GMT 400 Hydroboost swap

[Chris253]

Just a question for clarification about the evo sensor, can I just unplug it or do I have to use the delete kit?

 

[racprops]

A few years ago I converted my 93 Chevy G20 Van's vacuum brake booster to a hydrobooster. I got it off a 92 G30 Cube van.

On my van every thing lined up correctly.

I have never had the light pedal I expected. It is closer to a manual old drum system currently. All works fine just takes a strong push to make her stop fast.

Reading the thread I saw a post about matching the hydroboost to the correct pump.

Please tell me how to do that. http://www.gmc4x4.com is no more…

I have been told to change the master cylinder to Corvette master cylinder and change real drum brake’s wheel cylinders to larger pistons, which I have done. (This a 93 G20 Van with disk and drums)

I get two versions of this: I need a hydrobooster power steering pump, or I do not need a power steering pump for a hudroboost as they use the standard pump.

Which is it?? From reading this thread I feel it is the pump.

One other version is I just need the higher pressure spring in my standard power steering pump.

Please advice.

Thanks.

Rich

 

[Cokeman95]

A few years ago I converted my 93 Chevy G20 Van's vacuum brake booster to a hydrobooster. I got it off a 92 G30 Cube van.

On my van every thing lined up correctly.

I have never had the light pedal I expected. It is closer to a manual old drum system currently. All works fine just takes a strong push to make her stop fast.

Reading the thread I saw a post about matching the hydroboost to the correct pump.

Please tell me how to do that. http://www.gmc4x4.com is no more…

I have been told to change the master cylinder to Corvette master cylinder and change real drum brake’s wheel cylinders to larger pistons, which I have done. (This a 93 G20 Van with disk and drums)

I get two versions of this: I need a hydrobooster power steering pump, or I do not need a power steering pump for a hudroboost as they use the standard pump.

Which is it?? From reading this thread I feel it is the pump.

One other version is I just need the higher pressure spring in my standard power steering pump.

Please advice.

Thanks.

Rich

You can run either pump but if you run the regular pump you'll need to T the return line since the hydroboost system has 2 return lines. People have done it either way. Do whichever you feel most comfortable with.

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[racprops]

I did but I need something to increase the power, as it is now it is a two foot brake...as in I have driven cars where the power brakes are so powerful I only needed one toe to stop. Most cars I now have only take my toes to stop. This van takes a whole foot for easy stops but a full panic stop needs two feet to really make her stand on her face. It is not right.

A company in CA that does these conversions mage suggestions like to Corvette Master cylinder and wheel cylinders which helped, but not enough.

Rich

 

[Claybreaker]

I did but I need something to increase the power, as it is now it is a two foot brake...as in I have driven cars where the power brakes are so powerful I only needed one toe to stop. Most cars I now have only take my toes to stop. This van takes a whole foot for easy stops but a full panic stop needs two feet to really make her stand on her face. It is not right.

A company in CA that does these conversions mage suggestions like to Corvette Master cylinder and wheel cylinders which helped, but not enough.

Rich

If you look on Rock Auto they show the power steering pump without the reservoir with no mention whether the application is vacuum or hydro brake system. Master cylinder should be the same but you have to be careful that the rod that pushes the master cylinder from the brake peddle is the correct length, as long as you swapped the rod in from the donor you should be good.
I've done a couple of hydro boost swaps, the last was a 95 Astro Van unit into a 1962 F100 with a Crown Vic swap. I purchased the HB unit online, it was rebuilt. I had an issue with peddle feel and a whining when the brakes were applied. It turned out to be a bad hydro boost unit. One hydro test I read about is that when you start the engine the brake peddle should slightly depress automatically, with the brake interlock tied to the ignition it will be hard to tell this, but with no interlock on my F100 and a manual tranny it is noticeable. Good luck.

 

[GordonCustoms]

Well I just picked up a k2500 with hydroboost and I have a nbs master cylinder for it, I'll see if it will bolt up with no issues. Might have to wait till weekend before I can get to it and let you know through. I know the bolt holes line up I think its just the part that fits into the HB is bigger on the nbs MC so thats where the problem is. Unless the HB on my 2000 K2500 is different or was replaced before I got it.

Finally got around to seeing if the NBS master cylinder fit on the OBS Hydro boost, and it doesn't, well the 2006 3500HD one doesn't so I'm going to have to modify this HB to mate up the MC.

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[Jesse_Wenting]

Anyone know if/where I could get the intake manifold, vacuum port cap? Would prefer the cleaner look over a cap on the vacuum hose fitting

 

[Jesse_Wenting]

I ended up clamping a 1/2 rubber cap around the vacuum hose fitting. Fit really snug before I put the clamp on and after bleeding the HydroBooster I'm pretty confident it's working well. Also to maintain my budget I cut the steering gear return line roughly 1/3 from the reservoir, and used a 3/8 hose tee to connect the both unit's return lines to my OE PS reservoir. Will be replacing the PS pump and reservoir when I swap in my built 350

Can't remember if someone already linked the hoses required for this swap but just in case:
PS pump to HB pressure
HB to steering gear pressure

HB to reservoir return
Steering gear to reservoir return w/o cooler
Steering gear to reservoir return w/ cooler

Hope this helps someone

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[SpencerW]

I decided today that I'm switching my 97 obs to hydroboost. I just started LS swapping it. Lq9, big cam, gen 4 rod, holley intake, Terminator Xmax with a built 4l80. Currently painting the firewall on my OBS as I didn't do this originally. I still have my 06 denali that was my donor. Im pulling the hydroboost off of it. I've removed the vacuum booster and pedal from the OBS. But, my pedal off the denali has all sorts of plugs and cables. What will I do with all those, specifically that cylinder with cable coming out of it? I can take pictures if needed.

 

[Supercharged111]

I decided today that I'm switching my 97 obs to hydroboost. I just started LS swapping it. Lq9, big cam, gen 4 rod, holley intake, Terminator Xmax with a built 4l80. Currently painting the firewall on my OBS as I didn't do this originally. I still have my 06 denali that was my donor. Im pulling the hydroboost off of it. I've removed the vacuum booster and pedal from the OBS. But, my pedal off the denali has all sorts of plugs and cables. What will I do with all those, specifically that cylinder with cable coming out of it? I can take pictures if needed.

I think you may also need an adapter plate to run the 800 stuff on a 400 where it bolts to the firewall.