Brakes Looking to upgrade or get the most out of what you have stock? All brake discussions go here!

rear disc brakes on 84 Z/28

Thread Tools
 
Search this Thread
 
Old 08-03-2018, 10:52 AM
  #1  
Junior Member
Thread Starter
 
84 zee's Avatar
 
Join Date: Jun 2008
Location: Newfoundland
Posts: 26
Likes: 0
Received 0 Likes on 0 Posts
rear disc brakes on 84 Z/28

Have an 84 z/28 with rear drum brakes just purchased complete rear disc setup off an 2002 SS I have backing plates calipers rotors and hand brake cables is there any thing else I would need to fit this to my car.
Old 08-03-2018, 11:35 AM
  #2  
Supreme Member

 
midias's Avatar
 
Join Date: Oct 2004
Location: Henrietta NY
Posts: 4,370
Received 189 Likes on 149 Posts
Car: 1984 Trans Am L69
Engine: Sniper EFI Powered 355
Transmission: WC T5 w/ Steel Support Plate
Axle/Gears: 3.42 10 Bolt Posi
Re: rear disc brakes on 84 Z/28

I believe the holes on the backing plate flange are different between the drum and disk models. You will probably need to do a little drilling
Old 08-03-2018, 11:57 AM
  #3  
Supreme Member

 
mmadden55's Avatar
 
Join Date: Nov 2008
Location: Houson
Posts: 1,146
Received 6 Likes on 5 Posts
Car: 86 Firebird
Engine: 305 SBC
Transmission: 700 R4 TCI
Axle/Gears: 3.42
Re: rear disc brakes on 84 Z/28

no Just pull the old stuff off pull the dif cover and pull the axles put the 02 backing plates on and reassemble you will need to use the parking brake cables off the 02
Old 08-03-2018, 01:54 PM
  #4  
Supreme Member

iTrader: (58)
 
Drew's Avatar
 
Join Date: Jul 1999
Location: Salina, KS
Posts: 20,309
Received 1,052 Likes on 748 Posts
Re: rear disc brakes on 84 Z/28

The mounting flange on the housing is completely different on drum/disc cars. You'll likely need to cut the flange, and drill mounting holes. Precise alignment may take shims. Brake bias will probably be wrong without modding the proportioning valve and/or master cylinder.
Old 08-03-2018, 02:19 PM
  #5  
Supreme Member

iTrader: (11)
 
DynoDave43's Avatar
 
Join Date: Aug 2013
Location: MICHIGAN
Posts: 4,637
Received 751 Likes on 577 Posts
Car: 1988 Trans Am
Engine: L03
Transmission: 700R4
Axle/Gears: 10 Bolt 2.73 Open
Re: rear disc brakes on 84 Z/28

Originally Posted by Drew
The mounting flange on the housing is completely different on drum/disc cars. You'll likely need to cut the flange, and drill mounting holes. Precise alignment may take shims. Brake bias will probably be wrong without modding the proportioning valve and/or master cylinder.
This is what I get for not reading carefully.

I thought there was an aftermarket bracket you had to have to mount the LS brakes?

Old 08-03-2018, 04:24 PM
  #6  
Supreme Member

iTrader: (58)
 
Drew's Avatar
 
Join Date: Jul 1999
Location: Salina, KS
Posts: 20,309
Received 1,052 Likes on 748 Posts
Re: rear disc brakes on 84 Z/28

Some people have posted that they've just unbolted the LS1 rears and bolted them on the thirdgen drum rear after cutting the drum flange square and drilling a few holes. But it's also known that the axle tube outside diameter on disc and drum rears is different, discs being larger. So in theory anyway, the backing plate wouldn't be supported by the axle tube, but only by the bolts/flanges. Whether that matters... Who knows, GM must have thought it did. The other issue is centering the caliper on the rotor. Thirdgen disc rears use shims between the flange and backing plate. Most aftermarket setups shim between the caliper and bracket. I don't know how the LS1 setup is centered, might not matter. I'm just not sure I'd trust the quick conversion.
Old 08-03-2018, 04:35 PM
  #7  
Supreme Member

 
mmadden55's Avatar
 
Join Date: Nov 2008
Location: Houson
Posts: 1,146
Received 6 Likes on 5 Posts
Car: 86 Firebird
Engine: 305 SBC
Transmission: 700 R4 TCI
Axle/Gears: 3.42
Re: rear disc brakes on 84 Z/28

search invincible on you tube he has a video of him putting brakes off a 98 4th gen on his 68 Bird
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
BOTTLEDZ28
Brakes
2
09-16-2012 02:09 PM
MrDude_1
Suspension and Chassis
12
02-20-2004 10:18 PM
chekbaka
Suspension and Chassis
4
11-21-2003 07:14 AM
FormulaJoe
Suspension and Chassis
6
05-15-2001 11:27 AM



Quick Reply: rear disc brakes on 84 Z/28



All times are GMT -5. The time now is 09:15 PM.