Switching from hydraulic brakes to vaccuum. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**rs74** · 03-07-2013, 08:07 PM

I am going to look at a cab sunday and it has the hydraulic brake system on it. If I want to take that off and put the Vac brake booster and master cylinder on it what all do I have to do. Is it just a matter of unbolting one and bolting up the other. Are the rods different?

v30crewcab · 03-07-2013, 08:55 PM

I have run into the pin on the pedal being a different size, but not sure if they were all that way. otherwise it will bolt right in.

**rs74** · 03-07-2013, 09:36 PM

I am going to get the vin # so I can see what this cab was originally off of.

INSIDIOUS '86 · 03-07-2013, 10:11 PM

Why do you want to change?
Posted via Mobile Device

**rs74** · 03-07-2013, 10:12 PM

Just ran the VIN and it is a canadian truck that came out with a diesel. Looks like I would have to change the wiring harness as well. Not sure about anything else.

**rs74** · 03-07-2013, 10:15 PM

Quote:

Originally Posted by INSIDIOUS '86

Why do you want to change?
Posted via Mobile Device

I just figured that I would put the new cab back the same way the old one was set up. The new cab is from a diesel truck and has different brake system.

**hatzie** · 03-07-2013, 11:54 PM

I'd keep the hydroboost.

**rs74** · 03-07-2013, 11:57 PM

Quote:

Originally Posted by hatzie

I'd keep the hydroboost.

Is that supposed to be better than what came out on the gas engined c10's? I usually only see them on the diesel and one tons.

meatwagon83 · 03-08-2013, 12:04 AM

you only see them on diesels and one tons for a reason, they are a better braking system and dont rely on engine vacuum, designed for stopping the weight of a trailer in addition to the truck, i would surely keep the hydroboost!

**rs74** · 03-08-2013, 12:07 AM

I will have to do some reading up on hydroboost brakes then. I know absolutely squat about them. So bare with me if I seem to have some stupid question. Is it that hard to convert over to hydro if you are on vaccuum. If someone was wanting to do the swap then it is just a matter of putting the hydro on. What about prop valves and the like.

meatwagon83 · 03-08-2013, 12:31 AM

aside from getting the lines that go to the power steering pump, it should be a bolt in, just make sure you have good brake lines, that system puts out some pressure! my 6000 pound dually will stop on a dime!

83GMCK2500 · 03-08-2013, 12:46 AM

Quote:

Originally Posted by meatwagon83

aside from getting the lines that go to the power steering pump, it should be a bolt in, just make sure you have good brake lines, that system puts out some pressure! my 6000 pound dually will stop on a dime!

Not to mention the correct power steering pump reservoir. That 3rd line, the low pressure/vent return from the hydroboost back to the reservoir needs a home.

bilfman · 03-08-2013, 12:55 AM

I would stay with the hydro boost, built for better braking. Essentially it delivers much better braking when towing, often when towing you can get into low vaccum situations often = poor braking, the hydroboost delivers consistent braking no matter what engine load/vacuum levels.

**hatzie** · 03-09-2013, 08:54 AM

You can run a big cam without worrying about vacuum for your brakes.
And... The Hydroboost unit is much smaller than a Vacuum booster so it isn't in the way.

03-07-2013, 08:07 PM	#1
rs74 Senior Member Join Date: Jun 2010 Location: Illinois Posts: 2,957	Switching from hydraulic brakes to vaccuum. I am going to look at a cab sunday and it has the hydraulic brake system on it. If I want to take that off and put the Vac brake booster and master cylinder on it what all do I have to do. Is it just a matter of unbolting one and bolting up the other. Are the rods different? __________________ Roy 85 Short Bed Silverado- Work in progress. http://67-72chevytrucks.com/vboard/s...d.php?t=564818 1987 R10 shortie

