Replace Rear Drum Brakes to Disc
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Has anyone tried this? I've seen some of the early model GP'* with rear disc. Since these bad boy Bonnies can get up there I've found it necessary at times to need to stop pretty quick. I'm also having trouble with my front floating calipers. They rub the pads at an angle and when it'* time to stop they vibrate since they are cooling and heating at the same time. My shop tells me I need to replace the calipers with a replacement/repair kit I can get from the dealer for about $80.00 - $100.00 and also replace my rotors. The best price I could find were $200.00 a piece for rotors. It will fix the caliper and allow it to align correctly. I think I'd rather replace the calipers with 2 or 3 cylinder calipers instead, but what do I use? Any comments?
#3
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I have been looking at my neighbors 98 Grand Prix and it seems the front brakes use the same mounting and such. I am not 100% sure of that yet since I need to take off the wheel and look at it side by side with my car. But you could get a 2 piston system from Baer since they have a 2,4 or 6 piston system for the front brakes of Grand Prix'*. Also could upgrade to the 11.9" rotors that GM has also. Check on http://www.clubgp.com/forum and search in the suspension and brakes section and it will come up.
As for the rear disc conversion, it is such a pain that it is not worth it. It would be more intelligent to just put all the money in the front discs get a 4 piston system since the front brakes do 80% of the stopping in any car. And our drums in the back are big enough.
_________________
1999 Black Bonneville SE
3" I/E, Shift Kit (higest setting), Polyurethane Bushings, no MAF screen
<font size=-1>[ This Message was edited by: 99BonnevilleSE on 2002-05-25 13:14 ]</font>
As for the rear disc conversion, it is such a pain that it is not worth it. It would be more intelligent to just put all the money in the front discs get a 4 piston system since the front brakes do 80% of the stopping in any car. And our drums in the back are big enough.
_________________
1999 Black Bonneville SE
3" I/E, Shift Kit (higest setting), Polyurethane Bushings, no MAF screen
<font size=-1>[ This Message was edited by: 99BonnevilleSE on 2002-05-25 13:14 ]</font>
#4
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Thanks. My shop tells me the GP is identical in parts to the Bonneville'*. I'll check into it. I'd like ot go to the 11.9" rotor, but I might have a problem with the stock chrome wheels I have being in the way. I've seen those on a GP, but the wheels are a concern. I'm not ready to replace them yet.
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Here'* some info: THIS IS FOR GRAND PRIX'* BUT I THINK YOU CAN MAKE IT WORK!
Upgrading to Baer Brakes
Tools you will need:
Jack
Jack stands
Hammer or rubber mallet
Socket wrench
Sockets (10mm, 12mm, 13mm, 14mm, 15mm, and 19mm)
Box wrenches (10mm and 13mm)
Torque wrench
#30 Torx driver
Installing the Front System
Before starting, fit the brake assembly in one of the removed wheels to insure there will be no clearance problems
Remove the stock brake components (pads, rotors, calipers, hoses, etc.) using a 15mm socket wrench and 12mm line wrench
FOR SPORT SYSTEMS ONLY: modify spindle by grinding about 1/8" with a metal file.
Install the new bracket to the backside of the spindle and attach with 14mm bolts, washers and nuts
Insert bracket from behind with spacers pointing outboard
Insert bolt from behind (without the washer)
Put the washer against the aluminum upright and install nut
Torque to 110-ft. lb.
Place rotor over hub seat and secure with two lug nuts
Install caliper with bleeder pointing up
Using 12mm bolts secure and torque to 85-ft. lb.
Install brake hose
Watch hose throughout suspension movement to ensure it does not contact suspension, spring, strut, etc.
Keep hose clocked toward inner fender wall
Once finished installing, perform a final check on both rotors for clearance from all obstructions and for being properly centered between the calipers and brake pads. You may find that the ABS sensor'* bracket is touching one or both rotors and in this case, bend the bracket slightly back (1/8" or 3/16" should be enough). If other obstructions are present or if the rotors don't center properly between the pads, re-check all previous steps and correct any problems. Do not proceed until all concerns have been addressed.
Proceed to Installing the Rear System, or, if done, proceed to bleeding the System.
