The "Tan Brick" aka my 1997 Express Cobra conversion

[Fast355]

Finally finished this project and it has been very worthwhile. Test drive revealed much better handling and ride. The hydroboost/larger bore 1-ton master also works so much better than the vacuum setup. I am having to learn how to brake all over again.

[JeepsAndGuns]

Hahaha, I know the feeling. When I did the swap on my wrangler, I had already converted to rear discs and larger dual piston front calipers. I had more pedal travel than stock (but not a unsafe amount) I went from the stock disc/drum 1 inch bore MC, to a 1-1/8 bore disc/disc MC and hydroboost. First time I hit the brakes I thought I was going to stand it on its nose and go through the windshield.

[Fast355]

Hahaha, I know the feeling. When I did the swap on my wrangler, I had already converted to rear discs and larger dual piston front calipers. I had more pedal travel than stock (but not a unsafe amount) I went from the stock disc/drum 1 inch bore MC, to a 1-1/8 bore disc/disc MC and hydroboost. First time I hit the brakes I thought I was going to stand it on its nose and go through the windshield.

Mine was just the opposite. My stock master was 1 1/8" or 28.57mm. I had already stepped up to a 34mm 2003+ Express 1500 master cylinder for disc/disc. With the original master cylinder the pedal was very vague and then transitioned to rock hard with about 1" of height off the floor. With the 34mm newer master cylinder the pedal response was honestly quick, maybe even too quick, but the pedal effort was very high and under panic type braking, it really felt like it had less stopping power than stock and it may very well have. Not really enough to be dangerous IMO, but enough to be noticeable. The 1996-2002 G3500 single rear wheel master cylinder is 1.25" or 31.75mm bore and setup for disc/drum. Its right in the middle of the two extremes above. Perhaps the reason it feels like the best of both worlds. The pedal response is quicker than stock, a little slower than the 03+ master, yet with the Hydroboost the pedal effort is less than it was stock. It would be very difficult to explain the difference to somebody that had not already felt the difference in their own rig. When I first hit the brakes hard, I felt like I was going to face plant the dashboard which is no small feat in a 6,200 lbs Express.

[Fast355]

I drove it again this morning on my way to work. Out of a red light, aimed toward an on-ramp, I jumped on it. I noticed the axle wrap/wheel hop has been greatly eliminated. The thing screeched the right rear tire, the G80 in the 9.5" locked, felt like it jumped up, planted itself, and took off! I kept it planted on the floor for ~1/4 mile uphill on-ramp, glanced down at the top of it and was already rolling 85 mph. It happened so quickly and smoothly, I did not even notice I was rolling along that well. Cruising down the highway on my way to work, I noticed having new wiper cowls probably cut down 50% of my wind noise at 80 mph. Honestly speaking, I can't wait to get the rebuilt 1-ton suspension, brakes and rear-end under it and get the Hellwig rear sway bar ordered.

[jim_in_dorris]

Fast, I have a 90 Astro van with hydroboost brakes. Would that unit be adequate for installing in a 1/2 ton 4x4, or should I look for a 3/4 ton or 1 ton unit out of another pickup.

[JeepsAndGuns]

Fast, I have a 90 Astro van with hydroboost brakes. Would that unit be adequate for installing in a 1/2 ton 4x4, or should I look for a 3/4 ton or 1 ton unit out of another pickup.

One of those would be perfect for a 1/2 ton. The astro van hydroboosts are a very popular swap for the fullsize jeeps (wagoneer, cherokee, J-10, etc..) Everyone who installs one loves it.

[Fast355]

Fast, I have a 90 Astro van with hydroboost brakes. Would that unit be adequate for installing in a 1/2 ton 4x4, or should I look for a 3/4 ton or 1 ton unit out of another pickup.

Those Astro/Safari vans are basically 1/2 ton truck or 2nd generation F-car like brake setups. The Astros hydroboost sits at a downward angle on the firewall. Hydroboost is commen to find in the later G-vans as well. From about 1993 to 1995 it seems nearly all the G20s and G30s used hydroboost.

[JeepsAndGuns]

The Astros hydroboost sits at a downward angle on the firewall.

Not all. Most all I see at the junkyard are straight, only a few have been angled down. Not sure if its a year range thing or what. The ones with the straight mounting plate are usually really easy to adapt to other vehicles.