A few years ago I swapped all the parts from a salvage rearend to put the '89+ PBR brakes on my '88 GTA (it had the horrible disc design). Both the old discs and the "new" PBR disc setups have never had e-brakes that could hold the car over about 1,200 rpm in Drive. I never park on hills, and I don't drive the car too much, so the e-brake isn't that big of a deal - relatively speaking. (ironically, it was a quest for a better e-brake that made me do the PBR swap...)

What gets me is how the rear brakes are just along for the ride. On jackstands, they won't stop the rear wheels - I have to slide the selector into Neutral so the rear wheels will stop, then quickly push it into Park. I assume I had this problem with the original rear discs, but I never realized it until after the rear swap. Braking hard on the street feels no weaker now than it ever did.

The car has the original (or a replacement of original by previous owner) master cylinder and the original PV. I have been told that the master cylinder for '89+ PBRs is the same master cylinder used on '88 and older drums.

I am curious what my first step should be to get rear brakes that actually work. Do I need to get a new master cylinder that is the correct P/N for a '89+ rear PBR car? Does it need a different PV? I have read here and been told by friends that even the '89+ cars can be found with weak rear brakes. I saw one person post on here that after replacing the M/C and PV they still had no rear brakes.

I am also content just going to a Wilwood setup if that is the easiest route to take.

When I did the swap, the calipers were fine, and I put on new rotors and new pads. The car gets driven very little, so those parts are still "like new."

The system has been bled many, many times starting with the right rear and working forward.

Any advice is appreciated.

 

you need the correct proportioning valve you can adapt in a valve like this.

http://www.summitracing.com/parts/SUM-G3910

 

I like how that part has the hookup for the warning light. Would this swap eliminate any issue with the master cylinder if it's not the ideal P/N?

 

I think you also need a larger master cylinder BENDIX Part # 12263 I would contact moderator jamec hes the pbr expert. I converted my 67 camaro to j65 pbr's and used a ssbc adustable proportioning valve and stock master cylinder it works awesome.

 

In regards to the first paragraph:

My Parts and Illustration Cat. shows the same Cylinder, Brk Master GM 18014286, 89-91. Earlier years show different masters for J50 and J65. GM, however, pretty much made them interchangeable:

https://www.thirdgen.org/forums/susp...fferences.html

There are different combination valves (if only one was needed, why would GM design valves for different applications?). For exampe:

Valve, Brk Combo (1989 2nd Des) (J50) (1990 [and also 91]) (J41, J42) GM 10136839
J41 - BRAKE SYSTEM, POWER, FRONT DISK, REAR DRUM, CAST IRON
J42 - BRAKE SYSTEM, POWER, FRONT DISK, REAR DRUM, ALUMINUM

Valve, Brk Combo (1989 1st Des) (J65, 1LE, Y82) GM 14089496
J65- BRAKE SYSTEM, POWER, FRONT & REAR DISK
1LE - PERFORMANCE PACKAGE, SHOWROOM STOCK RACING
Y82 - MERCHANDISED PACKAGE, FORMULA

Second paragraph:

For best braking performance the first-design 1LE valve is your best bet. A couple of other areas where issues might arise: Check the slider pins, which can become useless with years of accumulated grime and ancient grease. Also, there's the question of 'free travel' if you haven't addressed that:

https://www.thirdgen.org/forums/susp...ear-brake.html

https://www.thirdgen.org/forums/brak...-i-adjust.html

EDIT: Another thought. Did you use the correct parking brake cables and did you adjust them at the tunnel-mounted adjuster above the drive shaft?

JamesC

 

 

Thanks for the replies everyone. I will study up on the advice and links over the weekend!

 

James, if i'm converting my rear drums to the pbr rear disc system, do i need to change my master, and/or my brake booster?

 

No and/or no.

JamesC

 

I'm having the same problem with my '88 GTA/'89 PBR disc conversion. Did you ever find a solution to your problem?

-cal30sniper