Rear drum brake diagram??

[tkisling]

I should also note that NO fluid is coming out on either side on the rear.

[Baron VonZeppelin]

You'll have to go into troubleshoot mode now.
What special tools do you have now to bleed the brakes ?
I'm supposing you don't have a MightyVac pump.

It could be your master cylinder, it could be something else entirely like clogged lines or sediment in the reservoir blocking the rear outlet, it could be multiple issues combined.

I haven't worked on a Rabbit since 1983, and it was a 75 model. So i'm not familiar with exactly how they are set up on the lines.
My 81 truck has 4 independent brake lines from the master cylinder that go to each wheel independently. I don't know if your car is like that or not.

Were both of the wheel cylinders bad/stuck/frozen ?
The longer one is left bad, the more damage/corrosion it does inside the brake line.

Without being there, all i can do is offer suggestions.

Is the lower rear portion of the brake reservoir clear, or is it dirty full of sediment on the bottom ?

If its sedimented pretty bad - you'll need to remove it to clean it out. But don't do that just yet.
And if/when you do - it is usually a very very delicate operation.
They can break easy, especially the nipple outlets that go into master cylinder body. It needs some special prep and proceedure to try to remove it without damage.

If you have a MightyVac, attach it to a rear brake line and trigger it up to about 30-35. If nothing comes out or nothing breaks free - you either have a very bad line or reservoir is completely blocked by sediment.

There are different ways i would approach it from here, depending on whether or not the reservoir is nice and clean looking on the bottom - or whether it looks like it needs to come off and be cleaned out.

Either way - clean or dirty - First i would get most the fluid back out of it as possible. Wick it out with a rag, or whatever works for you.

IF it is nice and clean - can you get the rear brake lines broken loose from the master cylinder ? If so, remove them and then pump brake pedal (covering ports with rag). If you get pressurized fluid - the master is probly good.

You can blow compressed air (about 10-15-20 psi) from the master cylinder lines to the rears - but remove the lines from the wheel cylinders First.

Those results should point you to next repairs needed.

IF the master lines are too difficult and don't want to come loose within reasonable effort. Then do it this way.
Loosely stuff a rag in the top of reservoir instead of putting cap back on.

Then blow low pressure compressed air (maybe 10-15 pounds) into the brake lines from back where the lines go into the wheel cylinders. Be careful moving the hard brake lines above the backing plate - to have clearance to operate.

Have your helper watch reservoir to see what kind of action goes on at reservoir. Hopefully some crap and some nasty fluid will blow back up inside. Try that on both lines.

If that works and both rear lines free up, then you'll probably need to remove the reservoir and clean it out real good afterwards. Then reinstall and Flush the lines Very Good. Then bleed.

Troubleshooting just takes some time and thought.
You want to do whatever you can to verify what is working and what is broken. These cars are old and most have been mistreated neglected or left sitting for extended periods.

If you can't get the lines to flow using above tactics, start removing them one piece at a time at any and every joint connection and find which pieces will flow and which won't.

Good Luck on it being an easy fix.

[tkisling]

Thanks, I'll try and work on it this week.

[tkisling]

Well, I think my culprit is a bad MC. When I push the brake pedal in I can  hear a wooshing sound coming from the engine compartment. Also I see a big wet spot behind the MC mounting area on the brake booster. I think that may be brake fluid from the MC failing. I figured  out my temp gauge not working was due to one of the three wires for the temp sensor was disconnected.

[Baron VonZeppelin]

Yeh, sounds like classic symptoms of bad master cylinder.

Were the front brakes working ? I was assuming they probably were.

While the lines are apart from master, perfect opportunity to blow them out - then do some fluid flushes through them. I'd do them all, front and rear.

Probly take better part of a quart of brake fluid to flush and bleed them all.

You need special flare nut wrench to get the best contact on the line nuts. An open end wrench will usually just round off the corners. And some are so corroded - nothing will grab them - except strong vise grips. Sometimes the nuts need to be heated with a propane torch. Spraying them ahead of time - several times - with penetrating fluid like PB Blaster is always good.

I would try to get reservoir out of way first, before getting too wild with the brake lines. Maybe you get lucky and yours roll right out, but usually its a battle with old line nuts at the master.

You have to swap your old reservoir to a new master.
Unless you find a pricey alternate that includes a reservoir.
The Parts Place . com sells used reservoirs if you get in trouble.

The reservoir has two plastic flared nipples that go into the master - through rubber grommets. Pull up on reservoir just a bit to a comfortable point - and lubricate the grommets around the nipples. Work reservoir up and down gently to work the lube in.
Do that several times for a day or two ahead.

