Rear Disk brake conversion

[laserjock]

Thinking up the road, one of the things I am going to really miss by back-dating trucks a decade are the 4 wheel disk brakes. Is there a kit out there to do this on the OBS trucks short of swapping the axle for a newer one? Seems like something worth while.

Thoughts?

 

[Blind Driver2]

I like to find a disc brake kit for my dually.

 

['94IDITurbo7.3]

there are kits available. BIG MONEY though. i've heard they are one of the best upgrades for these old trucks.....others have said that the drums were WAY better stopping power than the discs.

i have only seen single piston calipers for the rear. personally i am not fond of a single small piston trying to stop one of these trucks that are heavy when empty, let alone with a load.

even though i hate the drum brakes on these truck(at least my truck) i would say stick with the drums and spend your money on hydro-boost rather than a disc conversion.

 

[92F350CC]

I thought the best way was to switch to a 99+ E-Series rear axle? You get the disc brakes without going to a metric lug pattern.

 

[sassyrel]

I thought the best way was to switch to a 99+ E-Series rear axle? You get the disc brakes without going to a metric lug pattern.

the van axles,,are wider than a 250 or 350 axle.....but some have taken the parts off of one of these,,and made the brackets to switch it over....

 

[Blind Driver2]

http://www.pirate4x4.com/forum/axles-tires-wheels/854906-complete-sterling-disc-brake-kit-390-a.html

 

[Dieselcrawler]

http://www.ruffstuffspecialties.com/catalog/STER-DISC.html

 

[The Warden]

I've always liked the idea of a disc brake conversion, but every kit I've seen either incorporates a front caliper and you lose your parking brake, or incorporates a rear caliper meant for a passenger car, which has an integrated parking brake but is so small that I question its efficacy on a 1 ton truck.

I'd love to see a setup that uses a rear caliper meant for a full-size truck and somehow integrates a parking/emergency brake. Until then, I "get" to stick with drum rear brakes...as 92F350CC pointed out, the '99+ E-350 setup may provide an important key to this, but I don't know if anyone's actually done it yet...

 

['94IDITurbo7.3]

Read me!

 

[hce]

Here's a thought. Drum breaks are self energizing or as pressure is applied to the drums the rotation of the drums drives the shoe into the drum. The rotation is assisting in braking force in a drum brakes. Disk do not self energize they and require more hydraulic pressure to operate. This is why disc system are power assisted. Now if we remove low pressure self energizing drums and replace with high pressure non energizing disks where is the extra pressure or force going to come from to operate the rears.
1. Either the no pressure increase to the rear and there is not enough clamping force to the rears.
2. Rob force applied to the front and send it to the rear and reducing front stopping power.
3. Press on the pedal harder to compensate for extra needed force, you will need to start lifting weights for this.
4. Use a smaller master cylinder to raise pressure, but disk brakes need more volume to actuate then drums.
5. Increase force on master cylinder with a bigger booster or hydroboost.

Disks do work great and have advantages but disk need more pressure to work as effectively as drums.

 

[Leeland]

Crawler I've been looking at that same kit you posted
I used ruffstuff for a gm14 bolt disk conversion. They sent me a first set and before I even got them the owner called me to let me know they had a bad batch and that there was a new pair of brackets already on the way. I was happy with the brackets I installed and their customer service and it was way cheaper piecing it my self then the pirate kit.

 

[The Warden]

Here's a thought. Drum breaks are self energizing or as pressure is applied to the drums the rotation of the drums drives the shoe into the drum. The rotation is assisting in braking force in a drum brakes. Disk do not self energize they and require more hydraulic pressure to operate. This is why disc system are power assisted.

FWIW I'm not sure how much of a correlation there is between disc brakes and power-assist. My dad used to have a '67 F-250 that had drum brakes on the front and a factory vacuum booster; albeit the pedal was VERY touchy. OTOH there was my old Chevelle, which had no power assist and drum brakes on all four corners...that car took an act of Congress to stop in a hurry

 

[79jasper]

Now if we remove low pressure self energizing drums and replace with high pressure non energizing disks where is the extra pressure or force going to come from to operate the rears.
1. Either the no pressure increase to the rear and there is not enough clamping force to the rears.
2. Rob force applied to the front and send it to the rear and reducing front stopping power.
3. Press on the pedal harder to compensate for extra needed force, you will need to start lifting weights for this.
4. Use a smaller master cylinder to raise pressure, but disk brakes need more volume to actuate then drums.
5. Increase force on master cylinder with a bigger booster or hydroboost.

Disks do work great and have advantages but disk need more pressure to work as effectively as drums.

There are master cylinders to correct this. I believe it's from the f450. It has a bigger rear piston. I just read about it not too long ago. Would you like me to try to find it?

 

[laserjock]

Wow. Thanks for the conversation. So I completely get the brake pressure argument. I suspected that the master cylinder may need swapped to get the system to reach its full potential. If you have a minute to find the article on the f450 master I think it would be good information to have. After reading some of the links posted above, I can say that I can't imagine using eldorado calipers is a good idea. As big a yaht as those things were they were not 7000 lbs. The GM front caliper would seem to be a superior way to go and all that stuff should be readliy available. The other thing I am seeing is that people are claiming problems with axle seals. I'm really not sure why there would be an axle seal problem. Bracket bolts to the housing. Unless it just the change from applying the force radially as the drums to do applying the force just to one side the way the Disc does. Have to ponder on that one a while. I can't imagine that there is no advantage to doing this or new trucks wouldn't have them. I also agree that drum brakes have there place too. There's a reason that most semi trucks still run them although I've seen where there is a movement to switch them to discs too. There's a you tube video somewhere from a company that makes the semi truck disc brake sets. Its impressive.

 

[hce]

There are master cylinders to correct this. I believe it's from the f450. It has a bigger rear piston. I just read about it not too long ago. Would you like me to try to find it?

larger master cylinder means more volume, but less pressure will be exerted on the brakes unless you can push the master cylinder even harder. Basically stealing from force applied to front brakes to activate the rears, unless you can push on the master cylinder piston harder.

Also please check out faq on any brake site. Please look at the second one down