Failing Drum brakes.

[monza]

hey all,

my front drum brakes just started losing power.

theres powerbooster attached (looks like the old Duff model)

When i am coasting, or ticking over all pressure under the peddle drains away - and the brakes just dont brake any more...

if i accelerate a little - i'm back up to pressure and the brakes are strong.

can anyone give me a quick intro to how the brake system works

and the regular culprits for loss of pressure ?

where should i be looking - and for what.

its just plain dangerous at the moment.

thx,

monza.

 

[S_bolt19]

Sounds like you have the vacuum assisted brakes. Check all your vacuum lines and make sure they are connected and are in good shape. When you have pedal is caused by the more vacuum in the lines (higher engine RPMs), when you are sitting there idling there isn't the vacuum pressure (lower engine RPMs). It is the same thing that happens when the vacuum wipers on the early EBs doesn't work. But check and replace, if necessary, all your vacuum lines. That is where I would start.

 

[monza]

Sounds like you have the vacuum assisted brakes. Check all your vacuum lines and make sure they are connected and are in good shape. When you have pedal is caused by the more vacuum in the lines (higher engine RPMs), when you are sitting there idling there isn't the vacuum pressure (lower engine RPMs). It is the same thing that happens when the vacuum wipers on the early EBs doesn't work. But check and replace, if necessary, all your vacuum lines. That is where I would start.

THX,

am i basically checking any hose that connects the power booster and master cylinder to *anywhere* else ?

Monza.

 

[S_bolt19]

Just the brake booster. Anything coming off the MC is a brake line, but check them too for any seeping.

 

[monza]

heres a question...

any chance the failure is in the carb ?

i only wonder coz i am having some fuelling probs - lumpy starting, runs rich - until warm

and the power booster is fed from the carb...

any chance i have a seal or gasket blown in the carb which is monkeying with both the break pressure and the starting ??

thx again,

Monza.

 

[monza]

heres a question...

any chance the failure is in the carb ?

i only wonder coz i am having some fuelling probs - lumpy starting, runs rich - until warm

and the power booster is fed from the carb...

any chance i have a seal or gasket blown in the carb which is monkeying with both the brake pressure and the starting ??

thx again,

Monza.

 

[S_bolt19]

Have you checked the vacuum advance on the distributer? I know when I had a points system in one of my EBs, I had dual vacuum advance and it completely screwed with the timing, starting and overall running of the vehicle when a line was in bad shape. As far as the carb goes, I don't know what the brake booster is hooked up to on the carb. I never had vacuum brakes with a carb, so there might be something there that is causing the failure, again, I am not 100% because I haven't ever had the same set up you have. You might think about calling the guys at BC or WH and picking their brains for a few minutes. Those guys, either company, will go out of their way to help you figure out the problem. But just from what I remember about the carb/booster set up, definatly check all those vacuum lines, and for the running issues, just to be on the safe side, check the advance lines on the distributer.

 

[monza]

thx bro

will do.

Monza.