Brakes – no fluid coming out of bleeders 73 Brave

[The_Handier_Man1]

From: Cakeman2253  (Original Message)
Sent: 9/11/2008 6:29 PM

I have read through a lot of post and can’t seem to find the answer. Please help!

I have a 73 Brave w/ 318, 24 foot. It sat for about 2 years (now it has a good home). The brake pedal goes to the floor very easy. I tried to bleed the brake. I sucked out the old fluid, the rear chamber was almost empty. I refilled with new fluid. I was only able to get a few dribbles out of the bleeder valves (I tried all of them, only front passenger side gave a little more). A friend suggested I remove the brake line, passage rear to by pass the wheel cylinder just in case it was bad. Well bad move, it cracked, now it’s new, good learning experience. I tried one of the one-man bleeder bumps.  I am unable to suck any fluid out. I have also tried just pumping the pedal, nothing seems to come out. I am unable to get fluid out of the new line. How do I start to trouble shoot this? Could something be clog in the line, or do I need to start at the master cylinder? Do I look at the booster? The rest of the lines look good. I just can’t seem to get fluid through them.

By the way, what engineer designed the master to be inches from the floor and almost above the tire? At 6’4” and heavier than I should be. I need to be a contortionist with a mirror to see inside it. Any advise?

Thanks for all your help already, Bradley


From: denisondc
Sent: 9/11/2008 7:17 PM

If it sat with an empty mstr cyl. reservoir for months, it may take a few days for the fluid to fully ooze down into the master cylinder bore. The way I would advise bleeding it would be to do the boosters first. They may have one bleeder each, or two of them. Its worthwhile to use plenty of penetrating oil, and to soak the bleeders for a while (days), and to put a 6 point flare-nut wrench on the bleeder, and to strike it sideways with a hammer. Not hard enough to break it; but it helps to free up stuck bleeders. Then I would take the bleeder screws out and make sure they have a hole down the middle. It might be filled solid with rust! I have had them were I had to put a small drill down to clea it out.
I do the boosters, followed by the wheel cylinders, but not in any particular order. I have my wife push the pedal to the floor, and I open the bleeder. Then I close the bleeder and yell for her to let it up, and to push again. Repeat.
If you still dont get fluid out, I would suspect the master cylinder is the problem. They have tiny ports in the bottom of the reservoirs that can get clogged with muck from sitting. These 'compensating ports' are supposed to be open when the pedal is all the way 'returned'. If they are clogged up, the fluid wont flow from the reservoir into the master cylinder. If it were possible to look down into the master cylinder, you might be able to see the compensating ports, through clean new brake fluid. Though I dont recall if I ever looked on my Winny.
Several of the members have cut an inspection hole in the floor, right above the reservoir on the master cylinder. On mine I made a 2" hole almost where the driver's right heel goes. I should have made it a 2" by 4" hole. It doesnt seem to hurt the floor, but you need to make a plug for the hole, to keep cold air out in winter, and hot air out in summer.
There are several things I ALWAYS check before I take my Winnie out of the driveway. Coolant, motor oil, transmission fluid ---- and brake fluid. With the factory location of that master cylinder, its non-feasible to check the brake fluid. With the added inspection hole, its only a minor p.i.t.a.
By the way, to work on the master cylinder, I take the front wheel off, with the axle jacked up about a foot - so I can sit crouched in there on a milk-bottle crate. I also check my plugs, the compression, the health of the wiring harness, and check the pre-loading of the power steering box. I do this about once each year in getting the Winnie ready for its summer cruising.
With a modern car, checking the brake fluid a couple of times a year is adequate. On a vintage motor home I do it "Often". I would no sooner start out of the driveway without checking the brake fluid (and tranny fluid) beforehand than I would leave without my drivers license.



From: Cakeman2253
Sent: 9/12/2008 7:38 AM

Confused. How do you bleed the booster (big round thing attached to the master)? I only have one. I have looked and there are no fittings or screws or lines. Only the line going into the top from the engine or power streeing pump (sorry didn't pull up the engine hood to look exactly). I have 2 lines coming from the Master I could take off (hopefully, I already sprayed with PB Blaster). Thanks



From: denisondc
Sent: 9/12/2008 8:49 AM

If your vacuum booster is attached directly to the master cylinder, then there are no bleeders on it - the booster only carries air/vacuum. Some of the class A Winnies in the early 70s used a master cylinder without a booster connected to it. On that type of chassis the dual boosters were located remotely, on the inner side of the driver's side frame rail, a few feet behind the engine. Those are the kind that have bleeders, because they are a hydraulic piston (driven by the master cylinder) with a vacuum booster to increase the output fluid pressure.
Another thing to check if you cant get fluid to flow to the bleeders on the wheel cylinders, is whether the inside of the vaccum line that runs from the intake manifold to the booster, is wet on the inside with brake fluid. This would mean your master cylinder has a bad seal around the piston inside. Its not a real common failure, but does eventually happen sometimes.
If you ever install a new/rebuilt master cylinder, be sure to do a 'bench bleed' before you mount it onto the motor home. This gets the little bubbles of air out of the m.c. innards.



From: Cakeman2253
Sent: 9/13/2008 4:55 PM

Thanks for your help so far. I have been able to bleed the fronts today. I still can not get fluid to the rear brakes. I disconnected the line at the drum to eliminate the wheel cylinder. Any thoughts? Can the Proportioning Valve go bad? Can you test it? If I can get fluid to the front, I will assume my master cylinder is ok. I just can’t get any fluid to come out of the rear lines. Any additional thoughts are appreciated. Best Regards, Bradley



From: OldEdBrady
Sent: 9/13/2008 5:41 PM

If it were me--and I'm certainly no mechanic--I'd disconnect one of the lines both at the valve and and the wheel and try to blow through the thing.  If I could, then maybe either the master or the metering valve (if it has one) is clogged.  If not, well....



From: Cakeman2253
Sent: 9/29/2008 4:11 PM

Thanks for everyone’s help. I rented a power vac bleeder (sucker) and took the back bolt off the portioning valve. It made a slurping noise and then basically threw out some nasty thick old brake fluid. I heard the spring click back. Put all together and put the power bleeder back on and after several minutes it started pulling the old fluid out.