Where do the power boosters leak from? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67ChevyRedneck · 10-01-2016, 05:57 PM

Well, my 45 year old booster finally pooped the bed, but I can't figure out where it's leaking from (maybe the back side?)

With the brake pedal out you hear PSSSHHHHHHHH. Push the pedal in and silence. I pulled the hose and plugged it to verify it wasn't the hose cracked. I tried putting my hand over different areas, but the motor/fan are too loud to tell anything.

Just curious as to where it could be leaking from.

Also, does anyone have the P/N for a correct factory replacement 1971/72 C-10 2wd Power Disc Brake booster? Its a delco Maraine.

flashed · 10-01-2016, 06:04 PM

It may be leaking on the inside ,our 72 Chevelle leaked inside and I only figured it out when I changed the booster .I looked all over for a leak in the usual spots and found nothing .

Bigdav160 · 10-01-2016, 06:08 PM

AT rest, the valve in the booster keeps vacuum inside. When you step on the pedal it opens a valve to dump the vacuum to the atmosphere. Sounds like the valve is leaking

67ChevyRedneck · 10-01-2016, 06:09 PM

Ah, yeah the boot on the backside looks terrible... The inside diaphragm may look the same!!!

So I guess there was a delco and bendix? What the heck is the difference?

... and the pic is too small... great....

GM man · 10-01-2016, 08:39 PM

Mine was loosing fluid and couldn't figure out where it was going. When I removed my booster, it had fluid in it. Guess the master cylinder was leaking and allowing it to go inside the booster. Still can't figure out how that happened.
Looking at your pics, I would have said that you have a Bendix because the Delcos were kind of a gold anodized color, but yours says Delco on it. So I guess your booster got painted at some point. If I remember right, I think the only real difference between the two is that they have a different bolt pattern.

67ChevyRedneck · 10-02-2016, 01:06 AM

Thank you, so I'm definitely looking for a Delco, just have to pick where I want to buy it from.

Edit: Ordered a Delco Maraine Reman unit.

Yes, it was that anodized color at one time, I'm the one that painted it black (my truck is far, far, far from stock). I took everything off of a 1971 GMC 1/2 ton from a junkyard in 2000-ish, the entire cross member with all suspension parts, steering box, booster, MC, and all lines, brackets, and rods (the MC has since been changed out). I think I stole it all for like $150.

67ChevyRedneck · 10-02-2016, 03:03 PM

Something is stuck.

I went to move it this morning and it was hissing with the brake pedal out, at rest - it was leaking with it pushed in. Then I go to move it again this afternoon... no leaking... so I took it for an hour cruise... no hissing.

I ordered a new one last night, it's still getting swapped.

stsalvage · 10-02-2016, 08:36 PM

A power booster will last 20 years but one bad master 6 months tops that new brake fluid is really nasty.it will east pain in 6 hours clear coat it take a little more time.Plus are parts are made in china not the best rubber on the planet there

10-01-2016, 05:57 PM	#1
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Where do the power boosters leak from? Well, my 45 year old booster finally pooped the bed, but I can't figure out where it's leaking from (maybe the back side?) With the brake pedal out you hear PSSSHHHHHHHH. Push the pedal in and silence. I pulled the hose and plugged it to verify it wasn't the hose cracked. I tried putting my hand over different areas, but the motor/fan are too loud to tell anything. Just curious as to where it could be leaking from. Also, does anyone have the P/N for a correct factory replacement 1971/72 C-10 2wd Power Disc Brake booster? Its a delco Maraine. Attached Images __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

10-01-2016, 06:04 PM	#2
flashed Registered User Join Date: Oct 2009 Location: canton ga Posts: 12,724	Re: Where do the power boosters leak from? It may be leaking on the inside ,our 72 Chevelle leaked inside and I only figured it out when I changed the booster .I looked all over for a leak in the usual spots and found nothing .

10-01-2016, 06:08 PM	#3
Bigdav160 Registered User Join Date: Apr 2011 Location: Klein Texas Posts: 3,852	Re: Where do the power boosters leak from? AT rest, the valve in the booster keeps vacuum inside. When you step on the pedal it opens a valve to dump the vacuum to the atmosphere. Sounds like the valve is leaking __________________ My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe Last edited by Bigdav160; 10-01-2016 at 06:14 PM.

10-01-2016, 06:09 PM	#4
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: Where do the power boosters leak from? Ah, yeah the boot on the backside looks terrible... The inside diaphragm may look the same!!! So I guess there was a delco and bendix? What the heck is the difference? ... and the pic is too small... great.... Attached Images __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

10-01-2016, 08:39 PM	#5
GM man Registered User Join Date: Aug 2011 Location: Gainesville, Texas Posts: 127	Re: Where do the power boosters leak from? Mine was loosing fluid and couldn't figure out where it was going. When I removed my booster, it had fluid in it. Guess the master cylinder was leaking and allowing it to go inside the booster. Still can't figure out how that happened. Looking at your pics, I would have said that you have a Bendix because the Delcos were kind of a gold anodized color, but yours says Delco on it. So I guess your booster got painted at some point. If I remember right, I think the only real difference between the two is that they have a different bolt pattern. __________________ 1972 GMC Jimmy 6.0/4L65 1972 Chevrolet long bed 1/2 ton Last edited by GM man; 10-01-2016 at 08:45 PM.

10-02-2016, 01:06 AM	#6
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: Where do the power boosters leak from? Thank you, so I'm definitely looking for a Delco, just have to pick where I want to buy it from. Edit: Ordered a Delco Maraine Reman unit. Yes, it was that anodized color at one time, I'm the one that painted it black (my truck is far, far, far from stock). I took everything off of a 1971 GMC 1/2 ton from a junkyard in 2000-ish, the entire cross member with all suspension parts, steering box, booster, MC, and all lines, brackets, and rods (the MC has since been changed out). I think I stole it all for like $150. __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications! Last edited by 67ChevyRedneck; 10-02-2016 at 02:45 AM.

10-02-2016, 03:03 PM	#7
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: Where do the power boosters leak from? Something is stuck. I went to move it this morning and it was hissing with the brake pedal out, at rest - it was leaking with it pushed in. Then I go to move it again this afternoon... no leaking... so I took it for an hour cruise... no hissing. I ordered a new one last night, it's still getting swapped. __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

10-02-2016, 08:36 PM	#8
stsalvage Scrapper 1 Join Date: Jan 2007 Location: Riverside Calif Posts: 1,649	Re: Where do the power boosters leak from? A power booster will last 20 years but one bad master 6 months tops that new brake fluid is really nasty.it will east pain in 6 hours clear coat it take a little more time.Plus are parts are made in china not the best rubber on the planet there



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