Ok. I need a second opinion or advice..whichever. I just got my engine/tranny that will eventually go in my truck. I managed to get these before money got tight again. It will pass...lol...but for now I'd like to throw an idea out. I got a 90 mustang 5.0L fuelie and AOD transmission. They are going to sit. Meanwhile the 3 speed and factory 4.27 rear gear isn't fun on the freeway. I also got an explorer rear with discs, ebrake cables and sway bar intact. Has 3.55 gears. My concerns.....1) putting a disc rear in with all other brake parts unchanged (factory). 2) what other expenses involved in the install those of you that have done this swap. 3) anything I'm forgetting?
I think this will make the truck more drivable for now and will work great with the future drivetrain. I just have to spend almost no money putting it in....possible?

 

Disc brakes are not going to work with a stock master cylinder and drums up front.

 

Thanks for the reply. I was looking for some options from some of you guys...suggestions....other than "it wont work"...lol.....I'd like to know why? I read a thread on here where a member put discs up front with the stock drums out back and left everything else the same. Said he'd been driving it that way for a few years now. Seems like hydraulic pressure to the drums or to calipers wouldn't be that different. The rears are the least used anyway. With all the folks that have done explorer rear end swaps surely there are some suggestions floating out there. Waiting patiently......

 

What one person considers acceptable to drive isn't the same as what is "right" or what should be used as a goal for your build.

Disc brakes and drum brakes have very different characteristics, especially with respect to residual pressure maintained when they are released. The stock MC maintains 10 psi in the system to keep the drum system ready to apply. That pressure maintained on a disc system will cause significant drag. The pressure needed for effective braking with a disc system is also higher, so factory disc/drum systems frequently have proportioning valves to limit the pressure to the rear drums, to prevent lock-up on the rear.

You could probably cobble up a system that worked well with front drum/rear disc. It would have to have expensive regulating/proportioning components, and would have to be completely re-done if you later went to discs all around.

 

There's a huge difference between having discs on the front and drums on the back vs. drums on the front and discs on the back. It's all a matter of kinetic energy and stopping power. Stopping power is not evenly distributed to every single wheel. The front wheels always share the bulk of that responsibility. Even if you did have the correct master cylinder with the correct proportioning valves to do such a thing, there's a reason that no factory vehicle comes out with rear discs and front drums. I used to have a buddy in high school who thought it was really cool to pull the park brake (rear brakes) at full speed. It was a hell of a ride. I stayed out of his car.

 

Thanks Ross.....I had another thought. I have a Mustang 8.8 with drums and of course its the wrong width. BUT....I'm doing some research into swapping the drums to the explorer disc rear end and vice versa. Any thoughts on that while I'm digging?

Doc....I know it's totally hookey to try this. I have just hit a "low money spot"...new phrase...and would like to get this 3.55 rear in there to help out. Your opinions on the above I just posted???

 

To answer your original question, there is no alternative rear end you can just drop in there that will not have added expenses for driveshaft mods, brake line mods, etc. If you can find a 48-50 stock 3.73 rear end, that would truly drop in without any changes or $$$.

 

^^^ What he said! It's the only way to keep it completely simple. My truck cruises "tolerably" with its 3.73 on the bigger roads.

 

#1 right off the bat you mention funds are tight so I'll comment with that at a priority

If I had an explorer rear and was about to put it in no matter what..... I would evaluate these cost items
1) will it be cheaper to convert the front to disc as well using a kit
2) will it be cheaper to flee-bay the explorer rear and get a drum rear setup (72 F100 - 9")
3) will it be cheaper to swap the front axle and get disc up front (bronco?)

how badly do you want "a modern brake system"? drums are fine but have some quirks (try going down a rocky mountain pass... can you say heat fade)...

DO NOT go with a drum/disk (drum up front) setup - you'll either have a train wreck or a million dollars tied up. there are no OEM's that do it for a reason (as doc stated).

I think you bought the rear end cause you want modern rear brakes (either that or you have a good set of modern metric rims to match) - you mention driving it on the freeway... so I'll ask you have the old 5 on 5.5 rims now right - obviously those aren't staying if you are going to explorer rear.

if funds are tight, and you want to drive it on the freeway.... I'd stop buying any parts (new or used) and really research what you can afford... some things don't mate together (old SAE rims and metric hubs), some things don't work engineer wise (drum/disc setups). lay it all out for us... what rims do you have/want, what speeds do you want to go (I have drum/drum - designed for 45mph, and I have declared that 65mph with a big cushion of "as many car lengths as I can get" in front of me is max).

and most importantly what is your budget - we can help you hit most all of those... you may have to give on some items though.

 

You can not swap brakes between mustang and explorer 8.8 without changing axle housing ends. The explorer has a late big ford hosing end. So not a cheap conversion!

 

Good responses guys...thanks.
1) The ONLY reason I'm wanting to put the rear end in is for gearing...see "more drivable above"
2) I don't have a specific budget. I just know I can't spend $500 right now. Things change daily/weekly for me in that regards which I know makes it tough.
3) My friend has no problem swapping me an explorer drum rear end for the disc rear end. He has several.
4) My factory engine doesnt like anything above 50-55 mph. Truth be told it really likes 45 mph. Sounds like I'm going to blow something even though it runs just fine and doesn't get hot. So I'd like to be able to ride on the freeway at about 65 mph. No more than that with the stock front end (death trap....KIDDING)!!!
5) Not touching the front axle/suspension for now. I'd like one day to put a FatMan front suspension in there. And even then I don't mind the rear still being drums
6) Yes the explorer has different bolt pattern wheels. I run steel wheels now and want to keep that look so I have located some car wheels that will work with my trim rings and hubcaps......They are stainless and are pretty new.


That's all I can think of right now. So IF i swap for the drum braked explorer rear end....I should keep cost to a minimum huh?

 

explorer even in rear drum will be a metric wheel pattern and the hubs are too small to drill out a 5 on 5.5 pattern. your best bet is to let the explorer rear end go for now, find a 69-72 f100 9" rear end in the right gears - 3.50 is perfect. they are available and should not be a killer price... 57-72 will work, 68 was a unique brake year, 69-72 will get you the best modern brakes you can get (self adjusting, wider shoes, etc).
a ford 9" from one of these donors (57-72) is for all intense purposes a drop in replacement - same spring perches, same tilt, all your got to do is deal with the shock mounts. there are a dozen people posting about the 57-72 f100 9" swap, a whole article written in the old forum.
that's the way to do the rear end on a basic budget - you keep your wheels, you don't have to fab, you don't have to hire a welder, you don't have to drill out hubs or use wheel spacers, etc - like I said, "drop in"

my speed limit before I swapped rear ends was 49mph and it sounded like it was gonna blow up (4.27 gears). now if I had the aerodynamics I could do 75 - problem is aerodynamics... I've seen 70 and change, but don't have the umph to get over 71.

 

Not metric, 5 x 4.5". I'm doing a Explorer rear disc brake swap on my 9" with a 5 x 5.5" bolt pattern.

 

The Explorer also even uses imperial studs!

 

I don't mind being proven wrong, but I had to do some lookin up after 2 people indicated I was off... to the PO - what year explorer rear end do you have?
(a quick lookup shows the older explorers - 2001 and previous do indeed have 5 on 4.5 or 114.3.... haven't found the new models, but I would swear they are metric)