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Help! No Brakes, Have to stop like Fred Flintstone

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77_MG_Midget

77_MG_Midget

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My 77 midget has lost all brakes. They were fine when I drove it about 4 months ago, but since that time, they're all gone. Now I know I need new rear brake cylinders as they are leaking a little, but I bled the system and within 10 minutes, no more brakes again. This is something I plan to fix while the motor is in the machine shop (TODAY... YEA!!!). Any ideas on what's wrong or what I should be checking first? And why would all the brakes, front and rear, go out? Aren't they on seperate systems? Oh, by the way, even though there was no brake pressure, the brake warning light never came on???
 
Re: Help! No Brakes, Have to stop like Fred Flints

If you can pump the brakes a few time and feel pressure for a few seconds, then there is still air in your brake lines.

Getting a vaccuum bleader will really help get the air out of these little cars.
 
Re: Help! No Brakes, Have to stop like Fred Flints

I got pressure only when bleeding the brakes. Now, if I pump them, nothing. The pedal goes straight to the floor and doesn't build any pressure.
 
Re: Help! No Brakes, Have to stop like Fred Flints

We assume the fluid resevoir is full? Are there any signs of fluid leaking out anywhere such as from the master or slave cylinders? Check the drivers side floor for master cyl leak.
 
Re: Help! No Brakes, Have to stop like Fred Flints

Have you done anything with the rear brakes other than observe the leak? Have you tried adjusting them? If the shoes are not adjusted properly you'll have excessive pedal travel on the "first" pump of the brake pedal. If you pump the pedal again (a fraction of a second later) AND the pedal feels firmer, spend some time re-adjusting the rear brakes.

If after adjusting the rear drums they still feel squishy, bleed the brakes again. If they still feel OK for a couple of minutes and then after 10 minutes are all squishy again, I'd be looking at the master cylinder. You know the wheel cylinders are leaking, it's only a few more dollars for the MC rebuild kit.

BTW, what method are you using to bleed the brakes? Are you doing a two-person "pump-hold-release" method, or are you using the "pump-pump-pump-open the bleed nipple" method? I only use the first method on LBCs.
 
Re: Help! No Brakes, Have to stop like Fred Flints

I would suspect something with the master cylinder. What are the front brakes doing? Even if the rear brakes leaked down, the fronts should still be doing something. Do you still have brake fluid in the front half of the reservoir when the pedal is going to the floor? You could have leaks inside the master cylinder, in the front brake circuit, or possibly in the brake failure switch. And as far as the brake failure switch not working, the switch pushrod on mine had some rust that had built up that kept it frozen in place. You can unscrew the electric switch from the PDWA body to see if this is the case. And if you get lots of brake fluid out when you unscrew it, your PDWA seals are shot. Hope this helps!
 
Re: Help! No Brakes, Have to stop like Fred Flints

I would also say it sounds to me like the problem is somewhere between the MC and PDWA. I rebuilt both of those units last summer because I was having similar problems to what you're describing and it worked. I wasn't getting any fluid to the rear brakes ever because somethign was screwy in the PDWA. I replaced the brake cylinders, rebuilt the Master and PDWA and my car has stopped on a dime ever since then, no fluid leaking, no squishiness.

The added piece of advice, the reason I'm posting this is to mention that since my Dad died, I've been working solo on my Midget which is not a problem until it comes to the two man job of bleeding hydraulics. However, I found that the self-checking "speed-bleeders" that are off the shelf in most auto parts stores fit both the front and backs of my midget. I was skeptical about how well the would work but bleeding the brakes to NO time at all and was SOOO easy and the brakes are better than I have felt in any MG for a very very very long time.

The other trick is to follow the instructions on bleeding order. Because of the PDWA you can't use the "one at a time" method of starting furthest from the MC and working around. You have to do TWO at a time which means it would be a three person job the old way. With the speed-bleeders I would just open to at a time, pump away, close'em and good to go.

JACK
 
Re: Help! No Brakes, Have to stop like Fred Flints

Wow... lots of info... The MC was empty, but I don't see any fluid laying anywhere. Filled the MC and bled the brakes, using the 2 person pump-hold-release method, but I was doing it furthest from the MC first, one wheel at a time. I've never heard of doing TWO at a time. Anyway, got fluid out of both rears just fine. Again, by the time I got the front of the car jacked up, no pressure again. The fluid had to go somewhere, but it's not on the garage floor and not inside the car on the drivers side floor board. I found last night that although the brake pedal hits the floor, there is just a little bit of brake power, but not enough to stop the car. I have no idea if the MC or PDWA were ever rebuilt, and being the car is 28 yrs old, maybe it would be best to just do it while the engine is out.
 
Re: Help! No Brakes, Have to stop like Fred Flints

Sounds like you still have air in the system. You will need to bleed the brakes many times over if you started with a dry MC.
 
Re: Help! No Brakes, Have to stop like Fred Flints

If the master cylinder went dry, you may also have air trapped in the master. I bench bled mine before putting it in the car by plugging the outlets, filling with fluid, and depressing the plunger. Without removing yours, you might try pumping the pedal several times before bleeding it. Are you still losing fluid? I'd stop and find the leak first, especially if you say the reservoir was empty. Brake fluid does nasty things to anything painted. The alternative to bleeding using the 2-person method is a vacuum bleeder. I used this when I replaced the master cylinder and brake lines on mine, and it has the benefit of not disturbing the PDWA switch. For some reason, my '77 and another member's '77 have a PDWA that latches in position, which requires unscrewing the switch from the PDWA body to reset it. Good luck!
 
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