Hydroboost

Want some new struts? What brand springs to buy? How much camber to run? What brake pads? What's the best setup for your situation....
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Koots
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Hydroboost

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I don't know if many of you guys have much seat time with a vehicle with hydroboost brakes, but they are superior in every way (can be pretty hard on PS pumps though for trucks with big tires and lifts). I want to adapt one to my Corsica, for engine bay room and rock solid braking.

The reason for posting was to bounce the idea off of you guys. I have a spare parts truck (an 04 2500HD truck) that has a perfectly good hydroboost setup, but wanted to know if a truck master cylinder would be too large for such small cars as ours?

I've got to get the car running and on the road first, but I've got the parts truck for the MC and hydroboost unit and I've got a Malibu I plan on doing the front end swap with to get it's brake setup. I know it's a lot of work, but I plan to strip it all down and pretty much have it ready to swap into the Corsica as soon as i rip the old crap out.


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Koots
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Re: Hydroboost

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It's probably gonna need some spacer or some serious reworking to fit into a FWD sedan. If the Astro van versions are smaller (which they don't appear to be externally) then I might go with it. If it is smaller at all, it will be internally, but those astro vans are built for handling a fair bit of human cargo and could definitely use the extra power.

So I don't see an issue other than maybe having brakes that lock up immediately, which I'm afraid of.


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woody90gtz
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Re: Hydroboost

Post by woody90gtz »

I've gotta think your pedal travel will be very little from disengaged to locked. The calipers on those HD trucks are huge, so the hydroboost master is going to move a lot more fluid. And I don't think a FWD master will fit on a RWD hydroboost to fix that issue. Mounting will also take some fab work I'm sure.

Vacuum boost to hydroboost was a huge upgrade on my truck, so I know why you're thinking about it...but I don't know how good it would be for a Corsica.


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Koots
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Re: Hydroboost

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If not, the Astro van hydroboost units would probably work better. I believe they have a smaller cylinder.

I plan on removing the ABS anyway, regardless of plan, So I will have some small line changes to fit anyway.

There isn't a lot of information about the GM hydroboost units, I know that the early 80's version I have in my Jimmy is slightly smaller cylinder diameter, so I might swap it to the larger newer version and swap that one into my car.

I've been reading about a few people running Astro van hydroboost and other than some modification, they sound very pleased.


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Barry
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Re: Hydroboost

Post by Barry »

Just look up bore diameters and piston diameters/quantaties and you can do some simple math to estimate how it will work. Smaller master bore will give you more pedal travel and larger bore will offer more


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Koots
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Re: Hydroboost

Post by Koots »

I'm just gonna have to measure them myself, because I couldn't find much information about the actual differences between them. If not I'll try and pick up a 99+ Mustang unit.


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Re: Hydroboost

Post by daguse5853z »

I was toying with the idea of putting hydroboost in my S10 when i get some spare change to throw at it.


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Koots
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Re: Hydroboost

Post by Koots »

After doing some looking at my 2500HD hydroboost unit, then looking at the astro van unit pics online. I can see that the 2500HD's weird mounting plate bolt pattern won't work, but it's much flatter faced than the astro van unit. So it might not fit right in.

I'm gonna try to get a detailed look at it all tonight. My working 2500HD w/hydroboost is not nearly as ridiculously overboosted as those on my K5. So it should feel sensible and also means I can upgrade brakes without every worrying LOL


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88*Beretta
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Re: Hydroboost

Post by 88*Beretta »

Koots wrote:hydroboost unit,
Putting an over-sized hydrovac unit in will bring about a serious braking issue...one light touch on brake pad may lockup brakes.

My brother and I did it years ago...from like a Blazer to a smaller S-10 vehicle...wrong, wrong, wrong.


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Koots
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Re: Hydroboost

Post by Koots »

The newer units aren't nearly as aggressive as the older units, in my experience.

I have the 2 generations of GM truck hydroboost, with my 6.2 diesel 1983 K5 Jimmy and my 2002 2500HD Silverado. The Jimmy can slam a person through the windshield, and this is pretty much the same unit used up until 2001. My 2500HD just feels normal, but with very consistent brake boosting. I don't get any of that "head through the windshield" feeling when I slam on the brakes...even with huge 4 wheel discs (13.1" rear discs alone)


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Koots
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Re: Hydroboost

Post by Koots »

88*Beretta wrote:
Koots wrote:hydroboost unit,
Putting an over-sized hydrovac unit in will bring about a serious braking issue...one light touch on brake pad may lockup brakes.

My brother and I did it years ago...from like a Blazer to a smaller S-10 vehicle...wrong, wrong, wrong.
I should also mention that I will be doing this along with an N-body brake swap and I'll also be running larger tires as well to fill out the wheel wells and get some extra ground clearance.

SO I should be able to make use of the extra boost. If not, then I'll see if the Astro van units are any better, but they don't seem like it, other than how it mounts and some part angles. The Bendix hydroboost units went through very little changes and they should be all the same year to year, with the aforementioned 01+ switch over being the difference between all the 82-present units.


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88*Beretta
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Re: Hydroboost

Post by 88*Beretta »

Koots wrote:N-body brake swap
I own a 1984 244 Volvo, and serveral years ago, I plugged the hydrovac unit's vacuum line since hydrovac was defective and sucking vacuum off.

Yes, to lockup brakes now requires a pinch more "manpower," but I like it just fine; and being the only driver, it works for me.

Think of the savings, some $100.00, and an extra few hours to do something else :crazy: :-)

Seriously, I prefer having a firm pedal action, especially in winter time, with snow/ice around. I never did like "power brakes," especially on automatic vehicles in winter time.


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