whats wrong with my brakes

[gingerbreadman]

its on my 1978 fj45 . if i double pump the pedal my brakes work ok . but if i go to use the brakes normally and single press them they almost go to the floor before anything happens ..and then after a few seconds of braking it seems like i run out of vacum and the brakes are full manual which is absolutely useless (might as well not have brakes).

its a terrible habit but just since the last few days as this has been happening i have been double pumping just to get me out of trouble.

[V.W.Dave]

sounds like you have air in your lines or the booster is starting to pack it in.

Have you had a look at your brake fluid level? How much brake pad do you have left? What condition is the vacuum line going to the booster in? Have a quick look at the rear drums to see if they are leaking? Is there brake fluid running down the fire wall behind the booster? Do you have aq vacuum gauge set up you can test the vacuum going to the booster?

Just a few things to look for to help us help you.

[Frankenyota]

Check for fluid leaks, and if you have 4 wheel drum brakes check there adjusted properly.
If the drums are badly worn they can go oversize, and they will always cause the brake pedal to pump up.

Matt

[skips_BIGRED]

i had the same issue just recently, it was the front wheel bearings.

the theory goes, if your wheel bearing are loose, they can create a whobble in the hub which makes it hard for the brake to clamp.

[McLarryBob]

i had the same issue just recently, it was the front wheel bearings.

the theory goes, if your wheel bearing are loose, they can create a whobble in the hub which makes it hard for the brake to clamp.

Almost. If it's a disk front end (maybe drum too) the loose wheel bearing can allow the disc to wobble and push the pads back into the caliper. Now there is a large air gap between the pad and the disc and it will take more pedal travel to clamp the pads onto the disk. (Or shoes onto drum, but i'm not sure about that)

But the basic checks like VW Dave said along with this will more than likely find your problem.

[loosecanon]

im having problems with this aswell, do you have the twin rear wheel cylinders (early models) or the single wheel cylinders on the rear?
prob good to find out where it's happening, so clamp the fronts off and see if it's any better if not clamp the rear and see if it's any better, if it does you know that end has the air in it.

let us know how you fixed this, or if you already have,

cheers