S10 blazer rear disc brakes on gm 10 bolt axle?

[qbeanie]

Considering rear disc brakes on my 57 chevy truck. The rear axle is a gm corporate 10 bolt. Has anyone ever installed s10 blazer rear discs on a tri five truck with a gm10 bolt?

[whitedog76]

First off, what is your wheel bolt pattern?

Most early trucks were 6 lug. Then GM went to the 5X5, S10's are 5X4.75.

[qbeanie]

The original rear axle was replaced with '79 gm corporate 10 bolt with limited slip with drum brakes. The bolt pattern is 5x4.75. The s10 disc are reportedly a bolt up modification.

[whitedog76]

I personally have never done it. Only good things can come from getting rid of drums.

Here's an article.

http://www.trucktrend.com/how-to/whe...ke-conversion/

Here's a kit that uses drum style E brakes.

http://www.ebay.com/itm/1970-81-Chev...NT~5QT&vxp=mtr

Here's the E-brake/caliper kit.

http://www.littleshopmfg.com/gm-earl...r-disc-brakes/

[joedoh]

rear discs are a marketing item. there are some small benefits like shedding mud and smalll stones if you take it offroad and of course the heat dissipation benefit in continuous heavy use, but in most (not all) street driving you wouldnt really notice if the rear brakes werent working at all. if you want better braking performance even a very small upgrade to the front brakes will have more net effect on braking distance.

Also, properly sized drums will work as well as discs with lower pedal effort.

now for LOOKS, if you have an open wheel, nothing looks better than some disc brakes.

[mr48chev]

Beg to differ there, having both 4 wheel disk brake rigs and disk/drum rigs in the fleet the same size car with 4 wheel disk stops a lot better n the one with disk/drum primarily straighter when you really have to nail the brakes.

A bit of hunting brings up this article that should answer the original question.
http://www.hotrod.com/articles/ccrp-...kyard-builder/

[joedoh]

Originally Posted by mr48chev

Beg to differ there, having both 4 wheel disk brake rigs and disk/drum rigs in the fleet the same size car with 4 wheel disk stops a lot better n the one with disk/drum primarily straighter when you really have to nail the brakes.

I'll agree to disagree, there is likely no chance it was apple to apple comparison because disc rears upgrades are usually offered on the upscale models with different shocks, springs, wheels and tires, and those were likely the cause of the difference, not the rear discs. especially in a panic stop where 90% or more of the braking is done by the front brakes, weight transfer is forward and drum or disc can lock up with even the smallest portion of brake energy.

[mr48chev]

True, two out of the three of my 4 wheel disk rigs are upscale but I'd rather have 4 wheel disk on my 48 with the proper master cylinder setup so it can stop rather than try to figure out how I am going to pay the above and beyond the insurance coverage I have to fix a new BMW that slams on the brakes in front of me. I always give myself an extra car length or two between me and the rig in front of me but quite often that extra space is the exact space some aggressive driver that is either foot on the gas or foot on the brakes wants to be in for some reason.
Plus those little brake drums and shoes on the back of GM 10 bolt rears never have stopped all that great to begin with when you compare them with other drum brake axles like a nine inch Ford. The Nine inch rear I brought home Saturday has almost twice brake shoe contact area as the 10 bolt under my 48 has.

I'll comment to dissuade guys from doing some things that I don't think are necessary but when it comes to someone wanting to increase the potential safety of his truck I am not going to try to talk him out of it.

[BBPanel]

Originally Posted by qbeanie

Considering rear disc brakes on my 57 chevy truck. The rear axle is a gm corporate 10 bolt. Has anyone ever installed s10 blazer rear discs on a tri five truck with a gm10 bolt?

To answer your question directly - yes, its QED. And I prefer the S10 over the LS1 because of the integral e-brake bracket:

[whitedog76]

I'm going with idea that 4 wheel disks are safer.

There's always the argument that GM, as well as others, are still using drum brakes. Well, most manufacturers do whatever is cost effective on the assembly line, net necessarily what's best.


I can say for sure that the 02 Dodge Ram I had with 4 wheel disks, stopped 100% better than the 82 B250 van or even the 85 Ramcharger I was driving previously.

The argument of a "properly adjusted" drum brake stops just as well. I won't argue that. But, in my own experience, I have yet to ever take apart a drum brake setup that didn't have the adjuster frozen, or a brake spring broken or missing. A disk brake setup uses fewer moving parts and simplifies things.

