stupid brakes

Ok.. On her 1g... With the car off, i have good solid pedal. Seems perfect. As soon as I start the car, the pedal will almost hit the floor, and wont lock the wheels. I have changed the master cylinder, rotors and pads, blead the lines over and over, and nothing is helping.

If the booster diaphragm was toast would that be the symptom? Seems to be the only thing you haven't touched.

Also how did you bleed them? Also master cylinder is brand new or a used known working piece?

Did you make sure to properly bleed the master before installing it? They're a PITA and usually need to be bench-bled, at least on the cars I've changed masters on (no DSMs, for the record).

Is your fluid level staying consistent when the system is sealed up and you're pressing the brake pedal? Does it still have the stock rubber brake lines? Did you inspect the caliper (boots)? Any slow leaks on any of the components?

The brake pedal will always feel stiffer with the car off because there's no vacuum, especially if you press it multiple times. It's supposed to be much easier to press with the car on.

Lines are good. I know one rear caliper boot is on its way out. Keeping my eye out for a replacment. But it dosent leak and still holds the rotor good when someones pressing the pedal. As do the rest. Fluid dosent change. I bled the new MC as instructed. But it was doing the exact same thing before I replaced the MC

I always thought that if the booster was bad, it would have the opposite effect and not help the pedal hit the floor.

I was just spit balling based on what other people with the same issue were saying.

Try holding the pedal down and then turning the car on, if it changes the situation than I would say something with the booster

A booster, if defective, would cause a stiff pedal.

Your going to have to break this down systemically. Buy some brake fitting plugs (or make them, m10x1.25 IIRC) and seal off the outputs from the MC, then Give it a try. If the pedal is at all soft, it's the MC. Is it a brand new or rebuilt MC? I've purchased "new" rebuilt MC's that had bad internal piston seals (both front and rear pistons) that caused this problem.

If it's nice and stiff, you'll have to then move onto the individual calipers. If you still have the stock rubber brake hoses you can pinch them (I used hemostat forceps) and try each corner to see if the brakes feel stiffer when one is pinched off to locate the culprit.

Does it have ABS? If so, the pumps have to be bled as well.

Good luck man

I was gonna try the pinching of the rubber lines.

Its a new but cheap MC so I wouldnt be surprised if it was faulty.

Ok.. So i pinched the brake lines... And it seemed it felt alot better when each front caliper was pinched. So since I had a set of 2g front brakes.. I guess im upgrading! Ill do that tomorrow and see if it gets any better.

So i started to clean up my 2g calipers and I broke a slider pin!!!

But as I took the caliper apart, i got wondering... How is it causing y pedal to gi to the floor if its not leaking??????

The only way it could be the calipers is if the seal around the piston is leaking fluid into the dust boot. Brake fluid evaporates quickly too.

It does sound more like a master cylinder issue to me but brake issues are such a PITA sometimes.

One other thing to do, after you bleed the brakes, engage the e brake a bunch of times. it's the back brakes that control your pedal height. This will get the pads to snug up the rotors. Then bleed again.

The ebrake on this car dosent work. One cable snapped

Ok.. I swapped in an old 2g maste cylinder from my parts car. And that didnt seem to do anything. The I swapped in the 2g front calipers and brakes.

The pedal still goes to the floor... But the car will stop now.

Yay!

Good thing to... My wideband sensor stopped working in my 2g.

Air in the lines.

You would think.. But ive gone thru 3bottles of brake fluid bleading them. Im thinking the used MC isnt as good as I was hoping... So i may look for a known working unit.

Id like to find a running parts car realy.

Send Robert Dike a message. He may have just what you need.

Usually masters go bad when they leak, internal problems with the valves are rare. You bleeding the system with a hose connected to the bleeder into a bottle with brake fluid? If your doing the pump and hold while someone cracks the bleeder, it takes along time to get all the air out of the system when you put a master in dry which it inst bench bled. Regardless I hope you figure it out!