MC is leaking fluid - The 1947 - Present Chevrolet & GMC Truck Message Board Network

65-72 chevytoys · 02-25-2007, 05:04 PM

Earlier this week the brake pedal went soft all the way to the floor with manual brake equipped. Well today I opened the MC cover and found the back resivoir (disk/drum) MC was empty

. So I start looking for leaks and all of the lines under the truck are dry. So I keep trouble shooting and wonder if it if the pedal rod came loose. After getting under the dash I notice the floor is covered in brake fluid.

I am assuming the rear seal on the MC piston is shot because when I pulled the MC away from the firewall it was wet.

Anyone ever have this problem before? Can the MC be fix or do I need a new one? Anyone have any recommendations on where to get a new one that will last? Help please my truck is parked until I get the brakes fixed.

dave2953 · 02-25-2007, 05:15 PM

Mine did the same thing; I got a replacement from Advance Auto about 2 years ago and haven't had any problems. IIRC it has a lifetime warranty and was pretty cheap. I did benchbleed mine before installation.

Longhorn Man · 02-25-2007, 05:16 PM

That is a common master cylinder failure.
Time for a new one, inspect your wheel cylinders while you have the truck disabled.

Big Block · 02-25-2007, 05:23 PM

Definitely check rear wheel cylinders they are prone to leak with age.

cableguy0 · 02-25-2007, 05:30 PM

i agree with everything said and while your at it now is a good time to inspect lines for rust. too much rust or flaking badly and you should probably consider replacing them shortly.on the wheel cylinders pull back the dust boots or put a very small hole in them using a pick if theres fluid inside that boot its time to replace the wheel cylinders as well.

65-72 chevytoys · 02-25-2007, 05:47 PM

Thanks I wasnt sure if this was a common problem or not. I check all the lines but not the rear cylinders. In addition all that fluid at the paint off my floor boards so I am going to pull the seat out clean up all the flud and use some rust encapsulator on the floor when I fix the MC.

Longhorn Man · 02-25-2007, 06:07 PM

Take the carpet or rubber mat to a car wash and clean it with the high pressure... if you have access to a steam cleaner, that'd be even better.
I would dispose of any padding or insulation under the carpet too.

65-72 chevytoys · 02-25-2007, 06:53 PM

Yes padding is done for it is going in the trash. It soaked up all the fluid. I will clean the carpet just for good measure.

stsalvage · 02-26-2007, 03:15 AM

I remmber back when i got my 1965 3/4 ton chevy yes at one time i rebuilt my MC and Now days on how these chicken bastords drive i wont rebuild crap no you want new yes they sell rebuild kits but if you don't do it right and you kill some one by running them over that man slatter 10 years of your life for hitting a kid in a cross walk or any one walking

**special-K** · 02-26-2007, 12:02 PM

stsalvage,don`t take this the wrong way...You any relation to Boomer on King of the Hill?

Orange · 02-26-2007, 02:10 PM

Quote:

Originally Posted by special-K

stsalvage,don`t take this the wrong way...You any relation to Boomer on King of the Hill?

I nearly spit out food on that one!

No kidding man - use some periods every so often.

**special-K** · 02-26-2007, 06:32 PM

Glad you laughed

.

TTT for more

02-25-2007, 05:04 PM	#1
65-72 chevytoys Registered User Join Date: Dec 2006 Location: Wesley Chapel, Florida Posts: 1,113	MC is leaking fluid Earlier this week the brake pedal went soft all the way to the floor with manual brake equipped. Well today I opened the MC cover and found the back resivoir (disk/drum) MC was empty . So I start looking for leaks and all of the lines under the truck are dry. So I keep trouble shooting and wonder if it if the pedal rod came loose. After getting under the dash I notice the floor is covered in brake fluid. I am assuming the rear seal on the MC piston is shot because when I pulled the MC away from the firewall it was wet. Anyone ever have this problem before? Can the MC be fix or do I need a new one? Anyone have any recommendations on where to get a new one that will last? Help please my truck is parked until I get the brakes fixed. __________________ 2004 Chevy Silverado 1500LS SWB 5.3L 2004 Corvette Z16 #770 Wish I had not sold 72 blazer

02-25-2007, 05:15 PM	#2
dave2953 Dave's not here, man Join Date: Jun 2004 Location: Winder, Georgia Posts: 2,000	Re: MC is leaking fluid Mine did the same thing; I got a replacement from Advance Auto about 2 years ago and haven't had any problems. IIRC it has a lifetime warranty and was pretty cheap. I did benchbleed mine before installation. __________________ - 2014 VW Jetta - 2015 VW Jetta - 1966 Ford F-250 Last edited by dave2953; 02-25-2007 at 05:16 PM.

02-25-2007, 05:16 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: MC is leaking fluid That is a common master cylinder failure. Time for a new one, inspect your wheel cylinders while you have the truck disabled.

02-25-2007, 05:23 PM	#4
Big Block Big Block Join Date: Mar 2005 Location: Durham, N.C. Posts: 1,649	Re: MC is leaking fluid Definitely check rear wheel cylinders they are prone to leak with age.

02-25-2007, 05:30 PM	#5
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	Re: MC is leaking fluid i agree with everything said and while your at it now is a good time to inspect lines for rust. too much rust or flaking badly and you should probably consider replacing them shortly.on the wheel cylinders pull back the dust boots or put a very small hole in them using a pick if theres fluid inside that boot its time to replace the wheel cylinders as well. __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

02-25-2007, 05:47 PM	#6
65-72 chevytoys Registered User Join Date: Dec 2006 Location: Wesley Chapel, Florida Posts: 1,113	Re: MC is leaking fluid Thanks I wasnt sure if this was a common problem or not. I check all the lines but not the rear cylinders. In addition all that fluid at the paint off my floor boards so I am going to pull the seat out clean up all the flud and use some rust encapsulator on the floor when I fix the MC. __________________ 2004 Chevy Silverado 1500LS SWB 5.3L 2004 Corvette Z16 #770 Wish I had not sold 72 blazer

02-25-2007, 06:07 PM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: MC is leaking fluid Take the carpet or rubber mat to a car wash and clean it with the high pressure... if you have access to a steam cleaner, that'd be even better. I would dispose of any padding or insulation under the carpet too.

02-25-2007, 06:53 PM	#8
65-72 chevytoys Registered User Join Date: Dec 2006 Location: Wesley Chapel, Florida Posts: 1,113	Re: MC is leaking fluid Yes padding is done for it is going in the trash. It soaked up all the fluid. I will clean the carpet just for good measure. __________________ 2004 Chevy Silverado 1500LS SWB 5.3L 2004 Corvette Z16 #770 Wish I had not sold 72 blazer

02-26-2007, 03:15 AM	#9
stsalvage Scrapper 1 Join Date: Jan 2007 Location: Riverside Calif Posts: 1,649	Re: MC is leaking fluid I remmber back when i got my 1965 3/4 ton chevy yes at one time i rebuilt my MC and Now days on how these chicken bastords drive i wont rebuild crap no you want new yes they sell rebuild kits but if you don't do it right and you kill some one by running them over that man slatter 10 years of your life for hitting a kid in a cross walk or any one walking

02-26-2007, 12:02 PM	#10
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: MC is leaking fluid stsalvage,don`t take this the wrong way...You any relation to Boomer on King of the Hill? __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

02-26-2007, 06:32 PM	#12
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: MC is leaking fluid Glad you laughed . TTT for more __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~



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