03-07-2013, 08:55 PM	#2
v30crewcab Registered User Join Date: Apr 2012 Location: Chatt Tn Posts: 969	Re: Switching from hydraulic brakes to vaccuum. I have run into the pin on the pedal being a different size, but not sure if they were all that way. otherwise it will bolt right in. __________________ 88 military v30 crewcab shortbed 5.9 cummins, nv4500, 205 86 k30, 89 diesel burb, 76 gmc pathfinder 71 longbed 5.3 4l80 http://67-72chevytrucks.com/vboard/s...d.php?t=522535

03-07-2013, 09:36 PM	#3
rs74 Senior Member Join Date: Jun 2010 Location: Illinois Posts: 2,957	Re: Switching from hydraulic brakes to vaccuum. I am going to get the vin # so I can see what this cab was originally off of. __________________ Roy 85 Short Bed Silverado- Work in progress. http://67-72chevytrucks.com/vboard/s...d.php?t=564818 1987 R10 shortie

03-07-2013, 10:11 PM	#4
INSIDIOUS '86 Registered User Join Date: Jul 2009 Location: washington Posts: 4,178	Re: Switching from hydraulic brakes to vaccuum. Why do you want to change? Posted via Mobile Device __________________ 377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511

03-07-2013, 10:12 PM	#5
rs74 Senior Member Join Date: Jun 2010 Location: Illinois Posts: 2,957	Re: Switching from hydraulic brakes to vaccuum. Just ran the VIN and it is a canadian truck that came out with a diesel. Looks like I would have to change the wiring harness as well. Not sure about anything else. __________________ Roy 85 Short Bed Silverado- Work in progress. http://67-72chevytrucks.com/vboard/s...d.php?t=564818 1987 R10 shortie

03-07-2013, 11:54 PM	#7
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,950	Re: Switching from hydraulic brakes to vaccuum. I'd keep the hydroboost. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

03-08-2013, 12:04 AM	#9
meatwagon83 Registered User Join Date: Dec 2012 Location: Preble county ohio Posts: 1,914	Re: Switching from hydraulic brakes to vaccuum. you only see them on diesels and one tons for a reason, they are a better braking system and dont rely on engine vacuum, designed for stopping the weight of a trailer in addition to the truck, i would surely keep the hydroboost!

03-08-2013, 12:07 AM	#10
rs74 Senior Member Join Date: Jun 2010 Location: Illinois Posts: 2,957	Re: Switching from hydraulic brakes to vaccuum. I will have to do some reading up on hydroboost brakes then. I know absolutely squat about them. So bare with me if I seem to have some stupid question. Is it that hard to convert over to hydro if you are on vaccuum. If someone was wanting to do the swap then it is just a matter of putting the hydro on. What about prop valves and the like. __________________ Roy 85 Short Bed Silverado- Work in progress. http://67-72chevytrucks.com/vboard/s...d.php?t=564818 1987 R10 shortie

03-08-2013, 12:31 AM	#11
meatwagon83 Registered User Join Date: Dec 2012 Location: Preble county ohio Posts: 1,914	Re: Switching from hydraulic brakes to vaccuum. aside from getting the lines that go to the power steering pump, it should be a bolt in, just make sure you have good brake lines, that system puts out some pressure! my 6000 pound dually will stop on a dime!

03-08-2013, 12:55 AM	#13
bilfman Registered User Join Date: Dec 2011 Location: Regina, SK, Canada Posts: 622	Re: Switching from hydraulic brakes to vaccuum. I would stay with the hydro boost, built for better braking. Essentially it delivers much better braking when towing, often when towing you can get into low vaccum situations often = poor braking, the hydroboost delivers consistent braking no matter what engine load/vacuum levels. __________________ 1979 Chevy Dually Crew 4X4 454, D60 Tru-trac, D70 Detroit Locker, 3.73, 4L80E/NP205 1971 GMC 3/4 Ton 4X4

03-09-2013, 08:54 AM	#14
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,950	Re: Switching from hydraulic brakes to vaccuum. You can run a big cam without worrying about vacuum for your brakes. And... The Hydroboost unit is much smaller than a Vacuum booster so it isn't in the way. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.



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