Installing the Rear System
Remove the rear brakes, hubs, and parking brake mechanisms. You will need a 13mm wrench, 10mm socket, and #30 Torx driver
Using original bolts, install the new bracket and hub
Caliper should be clocked to the rear of the car and up
One bolt is shorter than the other - this one goes to the bottom and front of the hub so as to not run into the control arm
Torque to 40-ft. lb.
Install rotor and secure with two lug nuts
Install caliper behind the axle with 12mm bolts, washers, and nuts using a 19mm socket
Torque to 85-ft. lb.
Install brake hose
Install at caliper end first and loosely secure with banjo bolts - hose should point to the outside of the car and then curve up over the upright
Use Adell (cushion) clamp to secure the hose to the upper caliper mount
Clamp goes on inside of bracket
Hose should run up to the clamp, then run horizontally as in the figure below
Attach hose to flare bracket and hard line
Tighten clamp and banjo bolt making sure hose will not rub on anything
Reinstall factory parking brake cables
Proceed to Bleeding the System
Bleeding the System
Seasoning the Rotors
Bedding the Pads
Upgrading to Baer Brakes
Tools you will need:
Jack
Jack stands
Hammer or rubber mallet
Socket wrench
Sockets (10mm, 12mm, 13mm, 14mm, 15mm, and 19mm)
Box wrenches (10mm and 13mm)
Torque wrench
#30 Torx driver
Installing the Front System
Before starting, fit the brake assembly in one of the removed wheels to insure there will be no clearance problems
Remove the stock brake components (pads, rotors, calipers, hoses, etc.) using a 15mm socket wrench and 12mm line wrench
FOR SPORT SYSTEMS ONLY: modify spindle by grinding about 1/8" with a metal file.
Install the new bracket to the backside of the spindle and attach with 14mm bolts, washers and nuts
Insert bracket from behind with spacers pointing outboard
Insert bolt from behind (without the washer)
Put the washer against the aluminum upright and install nut
Torque to 110-ft. lb.
Place rotor over hub seat and secure with two lug nuts
Install caliper with bleeder pointing up
Using 12mm bolts secure and torque to 85-ft. lb.
Install brake hose
Watch hose throughout suspension movement to ensure it does not contact suspension, spring, strut, etc.
Keep hose clocked toward inner fender wall
Once finished installing, perform a final check on both rotors for clearance from all obstructions and for being properly centered between the calipers and brake pads. You may find that the ABS sensor'* bracket is touching one or both rotors and in this case, bend the bracket slightly back (1/8" or 3/16" should be enough). If other obstructions are present or if the rotors don't center properly between the pads, re-check all previous steps and correct any problems. Do not proceed until all concerns have been addressed.
Proceed to Installing the Rear System, or, if done, proceed to bleeding the System.
Installing the Rear System
Remove the rear brakes, hubs, and parking brake mechanisms. You will need a 13mm wrench, 10mm socket, and #30 Torx driver
Using original bolts, install the new bracket and hub
Caliper should be clocked to the rear of the car and up
One bolt is shorter than the other - this one goes to the bottom and front of the hub so as to not run into the control arm
Torque to 40-ft. lb.
Install rotor and secure with two lug nuts
Install caliper behind the axle with 12mm bolts, washers, and nuts using a 19mm socket
Torque to 85-ft. lb.
Install brake hose
Install at caliper end first and loosely secure with banjo bolts - hose should point to the outside of the car and then curve up over the upright
Use Adell (cushion) clamp to secure the hose to the upper caliper mount
Clamp goes on inside of bracket
Hose should run up to the clamp, then run horizontally as in the figure below
Attach hose to flare bracket and hard line
Tighten clamp and banjo bolt making sure hose will not rub on anything
Reinstall factory parking brake cables
Proceed to Bleeding the System
Bleeding the System
Seasoning the Rotors
Bedding the Pads
#8
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I do know one issue with switching from drum to disc brakes is the master cylinder. Drum brakes require much less pressure to operate than disc brakes do. So if you were to convert, you would probably have to install a complete custom brake system. What a PITA!
Lee
Then again, we could just copy what the 2k+ bonnevilles have.
Lee
Then again, we could just copy what the 2k+ bonnevilles have.
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