Modern brakes on p15 rearend

[Young Ed]

Somewhere either here or on the 39-47 truck yahoo group I saw a post where someone had adapted more modern drum brakes onto the factory rear end in their vehicle. Anyone know where I saw that or how I can duplicate it? Thinking of ways to get the ebrake back if I swap to a T5 in my next truck project.

[Don Coatney]

Ed;

I recall reading that here and it was not that long ago.

[Young Ed]

Here is what I was talking about. After Don confirmed he saw it here I went looking. Oddly enough the thread was in the parts for sale section. Now my only question after re-reading it is what actual mods were required to the backing plate to use the factory drum.

http://www430.pair.com/p15d24/mopar_forum/showthread.php?t=7811&highlight=mustang+brakes

[Don Coatney]

Ed;

PM the poster. He has 37 posts here so he is probably still around.

[Young Ed]

Already sent. I asked him to read and reply to this thread so everyone will benefit. Should be good info to be shared.

[Norm's Coupe]

I made backing plates from a '65 mustang work on the factory rear axel. Using all mustang shoes, wheel cylinders and hardware etc. Gave me a parking brake as well but had to modify the drum and backing plate so they didn't rub.

Ed, I think if I was going to go through all this work, I'd just put the rear disc brake kit on.

Looks like he drilled a hole in the bottom of the backing plate for the spring to go through to control the ebrake. Also looks like he removed the shoe adjusting parts, then installed the mustang self adjusting springs to replace the old adjusting bolts. He probably also cut a slot for the self adjusting star on that adjuster at the bottom of the backing plate. Changed the location of the return springs and also installed a locking pin with horseshoe clip at the top of the front shoe. He probably also needed to modify the mounting for the Mustang cylinder also. Said he had to modify the drum so it wouldn't rub. In the first picture it looks like all he did there was grind the outside of the drum edge down a little.

Or, he simply installed all or part of the Mustang backing plate over the original Mopar plate. If you had all those parts you could probably figure it out if he doesn't respond.

Thats a lot of work when you consider the rear disc brake setup is just a bolt on. Plus, you'd have much better braking with the rear disc over drums. Not only that but it will be much easier to find disc pads and rotors than it is to find old drum brake parts.

[Young Ed]

Norm thats a mustang backing plate. Looks like all he did to it was weld the holes shut and drill 5 new ones. I'm sure those brakes are quite easy to find parts for. That system looks identical to whats on my dakota. And I'm sure its lots cheaper then that disk brake kit.

[Norm's Coupe]

Ed,

Did you measure the Dakota backing plates? I'd be willing to bet if you checked out other model vehicles rear brake systems you could probably do the same with one of those. Just a matter of finding the right size to fit. Just look at all the different homemade and new kits out there for the front disc brakes.

That said, if I was going to change the rear brakes I'd still go with the disc setup. May cost a little more but it would save me all that time and headache hunting down, then modifying the right parts to do a drum system swap. By the time I finished hunting down the right parts and modifying them for the drum swap system, I could buy the disc setup and have it on. That's why I opted to buy the complete disc setup from ECI instead of hunting for the hoses, rotors, etc at an auto parts store. Ed Gross did his disc brakes probably a lot cheaper too, but he had to scrounge up all the parts from salvage yards and the auto parts store, then modify them to make it work.

Thats just my opinion on changing brake systems. I know not all will agree with that.

[Young Ed]

Norm I totally agree the disks would be easier. Sadly I've got more time then money which is why I'm investigating the other option. Now the easier option and one I still may go with is just to swap the entire rear end. Just looking at different options.

[Norm's Coupe]

Now, changing the rearend is a different story. There you would not only get modern drum brakes but would also pick up better highway speed. Plus, like you said thats an easier way to go too. So.........you get two for the price of one.

As for the time and money issue, I use to say the same thing. However, some years ago I changed that thinking. Here's my take on that subject.

When you are at work you are either earning a straight salary of X amount of dollars, or you get paid X number of dollars per hour. If straight salary you divide that straight salary by the number of hours you work to see how much you get per hour. What does that have to do with anything when you are on vacation or just a weekend or day off? A lot. Usually, your time off is more valuable than when you are at work because you have less time off. So.........if you just go with that hourly pay for work, that's what it cost you to do anything on your time off. So.........if you can do something easier and faster, you make more money on your time off. Maybe not in cash that you actually see, but in the other things you can get done on your time off.

It's the same when working on your house. Recently we had a contractor come in and redo our bathroom. Before that I figured out that I could do the job with my sons help for about 1/3rd the cost. However, to do all the plumbing, replace the tub and wall it would have taken us at least a week or two on our time off. That also meant the house and bathroom would have been a mess all that time, and not usable most of that time. So.........it was cheaper and easier to have the contractor do it because he did it in about a day and a half. And, during that time we had no mess and could keep using the bathroom overnight. That also freed both my son and I's free time for something else.

Same thing applies to the cars as far as I'm concerned.

