mowrey96

This is a 99 coupe with almost 100k miles. I am pretty sure it is the reservoir. It is the part in this picture
http://www.pfyc.com/pc/VT3043/VTUNDE...Cap+Cover.html

Right around the seam in the middle there appears to be a leak. I wipe it dry and a day or two later it has fluid on it. Is it likely coming from the seam? I could not find one post about this. Can the Master Cylinder Brake Reservoir be replaced without replacing the enitire master cyclinder? Is it difficult?

ICUALL

GM PART # 18047557
CATEGORY: Brake Master Cylinder Reservior Hardware
PACK QTY: 1

Includes O-rings Reservior and Spring Pin

mowrey96

Thanks! Is this a difficult install? This is for a 2005. Is it the same for 99 c5?

ICUALL

The part number I listed is the latest that superceeded the old number
18029858 it should be the same. Looks pretty simple to me, I haven't done it so maybe someone else can chime in. Since the reservior is located on the top of the master cylinder I would say the 2 pins Number 4 in the drawing) need to be removed and then remove the connector and level unit (#1) lift the reservior off, replace the 2 o-rings (#6 & 7 ) and install the new reservior. Reinstall the fluid level sensor (#1). Pay attention when you remove the Fluid level sensor and make sure you put it back the exact same direction as it was removed.

yellow01

Hmm, good to know you can buy the M/C parts separately, I didn't htink you could.

I have a similar problem but it is a leaky cap. Are you sure the seam itself is leaking? If the cap leaks, the fluid will drip down into the seam and sit there (the seam has a bit of a catch).

I'd check the cap first.

TEXHAWK0

I would bet Yellow01 has it right. I have never seen the seam of the reservoir leak, but I have seen several cases where the gasket under the cap loses its flexibility and fluid will seep by the gasket and collect at the seam.
You can buy the cap separate. That is the first thing to try before you replace the reservoir.

Point & Shoot

mine was leaking from the cap.

00Corvette

My resevoir is totally cracked. I'll be using that GM PN on Gene's site tommorrow. lol.
Thx,
dZ

TNX ZORA

I cut a thin piece of plastic to the same size as the rubber gasket under the cap and installed it under the gasket (on top really) which created the needed pressure to stop the leak. If you do go to buy a new one I'd make sure the cap feels like it twists on good and tight before you hand over your money.

mowrey96

That was it. $29 for a new top and diaphram. Not a drop anywhere! Thanks for the tip!!!

gstandard

Where did you get it for 29.00?

corvettejoe98

Had the same problem just replaced the cap and no issues anymore.

Lloyd Christmas

Anyone know where to get these for less than $60?

Lloyd Christmas

Also, did we ever figure what could cause them to just crack everywhere like that? Mine looks about the same.

Grantham75

Where did you find one for $60 at.. I need one and the only price i have gotten is $155..

justin1990

Great advice. I thought for sure I was going to have to replace the reservoir when I first logged on as I had an accumulation of brake fluid recurring at the seam mentioned above. I took a trip to the recycle bin and used what looked to be a pringle's lid, cut to size, slipped under the rubber gasket, and no more leaks after a couple months of close checking.