The Stovebolt Site Forums The Shop Area Engine Shop changing out rear drums for disc

id like to know is it possible to change the rear brake drums from a ho52/72 4.10 eaton axle to discs? without swapping axles? and am i able to mantain an 8 bolt hub. ive read these axles are inter changable with 14 bolt ff axles

I am sure someone has a kit to do it. When I say kit, I really mean weld on calliper bracket. The hard part will be finding a calliper with parking brake wide enough for a 3/4 ton rotor. They are out there, but they are very spendy. One way around the parking brake calliper is to use a pinion mounted brake.

Check out this 14 bolt disc brake caliper bracket. It also
fits Eaton...it is a bolt on. Click here.

Depending on how old your hubs are, you may need to drill them
out for 9/16" studs. (from 1/2")

There are many other kits out there as well. Check out some of the 4x4 forums.

hey ghost i went through your photo album, thats the stage im at with my truck. stripped down to a rolling chassis and soon stripping the chassis for paint.is that por 15 on the frame or what did you paint with? and i have the same rear end i believe mine is an eaton ho52 from what i read pre 72 eatons ho52 also had the ring gear tension bolt on the 3rd member like that found on the 1 ton ho72 after 1972. but you have a nice 52 im working on a 71 c20 cheyenne. the reason i m asking about the rear disc brakes and keeping the 8 bolt hub is i have a set of eagle alloys that are 8 bolt and it would be a shame not to be able to use them on my truck. i will look into some 4xz4 sites

Here is another kit...scroll down for the Eaton.

I did my frame with POR-15 in gloss black. Didn't like the looks of it so I scuffed it and sprayed it with Krylon semi-flat.

My question is why would you want to go to that trouble when only 20% of braking action comes from the rear brakes. Even most modern vehicles are set up disk/drum.

Not true. Most modern cars have 4 wheel disks, exept for the very small economy cars. One exeption is the 1/2 ton Silverdos and Sierras from about mid-'05 up, they do have drums on the back. Most modern cars, though, use a considerably smaller, usually solid cast, rotor on the rear, as most of the braking is on the front. However, a truck is different as they require more braking on the rear, namely whan they are loaded.

I have had disc brakes at both ends of two different trucks, both over 1 ton rating, and the calipers and rotor size was the same front to rear.
Both trucks stop very well, and even with a load have no problems stopping quickly.

On another note, I had a 95 VW Jetta, all disc brakes. Traded it for a 98, and the newer car has drums in the rear, I figure that is a step back wards.

Grigg

If you want to go through the expense and aggravation of putting disks on your rear wheels, go for it. Modern cars use disks all around because they are cheaper to manufacture. As mentioned, the rear brakes do almost no work.

Rear disc brake assemblies are heavier than drums and in snow country are prone to freezing and corrosion from road salt being kicked up from the front wheels.

More....
In today's automotive pantheon, it's not uncommon to find four-wheel disc brakes as standard equipment on medium-priced, non performance-oriented models. The majority of new vehicles, however, continue to utilize a front-disc/rear-drum brake setup. What does this say about the current state of braking systems? Are these manufacturers sacrificing vehicle safety in order to save a few bucks by installing disc brakes on only the front wheels?

While a "yes" answer would certainly be great for increasing Town Hall traffic, the truth is that today's disc/drum setups are completely adequate for the majority of new cars. Remember that both disc and drum brake design has been vastly improved in the last 20 years. In fact, the current rear drum brake systems on today's cars would provide better stopping performance then the front disc setups of the '70s. And today's front disc brakes are truly exceptional in terms of stopping power. Combined with the fact that between 60 and 90 percent of a vehicle's stopping power comes from the front wheels, it's clear that a well-designed, modern drum brake is all that's required for most rear wheel brake duty.

High performance cars like the Viper, 911 and Corvette can justify a four-wheel disc brake system, especially if their owners participate in some form of sanctioned racing activity on the weekends. The rest of us get more of a benefit from the lower cost of drum brakes. Expecting every vehicle built today to come with four-wheel disc brakes would require an across-the-board increase in purchase price, and that could stop new car buyers much quicker than any brake system.

Still more....

The biggest disadvantage of disc brakes is that they are exposed to dirt. Dirt and dust between the rotor and pads can wear the disc quickly. If the rotor is too thin, it cannot dissipate the heat and in extreme situations it can crack; rotors that are worn too much must be replaced.

Front disc brakes sit in relatively clean air, but rear discs are exposed to all the dust and debris thrown up by the front tires. This is why rear disc brakes often wear faster than front disc brakes, even though they are only doing a small percentage of the braking.

Anti-lock brakes work best with disc brakes because they release quickly and smoothly. Changes to shoe design and placement have helped drum brakes release quicker, but discs are still better. For this reason, and for maximum stopping power, you find four-wheel disc brakes on many vehicles.

I personally prefer front discs and rear drums. I still get all the advantages of discs on the front and can stop very well, but rear drum brakes are not exposed to the dust so they wear much slower under many conditions. Less rear brake maintenance leaves more money in my pocket. Just don't ask me to go back to four wheel drum brakes - they were scary!


Jim Kerr is a master automotive mechanic and teaches automotive technology. He has been writing automotive articles for fifteen years for newspapers and magazines in Canada and the United States, and is a member of the Automotive Journalist's Association of Canada (AJAC).

from what iv gathered from all i read replacement parts for 10 bolt eatons ho52/72 are next to non existent and costly. so if im going to up grade an 8 bolt drum system that has a cost as well just to be able to get replacement parts to fix why not make it 4 wheel disc. i own a 03 silverado that has 4 wheel disc and from previous vehicles that i used for towing with drums i like the the performance of the rear discs and i find smoother stopping all around. so if u can direct me in where to find replacement parts for an eaton ho52/72 drum brake assembly point me in that dirction and again it comes down to initial cost rear discs kit $540 and up and as far as rear drums and cylinders im am yet to find.but again it comes down to what i need to do to the existing brakes and availability of replacement parts

hgey ghost how does the por 15 semi look or was it not an option. im going to be brushing it on so i like the fact that it self levels and has a powder coated look finish. so thanks for the info about the gloss finish i think semi with some ss hardware will look just fine. and thanks for the info on the disc brake kits. hopefully by the fall i will be ready for that part of the job. how do u post the web shot site to your replies?

I wanted semi-gloss, but I bought the gloss POR-15 by accident.
One gallon did my frame and my dad's '55 Chevy car frame.

Check the glove box manual for info on linking photos.

BTW...my last three trucks have all had 4 wheel disc brakes.
'00 Chev 2500, '03 GMC HD 1500, '06 Chev HD 2500.

I heard the same thing as oldblu49 and in fact I understand that there is a trend in the new trucks going back to drums on the rear. I guess with a 3/4 or 1 Ton AD, there would be the problem of the parking brake.

Seems most all the new "medium duty" trucks that still have hydraulic brakes have four wheel disc brakes. Don't see many hydraulic drums on big trucks any more, just air drums.
Even air disc brakes are starting to show up on semi trucks and trailers, and are quite popular in Europe already.

I'll stick with the disc brakes at all four corners, I have had no problems like those mentioned by olblu49. Many of his arguments I don't fully follow or agree with, for one, a loaded truck will use a significant amount of the rear brakes. Yes, for a car the fronts do most of the work, but it's somewhat more equal with a loaded truck, and thus disc can be a good idea in a truck.

Grigg

Right now, the only full size truck with rear drums are the 1/2 ton GMs, everybody else is using 4 wheel disks, usually grossly oversized (Dodge and Toyota) and strangly enough, not as effective.