Quote Originally Posted by 1project2many View Post
I probably should have mentioned this before your swap. The Savana / Express HB Master Cylinder is "quick takeup" design. On our buses with 3 1/2 X 13 rear drums, several factors including this MC contribute to rear shoe overheating. We have gone a long way toward making the rear brakes on the '97-'02 buses last as long as they did on the 95 and down vehicles, and one experiment was using the older MC in the newer van. With the older cylinder the brakes apply quickly without the slow, lazy feeling that accompanies most quick takeup m/cyls. It requires a little more pedal effort but it's really not bad. Ultimately, anyone wh's driven for years appreciates the "direct" feeling provided by the older m/cyl.

Additionally, if your van has "auto adjust" built into the park brake pedal, this mechanism works to keep tension on the park brake cable so the brake is always in adjustment. We've found this can prevent shoes from retracting fully when the brake is released. We switched long ago to a park brake pedal from a '99 K30 truck (others may be the same). If you decide to pursue this change I can provide a few more details.

Finally, we've replaced the rear wheel cylinders with smaller diameter versions from a 3/4 ton van and tried to choose front pads that are a bit more agressive. This places more of the work to stop the vehicle on the front brakes. We get about 20k miles between pad swaps for these stop and go, in city vehicles. This may not seem optimal but a pad replacement can be done in 1/2 hr where a rear brake job including replacing drums can require 4 hrs or more.

Anyway, keep up the good work.
I appreciate the input, might end up having to talk with you on the 99' K30 pedal. I have not looked yet, but I seem to remember my parking brake pedal having a goofy contraption on top of it.

Atleast initially I will be running the Hydroboost cylinder on the 1500 brakes (8,800 gvw front calipers/pads). I am sure the larger cylinder will make the brakes feel more direct as well. I noticed on the truck sites that the GMT400 truck guys tend to upgrade to larger GMT800 master cylinders to obtain a better pedal feel. On the vacuum booster setup I was running the larger 2003+ Express master cylinder from a van that had a vacuum booster.

Are you using the wheel cylinders off the 13 x 2.5" brakes or the 11 x 3"? When I put the light duty 6 lug 3/4 ton 9.5" rear end in my Express I was able to reuse the 8.5" backing plates, brake shoes and wheel cylinders and merely changed the drums.

13 x 3.5" is what I will be running in the rear with the 10.5" 14-bolt as well.