Rear end... Disc or Drum?

[FINE'49]

With the body work done and in primer, I've started accumulating drivetrain and suspension components. I will be using a weld in Mustang II type front end with dropped spindles/disc brakes/rack. Now, shopping for a rear end. My local "pick your part" has a good selection of S10's, Blazers, Bravada's. A couple have disc brake rear ends. I know a lot of guys use entire S10 frames under their trucks, so I'm guessing the axle width will work great, mated to my original frame. I'm curious which the majority of you would choose, the drum or disc axle? (Cost is the same for either)
Also..... I'll be using a 350/700R4, any issues with the durability of these rear ends behind this combo? I'm planning on bagging the truck and think I will remove all leaves except the main one, letting the truck drop as low as I can. Anyone done this, or is there a reason why it shouldn't be done?
Thanks for all suggestions!

[Rickysnickers]

If you have a choice, I would go with a disc brake rearend. That's just my personal opinion/preference.

[iowaboynca]

What's the bolt pattern on the MII front end?

If its a chevy pattern go for 4x4 blazer rear end. If its the ford, go find an 8.8 out of a mid 90's explorer.

[andrewmp6]

Running bags on a mono leaf is a bad idea it will destroy the leafs over time.If you want to bag it go 4 link or even a 3 link with a upper wishbone will do.As far as disc or drums thats more of a personal thing.I rather have rear drums then disc,The drums will last a lot longer and cheaper to replace later on.Rear disc are good if you tow or want to road race.

[1project2many]

The park brake on the S10 disc rear is tiny. Not much holding power. Drums with brake set are better when loading / unloading my car trailer and weight comes off rear of vehicle.

Do you need park brake in your area? GM rear disc park brake systems with internal shoes get rusty if not used. If you go disc you might look for calipers with built in park brake... mid '80s Cadillac vehicles used them. So did 1980 Formula Firebird. Look for 8.5" GM rear if possible. It's slightly stronger and can be found on ZR2 and some non-ZR2 4X4 models.

Drum parts are super simple and often last for years. There aren't many reasonably priced options to put larger discs on the S10 rear but you can switch to larger drums from a mid '70s Malibu wagon (11" vs S10 stock 9.5") fairly inexpensively. Most of the parts are available new or in good used condition for fairly cheap $$.

[agnes the dog]

I went with a disc brake rear this spring and I'm really happy. I got a rear out of a 2000 Blazer, 3.73 posi. I put new rotors, pads, and parking brake assemblies. I had to run 2" spacers for now on my '59. I'm planning to go with wider wheels and put some fender wells in the bed soon so the spacers are only temporary. Should be a pretty good width for an AD truck. I like the discs a lot, nothing to adjust and they provide great stopping power reliably. Before I got rid of them, the drums stopped good too, but I never really got them adjusted quite right.

[mr48chev]

All I a going to say is that a lot of those cars that like to whip into the lane in front of you coming up to a stop run 4 wheel disk brakes and having the extra stopping power trumps some of the hassle with the park brake setup. The more room we try to give ourselves running drum brakes the more idiots there are that firmly believe that we left room for them to pull in with their BMW or Audi.

[Speedbumpauto]

To add to above caveat(s). I've had poor experiences with kits using the GM calipers with "built in" parking brake, to the point where I will NEVER use one again. I'll gladly pay more for the drum park brake. AND disc brakes don't ever need to be adjusted! I have big drums on my 55 rear for the purpose of holding at the starting line when leaving off the foot brake. The servo action of that brake system is actually superior in that application. The plan started many years ago when I was thinking about "drag week". That plan died many years and dollars ago, about the time "street" cars started going in the 8"s. Will change to disc in the somewhat near future. Just sayin'.

[joedoh]

most of your stopping power comes from the front brakes. if you are upgrading brakes for the purpose of stopping, even a very small upgrade to the front brakes will have more benefit than changing from drums to disc in the rear. I would wager that you could disconnect the rear brakes entirely and in 99% of all driving, no one would even notice.

disc brakes have better heat dissipation for brake fade than most drums, but drum brakes are inexpensive and work tremendously well.

that said, if they are the same price, fire up the discs.

