ok .. after researching and finding a good deal on a rear disk setup form an 88 gta

**(new calipers&pads rotors,metal & rubber lines. parking brake cables)


after searching.. i know that the master cilender that i have will work jsut fine. now i know i will need to either modify the 9bolt back plates or get 2 from a 10 disk rear. The questions i have is what else do i need to get this conversion done.

parts that i have questions on are the brake balancer i think drum rears are 70/30 and 4 wheel disk is 50/50 thus my thinking is i would need to find one of these.

the other part is the prportioning valve.. not sure if i need a new one of these or not. help me out..

last think is ive read that you have to modifiy the axles somehow to get this stuff to work, could use help on this also.. Also read the if you use 93-97 rotors that you done have to do anything to the axles, could someone let me know if this is the case. this would be the easiest option for me

I know this is alot but i not to knowledgable about brake parts


thanks as always.

 

Well, my question would be why do you want '88 rear disc brakes for your '91?

The '88 and earlier rear disc brakes aren't all that great. These are the cast iron 10.5" discs. Plus, you're going to have to hassle with getting a 9-bolt disc set-up to work on your 10-bolt. In my opinion you'll be putting too much time and energy into a so-so brake set-up.

The better way to go would be to simply buy the '91 and up rear disc parts. Everything is readily available thru GM and Autozone, it's already designed for a 10-bolt, and you'll have the 1LE style 11.xx" set-up with aluminum PBR calipers. This is a far better system and will be an easier swap.

You will also need to swap the proportioning valve. I can look up the part number for the valve you'd need later tonight.

 

hmm... ok.. intresting point you made.. maybe i will re think this . I through the rotors where the bigger ones.. and just the calipers were iron and not allimnum. maybe this isnt really work it after all...

 

hey can we keep this thread going? i have a 1991 z28 drum rear and i would like to swap disc brakes onto it. ive done some searching and havent really found what i was looking for. what all would i need to complete this swap. i dont need anything crazy but just a little better stopping power.
aside from the parts what modifications to the car would be needed??????

 

All you need is all the brake components, correct hard axle lines for the new brakes, and new e-brake cables to fit the brakes. To mod the axle flanges to allow the disc backing plates to fit, you will have to mod them like this:

https://www.thirdgen.org/newdesign/t...reardisc.shtml

Ed

 

You can go with the factory 91 rear disc set-up. From 90-92 GM used the 1LE style PBR disc brakes in the rear on all f-bodies. All 90-92's use the 10 bolt rear end. This will be the easier swap.

What you'll need:
1) 10 bolt PBR backing plates - I believe these are still available from GM
2) PBR calipers and carriers - AutoZone
3) New axle hard lines - do a search, I'm sure someone will have a good source
4) New flex lines - you can get OEM rubber thru AutoZone or go with Earl's braided lines from Summit
5) 90-92/1LE rear rotors - these are 11.xx" compared to the 10.5" '88 and earlier style rotors
6) New proportioning valve - GM or gmpartsdirect.com
7) New parking brake cables - AutoZone

If you don't mind a little extra work, follow Ed's thread and go for the 98+ LS1 rear brake swap. The really nice feature about this swap is the superior parking brake design.

 

thanks for all the info. that was extremly helpful i defenitly going with the swap here in a few weeks now.

 

The only thing I don't like about the LS1 rear brakes and their superior parking brake design is just that...the parking brake design, especially when trying to install it on our cars. The PBR LT1/1LE style is MUCH easier to install and bolt up and won't give you any hassles trying to hook up that damn parking brake. For all the work they do, the 1LE/LT1 PBR rear brakes are fine.


Ed

 

yea i would like the bigger brakes but i think the ile upgrade will do just fine. my original parking brake hasent failed yet and i would rather have it easier to install..............btw i dont even know why rear brakes matetr right now because ill have to get a new rear when i swap in the lt1!

 

Baer Brakes has a rear upgrade kit that will use the 93+ LT1 style rear caliper setup. It's comparable to other systems and comes with a 12" rotor.

ttyl,
Colin

 

You can find rear setups like that for a lot less than Baer, just take a little time searching for them.

Ed

 

hey ebmiller88,
Yes, if you piece together a stock system but if you want to go with a larger rotor than stock you cannot use Brembo. Wilwood does not have complete kits, and in fact I believe they only really sell drag kits or their 6 piston kit, and that is $$$..

If you want to use larger rotors you will need to upgrade to the Baer Touring claw system part number 4302020 which comes with 12" rotors, backing plates, brake pads, and parking brake setup. Baer does not yet offer a 13" rotor for the rear.

The rear Baer kit will run around $1000 shipped, not bad considering the larger surface area of the rotors.

 

My point is the Baer rear kit is the same as the '89-97 1LE/LT1 PBRs, no difference except the name "Baer". You can get the same brakes for less than the $800 they want for theirs.


Ed

 

That may be true, but some people want new parts. I'm not speaking for this guy, but for the guy that's going for a show car they want people to see their upgrade. As well, polishing/2-piece rotors never came factory on GM stuff

I'm just messin', but I know exactly what you mean.
take care,
Colin

 

I hear ya, man...if it's a show car, he should go with Baer or the like.



Ed

 

well i dont car about a name or new parts but thats just me. i juust want something that will stop me because right now i can hardly get my car to lock up the tires. i almost went into an intersection one day because my car just would not stop.............still havent figured out why

 

? That's odd. My G92 IROC stops so hard that it feels like my nose will hit the ground, LOL..

The tires will not lock up, but I'm running good tires, Nitto NT450..

Mind you, my car is 4wdb but drum rears shouldn't be 'that' bad. Have you changed your brake fluid recently.. if you have an accumulation of moisture the brake fluid will quickly overheat and may cause brake fade..

I understand where you're coming from with the rear disc conversion though.. I was just stating that the Baer kit is an alternative to scrounging for parts.

later,
colin

 

i have to double check my fluid and change my brake shoes im pretty sure however after riding in my frinds 93 1LE i need good stopping power...................his car would stop on a dime!!1

 

I'd also like to add that my G92 IROC does not lock up the tires, either. I've literally slammed both feet on the pedal as hard as I can and they will not lock up.

It's like I have free ABS:lala:

Seriously, though.. an upgrade both front and rear will make a huge different. From what I've heard, 4wdb cars had a closer to 50/50 distribution and drum cars had a 70f/30r distribution.

Either way, I would look into upgrades for both if you are trying to stop that quick

take care,
colin

 

correct me if i'm wrong, but I was under the impression that nothing was a direct bolt on as far as factory rear drum to disc is concerned.

 

https://www.thirdgen.org/techbb2/sho...hreadid=249098

JamesC

 

weren't you going from disc to later model disc? I have factory drums and want to go to disc.

 

You might consider a search on the drum to disc conversion. As I recall, the axel flange on the drum rear requires a simple modification to accept the disc backing plate.

JamesC

 

thats what i thought also, but not what i just read. plus that conversion is for lsi type not stock 91-92

 

Regardless of which system you go with (LS1 rears or '91-92 1LE style), the axle mods for a DRUM rear are the same, that's why he posted that link. Other than that it's just the minor differences in the brake parts. A backing plate is a backing plate and will bolt on the same.

Follow this link on modding the drum rear also:

https://www.thirdgen.org/newdesign/t...reardisc.shtml

Install the plates and brakes, bleed, and go.


Ed

 

thanks for that verification. It semmed like everything I've searched leaned that way but I wanted to be sure. Thanks again for the help.