I can't stop!!!!!

[lippy 882]

Ok, I can stop, but it takes too long for my liking. My brakes are starting to go on my Sprint. The pedal is real spongy, and it doesn't seem to be grabbing untill it's damb near to the floor. We bled them, no change. Yesterday we changed the master cylinder, then bled them again with a suction gun. I'm seriously amazed at how long we spent on each wheel before we were consistently getting clean fluid and no air. But after about 6 hours of messing with it, it ain't much better than when we started. We know we've got a good MC, and the lines from the MC down are good. I'm not real mechanical, but a couple of friends of mine who know their shit are baffled.
Any mechanical types got some suggestions?

I got nuthin

[dbattman 0]

Do you have a leak somewhere?

[davelepka 4]

If your pads (or shoes) are thin, the pistons may have to push too far to actually make contact. Also, I'm pretty sure your bakes are power assisted (I think they all are nowadays) so check the vaccum lines going into the master cylinder. If all the lines are hooked up (and no cracked or broken) look for a vaccum leak somewhere else in the system. A leak in the intake manifold will cause a weak vaccum as well, so check that area also. When my Stiletto doesn't want to stop, I drag my feet on the ground, so thats another option as well.

[JohnnyD 0]

Make sure your horn works.

[nacmacfeegle 0]

Bite the bullet and take the car into one of those brakes, tyres, and exhaust places.
Its just not worth screwing around with it, it is your life after all.

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He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me. Thomas Jefferson

[lippy 882]

The vacuum is good, and isn't a factor here b/c we're seeing the problem when the car is off ie: No power assist.
I'll take it to one of those places first thing Monday, but it just ain't an option until then.

I got nuthin

[hookitt 1]

I don't know what kind of brakes are on a Sprint. If it's rear drums then try this.

While parked, Hit the brakes then quickly release then hit it again.... does the pedal become firmer and come up higher from the floor?

Set the Parking brake and hit the brakes a couple times does it start feeling more like it should?


Either one of those would indicate the need to adjust the rear brakes properly.
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Did you bench bleed the master cylinder prior to installation? Since you power bled the brakes I'll guess that the air is actually out of the system but I had to ask.

What is the condition of the brake lines? do they have any bulges in them?

You didn't say if you performed any thing else but a master cylinder replacement.
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My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[VectorBoy 0]

When bleeding don't recycle or reintroduce the same fluid into the system. Any water in the brake fluid will drop the boiling point of the total fluid and give you a radical spongy feel. Although I doubt it in this case because it usually manifests itself in uneven braking front to back and side to side, providing you with some radical unintended lane changes even at slow speed.
I would really look into a possible vacuum leak.

[wmw999 2,334]

Sounds like you still have air in the system, or again have air in the system. Try bleeding them again tommorrow -- if so, then there's a breach. If not, well, try the pads, and see if pumping them helps. But we've about run past my brake expertise...

Don't try too hard to save money on brakes. They're much more complicated than your reserve, and you use them a whole lot more often.

Wendy W.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[oldnewbie 0]

I'm not sure what a sprint is, or what kinda brakes that it would have, assuming that i knew what it was!!! However, if it has antilock brakes, depending on the car (general motors, ford, chrysler, honda etc., etc., you need to *excercise* the valves in the anti-lock brake unit.. This may require a factory scan-tool to do. I have seen people try bleeding their brakes (antilock cars) for hours and hours and the can NEVER get them bled.

I think hookit mentioned that the mastercylinder needs to be benchbled. It probaby does. However, are you SURE that the rebuilt master cylinder is actually GOOD???? I have had many master cylinder that were bad right from the *cheap* auto parts store that i bought them from.

Anyways, if its antilock brakes, you probably need to excercise the valves in the antilock brake unit.

Isn't a sprint a general motors car??