Master Cylinder Puzzler.

todd_vette · 07-30-2010, 04:48 AM

Last week i replaced a master cylinder and started noticing a drop spot of brake fluid on the ground. After going through all the lines and fittings i couldn't find a leak. after about a week the reservoir had to be topped off twice...but i finally noticed that there is a good wet spot below the cylinder on the booster. It looks like the leak is from the rod contact in the rear. Is there a simple o-ring to replace to fix that or should i just order another one? How do i clean the brake fluid out of the booster with-out removing it? I figure leaving it in/on the booster will damage the diaphram...is that right?
Thank-you for info...i have never had a new one do this...or an old one either now that i think about it.

DaveH_RRTX · 07-30-2010, 03:30 PM

New or rebuilt; My recommendation is to bring it back for a replacement.

If it is a simple nicked seal or ring. It is easy to replace.

However; if they scored the piston itself or the bore you have a completely different set of problems. Usually not very fixable, and certainly a lot of time and effort. Light scratches are easily buffed out, a gouge or deep score will require much honing and may even change the effectiveness of the standard seals for the worse.

Any parts guy will tell you that rebuilt parts have a high return rate. The quality of the repair materials is not as good and the rebuild factory does not measure up to the same standards as new OEM; both factors together means that there is a high probability of D.O.A. for most rebuilt parts.

Dave
Round Rock, TX

lonnie · 07-30-2010, 05:46 PM

Be safe and replace it. Brake fluid eats paint and you have a lot of shiny parts under your hood.

rock crusher · 07-30-2010, 08:32 PM

The brake fluid shoud not hurt your vac booster diaphram. Its made of the same type of rubber that is under your master cylinder cover. With master cylinder removed, release the vac in the booster, the internal spring should fully extend and push any fluid out( if there is even any in there, its not common ). like the boys say here take it back change it. And dont get brake fluid on paint, If you do, lots of soap and water works great for getting it off your car and parts

todd_vette · 07-30-2010, 08:49 PM

This is a rebuilt from Oriely's i put on about 10-12 days ago. It isn't on the blue Vette.
What i am still worried about is if it is possible that the fluid got into the power booster. I am just worried about how to prevent that from getting destroyed right now. i am currently in a bad money situation.

justins84 · 07-31-2010, 07:07 AM

Can you get a different one?

07-30-2010, 04:48 AM	#1
todd_vette Smokin 750HP Supercharged Club Join Date: Oct 2008 Location: Colorado Posts: 847 Smokin' Bucks $17.16 My Gallery	Master Cylinder Puzzler. Last week i replaced a master cylinder and started noticing a drop spot of brake fluid on the ground. After going through all the lines and fittings i couldn't find a leak. after about a week the reservoir had to be topped off twice...but i finally noticed that there is a good wet spot below the cylinder on the booster. It looks like the leak is from the rod contact in the rear. Is there a simple o-ring to replace to fix that or should i just order another one? How do i clean the brake fluid out of the booster with-out removing it? I figure leaving it in/on the booster will damage the diaphram...is that right? Thank-you for info...i have never had a new one do this...or an old one either now that i think about it.

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07-30-2010, 03:30 PM	#2
DaveH_RRTX Smokin Member Join Date: Jun 2010 Location: Round Rock Posts: 20 Smokin' Bucks $5.60 My Gallery	New or rebuilt; My recommendation is to bring it back for a replacement. If it is a simple nicked seal or ring. It is easy to replace. However; if they scored the piston itself or the bore you have a completely different set of problems. Usually not very fixable, and certainly a lot of time and effort. Light scratches are easily buffed out, a gouge or deep score will require much honing and may even change the effectiveness of the standard seals for the worse. Any parts guy will tell you that rebuilt parts have a high return rate. The quality of the repair materials is not as good and the rebuild factory does not measure up to the same standards as new OEM; both factors together means that there is a high probability of D.O.A. for most rebuilt parts. Dave Round Rock, TX

07-30-2010, 05:46 PM	#3
lonnie Smokin 200HP Club Join Date: Feb 2009 Location: cuyahoga falls ohio Posts: 205 Smokin' Bucks $5.51 My Gallery	Be safe and replace it. Brake fluid eats paint and you have a lot of shiny parts under your hood.

07-30-2010, 08:32 PM	#4
rock crusher Smokin Member Join Date: Apr 2010 Location: Sudbury Posts: 26 Smokin' Bucks $0.85 My Gallery	The brake fluid shoud not hurt your vac booster diaphram. Its made of the same type of rubber that is under your master cylinder cover. With master cylinder removed, release the vac in the booster, the internal spring should fully extend and push any fluid out( if there is even any in there, its not common ). like the boys say here take it back change it. And dont get brake fluid on paint, If you do, lots of soap and water works great for getting it off your car and parts

07-30-2010, 08:49 PM	#5
todd_vette Smokin 750HP Supercharged Club Join Date: Oct 2008 Location: Colorado Posts: 847 Smokin' Bucks $17.16 My Gallery	This is a rebuilt from Oriely's i put on about 10-12 days ago. It isn't on the blue Vette. What i am still worried about is if it is possible that the fluid got into the power booster. I am just worried about how to prevent that from getting destroyed right now. i am currently in a bad money situation.

07-31-2010, 07:07 AM	#6
justins84 Smokin 50HP Club Join Date: Nov 2007 Location: Mississippi Posts: 94 Smokin' Bucks $2.87 My Gallery	Can you get a different one?