[Keith Seymore]

Originally Posted by joedoh

most of your stopping power comes from the front brakes. if you are upgrading brakes for the purpose of stopping, even a very small upgrade to the front brakes will have more benefit than changing from drums to disc in the rear. I would wager that you could disconnect the rear brakes entirely and in 99% of all driving, no one would even notice. *

disc brakes have better heat dissipation for brake fade than most drums, but drum brakes are inexpensive and work tremendously well.

This is absolutely correct.

We usually release rear drums for the most cost optimized solution. Then one of the competitiors will come out with a rear disc setup so we succumb to market pressure and release one, too. Then when no one is looking we go back to drums.

Additionally - the drum brakes normally have extra capacity that is not being used due to the pressure split in the proportioning valve. One quick solution to bumping up the performance of the rear brakes would be to pump up the pressure going to the rear.

K

*also - I have done this. The M/L Astro/Safari vans were designed on the heels of the X car fiasco (remember that - too much rear braking on the Citation?). As a result the M/L vans were very front biased.

We did a noise/vibration ride where we were swapping rear axles frequently and then allowing upper management to evaluate the changes. We didn't hook up the rear brakes during those iterations and not one person noticed.

[1project2many]

I've had poor experiences with kits using the GM calipers with "built in" parking brake, to the point where I will NEVER use one again. I'll gladly pay more for the drum park brake.

That's too bad. Was it poor kit design, or because the calipers had troubles? We see a lot of trouble out here with aluminum calipers and steel hardware. Corrosion can be a nightmare for that combination. The old Caddy / F-car parts are cast steel and can last much longer ime.

it's a good idea to make sure the braking is balanced to the vehicle weight distribution. Brakes that seem to behave well in mild stops should not become unpredictable in an emergency situation.

[Speedbumpauto]

Mostly street rod applications and most are auto trans vehicles where the brake doesn't get used a lot, and I guess that can affect adjustment? In conjunction with the Lokar brake handle, I can never seem to get the adjustment up tight enough where the parking brake is effective and it never seems the rear pads are up tight enough to the rotor where the rear brakes are as effective as they should be. Thought it was me for a while(and it could be) but I'm done.

[dsraven]

if you go with a rear disc set up, try to get the master cylinder as well. you will need a master that is for disc/disc or disc/drum, whatever you decide. personally, I would have no issues with the s10 rear discs. i nearly went with one for my 57 but it was too narrow and I am not a fan of wheel spacers. I ended up with a ford 8.8 from an explorer. discs as well and they are supposed to be really tough. they have an offset centre section though. that could be good for you if you went that route and then just plan on shortening one side to fit your narrower width, you could then just use 2 of the shorter axles. the s10 zr2 package has a wider stance so that rear end is actually wider again, if you are at the wrecker and find one remember to keep that in mind.

[FINE'49]

Thanks to all of you! I believe it will be the DISC brake rear for me. The one comment discouraging me from using a single leaf with bags has me nervous!
I've never installed a 4 link from scratch, Is there a kit out there that you've used and like?

[Rickysnickers]

I have no experience with this particular kit, but Heidt's makes nice stuff. Here's just an example of what's available, http://www.summitracing.com/parts/hd...FciIfgod8AkI6w

[1project2many]

(remember that - too much rear braking on the Citation?).

Yes... all to well. Along with the Citation issues we got front brake noise / vibration and rear brake lockup in the Celebrity to work on and both issues were followed by Corsica / Beretta brakes that had a pile of issues.

We did a noise/vibration ride where we were swapping rear axles frequently and then allowing upper management to evaluate the changes. We didn't hook up the rear brakes during those iterations and not one person noticed.

I suppose that illustrates just how difficult it is for an untrained person to properly evaluate brake performance. "It stops when I pres the pedal" is not enough to decide whether or not system is well designed.

[Cape Codder]

The advantage of discs over drums is the fact that they cool faster so you don't get brake fade on repeated stops. Unless you are driving down mountains or racing they really have no advantage. Now for every day use I feel drums are a much better choice for all the park brake issues listed already. I am an old timer that has had many cars and trucks with all drums, they still locked the wheels when you hit em hard. I like the disc brakes up front as they stop straight all the time. My last truck was disc front drum rears and when I hit the brakes I could lock all 4 wheels,tires are then the deciding factors for stopping. Present truck has abs so not an issue.