21 July 08
Decided to replace the drum brake rear end with a disc brake unit. Here's the deal on that.
1. The disc brake rear on the newer model Blazers and S10's through 2005 models will bolt in place of the old drum rear perfectly.
2. The rear must be from a 2WD if your vehicle is 2WD. Actually you may could use 4WD units, not really sure but they are about 5" wider. The lower shock mounting bracket on the 91 goes right back in place under the leaf springs. Cost from salvage yard, $400 with good rotor, pads and no leaks!
3. The brake cables are totally different on the newer models thus they won't just hook right up. And you HAVE to have a functioning emergency brake on an electric vehicle with a manual transmission since theres no engine compression to stop it from turning. Forget to set the brake and if you're on a slight hill, your car is going for a ride all by itself! We're going to get a compression cable fitting or just use U-bolts to tie the cables together.
One important note to remember, the newer cable operates with a bracket (see last photo) that both cables tie into, sort of like a Y. When the emergency brake is applied it pulls the brake cables toward the front, the bracket pulls the passenger side cable until brake is applied. When those pads contact the rotor, the brake cable of the driver side then pulls as the bracket holding it can't move now. The way it is setup, one inch of travel by the cable from the brake pedal will pull each cable to the brakes only half that amount.
The older cables are tied end to end and loop around a horseshoe type guide. When the pedal cable moves one inch on this one, both cables move one inch. This may be as clear as mud now but before you buy the new one, look at your existing brake cable connection method then look at the newer style setup and you'll see what I mean.
There are codes in your glove box that indicate options such as limited slip and the gear ratio. My code was GU6 which means it has a 3.42 gear. I'll list the other codes below. For hauling all those batteries you want a lower ratio if you can get it which means a higher number such as 3.73 or 4.10. However I haven't found one for this rear end. A critical measurement to keep in mind to make sure you don't get the wrong one is 54.5" That is the distance between the wheel mounting faces. For the 4WD models it is 59" and those may come with lower gears.
Glove Box Codes:
GU4 = 3.08 GEARS, GU6=3.42, GT4=3.73, GT5=4.10 G80=Limited Slip.
I haven't figured out how to label the photo's but the last photo is the above brake cable bracket on the new rear.
one comment:
Sir,
You will want to get a master cylinder from the new truck also as the internal dia and throw may be different for the rear disk. Also you will probably want an aftermarket proportionaing valve (adjustable) to balance out the front and rear braking.
Have you decided on the motor/controler/battery combo yet? I have gone through all of the completed S-10/S-15/Rangers and created a spread sheet on combos used to help me in making the decisions. I can email you a copy if you like.
Hopefully I will locate a truck to start on soon, and begin my own project.
Avn-Tech () - 22 07 08 - 15:09
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