57 Chevy has no brakes!

BFS57 · January 28, 2010, 08:29:53 AM

Hello;
The other day, I decided to put some new disc pads and wheel bearings on my 57. It has a upgraded system (5 years ago) to power disc/drum with a duel 8" booster and corvette style MC.(From Speedway)
Well, after I did the bearings and new pads, NO BRAKES!! What the heck!
Discovered a leaking rear break area but that was just loose where the backing plate bolts on to the end of the rear end housing.
Have spongy pedal while bleeding, start the engine (Vacuume in the booster) and Breaks (pedal) on the floor!
Still no breaks!! Bleed the snot out of them, Still no Breaks! Does this mean, my master is ka-poot? Someone mentioned that some kind of crud might kad worked it's way into the booster, the fluid coming out is kind of nasty looking.
Anyone got any handy hints of any kind of test or "words of wisdom"?
Everything worked fine (or seemed to) before I tore it down!/
HELP!!!

Bruce

kb426 · January 28, 2010, 01:02:10 PM

Did you bleed the master first?

BFS57 · January 28, 2010, 03:59:42 PM

Hello;
Did the master removal and inspection. Found tons of gritty crud inside! Time for a new one!!!

Don't know how I am going to go about flushing the lines yet!

Bruce

papastoyss · January 28, 2010, 05:06:29 PM

lasso a friend with a strong leg & bleed til clean fluid comes out.

BFS57 · January 28, 2010, 08:02:10 PM

Hello;
While the Master is off, I'm thinking I want to hook up the compressor to the lines and just blow until clear. Next I have some spray cleaner I am thinking about spraying in the lines to try to clean them out.
Anyone have a better way to go about this?

Bruce

wayne petty · January 28, 2010, 08:03:43 PM

you might also want to rebuild the front calipers .. if they are gm style they are not hard to do...

the varnish and crud build up behind the seal and prevent the designed in kick back on the piston.. increases mileage... pads last longer also...

why???

this is the caliper seal groove.. \_| the seal fits in the top... when the piston is pushed out.. the seal flexes slightly.. when pressure is released.. the seal tries to straighten up... pulls the piston back just enough.. just a thought...

reborn55 · January 28, 2010, 09:19:42 PM

just curious--are the calipers moving when you apply the brakes

Mac · January 28, 2010, 10:52:52 PM

Quote from: "BFS57"Hello;
Next I have some spray cleaner I am thinking about spraying in the lines to try to clean them out.
Bruce

Be careful of the cleaner you use if it comes in contact with the rubber parts ie: cups, seals and o-rings. It's best to use just clean brake fluid.

BFS57 · January 29, 2010, 05:26:16 AM

Hello;
Ken, