Brakes Wont Work, LS1 Rear Disc Swap
05-22-2011, 03:37 PM
#1
Senior Member
Thread Starter
iTrader: (15)
Join Date: Jul 2008
Location: Northeast CT
Posts: 679
Likes: 0
Received 0 Likes
on
0 Posts
Car: '89 IROC-Z
Engine: LSx
Transmission: T-56
Axle/Gears: 3.42
Brakes Wont Work, LS1 Rear Disc Swap
I swapped in a 2000 rear end with the 12" discs, I got a porportionary valve from a disc/disc iroc and the rear brakes dont even have enough pressure to stop the wheels at an idle. I thought maybe I got a bad valve so I got another porportionary. I bled the system the brake light went out and same situation. Does anyone have any idea what the problem could be? Thanks.
James
James
05-22-2011, 03:59 PM
#2
Re: Brakes Wont Work, LS1 Rear Disc Swap
I swapped in a 2000 rear end with the 12" discs, I got a porportionary valve from a disc/disc iroc and the rear brakes dont even have enough pressure to stop the wheels at an idle. I thought maybe I got a bad valve so I got another porportionary. I bled the system the brake light went out and same situation. Does anyone have any idea what the problem could be?
JamesC
Last edited by JamesC; 05-22-2011 at 04:02 PM.
05-22-2011, 04:00 PM
#3
Member
Join Date: Nov 2009
Location: Pasco, WA
Posts: 415
Likes: 0
Received 0 Likes
on
0 Posts
Car: 88 Iroc Z, 00 SS
Engine: 5.7 HSR, 5.7 LS1
Transmission: 700r4, T56
Axle/Gears: 3.23, 3.42
Re: Brakes Wont Work, LS1 Rear Disc Swap
sounds like he used a regular Iroc proportioning valve
05-22-2011, 05:30 PM
#4
Senior Member
Thread Starter
iTrader: (15)
Join Date: Jul 2008
Location: Northeast CT
Posts: 679
Likes: 0
Received 0 Likes
on
0 Posts
Car: '89 IROC-Z
Engine: LSx
Transmission: T-56
Axle/Gears: 3.42
Re: Brakes Wont Work, LS1 Rear Disc Swap
I was told it was from an 89 Formula with PBR disc's, is there anyway to tell by the numbers stamped on the side? Thanks for the quick responses.
05-22-2011, 05:53 PM
#5
Re: Brakes Wont Work, LS1 Rear Disc Swap
JamesC
05-22-2011, 06:01 PM
#6
Supreme Member
iTrader: (7)
Join Date: Mar 2000
Location: Orange, CA
Posts: 5,674
Likes: 0
Received 106 Likes
on
65 Posts
Car: '90 Trans Am-12.45@110.71
Engine: 355 w/AFR 195's Elem. 400/430 HP/TQ
Transmission: Tremec T-56
Axle/Gears: 12 Bolt 3.73
Re: Brakes Wont Work, LS1 Rear Disc Swap
You just need to change the spring in the front like 89TransAmGTA said.
05-22-2011, 06:05 PM
#7
Senior Member
Thread Starter
iTrader: (15)
Join Date: Jul 2008
Location: Northeast CT
Posts: 679
Likes: 0
Received 0 Likes
on
0 Posts
Car: '89 IROC-Z
Engine: LSx
Transmission: T-56
Axle/Gears: 3.42
Re: Brakes Wont Work, LS1 Rear Disc Swap
So is there anything else that could be causing my problem? My front brakes work fine, but like I said I lifted the rear end up and with the pedal to the floor it couldnt stop the wheels idleing in gear, theres not enough pressure to hold to pad to the rotor and it squeeks horribly and is very annoying. I might just to have to start hunting for a disc/disc car around here and pull it myself. Is it 90 when the threads changed?
Trending Topics
05-28-2011, 05:27 PM
#9
Senior Member
Thread Starter
iTrader: (15)
Join Date: Jul 2008
Location: Northeast CT
Posts: 679
Likes: 0
Received 0 Likes
on
0 Posts
Car: '89 IROC-Z
Engine: LSx
Transmission: T-56
Axle/Gears: 3.42
Re: Brakes Wont Work, LS1 Rear Disc Swap
Update: I tried removing the spring and plunger and using a plug which correct me if I'm wrong should give almost 100% to the rears? Well the brakes work a little better, I can get them to hold the coverter to 2000rpms but there still isnt enough pressure to keep the pads against the rotors and I still get the annoying squeek while driving. What do I do from here?
Thread
Thread Starter
Forum
Replies
Last Post
hectre13
Engine/Drivetrain/Suspension Parts for Sale
2
12-11-2023 08:14 AM
1992 Trans Am
Engine/Drivetrain/Suspension Parts for Sale
1
08-08-2015 08:16 PM
