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Old 05-15-2002, 08:48 PM   #1
Scrub
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Post Hydro boost Brakes

I have two trucks that have newer 1 ton front ends. A 2x4 70 gmc and a 4x4 72 Chevy with a newer dana-60.
I think I need to put the hydro boost on these as I get a lot of brake fade with a big load on.

Anyone ever do this swap. Anyone have a hydro boost to sell?

Thanks in advance


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Scrub
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
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Sisters, Oregon - Home of the Sisters Rodeo.
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
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Old 05-15-2002, 09:15 PM   #2
Longhorn Man
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The hydro boost will only help maintain vacume, the brake fade is caused by the gasses and heat created in the drum, therefor causing the shoes to be forced away from the drum surface.
Onless by fade, you are refering to only getting a couple times pressing on the brakes, then the pedal gets hard...as if the engine was shut off. Then the hydro boost will help. Look under the hood of '73 - '87 6.2 diesel trucks. And Hummers have the same thing, but...not like you'll find a hummer in your junk yard.

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
E-mail longhornmail@yahoo.com
My name is Andy...not Randy...I'm in Ohio...Not Illinois...close enough?
Columbus Ohio


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Old 05-15-2002, 09:43 PM   #3
Scrub
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Thanks LonghornMail. Nice to hear the good news about your wife.

BY fade, I mean when the truck is empty, I have plenty of brake, but when I get a really big load (Like a 10,000 pound trailer with no brakes) I about push the seat through the back of the cab trying to stop. The front discs are those huge bendex things that always have a hydro-boost on them. I was told I could use a 72 1-ton master cylinder with vacume boost, but it really isn't right.

The hydro boost system doesn't use any vacume, it works off the power steering pump. I just wanted some pointers on installing one as it seems like it is tied into the steering shaft or something.

Thanks again

------------------
Scrub
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
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Scrub
Sisters, Oregon - Home of the Sisters Rodeo.
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
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Old 05-15-2002, 09:56 PM   #4
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I have a hydraboost on my C30 carhauler. The requisite brakes are gigantic and require huge amounts of brake fluid. Hydraboost master cylinders have 1 1/4" bores for lotsa volume, but that large of a bore needs a booster. Normal vacuum-boosted masters are 1 1/8" and 1", while manual brake bores are 7/8" or 15/16" for easier pushing at the cost of longer pedal travel.
Hydraboost will help you if you run out of pedal travel, but your case sounds like the pedal is still hard and you're not stopping, which means fliud fade (boiling) or pad fade.
Bigger brakes or maybe fresher fluid will help.
The power steering pump powers the hydraboost booster and THEN the steering box.
You might try Eldorados and toronados for small hydraboost setups.
And you'll need a pedal pushrod 15/16 or 1" longer after you adapt the booster bracket to the firewall mount.


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Old 05-15-2002, 09:56 PM   #5
Longhorn Man
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Ok, the hydro boost is a vacume pump that is run off they hydraulics from the power steering pump. If you have the brake booster already, and have good engine vacume, it'll do nothing but clutter your eng compartment.
Also, you'll have to chainge over to the newer style acc brackes being that it needs to be mounted on the upper drivers side...right where your alt is (if you have a small block anyways)

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
E-mail longhornmail@yahoo.com
My name is Andy...not Randy...I'm in Ohio...Not Illinois...close enough?
Columbus Ohio


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Old 05-15-2002, 09:57 PM   #6
BLAZERMAN
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I found my hydro boost at a local truck salvage yard,it came off an 84 2 wheel drive 1 ton wrecker, got it, the pump and brackets and the steering box for 100.00, found a complete rebuild kit for the booster on ebay, havent got it all on yet, I have started on an adapter to bolt it to the firewall and an adjustable pushrod.

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72 Blazer CST, 2-1/2" skyjacker lift with 33x12.50 bfg's

71 Cheyenne K-20,4" tuff country lift with 36's.

69 Custom 30 long stepside 4" rancho lift 36" directional tires,14 bolt rear with detroit locker,dana 60 front with trac-loc

1987 k-5 blazer

2001 Intrepid

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Old 05-15-2002, 10:17 PM   #7
BLAZERMAN
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Scrub, heres a pic of one installed on a 72 burb, you can use your brackets with the special power steering pump these use, and I think they give much more room in the engine compartment, especially on a 4x4.


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72 Blazer CST, 2-1/2" skyjacker lift with 33x12.50 bfg's

71 Cheyenne K-20,4" tuff country lift with 36's.

69 Custom 30 long stepside 4" rancho lift 36" directional tires,14 bolt rear with detroit locker,dana 60 front with trac-loc

1987 k-5 blazer

2001 Intrepid

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1970 GMC 3500 157" W.B. single wheel C&C
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Old 05-15-2002, 10:24 PM   #8
Longhorn Man
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offf, thanks guys, I thought it was a vacume pump. Oh well, he got the info needed...all that matters.

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
E-mail longhornmail@yahoo.com
My name is Andy...not Randy...I'm in Ohio...Not Illinois...close enough?
Columbus Ohio


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Old 05-15-2002, 10:35 PM   #9
Scrub
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Thanks,

So I reroute the powersteering pressure-side hose to go through the Hydro-boost and then to the Steering box. then I take the return line from the hydroboost and "T" it into the return line from the Steering box.

Is that correct?

Do I need a bigger pump? I have an AGR oversized pump on the 4x4(OK it's still in the box) but the 2x4 is still stock.



------------------
Scrub
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
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Scrub
Sisters, Oregon - Home of the Sisters Rodeo.
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
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Old 05-15-2002, 11:45 PM   #10
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High pressure line out of the pump to the inboard side of the booster. Another high pressure line from the outboard side of the booster to the high-pressure side of the steering box. Return from the steering box can tee with another return from the booster (3 lines total to the booster), or I've seen hydraboost pumps with two return barbs.

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Old 05-16-2002, 04:57 PM   #11
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BlazerMan,

What was involved in mounting the assembly to the firewall? Did you use a donor pedal assembly?

I really want to do this on my '72 Jimmy 4x4 project. I'm going D60/14-Bolt and 4-wheel discs so I *know* my original 1/2 stuff ain't gonna cut it. If this swap wasn't too painfull it looks like a killer way to go!

Any words of wisom are greatly appreciated!

Sledge
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Old 05-16-2002, 05:25 PM   #12
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sounds like you just need a bigger truck or larger axles for the larger brakes, or get those trailer brakes, before you end up eating the back of a vehicle..
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Old 05-16-2002, 05:41 PM   #13
Scrub
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I have the big axles and big brakes. The front discs are 1-ton with 1.25 inch thick rotors. The back are 1-ton Corp-14 with 12 inch drums.

I just need the correct master cylinder. The brakes where made for the hydro-boost system.

Trailer brakes would be an inteligent choice too, but no ever accused me of having any brains.

Thanks

------------------
Scrub
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
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Scrub
Sisters, Oregon - Home of the Sisters Rodeo.
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
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Old 05-19-2002, 12:32 AM   #14
Scrub
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Does anyone know if a Hummer Hydro boost is the same creature as the chevy?



------------------
Scrub
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
__________________
Scrub
Sisters, Oregon - Home of the Sisters Rodeo.
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.
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