Rear Disks on 3/4 ton 99 burb?

[venture]

Time for a new project. How about rear disks on a 3/4 ton burb. Has someone made the conversion and what did it take to complete? It looks like it should be strait forward. Thinking a later burb, truck, or H2 will be the donor. Any tips or info is a help. Will keep you updated.

[jspringator]

Do a search in the members forum. There was a lengthy thread in this exact issue some time ago. I decided it wasn't worth the effort. I concentrate on adjusting the rear brakes, locating blown rear axle seals, and using good friction material on the rears.

[rjschoolcraft]

More Power converted the Duramax project truck to rear disks and wrote a couple of articles about it. Check out the member's area.

[GMCfourX4]

I have a rear-disc conversion on my truck, using a kit from TSM Manufacturing (http://www.tsmmfg.com/General_Motors_truck_rear_axles.htm) It uses calipers from a '76-'78 Eldorado with e-brake arms. I'm happy with the kit, but the e-brake doesn't hold as well as I'd like (since my truck is a 5-speed, and I like to leave it running in the really cold weather if I'm just running in some place really quick). The kit drops something like 70lbs from the rear axle. The other reason I'm thinking about switching back is that when I'm running empty, the back of the truck is just too light, and I end up spinning tires instead of going.... Long story short, I'd be willing to sell the kit if someone makes me a reasonable offer for it. The kit cost me about $700, including braided stainless flex lines, calipers, pads, rotors, and the brackets.

-Chris

[More Power]

Just about any way you go with a conversion, it'll cost you upwards of $1000 to get a good and properly designed disc brake conversion kit.

Personally, I would go with a replacement rear axle that has factory disc brakes. You can get one for about $800-1000. If by chance the spring perches need moved, that's a whole lot easier than doing a conversion.

In my case, there was no GM 9-1/2" semi-float rear axle with factory discs and six-lug axle flanges. All of the current disc brake equipped 9-1/2" rear axles are 8-lug. This is GM's light-duty 2500 axle.

Once you get the disc brake equipped axle under your rig, you'll need to think about ABS and parking brake (cables & overall effectiveness)... It would appear the parking brake pedal assy on either a drum or disc equipped truck uses a different length lever arm. This means your parking brake effectiveness will be lower with the same amount of pedal push as when you had drums.

I'm real pleased with the disc conversion on Lil Red. The brakes themselves are so much more effective than the 10" drums the truck came with.

Jim

[GMC Hauler]

Someone brought EGR Brakes (http://www.egrbrakes.com/index-main.htm) to my attention. They have a rear disc brake conversion kit that is very nice and the price isn't too bad.

Something else they sell for those of you who don't want to switch the rear brakes to disc is a replacement wheel cylinders which are larger than factory. If you have ever examined the brakes you will find that the front pads wear much faster than the rear shoes. The rear shoes do very little stopping. What is needed is for the rear shoes to be applied more in proportion to the front pads. These new rear cylinders do just that, and at $39 each (2 required), it is a perfect upgrade for those who don't want to do a whole upgrade, but would like more stopping power on the cheap.

I haven't done this yet, but is a future upgrade.

[jspringator]

My order for those wheel cylinders is going out tomorrow. I made a promise to myself to try to improve brakes after I rearended those 4 cars.

[ 12-27-2005, 04:08 PM: Message edited by: James Springate ]

[Turbine Doc]

Venture,

I'm finishing up this evening a refit of drum to disk with an EGR company conversion kit. Will let you know if worthwhile or not, was a PITA to figure out, Instructions only 5 paragragphs (remove old-install new-adjust was literally extent of them) for the 20 or so steps involved, incorrect part list, and only 1 photo, they took it on faith that installer had done this before.

I figgered it out, lot of head scratchin but I got it done; my K1500 had 11-5/32" drums & 2.75" wide shoes fairly substantial in stopping power when adjusted, keeping them adjusted was why I went to disc change.

I went with cross drilled rotors, stainless lines, and performance pads, prior to this swap and that really helped stopping, constant maint on rears is why I decided to try pads. As far as stock, drilled, slotted, or both, is subject of debate, probably if doing it again I'd go slotted next time with set from SSBC who sold me the front calipers.

I also swapped to SSBC's 2 piston front calipers, so which helps the most in stopping with take some time to figure out. The front calipers now have 2 smaller pistons either side of pad, vs 1 large center piston, since I spent the money it's got to stop better right ???? I hope so.

In retrospect, I think you might be just as well served with new rotors drilled or slotted, on front, and high performance pads, make sure system has fresh well bled fluid, and larger pistons on rear shoes, (maintain adjustments, check often) and also make sure axle seal isn't letting differential fluid get on shoes, mine was starting to leak.

I'm still bleeding system just took a break from it, will road test later this evening.

[jspringator]

I am taking the cheap route. Ordered the wheel cylinders. After they are on I'll report back. How does the EGR friction material and rotors compare to Praise Dyno?

[Turbine Doc]

I've never seen praise dyno pads, but stuff on EGR pads is good looking stuff, no marking to say who made them and part list shows replacements as a EGR part.

Some pics of the installed caliper unit in this link http://www.imagestation.com/album/pictures.html?id=4288826053

[ 01-01-2006, 11:37 PM: Message edited by: tbogemirep ]