will need and adjustable proportioning valve iy's trial and error you will have to take away braking power from the rear how much depends on rear weight tires and how much anti dive built-into the frt suspension

 

i was going to do the same,yes it can be done and yes it will work.
you need a adjustable prop valve to dial in the pressure to take away some of the rear pressure. but then you back to 4 wheel drum stoping power..and that why im buying a disc kit for my front to match the rear.
if you give the rear too much brake it will work,there are some street/strip cats with only rear brakes..but they are light cars that will not see rain or traffic,still not the best way to go at all.

 

Chevynut55, I hear you. I know it can be done also, as I have seen it. You guys have to realize that the front brakes originally stopped about 3200 pounds of iron. My car with all fluids won't run over 1800 pounds. At half the weight and with all new components I don't see an issue. Too be honest I was asking for the set up, I was really asking for psi pressure difference between drums and discs. I am under the impression that the 10 pounder goes to the drums and the 2 pounder to the discs. With an adjustable valve to the rear, I think I should be able to dial it all in. As far as the self energizing, I understand that, and I am pretty sure you can pull the grommet from the master in the second reservoir to get rid of the self energizing. I gotta’ hit the books. I was hoping that I would get it all from here, but I will dig around. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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I dont see much of an issue with what type of braking system is used, as long as a proportioning valve is utilized to keep the braking effort in check.

The only issue would be with repeated, constant use, brake fade would affect the front drums more than the rear disks-this could cause the car to swap ends if a panic stop happens after the brakes are already very hot. (the drums fade, and a panic stop locks the rear discs, which cause them to p*** the drums which are still slowing the front a bit)

HOWEVER; it's not a track car. dont drive like a ***** and heat up the brakes to the point of fading (shouldn't want to fade too much in a lightweight vehicle).

 

I don't think you do understand the Self Energizing - it has nothing to do with the master cylinder. It has to do with a rotating motion in the brake causing the shoes to apply more pressure due to a rocker system designed into the pivots.
I strongly recommend that you buy and read this book

 

Without being derogatory, you don't have a clue on how to build a proper brake system, or how it and certain components work. Some basic vehicle brake ABCs would be mandatory! What production vehicle made so far has anything close to what you think will work??? 2 PSI adjustable prop valve???
This post was a joke, right? [/QUOTE]

Yeah, Hot Rod Bob,
I can see that you really went outside the box with that orig**** ride of yours. I have never seen a red-rimmed, primered black, roadster hot rod with a flathead in it. Whoooohoo.

Pork

 

HOWEVER; it's not a track car. dont drive like a ***** and heat up the brakes to the point of fading (shouldn't want to fade too much in a lightweight vehicle).[/QUOTE]

Thanx 69 Fury. I have to really research the pressure and even the factory GM proportioning blocks to see what they have to offer. But all this conversation is at least getting me closer to some answers. Keep commenting; it is working, bit by bit, little by little. Oh, Merry Christmas! Also, thanks for the manual\text suggestion. I will stop by Borders after school one day and see what is available. I did find a very detailed article from a stockcar builder, and he was recomending a leveling bar with a split master. I agree with one of the past posts also, that I will probably end up killing so much of the back brakes that it will have the same stopping power of a drumed rear. Still , under 1800 pounds shouldn't take that much to stop. It will be a lot of trial and error that's for sure. Biiiig Arrrse parking lot and factory by my uncle's shop where I can get some safe p***es.

Porkchop

 

Yeah, Hot Rod Bob,
I can see that you really went outside the box with that orig**** ride of yours. I have never seen a red-rimmed, primered black, roadster hot rod with a flathead in it. Whoooohoo.

Pork[/QUOTE]

...And a Merry Christmas to you, Pork

 

You too; seriously though, Happy Holidays!
The Pork

 

If adjusted correctly - it will stop the Car?