[Young Ed]

Time is valuable for sure. But I still only make so much an hour and owning a home by myself doesn't leave much to play with cars. Except for 2 bonus months I get 2 paychecks a month. The one covers my house payment with about $20 bucks left. So that leaves 1 check a month to cover many things. So doing it myself basically pays me to have actual paper money for stuff I really need to buy. I've had my house about 6 years now and have yet to hire a pro for anything. While there its gotten new front steps, all but 1 window replaced, new drains and faucet in the kitchen, and both garden hose faucets changed to frostless. Now if I had hired pro's for all that work I probably wouldn't own my 48 right now. Only one of those I wouldnt do again is the steps. Concrete work is brutal!

[Norm's Coupe]

Concrete work is brutal!

You said a mouth full with that statement. I use to do everything myself too. Even gutted the kitchen when I first bought the house back in 1973. From 1973 to sometime in the mid 90's I only called a contractor once. That was to take out a 1700 square foot concrete patio that was about 6 inches deep, all wire and steel rod reinforced. No way I was going to tackle that job and I was young enough to try then too (late 30's at the time). I did spread the dirt and sod the area, then build a much smaller deck in it's place though. I still do little jobs myself now, but not the big stuff, especially plumbing. I've always hated that. We just have to know where to draw the line in the sand, like concrete work. The only plumbing I'll do now is plunge a drain or change a faucet. If a drain needs snaked, I call the plumber.

As you get older you'll probably do more contracting too. Seems like the older you get the faster the time flies, so there's less of it. As for the money to pay the contractor. Well.........We can't take it with us in the end anyway.

[FMSPEED49]

I wonder if somthing similar could be done to the front brakes, yes, i am aware of the disk set up. no I don't have the disk set up.

But I do know a few people with a lot of parts from mustangs and such.

[greg g]

I believe if you look at most MOPAR axles up untill stuff went metric, you can swap backing plates bolt for bolt, then use the new parts for what ever backing plates you sourced. I would look at B body axles, Jeep cherokee, and Dakota items. I believe the same logic applies to front drums, swaping to more current backing plates and then hardware and drums, except yoou have to account for spindles bearings and seal up front.

[Kustom52Mopar]

Ed let me run through as best I can what I did here for ya.

I took a backing plate from a '65 stang, it's a 9 or 10 inch drum(escapes me at the moment, but same width as the stock either way). Ford used that size on many cars in the 60's and early 70's on the 8 and 9 inch axles. The shoes are 2" wide same as the originals. I actually had to drill the axle housing to match the backing plate and also had to cut the center section from the stock backing plate to retain the axle seal. I found it may not be the most practical solution but it has worked well for me thus far after 5,000 plus miles. The parking brake doesn't work for me right now only cause the cable attatched to the handle in the cab is frozen but pulling on the cables it does engage. If i think of any more I chime in or if you have any Q's let me know.

[Niel Hoback]

One more thing, it looks like you ground off the ring around the edge of the drum to allow it to fit into the groove in the backing plate. Is this what you did? Are the drum inner edges aligned with the edges of the shoes, or are the shoe edges inside the drum edges?

My concern is that the drums are not adjustable laterally on the axles, but the backing plate with shoes mounted could be shimmed out to get the shoes farther into the drum. That is, if they are not too far in already.

Did you use the center of the old backing plates between the axle housing and the new backing plate? Did that cause the interference between the drum edge and the new backing plate?

Sorry for the interrogation, but this looks like s realy good project for me.

Your help is very much appreciated.

[Kustom52Mopar]

Neil, Yes I did take some out of the drum ring and "massaged" the backing plate a lil. Didn't want to do too much fearing warping and screwing it all up. I didn't do too much as far as aligning goes cause the 2' shoes didn't rub and they are the same width as the originals. So I guess its hokey but figured its close enough but did do lots and lots of measuring to find where the shoes would sit. But ya the backing plate as a whole is adjustable with shims. To center the new backing plate, well I'm not the most precise or mathmatically gifted person. The opening was just a hair diff but one of the wholes did line up nearly perfectly and used it as a guide and measured and measured and measured 10 more times to get it as center as humanly possible. One side I think is just a hair off, seems to drag a lil but no affect on braking at all. As far as the axle seal goes, I put it on top of the new plate, on the old the axle seal was a seperate plate spot welded on it. So I drilled em out and used a bit of silicone, to ensure it wouldn't leak, and put on there with new seals of course.

But I just pulled my rear end out last Sunday cause I'm starting my T-5 swap. If you're down this way you can have my old one. If there is anything else I missed let me know.

[Kustom52Mopar]

One more thing, if you do this make sure you get the parking brake bar that goes between the shoes. They don't make that anymore but everything else you can still buy.

[Norm's Coupe]

I wonder if somthing similar could be done to the front brakes, yes, i am aware of the disk set up. no I don't have the disk set up.

But I do know a few people with a lot of parts from mustangs and such.

This is what I was talking about in one of the other post. You can do a disc brake job on the fronts without spending a lot. Ed Gross did his. Check his profile "dndrodshop". If you click on his web site out of the profile, you'll find out how he did it and what parts from other cars. I don't think he did anything with the rear brakes except change over to a more modern rearend. It's worked good for him. He drives his P15 all over, including from Wisconsin to Florida.