Question about brake job gone bad!!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69 Big Block · 07-19-2003, 11:53 PM

Replaced the shoes, wheel cylinders, Master Cylinder and Power Braker Booster. Bleeding was completed with an air powered power brake bleeder. Now when you apply the brakes the damn thing whistles and spits brake fluid out from under the master cylinder cover. Where the heck did I go wrong?

knucklebuster · 07-20-2003, 12:05 AM

Make sure the top is seating on the master cylinder good.it may have a factry flaw in it.Check it with a straight edge and if it's off take it back or use a file to level it but make sure you put a rag in the cylinder to keep shavings out

nu2-72 · 07-20-2003, 03:44 PM

And make sure the rubber seal is good. Did you bleed the master before you did the rest of the brakes.

Class of 69 · 07-20-2003, 09:32 PM

I'm concerned about how much pressure was applied by the pressure bleeder. If I remember correctly, they only need about 30 lbs to bleed the system. They will all spit fluid up into the reservoir, but I've never heard one whistle. Maybe the whistle is coming from the booster? I agree with knucklebuster, and nu2-72 about the cover and gasket seating squarely, and tightly.

knucklebuster · 07-20-2003, 10:09 PM

Also check the little rubber grommet on the booster that could be the whistle

69 Big Block · 07-21-2003, 08:19 AM

Thanks for the replys. I've never seen one or had any one tell me of one doing this before. I figured I just flat screwed up!!! Anyway, I hope to be under the hood tonight checking these issues out.

Thanks for the replys!!!

07-19-2003, 11:53 PM	#1
69 Big Block Must get more toys!!!!!!! Join Date: Feb 2002 Location: Heart of Ohio Posts: 141	Question about brake job gone bad!!! Replaced the shoes, wheel cylinders, Master Cylinder and Power Braker Booster. Bleeding was completed with an air powered power brake bleeder. Now when you apply the brakes the damn thing whistles and spits brake fluid out from under the master cylinder cover. Where the heck did I go wrong? __________________ 69 GMC 3/4 Ton Custom Camper 396 / Turbo 400 w/shift kit!!!!! She's all there and solid as a ROCK!!!!!

07-20-2003, 12:05 AM	#2
knucklebuster Failure is NOT an option! Join Date: Feb 2003 Location: greenwood s.c. Posts: 811	Make sure the top is seating on the master cylinder good.it may have a factry flaw in it.Check it with a straight edge and if it's off take it back or use a file to level it but make sure you put a rag in the cylinder to keep shavings out __________________ House payment or truck parts?????.........why does life have to be so complicated? 1969 Chevy Shortbed Fleetside 1969 Camaro ps pb a/c(drove in high school now it's just a yard ornament,but it's next on the list for resto) 1990 Ni$$an hardbody( daily beater that has been really beaten!) 1999 Grand Am GT(wifes ride...never buy a pontiac!!Trust Me)

07-20-2003, 03:44 PM	#3
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	And make sure the rubber seal is good. Did you bleed the master before you did the rest of the brakes. __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

07-20-2003, 09:32 PM	#4
Class of 69 Registered User Join Date: Mar 2003 Location: Stillwater MN Posts: 1,166	I'm concerned about how much pressure was applied by the pressure bleeder. If I remember correctly, they only need about 30 lbs to bleed the system. They will all spit fluid up into the reservoir, but I've never heard one whistle. Maybe the whistle is coming from the booster? I agree with knucklebuster, and nu2-72 about the cover and gasket seating squarely, and tightly. __________________ 69 GMC K10 ..some restoration required....still..

07-20-2003, 10:09 PM	#5
knucklebuster Failure is NOT an option! Join Date: Feb 2003 Location: greenwood s.c. Posts: 811	Also check the little rubber grommet on the booster that could be the whistle __________________ House payment or truck parts?????.........why does life have to be so complicated? 1969 Chevy Shortbed Fleetside 1969 Camaro ps pb a/c(drove in high school now it's just a yard ornament,but it's next on the list for resto) 1990 Ni$$an hardbody( daily beater that has been really beaten!) 1999 Grand Am GT(wifes ride...never buy a pontiac!!Trust Me)

07-21-2003, 08:19 AM	#6
69 Big Block Must get more toys!!!!!!! Join Date: Feb 2002 Location: Heart of Ohio Posts: 141	Thanks for the replys. I've never seen one or had any one tell me of one doing this before. I figured I just flat screwed up!!! Anyway, I hope to be under the hood tonight checking these issues out. Thanks for the replys!!! __________________ 69 GMC 3/4 Ton Custom Camper 396 / Turbo 400 w/shift kit!!!!! She's all there and solid as a ROCK!!!!!

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