Get as much of the fluid out as you can before trying to take it off.

To get it off - you have to pull it STRAIT up from master.
Its risky business - but has to be done.
Take your time and work with it.
Best to do it while master is still secured on car.

If you pull up with uneven force - or one nipple comes out first - it will likely break the other nipple off, or crack it at minimum.
The first one i did - the front nipple pulled out first - the overload force and subsequent tilting caused the rear nipple to bend and crack - but it came out. It happened so fast - no time to react.
I was holding a damaged product in the blink of an eye.
I rushed it, and paid the price.
Learned a little though.
Have done numerous since without damage.

[tkisling]

I picked up a new MC today and am going to install it. The manual says to bench bleed it before I install it to the car. But since I don't have access to a vice at the moment, I am thinking of bleeding it once I get it installed. I saw in a tutorial that said if the MC is mounted horizontally without an angle I can skip the bench bleed.  Does this sound like a good idea?

[Baron VonZeppelin]

You can "bench-bleed" it on the car - after its bolted up - before lines get connected.

Or if you flush your lines out good with brake fluid using the brake pedal/master cylinder - that will bleed it plenty too.

[tkisling]

Well, I got it in the car but the MC reservoir leaks at the grommets where it mats with the MC. I tried cleaning the surfaces but it didn't help.  After pulling it out several times one of the necks on the reservoir cracked. Now I gotta try and get a new one.

[tkisling]

On a positive note, the system seems to be working because when I turn the bleeder screws at the wheels, fluid comes out.

[Baron VonZeppelin]

Sorry to hear about the reservoir .... it can happen to anyone.

www.partsplaceinc.com sells good used ones for $15-20.
They specialize in these cars, and will have about anything you might need for your Rabbit - that you can't find locally.

They have every piece for Rabbits like yours, basically.
They parted out a bunch of them.
Ask for their free catalog if you contact them.

In Auburn Hills, Michigan (248) 373-2300
They could get you one to Wisc. pretty quickly.

Last i checked - new reservoirs were $100+  
Couldn't find new aftermarket ones anywhere.
Someone needs to make these.

[tkisling]

Well, I was able to hot glue the cracked end of the neck on the reservoir and transferred the grommets from the old MC to the new one. Seems to be working just fine, no leaks, for now.  But I still have my same problem, the humming/low wheezing noise coming from the MC/brake booster area. I'll try and bleed air out of the system tomorrow.

[tkisling]

The car is now back together again. The drivers side drum did not turn easily at first. But after driving it turns easier now. But that side gets really hot sand smokes. Should I just let the shoes wear in on that side or should I take it apart again so that it turns a freely as the passenger side and doesn't smoke.

[Baron VonZeppelin]

The drivers side drum did not turn easily at first. But after driving it turns easier now. But that side gets really hot and smokes

Bad signs.

Shouldn't have left the driveway until both sides verified as easy to spin without wheels mounted - after cycling brakes numerous times to verify.

Both drums need to be equally easy to turn by hand (without a wheel mounted).
By easy - they should spin on their own when you give them a brisk roll by hand. Having a wheel mounted can give false reports because of the extra momentive force from the weight of the wheel.

That much heat can disolve the bearing grease pretty quick - and then wheel bearing goes bad, along with other things, like the rubbers in your new wheel cylinders melting, etc... 15 to 20 minutes steady driving is about all it takes.

With good luck, none of that has happened.

The auto-adjuster wedge must be too far down.
Need to pull it back upwards so that the top of the wedge is about even with the top of the shoe.
Then mount drum, check for rolling resistance.
Then work brake pedal about 10 times, check for rolling resistance again after the brakes have cycled some.

If thats checking out - then you can mount wheel and test drive again. Bring it back home and pull wheel to re-check resistance by hand. If all is still well - should be good to go. And can move on to adjusting eBrake cables.

Be careful about grabbing ahold of a potentially hot or super hot brake drum. fwiw

IF the auto brake adjuster wedge keeps dropping down by itself repeatedly and making brakes too tight again and again time after time - it (the wedge) will need to be deleted for now.

In that case - you have to compensate the brake adjustment on that side - with the adjustment of the eBrake cable on that side.

[tkisling]

I drove it after it had cooled down. I drove it around town at about an average of 35 mph. I didn't seem to be nearly as hot and defiantly wasn't smoking. I'll look into moving the self adjuster asap.

[tkisling]

I finally am on the road again thanks to "Baron VonZeppelin" and is detailed tutorials. I adjusted the self adjuster lever and now everything seems to be great. I think the system needs some adjustment because of sponginess, but is good for now.