Vacuum to Hydro...Can someone write guide?

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usar17

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So I'm planning out long term things while i save money for more parts and projects. I'd like to upgrade to hydroboost eventually. My current 305 has horrible vacuum so my brakes suck. I'm replacing it with a rebuilt 350 so that will help some. But i'm also planning on doing the serpentine belt conversion, at which point I can use a power steering pump designed for hydroboost.

What all needs to be switched over???

I assume:
Brake Pedal
Vacuum booster to Hydrobooster
Master Cylinder



Do any of the brake lines or threads NEED to be swapped? Or could I just swap the above for now and later change over to the bigger calipers?

It would be nice if someone did a how-to write up on this conversion :)
 

usar17

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I actually am about to swap the front axle to the 3/4 ton. Can I switch to the round banjo calipers now while I still have a jb6 system? I know I would need new hoses but will the 8+k gvw hoses direct fit with the current hard lines? The steel brake are mainly what I'm asking about for this whole thread
 

chengny

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Master cylinder remains the same as do the brake pedal and linkage.

Nothing gets changed on the brake high pressure hydraulic side - don't even need to remove pressure lines. Just replace the complete vacuum chamber assembly with a hydroboost unit.

Some different steering pump/hydroboost hydraulic hoses must be installed. If your P/S pump doesn't have an extra return port, you need to tee into the return from the steering gear unit.

Basics on Hydroboost - post #6:

http://www.gmsquarebody.com/forum/showthread.php?t=2757

Couple of images showing piping:


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I will provide better images soon.
 
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Jeff Dodson

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I have HYDROBOOST on my 82 K20 4x4, it AINT all that. My truck WAS as diesel but it now has a 350. BTW, why do you not have enough vacuum.
 

SlickGTP

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I'll be doing the swap here sooner or later... When I do it, I was planning on doing a write-up. Have all the parts, just have to clean it all up and make it look pretty before I get to it.
 

skysurfer

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Master cylinder remains the same as do the brake pedal and linkage.

Might be a model-specific issue, but I had to change the brake pedal also. The attachment point for the push rod is in a different location on the hydroboost pedal. The vacuum pedal might work, but I wanted to be sure the foot pedal stayed in the same position in relation to the floor.

Another difference is the orientation of the hard lines coming out of the master cylinder. The original vacuum setup had the large reservoir with the small line towards the front.

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The hydroboost m/c was reversed with the large reservoir towards the firewall.

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It's not an issue, just a matter of carefully bending the lines to line up with the correct ports. When the hydroboost m/c failed, the replacement m/c came with the ports as they were originally so I reversed them yet again.

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The pumps all seem to be the same. The pump I used came from a mid-nineties Suburban and had the return port on the tank. After a while it started making some noise so I installed my original pump inside the tank with the return port and it works fine.
 

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