Stupid Brake Gremlins

Are the back brakes adjusted properly?

i have been working on car about 40 yrs. and can do just about anything, did brakes, engines, you name it.. but brake bleeding is not one of my specialties... when i need the brake bled i just go someplace and have it done for me... i could never be in the drivers seat pumping and under the car at the same time.. and the pumper could never just get it right or maybe it was me??? but most shops will have a pressure bleeder to pump the fluid in when the open and close the bleeder screw.. or you might try this web site for some new brake bleeder valve.. i plan on getting some for my cars eventually unless i make the pressure bleeder first????

Well I don't know how much you know about brakes, so I'm just going to say a bunch of things and hope one of them helps. If it sounds stupid, well, at least you know you're doing something right. How are you bleeding them? If you are pedal bleeding you need two people to get the job done.. pedal down, crack the bleeder, tighten the bleeder, hit it ( the caliper or cylinder ) with a rubber mallet a few times to get the air bubbles to the top, pedal down, crack the bleeder .. etc. You can't have your foot off of the pedal when you tighten up the bleeder, otherwise there will be air let back into the system. You also shouldn't push down very hard (medium pressure), unless you're checking for leaks in the washers around the banjo bolts, which you should do before you finish up. If there are leaks around the banjos, air will enter the lines, and you'll get your spongy pedal again. You probably know about bleeding rear-right, rear-left, front-right, front-left, so i wont touch on that. The brake booster only helps the driver by letting them use less force to give more braking power, so if it went, you'd still be able to brake, it would just take more effort. It wouldn't account for the spongyness. It could be just the regulator or the M/C, but when I think of spongy I think of air in the lines. hope some of this helps,

Brendan

Does the stock master cylinder have enough capacity to support the bigger calipers?

yeah, got bleeding brakes down pretty good. I was thinking the same thing with the spongeness being related to air in the lines. That why I went thru so much Dot 3. Cuz after you bleed them they feel ok. Not great but, ok. Then after you fire up the engine and test them, they're spongey again. The rear wheel cylinders are dry and the fluid level in the master remains the same. The only thing that i could think of was that maybe the seals were shot and that the fluid was partially circulating from primary to the slave. But now that you mentioned the banjos I'll go back and double check those.

If i cant find the problem I think I'm going to resort to throwing an anchor out the window to stop the car. At least until I can afford to upgrade everything to something like a Baer 4 wheel disk system.

Some sides notes for the other posters.

- rear brakes are drums and adjusted correctly and have good life in them

- the master is not stock but the same as in a Lincoln

- calipers, rotors, master, booster are upgraded

- lines and rear drum assemblies are stock

Thanks for help, Carl

Let me get this straight... you're going to drive a car with questionable brakes??? Make sure your premiums are up to date.

The booster adds it's own special feel to the system.... try an F-SuperDuty with the 7.3 and you'll find an un-neerving condition that Ford calls "step-through"...

All the same, driving the car will be the proof to the pudding. If the pedal is solid with the motor off, there is no air. If the pedal 'builds' with the motor off, you can almost bet that the rear brakes are out of adjustment. Check for siezed wheel cylinder pistons at the same time. Also, make sure the brake shoes are touching the anchor pins..... stuck brake cables can be a booger.

I would honestly suggest that you read up on brake hydraulics..... if we don't understand the system, we don't have a hope in hell of fixing it.

yeah, got bleeding brakes down pretty good. I was thinking the same thing with the spongeness being related to air in the lines. That why I went thru so much Dot 3. Cuz after you bleed them they feel ok. Not great but, ok. Then after you fire up the engine and test them, they're spongey again. The rear wheel cylinders are dry and the fluid level in the master remains the same. The only thing that i could think of was that maybe the seals were shot and that the fluid was partially circulating from primary to the slave. But now that you mentioned the banjos I'll go back and double check those.

If i cant find the problem I think I'm going to resort to throwing an anchor out the window to stop the car. At least until I can afford to upgrade everything to something like a Baer 4 wheel disk system.

Some sides notes for the other posters.

- rear brakes are drums and adjusted correctly and have good life in them

- the master is not stock but the same as in a Lincoln

- calipers, rotors, master, booster are upgraded

- lines and rear drum assemblies are stock

Thanks for help, Carl

I would think that the cam would cause a low vacuum condition resulting in a foot hurting hard pedal. If there are no leaks, check for a rubber hose that is expanding under pressure. (both front calipers as well as the one that goes to the rearend)