Hi all,

I knew my brake fluid was junk, so this weekend I attempted to do what I've read as a 'gravity bleed'.

I thought all I had to do was to take the rear wheel off, find the brake line going into the caliper, and loosen/remove the bolt holding it on, and let it drip slowly out until it is clear.

I tried using a 1/2" socket, 1/2" open end wrench, and couldn't get the darn thing off. I started slipping off the end of the bolt. I read my red FSM and it say something about using a 'open end box bleeder wrench' so I wasn't sure what the hell I was doing at this point, so I decided to leave the brakes alone and polished the aluminum and yellow shocks instead.

So first question, am I doing the right thing? Should I just be pulling a lot harder on that bolt/nut? I was afraid to damage/snap it or maybe I was pulling on the wrong thing.

Secondly, I know it is useless but I did it anyway, I used a turkey baster to suck some fluid out of the reservoir to refill with fresh. While I was doing this, I noticed a lot of black, very thin, flaky stuff floating around in the fluid. This is bad, I think? How bad? Like brakes gonna not work next weekend when I try to stop at the end of the dragstrip? How boned am I?

Thanks all for your help and support!
John

 

I have done gravity bleed on trailers and other cars in the past and I never touched the line just opened all the bleaders and kept adding brake fluid until it was all clean fluid coming out of the bleaders.

 

Unless my understanding is off, I thought you use the bleeder screws for a gravity bleed just the same as for the normal technique, so no need to disconnect the line.

I installed a used set of calipers on my car, and the old brake lines were in there really tight. If you really want to take them off, some prudent muscle is probably the trick. It's just a regular bolt head.

 

I use a good 10MM six point socket to break the bleeder loose, then use a good 10MM open end to open and close the bleeder. I don't gravity bleed them.

 

I guess I'm just an idiot, I don't see a separate 'bleeder', just one screw, that goes into a metal box that the brake line is attached to, that goes into the caliper.

I need better eyes or a better manual... maybe the Haynes will be more illustrative (for shame!)

 

Its the nipple on top side of the caliper, no bolt, some have a rubber cap over them...hook up a clear plastic hose to the nipple, into a clear container with 1-2: of clean brake fluid, submerg the hose and open the nipple, don't forget to check MC and don't run out of fluid in the MC or you'll have a airy line.

 

Thanks for all the replies: but what about all that black-flaky stuff in the master cylinder? Think it'll all just drain out through the bleeder valves, or am I in trouble here?

 

Use a turkey baster to suck up the black stuff and the old fluid, then add new fluid.

 

This is all great advice, and a 'gravity bleed' can work wonders.

If you can, jack up the front of the car when doing the rear calipers.

 

I would be concerned that the black flaky stuff is from a deteriorating seal, either on the reservoir cap or in the MC itself.

 

I don't know how much corrosion your Vette seen, but some times the bleeder can be a bitch (especially if it's never been touched). Use some penintrant and a GOOD six point socket. I've even resorted to some heat and a hand impact driver (on lesser vehicles ) and even THEN they might snap off.

 

 

That' a good start!

 

A copla years ago I had to replace the MC on my '88 and decided to flush all the lines. Well the RR bleeder was so frozen, even after the PB Blaster soaking, that I broke the 1/4" drive socket wrench while using a "little impact" to break it loose...

For the "flakes" in the MC, I'd try to get out all the fluid and wipe out all the flakes.

Then use the clear plastic tube into a container of brake fluid trick so that you can bleed the lines till clear fluid comes out. This way, after you pump the pedal, you don't have to worry about air being drawn back into the bleeder as you release the pedal.

 

i just replaced my master cyl a month ago .. i too noticed the "black crunchy bits" in the bottom of the master cyl....i suspect its a byproduct of autocrossing/drag racing..(possibly heat related) my fluid was a dark brown also...i bought a vacuum pump bleeder kit and changed every drop of fluid.

since then not any problems.
Bret

 

pr1mu5, the thread below may be of interest now
or in the near future.

- Frustrated beyond belief

.

 

Get yourself a set (four) of "SpeedBleeders", its fast, simple and a one man job. Also they're not expensive.

With speedbleeders, you can do a four wheel bleed in under 30 minutes.

 

I'll second this. Oh, and for those really stubborn line fittings that want to round off, I've introduced them to this type of vise-grip:



Your results may vary

 

pay more and get the "speedbleeder" brand - that other stuff is junk from my own personal experience.