Drum to Disc brake rear end swap how-to!

[rlith]

Well I got the new rear end in! I had wanted disc brakes for a long time, I came across a good deal on a g80 (limited slip posi) rear w/ disc brakes from a 99 blazer. It only had 33k on the rear and I got it for $180.00 bux! YAY.... So I finally get around to installing it this weekend with the help of Grappler...(Thanx once again bud)...

The install is fairly straight forward: (see notes at the end of this page): So I started by picking up the rear at my local wrecking yard. It's been sitting in mud for almost a year (the back end of the blazer it was on had no wheels and it's a messy yard)...

Here is the rear...As you can see there is a lot of surface rust...



Fortunatly the emergency brake shoes were in good shape as seen here...


Grappler taking a break before the installation... (see ending notes)



The dust shields were toast (rusted and bent) so I pulled the diff cover, then the axels and put new ones on.. In this pic you can see on the left side how bad they were banged up... on the right side I had already removed the dust shield...I also took the opprotunity to change the diff fluid... Sprayed out the casing with 2 cans of brake clean, let dry, then added Valvoline Durablend (dino/synthetic mix) 80/90 weight gear oil.



I used a wire wheel on an air rotary tool to get any scaling and debri (i.e mud) off of the casing. I then used a spray on rust inhibitor/converter/primer and let it sit overnight. (actually a couple of days because I couldn't get back to it). I then put on 2 coats of Rustolium Black w/ hammered finish on to it. This gives the benifit of being less rusty later on (gads I hate salt) and it actually looks good. I may do my whole frame in the stuff.

Here's a pic of it when it was half painted. You can see on the right the finished product while on the left it's still bare. Definatly an improvement.



I then cleaned up the calipers. Ground out the dirt and grease on the calipers themselves (aluminum, not iron, very light weight!) then cleaned and painted the actual caliper frame in the same color as I painted the rear itself.

In this pic I had test fitted the newly cut rotors and the calipers.... They came out very well...



rear side...



Once the new rear was finally ready for installation we of course had to pull the old one... This was simply a matter of diconnecting the vent hose, brake line T, emergency brake lines, u-bolts, drive shaft. Remember when you pull the u-joint, run some tape around both the end caps so they don't fall off when manuervering the shaft around.


Then we jacked it up and slid it out lengthwise....

My baby don't got back...



Here is the old rear in all it's glory (and salt)



Installtion is the same as extraction, just in reverse....

Grappler taking a break before the installation...



Without Caliper but with caliper frame: Note.. I took the opprotunity to install red polyeurethayne bushings on my swaybar to replace the OEM 10 year old rubber bushings....



With full caliper installed.


Angle 2


Finally when you've reattached all your brake lines, simply bleed all the air out of the calipers and lines. Test drive, enjoy!!!!



Some notes and conclusions:

Overall this is not a difficult swap. If I had been less concerned about the type of rear I was getting (g80) there is actually an easier way to do this. The above will work on 84 to current... This will also work... If you want to add OEM stock disc brakes to your EXISTING drum rear without changing the whole rear you would only need the following....

All 98 and up parts (these will work all the way down to 86)

Backing plates (27.00 per side )
Calipers (30.00)
Caliper frames (20.00)
Pads ($20.00)
Discs (36.00 per side at advance auto parts)
OR a loaded caliper from Advance autoparts (includes frame, pads, calipers, bolts, et-al)
Stock bolts
Dust shields (12.00 per side at the dealer)
Brake lines to the caliper...($15.00 each)

Simply remove your old shoes and the backing plates, install the new backing plates then the calipers, etc... Bleed and go...


EMERGENCY BRAKE INSTALLATION..

From the center of the body you will see a bracket where your pedal cable and your ebrake cables. From the bracket to the backing plates, those 2 cables will need to be replaced ($23.00 per side at the dealer) as the drum style has different ends and won't work with the new setup.. (This is only for 95 to current, 94 and below have a completely different cabling system so you would have to figure out on your own on how to go about making the ebrake work)



Definatly better stopping power than with my drums, the overall upgrade was well worth it. Overall time was about 4 hours (this included breaks and what not)

[chcknugget]

sweet!
This is really cool. Where did you get those rear rotors? They are nice- did they space out the wheels more?

[rlith]

Those are stock s10 rear rotors.... recut and then wire brushed, then the drum portion were cleared...

[ricksza]

If you have 4X4 make sure you get the correct gear ratio. Makes driving interesting if it's wrong.

[rlith]

Originally Posted by ricksza

If you have 4X4 make sure you get the correct gear ratio. Makes driving interesting if it's wrong.

Very true... or they can keep their existing rear end and simply replace from the backing plate out if they aren't looking to upgrade to posi...

[wolfox]

Dude, that rocks! Glad the project worked out for you - good show.

[rlith]

Thanx... I'll be following up with the e-brake cabling, just ordered them today...

[97blazermadness]

Nice pictures! I've always wondered about getting rear disc brakes on my '97.

[chcknugget]

Rlith, have you heard anything about the late 80's f-body (firebird, camaro) rear ends? I hear the have the same size rotors as our factory fronts, and they bolt up the same as the blazers too.

I'm just wondering if you looked into those.

[rlith]

I've heard of it being done....(check s10forum.com)...You have to switch the axels, as well on that..Not saying it's a bad upgrade iwth that though

[whipds15]

i have an 88 4.3 4x4. will this type of rear conflick with the four wheel drive?
the last time i changed the rear it was a disaster because of locking up and what not....will i be ok ?

[rlith]

Originally Posted by whipds15

i have an 88 4.3 4x4. will this type of rear conflick with the four wheel drive?
the last time i changed the rear it was a disaster because of locking up and what not....will i be ok ?

You just have to get it from a 4wd...(my truck is 4wd)

[jackass#1]

ive got a 91 rwd. id like to add disc brakes on rear, what options would i have in looking at replasing with salvage yard rearends?

[rlith]

Originally Posted by jackass#1

ive got a 91 rwd. id like to add disc brakes on rear, what options would i have in looking at replasing with salvage yard rearends?

Essentially any 98+ rear will work for you. Just make sure the gearing is the same if you have 4x4 other wise you will blow the system apart when you go into 4wd. If you have 2wd, and want to get higher gearing that's ok. Just remember, you have to move a 2wd to 2wd or 4x4 to 4x4 because teh 4x4 are about 3 inches wider than 2wd. But mainly make sure you're gearing is correct. Usually you'll find everything in 3:42 with smatterings of 3:73

[jackass#1]

alright thanks. 98 or above and makesure its 2wd to match my 2wd.