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MG MGB Technical - Emergency brake won't hold

The emergency brake won't hold even on a slight slope. I've replaced the wheel cylinders, cleaned up the brake area and replaced the shoes. Everything set up in accordance with the Bentley manual. I even took the MG to a mechanic. No luck. What am I missing?
G.E. Bulwinkle

Do you depress the brake pedal before engaging the parking brake?
C Holm

It doesn't seem to matter whether I depress the brake pedal or not. Also I adjusted the brakes and adjusted the emergency brake cable.
G.E. Bulwinkle

Are the cables tight when the emergency brake is applied? It's mechanical and if everything is adjusted correctly it should work. Does the handle pull all the way to it's limits? I don't understand why it should be necessay to apply the footbrake when the E brake is applied. It should work even if the foot brake doesn't work.

Clifton
Clifton Gordon

Remove the equalizer on the back of the rear axle housing, disassemble, clean and lubricate it and put it all back together. Unless you have a cable that is too long, that should get your hand brake working. Cheers - Dave
David DuBois

Looks like the swivel link behind the shoes may have seized. Remove the shoes and the links free them and lubricate and reassemble.
Iain MacKintosh

G.E. Is the cable the original cable? The one which is about 30 years old and has many thousands of use cycles on it?

You mention having done the first step--releasing the hand brake and properly adjusting the rear brake shoes.

What needs to be done next depends on on recently the brakes have been serviced and what condition the parts are in.

If the brakes have not been recently (within the last year) serviced, you need to take the parts associated with the hand brake and clean, inspect, and lubricate them. This is the two piece "bar" assembly which fits inside the brake drum and physically moves the shoes apart and the brake cable system. As Dave and Iain note, all of the various parts must be clean, lubricated and move freely. Unless you know these parts are working correctly, start with their inspection.

With all of the parts working correctly, cleaned and lubricated, the cable hooked up properly with good clevis pins between the cable ends and the brake shoe activators, it is time to adjust the cable slack.

Put the hand brake on three to four "clicks", then, use a small wrench or a pair of Vise-Grips to hold the solid portion of the threaded end of the cable assembly. (The piece just behind the attachment mechanism for the hand lever. The cable must be straight. If it has bent upwards in the front and downwards at the rear, the hand brake lever needs cleaning and loosening. Lubrication, just a small amount, is always a good idea.) Use a 7/16" wrench to tighten the brass "nut", taking any slack out of the cable. When it is difficult to turn the nut (the rear is a semi-circular notch, making it possible to only turn the nut 180 degrees at a time), test the functioning of the hand brake system. Unless the cable is stretched, and/or lost is tension, the hand brake system should be working fine now.

The cable is a form of minor spring. Instead of running in a straight line, as electrical wires do, the strands of the hand brake cable are wrapped in a spiral. This makes it a spring and, when the hand brake is applied, the cable strands are pulled slightly straighter, putting a spring tension on the rear brakes. As the cables get older, they lose the ability to stretch and apply a clamping force. This application of spring force can be felt when pulling the hand brake lever upwards when you understand what you are feeling. If you are not feeling the increasing spring tension as you pull the lever upwards, you might need to install a new hand brake cable. The difference in feel and performance between the new cable and an original cable can only be appreciated in a side-by-side comparison. I changed out the cable on my daughter's car, adjusted it, and decided to adjust the cable on my car since I was doing such work. Thought I had a good hand brake system on my car. It was immediately obvious that the new cable made a significant difference--one that anyone who operated the two immediately realized. They did not know why, but they recognized the difference between how the two systems operated.

Now, you know what needs to be done and how the system works. You should be able to go into the system on your car, make the necessary choices, and get the hand brake system working properly. If you have any problems, let us know and we will assist as necessary.

Les
Les Bengtson

I talked with the mechanic today. It seems he did everything I did. He seemed to think the levers at the drums were working properly. Suggested turning the brake drums might help. Oh, I forgot to mention the car is a 1978 MGB. The cable was replaced several years ago.

George
G.E. Bulwinkle

GE turning the drums will only help his bank account.
check, clean and lube everything that moves. you are missing something. RIC
RIC LLOYD

The slave cylinders have no effect on the effectiveness or otherwise of the handbrake. How far up does the handle go? Should only be 4 or 5 clicks. If more than that either the cable has stretched beyound its adjustment limits (nut below the handle in the tunnel, have you adjusted that?), or the notches in the levers inside the drums have worn too deep, or those on the shoes have worn too much, or the shoes have worn, or the drums have worn/been skimmed too much, the footbrake adjusters haven't been set properly. If it only goes as far as it should the handbrake cable (does it have a grease nipple by the right rear wheel?) and linkages could be partially siezed, or the cable has broken strands, shoes and springs incorrectly fitted, etc. etc.

When you have corrected any worn or siezed parts and know how the shoes and springs should be correctly orientated (the 'empty' part of the shoe i.e. the bit of the metal part without any friction material should be uppermost on the front shoe and lowermost on the rear, both sides), remove and grease the adjuster threaded part and the little blocks that open up the shoes as the adjuster is turned. With everything replaced as it should be adjust the footbrake correctly. Typically this results in rubbing noises, but not binding, but it differs car to car and the true test is does the drum get hot after a few miles with only gentle braking. It should be barely warm to the touch.

When the adjustment of that is correct pull up the handbrake, adjusting the cable at the handle for 5 or 6 clicks. If there is insufficient adjustment left you could have the wrong cable (steel wheel axle cables will be too long when fitted to a wire wheel axle) or it could have stretched. It's also possible that incorrect fitment of the levers inside the drums can cause this. When you can pull the handle up tight at 5 or 6 clicks look at the ends of the levers that come out of the backplate then point towards the back and have the cable attached. Ideally the part that points backwards should be pointing *directly* backwards i.e. parallel to the backplate. If one or other is pointing inwards slightly, either the notches in the levers are worn, or the shoes, or the drums, and it reduces efefctiveness. Likewise if they point the other way, but that is less likely.

When that is all OK finally put a thin smear of grease on every metal to metal contact point of shoes, backplate, levers, cable clevis, and the pivot on the diff case. Grease the cable if it has a nipple.

The handbrake is a parking brake, not an emergency brake. You might just be able to lock the wheels with it, which could cause loss of control, but you won't get much retardation with it. However it should hold the car on a pretty steep hill. BL handbrakes do need regular maintenance to keep them effective. I do the lubrication above anually, and at the last Government test the tester (experienced with MGBs and other classics) commented on how good it was, he said 'normally they are rubbish'.
Paul Hunt 2

The emergency brake works! I replaced the operating levers at the drums and greased the new ones. The old ones didn't look much different from the new ones, but I guess they were worn. THANKS TO ALL FOR YOUR HELP!

George
G.E. Bulwinkle

Took Paul Hunt's advice and took everything apart and greased everything. Also replaced all 4 shoes as two of them were glazed. Handbrake now works once again!

George
G.E. Bulwinkle

I enjoyed this thread - just wanted to say that the combination of comments from Dave, Les and Paul provided a comprehensive set of guidelines for all of us. regards, John.
J P Hall

This thread was discussed between 22/08/2007 and 22/12/2015

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