It’s been said (and well worth the repeating!) what a wealth of experience and knowledge for the Corvette community lies ‘between the pages’ of Corvette Forum! Thank you to all who support the ownership of this machine with technical advice seldom found elsewhere and a little light-hearted rib poking, too!

New to me 1999 FRC working on changing out fluids and came across a couple of things I am asking for clarification on. It is hard to tell from the jar of flushed brake fluid but commenced vacuum flush from RR to LR to RF and finally LF. I noticed the fluid exiting the front calipers had a distinct greenish pond water tinge. As expected, the rear caliper flush puked out the standard dark dregs of a neglected hydraulic system. Just curious about the greenish tinge and possible association with any other issues. The front shoes and discs look to have been very recently changed out and possibly any new fluid has a deep, dark green tint? Don’t believe I’ve seen any brake fluid this color.



Secondly, the cap for the reservoir twist-locks down but does not seem to completely seal. I cut a spacer (0.0035) from a plastic lid and tucked it behind the factory o-ring for the top and this removed the rocking element of the lid on the reservoir. I wanted to correct this as it doesn’t make sense to have so much ventilation to the atmosphere. Anyone notice this or am I missing something?


Full round 0.0035 plastic insert.


Any thoughts would be greatly appreciated, and thank you ahead of time for any input.

 

I do not see anything abnormal about the old brake fluid.

For the cap, why did you not just change the gasket?......it's obviously compressed from age.

 

I guess I'm a bit confused about the thickness the OP found. Your thickness is stated as only 3 and 1/2 thousandths thick. This is paper thin, literally. Do you mean .035" (35 thousandths)? I can't see how 3-1/2 thousandths would do anything, but I admit I don't know anything about the MC cap gasket.....

 

Hey, Lucky, and thank you for your thoughts. You were at least one of the more knowledgeable members I hoped to hear from. I didn’t mention that the spacer under the rubber seal for the cap is temporary. I was replacing the clutch master cylinder at the time and thought I would go ahead and flush the brake hydraulics. Given the age of the system the brake master cylinder should probably be replaced anyway.

Brake fluid being drawn from a single source through 4 different discharge ports that comes out being one color from the both rear calipers and another color from the front calipers is something I haven’t seen before. More difficult to tell from the jar as it did have a bit of the rear fluid in it when I started the front. Just being cautious about the difference. (And yes, new fluid was all sourced from the same bottle. )

The entire brake hydraulics will have to be gone through as I still need to diagnose DIC’s that include codes for the ABS, TCS, wheel speed and steering wheel position sensors, etc. I have gone through at least the nine body grounding points and have much further to go in troubleshooting issues. On a car like this, it seems one step forward, three steps back becomes the montra for a while.

Most excellent checking of the facts, Grinder, and well appreciated. You are correct in that I misquoted the caliper of the plastic spacer and that it is in fact 0.035”. I was definitely over zealous with my zeros and decimal placement. Hats off to you, good sir!

Thank you all for patiently taking the time to consider these things. I am frequently faulted for being too cautious and over thinking things. On the other hand, I can totally miss the obvious and more the reason for getting input from others. Thanks again, gentlemen, for your insights!