Alright boys, I've been at it all day long, and I'm at my wits end with this thing. I set out this morning to convert my '88 GTA with Delco-Moraine iron calipers to the PBR rear disks that I had on my Formula. I'm running into some serious problems with the brake lines though. Please try to follow what parts I'm using and see if you can figure out what isn't matching up.

Now, the 9-bolt in my Formula came out of an '85 T/A, and originally had the same iron caliper discs as were on my '88 GTA. When I swapped the '85 9-Bolt into the Formula, I grabbed some 9-bolt backing plates for PBR discs off of a junk '89 9-Bolt rear at the same parts yard. I then bolted on a set of almost new '94 Camaro PBR calipers with Earl's braided lines. Well, I tried to. When I tried to install the PBR brake calipers, I found that the passenger side braided line would not mate up with the hardline on the axle. If I remember correctly, the mile fitting on the hardline was far shorter than the female fitting on the brake hose, so I pulled one of the rubber hoses from the old iron calipers and used it instead. I ended up with a braided line on the drivers side, a rubber line on the passenger side, and all was good.

Today I tried to swap the whole brake kit over to the 9-bolt on my GTA (including hoses). Now the rubber hose on the passenger side won't bolt up to the hardline on the axle. The male end was now too long to fit into the female fitting on the passenger side brake hose. Seems like exactly the opposite problem I was having with my Formula. Unfortunately, I got rid of the spare braided line long ago, and resorted to simply swapping over the passenger brake hose from my iron caliper GTA to the PBR caliper on the passenger side. I'm now running a braided line from the 94 camaro on the driver side, and the original rubber line from my GTA on the passenger side. It works, but what gives? Why would it bolt up to my '85 9-bolt in the Formula, but not transfer to the same rear end and braking system in my '88 GTA? Did the change the hardlines somewhere in there? I want the same style hose for both sides, do I need to just go down to Autozone and order hoses for both sides for an '89 Firebird with rear disc brakes?

Why does the passenger rubber hose on my GTA have a much longer female fitting that will accept the longer male fitting on the hardline, where the '85 rear end (and brakes) had a much shorter female fitting on the rubber hose and a corresponding shorter male fitting on the hard line? Aren't they supposed to have the same hardline on the axle? What hoses can I order for both sides that will actually fit?

I really want to know why they are different. I figured this was going to be plug and play since I already had it working with the factory iron caliper hardlines in my Formula. Now I can't get the same hoses to bolt up to the factory iron caliper hardlines in my GTA. I'm rather puzzled.

-cal30sniper

 

Here's a bit more info gleaned from Autozone Part Numbers:

A 1989 Firebird with rear disc brakes would use:
-77832 for the drivers side http://www.autozone.com/autozone/par...6223_5913_3876
-78265 for the passenger side http://www.autozone.com/autozone/par...6223_2362_3876

A 1985 Firebird with rear discs would use
-77398 for the passenger side http://www.autozone.com/autozone/par...6223_5913_1711
(hard line directly to caliper on drivers side

Now, a 1988 Firebird with rear discs has two possible options:

(With Performance Package) -78265 for passenger side http://www.autozone.com/autozone/par...vice=204146197
(Without Performance Package) - 77398 for passenger side http://www.autozone.com/autozone/par...vice=204146197

Which means the passenger rubber line on the '88 uses either the 89 style line (if the car has the performance package), or the '85 style (if it does not have the performance package. Does this mean that my WS6 GTA has the performance package, and thus already had the PBR style rubber line on the passenger side. Is this why my '85 rubber line won't match up with the hardline on the GTA axle? I have no idea why they would use two different hardlines on the same axle with the same brakes, but did they change the fitting type for the WS6 performance package?

Still scratching my head here, but at least feeling safer using the factory rubber line from my GTA on the passenger side. Any help/experience with this issue would be GREATLY appreciated.

Thanks,

-cal30sniper

 

The performance package is the so-called 1LE set-up (with 11.7" rotors and PBR calipers, 89-92).

I've never heard/experienced/read that the lines from 83 to 88 are different--at least from the factory. You could simply purchase the correct hard lines from one of the following companies and eliminate the issue:

http://www.flynbye.com/catalog/i212.html

http://www.finelinesinc.com/

http://www.classictube.com/

http://www.inlinetube.com/

JamesC

 

I'm not certain why Autozone lists a "Performance Package" for 1988 that uses the same passenger line as the later PBR setup, but the hose looks identical to the non-performance package hose except for the fitting end that's not working on my '85 hardlines. I'm going to try to get what I have working for now, and go ahead and order the complete hardlines and braided lines from EBMiller.

Thanks for the help, feel free to add any more info if somebody has some.


-cal30sniper

 

Don't forget that 1988 was i guess you can call it a transition year. My understanding is that a very VERY few got the PBR brakes.
The odds of any of us having one of those cars is pretty much nil, but I guess the parts places have to list the performance package for 88 regardless.

 

Don't use a braided line and a rubber line!
They must be replaced as a pair and of the same material!!
If you had done this on the front you'd put your car in the ditch the first time you hit the brakes.
Fix it quickly!!!

 

Also You need the hard lines off of a 89-92 rearend to properly do the swap.
Or make your own Hard lines.

I just looked @ the 2 autozone links you posted for 88 and one said hose is for the front and the other is the rear??

 

They're all rear brake lines, I just checked the links. They may fit some vehicles front line, but they're all rear lines for a Firebird.

To be honest, I put 15,000 miles on the Formula with one braided and one rubber line and couldn't notice any pull at all, even under very heavy braking (I autocrossed it that way several times). On the front, yes I'd probably notice it, but I don't think our rear brakes even do enough to be noticeable. I mainly did the swap to help fill up some of the gaping space with my 18" rims. Those little 10.5" discs just looked silly back there. I'll get it fixed one of these days, but I'm not terribly worried about it the way it is.

The hardlines for a pre-89 car work just fine for the PBR conversion, you just have to bend the driver line back slightly to make room for the rubber line. Two or three inches is all you need. I will eventually swap over to the 89-up hard lines when I redo the rear brakes, but I'm not too worried about that either. I've still got to change out the proportioning valve too, maybe that will bias a bit more to the rear brakes. I ran them on the Formula with a drum brake prop valve for the same 15,000 miles, and once more, never noticed a difference.

Swap is done, and I'm very pleased with how it came out. There is definitely two different types of hardlines for a pre-89 9-bolt rear though, I got under the formula today and checked. Apparently the earlier design ('85) has a shorter male fitting on the passenger side, where the later design ('88) has a longer male fitting on the passenger side. No idea why they would change (maybe it's a transition thing), but the '88 9-bolt that I have definitely uses an '89-up PBR brake line on the passenger side. Strange.

-cal30sniper

 

Good to hear you got it squared away. It could be somekind of update work done on some of the parts somewhere????
The rear won't throw ya into the ditch but the fronts really will scare ya!
I had a friend ask my y his car was pulling and I found out he replace just one rubber line on the front of his car! I bout filled my britches when I hit the brakes!.