[joedoh]

Originally Posted by mr48chev

I'll comment to dissuade guys from doing some things that I don't think are necessary but when it comes to someone wanting to increase the potential safety of his truck I am not going to try to talk him out of it.

my comment was actually that any small improvement to the front brakes would make more difference than upgrading the rear to disc. there just isnt enough benefit, supposed or actual, to warrant the cost unless its a "free" upgrade like switching rear ends.

whitedog, you are right, get a drum wet and you will see very quickly why most everything is front disc today. but comparing an 02 to an 82, come on man. you dont think there were ANY other brake advancements incorporated in 20 years?

I brought this up last year, said the same things (marketing, wouldnt notice if the rears were disconnected) and I think a GM truck engineer actually replied and agreed. I will dig it up.

edit: here it is
http://67-72chevytrucks.com/vboard/s...9&postcount=15

[qbeanie]

Thanks to all who provided info. Most of the articles refer to mix match of calipers due to interference with staggered shocks. But on our trucks the shocks are not staggered. So can I assume either the 2wd or 4wd disc will be compatible?

[BBPanel]

There are quite a few threads written about the S10 and LS1 rear brake conversions if you search on auto boards. I don't recall the mix of 2WD and 4WD parts but I think its detailed here (http://nastyz28.com/forum/threads/s1...ersion.109454/ ). I have used backing plates that allow both e-brakes to pull from the front.

[whitedog76]

Joedoh

Point(s) well taken. My reference of 82 vs 02 were from my own personal experience. My folks got the van in question when I was a kid. ALL of my siblings and myself learned to drive in that van. I was the youngest, so my Dad gave it to me after years of family service. Dad was diesel mechanic, so all our stuff was in great mechanical shape.

I do know the size of caliper, rotor, wheels, etc... make a difference also.

The 02 Ram I had was just a basic work truck. No options. Didn't even have ABS. Yes, ABS was an option in 02. Dual resevoir Master, Vaccum booster... Not much different than earlier trucks.

Guess we'll agree to disagree also.

[1project2many]

I'm going with idea that 4 wheel disks are safer.

Please go with the idea that properly sized and set up brakes are safer instead of just switching to disc "just because." Too much brake is as dangerous as too little, especially if it's in the wrong end of the truck or it comes in at the wrong time during a stop.

GM is notorious for opting for "just enough" brakes. Early '80s diesel Mercedes have larger brakes, better balanced and better performing, than those of a mid-90s fourth gen F car. An early '90s 4X4 Toyota compact pickup has a better brake balance and more effective area than the S10 even though both vehicles were rated for similar GVW. The brakes used on S-10s until 98 or so, after GM paid for help building braking systems, was based around a system designed for 2600lb Monte Carlo and Malibu's of the late '70s. A '96 Blazer can weigh between 3,000lbs and 4000lbs yet the brakes weren't any larger than the original S10 version. We would have been better off if GM used brakes from a 1/2 ton pickup or a '90s B body wagon with towing package.

Generally GM uses roughly the same rectangular bolt pattern on the rear axle at the backing plate for many of their light truck and passenger car axles. G body axles used a different flange with an interesting triangle design with the wheel cylinder comprising the upper attaching point and two smaller bolts below axle centerline. I believe the Australian F-car axles also use a different bolt pattern as well. I have seen S-10 disc brakes transferred to F and G car axles with a minimum amount of work. Generally the park brake cables are the biggest challenge after working out the correct parts to align the rotor with the caliper.

I shy away from any of the rear disc setups with park brake shoes. It's a service technician thing. In this part of the country, when it comes time to service the brakes, the park brakes are almost always inoperative, they usually require shoes and hardware to be replaced, and they often can't be "backed off" so the rotors can be removed. I'm sure that most areas do not experience the same additional work and cost considerations as we in the rust belt. But I do tend to keep a list of vehicles with the park brake integral to the caliper.

[1project2many]

I can say for sure that the 02 Dodge Ram I had with 4 wheel disks, stopped 100% better than the 82 B250 van or even the 85 Ramcharger I was driving previously.

There's sooo much involved when relating the brake pedal feel to brake performance. Did you know that when you apply the brakes in a power brake system, you don't actually feel the brakes applying with your foot? What you feel is feedback built into the booster by engineers so you can easily gauge how to match pedal application to applied braking. On forums folks will say over and over that converting from vacuum brakes to hydroboost made the brakes work better. The truth is the brakes don't change much but the pedal feedback is very different. In many cases switching to a larger vacuum booster could have accomplished the same result with less work.

[mr48chev]

I found out on my own rigs that the key to the integrated park brake working is that you have to use them all the time to keep them freed up. I'm as guilty as anyone else when it comes to not setting the park brake when I park.

[qbeanie]

Did you have any wheel clearance issues with the calipers?