B/F body brake swap questions

[85 Cutlass Brougham]

I just ordered a set of Global West Negative Roll upper control arms for my 1985 Cutlass and plan on getting a set of B body spindles and calipers to go with them. I want to use the 1LE 3g Camaro 12" rotors up front as they are identical to B body pieces save for the bolt circle.I need to know which brake hoses to use-donor B body or G body? Also, which Master cylinder has the right volume to use with these calipers? I am also thinking about using a 8.5 rear from a turbo Regal or 442 and wonder if the larger disc brakes off a 4g F body will bolt to the axle flanges, and if so, which master should I use with this brake combo? Can I just gut the Prop valve and use an adjustable aftermarket one to set the brake bias?

 

[joe_padavano]

I just ordered a set of Global West Negative Roll upper control arms for my 1985 Cutlass and plan on getting a set of B body spindles and calipers to go with them. I want to use the 1LE 3g Camaro 12" rotors up front as they are identical to B body pieces save for the bolt circle.I need to know which brake hoses to use-donor B body or G body? Also, which Master cylinder has the right volume to use with these calipers?

The B and G bodies of the 80s should use the same GM "metric" calipers, so your existing master cylinder and hoses should be fine.

I am also thinking about using a 8.5 rear from a turbo Regal or 442 and wonder if the larger disc brakes off a 4g F body will bolt to the axle flanges, and if so, which master should I use with this brake combo? Can I just gut the Prop valve and use an adjustable aftermarket one to set the brake bias?

You don't want to "gut" the proportioning valve, since that means removing the differential pressure switch piston. This would cause the front and back brake circuits to be connected together. If you plan to run an aftermarket adjustable proportioning valve, you can either simply bypass the factory valve completely (use a tee fitting to split the front pipes) or get the distribution block from a 67-72 drum brake GM car. The latter option will allow you to retain the differential pressure switch function while still using the adjustable proportioning valve.

 

[85 Cutlass Brougham]

Well, I was talking about removing the residual pressure valve that is there for the drum brakes but which causes the discs to hang up when it's left there. A friend of mine did this on his 88 Mustang when he swapped and it works fine. I am then assuming that the B body and G body use the same caliper piston volume? I thought that the B body has a larger piston which would then require a larger volume master to compensate and keep it from a mushy pedal. I know I swapped all of this when I did a F body rear disc swap because it lacked sufficient volume to pressurize the calipers. I also swapped the prop valve at that time. The F body calipers I want to use are the PBR calipers used on 88 and newer Camaros ( they replaced the crappy Delco-Moraine units used before them) along with the 11 inch rear discs so maybe I should look into getting the 4 wheel disc pieces from a Camaro and just use that Prop valve and master....

 

[joe_padavano]

...The F body calipers I want to use are the PBR calipers used on 88 and newer Camaros ( they replaced the crappy Delco-Moraine units used before them) along with the 11 inch rear discs so maybe I should look into getting the 4 wheel disc pieces from a Camaro and just use that Prop valve and master....

I talked to ECI brakes several years ago and they mentioned that the PBR calipers require a higher line pressure (and thus a smaller diameter master cylinder piston) than the GM calipers. Someone needs to check me on this, but if so, I don't think you can mix PBR and GM calipers on the same car. ECI had warned against it.

 

[Stoopud]

4th Gen F-Body Rear Brakes

Hi,

A freind of mine just converted his 3rd Gen Camaro (sam rear as a G Body) to 4th Gen Rear Brakes, and it was easy. If you use an early 4th Gen donor, the bracket adapts with minimal cutting and the bolt holes lined-up. You will need to re-route/ adapt the lines to work with the calipers, and add an aftermarket prop valve.

I plan on copying this conversion very soon (finishing body work first), and converting to 2002 Blazer front brakes (4 piston I think - but definetly better than stock G-Body).

If I can get more info (like how much was milled from the rear caliper bracket, I will re-post. Anyone with info on the Blazer conversion, please let me know how hard it is. It looks easy

Thanks,

Stoopud