The "Tan Brick" aka my 1997 Express Cobra conversion

[1project2many]

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.

[Fast355]

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.

[1project2many]

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.

Yes, the cylinders are from 13 X 2 1/2 brakes. 1 1/16" diameter cylinder. Carquest number EW79767. The original number is EW79768.

You can tell if your park brake has the auto tensioner by looking for a single flat piece of metal resting against a clear piece of plastic below the pedal arm. When you apply the brake this piece moves away from the clear plastic and creates friction to hold the drum that pulls the cable.

The full floating rear is a nice choice. If it's the one with slip on drums then the hubs are unique to that axle. The distance between the inner and outer hub bearings is smaller on the slip on axle and the wheel flange is located slightly closer to the inner wheel seal compared to most 14 bolts.

[Fast355]

Yes, the cylinders are from 13 X 2 1/2 brakes. 1 1/16" diameter cylinder. Carquest number EW79767. The original number is EW79768.

You can tell if your park brake has the auto tensioner by looking for a single flat piece of metal resting against a clear piece of plastic below the pedal arm. When you apply the brake this piece moves away from the clear plastic and creates friction to hold the drum that pulls the cable.

The full floating rear is a nice choice. If it's the one with slip on drums then the hubs are unique to that axle. The distance between the inner and outer hub bearings is smaller on the slip on axle and the wheel flange is located slightly closer to the inner wheel seal compared to most 14 bolts.

It has slip-on drums. My intentions are to run the really lightweight 16" alloy wheels from the newer HD trucks and a highway tread LT tire.



I just got off work a little while ago and about to start installing the KYB Monomax shocks I ordered on Amazon for it.

I couldn't turn down the opportunity to jump up to the 1-ton stuff. I got the whole used suspension for $350 and only payed $300 for the 10.5". Most places I couldn't pickup the forged upper control arms and spindles for what I paid for the whole suspension. I didn't even have to touch the stuff, they took it off, brought it too the shop, unloaded it in the floor and we chained up the rear axle to my cherry picker and unloaded that massive 10.5.

[Fast355]

You can tell if your park brake has the auto tensioner by looking for a single flat piece of metal resting against a clear piece of plastic below the pedal arm. When you apply the brake this piece moves away from the clear plastic and creates friction to hold the drum that pulls the cable.

I am having a hard time telling based on your description but I snapped some pictures. Tried to get many differemt angles.

[Fast355]

I have made some progress the last couple of days.

Got the old shocks off and the new ones on.





Noticed the rear bump stop/spring thing-a-majigs were wasted.



Got some new ones even though I plan to ditch this rear-end around fall for the 10.5.



Rear suspension is looking alot better. I hope the way it drives reflects the time and money invested.



It seems to sit higher with the new shocks on all 4 corners.


I got the junkyard hydroboost pedal cleaned up, the pin is closer to the pivot on the Hydroboost pedal on the left.



I cleaned and test fit the booster and master cylinder.




With the right parts Hydroboost is a bolt-on swap for a G1500 Express.


My harness was a mess due to lack of space when doing the 0411 swap a few years ago. I started cleaning up that aspect of the harmess but in doing so basically am having to do the swap over again.







PCM back in the holder only have the "BLUE" side left to rework, install the hydraulic hoses, install the booster, bleed the brakes, and hope the engine starts and everything works correctly after the wiring harness work. This project has kicked my butt! Oh and I finally ordered wiper cowls and grille clips that GM wants a small fortune for.

[JeepsAndGuns]

You are going to love the hydroboost. I have converted my 79 cherokee and 93 wrangler and I will NEVER go back to a vac booster.

[1project2many]

Attachment 9042

The lever (green arrow) is part of a spring wound around the cable take-up. The lever contacts the stop (blue arrow) when the brake pedal is released. This causes the spring to "unwind" slightly and release the take-up. The take-up is spring loaded and attempts to "wind up" the cable and take up slack. When the pedal is pressed the lever moves off the stop, the spring around the take-up contracts, and the take-up is held tight so the park brake can be applied.

[Fast355]

You are going to love the hydroboost. I have converted my 79 cherokee and 93 wrangler and I will NEVER go back to a vac booster.

I KNOW!!!! I have driven these with Hydroboost and don't understand why GM cheaped out so much on these Express vans as even the same vintage Astro/Safari vans came with Hydroboost.

Then again the brainiac that is truly to blame is the idiot that felt the need to offer a 1/2 ton van as an upfitter package for a conversion van. Should have been a 2500 series as a minimum with all the extra stuff it is carrying around. The weight killed the 4L60E TWICE in 78k miles (4L65E spec rebuild went in at 38K) and the 8.5" died shortly after the 4L80E went in. Then again it gets driven a bit hard and was not exactly stock for the 4L65E spec trans and the 8.5s death. As big and heavy as these vans are, NONE of them should have had the 8.5 or the 4L60E for that matter.