Power brake Problem. 1969 plymouth Barracuda

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trigger_andy

trigger_andy

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Hey all,
I have a major problem with my brakes since I disconected the master cylinder from the Booster to fit my header's. I also removed the steel band from around the booster in an attempt to give me extra clearance. I have since refitted the steel band and it look's OK. I then refitted the Master Cylinder in the same way it came off.

When everything was back together again I went for a short drive and now have no brakes. I still have a good pedal so I know no lines have been ruptured, I only get a momentery power brake effort before I have to realy lean on the pedal to get me to stop.

I have inspected the rubber seal for any tear's and cant see any. I have also removed the vacuum hose from the Inlet Manifold and gave it a suck. There is no vacuum but it is realy had to suck through. The only thing I can think of is the foam filter that sat between the master cylinder and the plastic clip disintigrated when I removed the master cylinder? Any idea's would be much appreciated.
 
Andy
Just a wild guess here, but I think when you took off the band around the booster, you disturbed the seal of the diaphram in the booster, and now have an internal vacuum leak in the booster itself. You might have to remove the front half and get the diaphram back in place properly. Wosrt case senario is to remove the booster, and rebuild it on the bench, or get a new one. If you remove it just make sure the rod lenght stays the same, ( measure it), so as not to throw it out of adjustment. Clean every thing uo and lube the end of the rod also. Do you have a fac service manual, ?? They will have all that info.
Hope this helps. Dave C.
 
you will know if your booster is bad by doing the following:
with car off, pump brakes to remove all vacuum from booster. next, with your foot on the brake, start the car. if the pedal drop slightly, your booster is working properly, if not its got a leak. a vacuum pump will diagnose a leak properly.
 
Cheers for the reply guy's. I hope you are right Dave, I'll have a look and see if I have damaged the seal. I did check that but I could have missed something I guess??

I found a company that sell's replacement unit's for $130.00. Is this good?
 
:salut: Hey all,
this Brake problem has turned out to be more of a problem than I had hoped for. After failing to find the problem with the Booster I ordered a new Booster and M/C but I was sent the wrong one and cant get the right one this side of the pond(UK) for a while. If anyone has a spare Booster core please let me know.

I was out today further investigating the booster problem and had a play around with the Booster and M/C. I now have a different problem, dont ask me why.

Now when I fire the mighty 318 :thumblef: up my brake pedal gets sucked to the floor. This gives me full assisted brakes again but not when I need them. Under the hood when I remove the vaccume hose I can see the rod linkage return to its original position slowly and when I reapply the hose from the inlet the linkage getts sucked right back in fairly quickly. Any Ideas guys?
 
bad booster? you mean the brake pedal actually gets sucked down like you put your foot on it?
 
Jim Lusk said:
Ditch the booster entirely. A-bodies did not need power brakes.
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I Agree with Jim. But i like to feel the road under me, so i dont have power brakes or steering. and its overrated.
 
Thanks for the replies guys. Redfastback, the pedal would actualy get sucked to the floor when I fired the engine up. When I removed the vaccume hose from the booster I could see the linkage moving back to its original position slowly. but when I reattatched the vacume hose the linkage/pedal would get sucked in quite fast.

Since then I have striped the booster down again and inspected it, rebuilt it as there is no signs of damage and now I have assisted brakes again.........to a point. The pedal works fine most of the way through its travel but if I brake hard the pedal will get sucked to the floor and i have to slide my foot uner it and lift it from the floor. Its the same at junctions, good braking force then the pedal will get sucked to the floor.

How do I go about converting the Brake system to manual? I have the KH four pot's at the front with the 11" HD drums at the rear.
 
trigger_andy said:
Thanks for the replies guys. Redfastback, the pedal would actualy get sucked to the floor when I fired the engine up. When I removed the vaccume hose from the booster I could see the linkage moving back to its original position slowly. but when I reattatched the vacume hose the linkage/pedal would get sucked in quite fast.

Since then I have striped the booster down again and inspected it, rebuilt it as there is no signs of damage and now I have assisted brakes again.........to a point. The pedal works fine most of the way through its travel but if I brake hard the pedal will get sucked to the floor and i have to slide my foot uner it and lift it from the floor. Its the same at junctions, good braking force then the pedal will get sucked to the floor.

How do I go about converting the Brake system to manual? I have the KH four pot's at the front with the 11" HD drums at the rear.
Click to expand...


There is a possabilty that your master has packed it in.. as the fluid is passing passed the seal.. mine did that once and a while and i could bleed the brakes till i was blue in the face to try and fix it but i replaced the master and its good to go now..

mind you.. its just a possability..

Cerwin
 
Get a manual brake pushrod. You can use the same master cylinder you are using now, but it is likely that it won't cover the hole in the firewal completely. Just use the sheetmetal cover that's over it now. You will have to bend the lines or get lines form a manual brake car.
 
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