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Brake Emergency

1819 Views 16 Replies 5 Participants Last post by  briano1234
My 82 rabbit's brakes are doing some abnormal things:

Brake light turns on when I brake, and recently the light stays on indefinitely regardless of braking.

Stopping distance has increased dramatically, to where it is no longer safe to drive.

Spongy brake pedal hits the floor with little resistance, a sound of air escaping is heard during pedal depression, brakes slow the car down but very ineffectively, pumping seems to have no effect.

Brake fluid reservoir level seems normal, I see no leaks at any line junctions, the brakes have not been worked on for 2 years so I don't imagine air has entered into the system unless gnomes are the culprits.

Emergency brake cable has been ineffective for over a year.

An unfamiliar hissing sound has been coming from the driver side of the engine compartment while the car is running for a few months now, before my braking issues, but I have not been able to locate it despite several attempts to block or alter the sound by feeling and or moving vacuum hoses, and feeling around the servo+master cylinder, nor do I know if the sound is even related to my brake system.

Bentley tells me to check my fluid, or adjust my shoes, or that the spring in my master cylinder is weak.

I've had a leak in my servo before, many years ago, but that made the pedal stiffer, not spongy, and more force was needed to brake but the car was still safe to drive plus the extra leg workout. This makes me think that the vacuum side of things is not part of my problem.

Could my master cylinder just be ****ting the bed? does this happen? could sticky shoes and seized E-brake cables be causing this?
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Better check the fluid level.
Sounds to me like you have blown a wheel cylinder and are out of brake fluid.
Check your entire braking system to find source of fluid loss.

Sent from my STV100-3 using Tapatalk
there is fluid in my reservoir. how do I determine if there has been a loss/what is the proper fill level?
Check the rear wheels, at the rear of the plate, inspect it from under the car, look for oily residue, and or splatter on your wheels.
Check your rubber hoses they can crack and leak, then burst.
Master Cylinders can leak out the seal and in to the booster so if you don't have any leaks showing on the hoses or rear wheel cylinders then
Your MC is suspect.

The sensor for the fluid pressure is on the MC on early rabbits.

Fluid level should be even with the top of the master cylinders filter about 1/2 way up.
from the outside it looks full.

Hissing is usually a vacuum line, and the hard line from the Booster to the Throttle body is suspect for failure of the brakes.
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My 82 rabbit's brakes are doing some abnormal things:

Brake light turns on when I brake, and recently the light stays on indefinitely regardless of braking.
The light comes on because your rear brakes have failed on one side. The proportional valve, that thing on the fender where the two lines coming out of the master cylinder go. That has a switch on the top that is sensing that one side of the brakes is not as well pressured as the other. Thus Light on continually.

You need to do what Briano suggests. Crawl under the car and look for wet oily rear brakes. Or a line of brake fluid coming down from the drums. Tear into them and clean them up or replace the pads. Likely they will be saturated by now. One of the reasons your stopping distance is so great, only the front discs are doing any good.

Repair the E brake cables too. There is no good reason to leave your vehicle in that condition. It saves on engine problems and transmissions problems to have that brake working. If you lived on the hill I do your car would creep slowly down hill unless you have a good E brake engaged. Compression alone won't do.

That hissing you hear is likely the vacuum coming out of the booster. If you can pull a vacuum on the line going to the booster and have it hold then maybe you have a cracked hardline from the booster to the pump on the engine. Maybe a check valve gone bad?

Take a look at the rear brakes, both sides and see what is going on with the cylinders, the pistons, the mechanism and the condition of the shoes in general. To get the drum off you need to take the wheel off, line up one of the holes from the studs on the self adjust mechanism, a small wedge of metal near the back and lift it up with a thin screw driver. That will allow the shoes to come away from the drums and then you can slide them right off. IF you don't bump the wedge up you will fight getting the drums off as they will likely catch a lip of rust on the outside edge.

Got a Bentley manual? Library might have what you want, the exploded diagram is good for replacing the springs back in their original position. I use a pair of vise grips to get a part of the spring arm and pull it to where it needs to go.

Best of luck, Keep us up to date.
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Rotate the drum so that you can get a screw driver thin blade straight slot in a bolt hole to push the wedge up.
(parking brake off)

The circled item is what you are pushing up.
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no spatter or signs of leaks anywhere at the rear wheels, nor along the brake lines. I did notice a greasy stain on the servo where the MC joins it. will a normal mechanic be able to deal with this on the fly or will I need to order special parts to service the servo/MC union?

also, in order to drive myself to said mechanic safely, my plan is to top off my fluid and hope for the best, perhaps topping it off along the way. but I realize if the pressure is low that I will never get the proper braking action. any advice is appreciated
master cylinders can fail the seal on the Push Rod seal. It will leak either out of the bottom of the m/c at the booster connection or leak into the booster itself.
I have had this happen.

Removing the mc isn't that hard but it does take care, that is you loosen the nuts off the brake lines, and then loosen the mc off the booster by turning the nuts equally at the same time, that is 5 turns on the left and then 5 turns on the right, the same when you return them.

You may have to take a rag into the hole of the booster and wipe out excessive fluid if it has collected in to the booster.
Check the Vacuum line for the whole length for cracks from the booster to the intake valve.

Since you live in a hilly region, I would hope there isn't a ton of hills between you and your mechanic.

The mc has a o-ring on the neck that inserts itself into the mc to seal it.

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replaced MC, brakes are now stiff. can't tell whether or not its the contrast from having a totally loose and spongy pedal thats making them feel extra stiff, and making me feel like im not getting vacuum assist. gonna drive around for a while, overhaul the rear brake drums, shoes, ebrake cables and cylinders, and check back in.

until then, thank you for all your help guys.
as a side issue, there are plastic bushings on the pin that holds the brake/clutch pedals to the housing mount--they have usually worn out on older vehicles
I would be taking a trip to the hardware store with pin or something of that size and looking for something in brass.
I would be taking a trip to the hardware store with pin or something of that size and looking for something in brass.
oilight bushings is the way to go. May have to drill out the holes a wee bit, but they usually last 30-40 years. Last time I looked my Hardware store had metric sizes for them as well.
oil light bushings is the way to go.
Exactly what I was thinking. Odd how some companies can sell these for pennies to you but the hardware store charges dimes. I guess if you needed a minimum of 500 or 1000 of them it would be cheaper to buy from the big boys.

I just pay the premium and let the store do all the work.
new: mc, e brake cables, rear drums + shoes + cylinders + bearings, all in place. pedal is stiff af, but the car stops! considering also replacing servo and vacuum lines. I see some sources out there for brake boosters, but anyone have a link to something solid they recommend?

secondly: rubber grommets that connect brake fluid reservoir on top of mc are only a few weeks old and are leaking. enough that I took in air from an empty reservoir and lost my brakes. yikes. ordered new grommets, but what will keep these from leaking in a few weeks?
Not all grommets are the same.

I have found over the years that some react to the type of fluid that you use and can get soft and leak as the fluid can deteriorate the
rubbers. I have found that not all brake fluid is the same. Years ago I rebuilt all the hydraulic parts of my systems (clutch and brake) with new seals, (this was on a MG) and used regular DOT3 Wagner brake fluid. In about 4 days of driving I lost my brakes and Clutch, as it ate all the seals. While IIRC the kits for the MC and Clutch were only about 20 bucks once I found the seals had weakened I talked with the Dealership of British Leyland, who said that the kits I were buying were "Natural" rubber and that Wagner would eat the seals. I switched to Castrol GT/LMA fluid and never had that issue again. I also stayed away from Wagner fluids or Generic Dot3 fluid.

Now-a-days I use only Synthetic on a new to me car since I have to flush all the systems anyway and don't have an issue either...
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this is very useful information thanks Briano. It should be written in a warning on all new brake parts that involve rubber, out of concern for safety. so should I also be concerned that the fluid has damaged the rubber seals inside the master cylinder as well?

and all the other rubber parts that are getting leaked on for that matter?? (cv boot, etc)
I suspect you never know what you are really buying these days, as well as the quality of the parts....
I do know that because it is newer don't mean it is Better. In the oldie days my MG's and Sprites all had Armstrong Lever Action Shocks which were a PITA.
They actually had Leather in them for seals and you have to renew the fluid all the time until I stopped using Hydraulic Jack fluid and switched to ATF...... I caused the leather to swell and retain the oil.....Something I picked up from a dad that used it to re-condition really really badly cracked leather seats.....
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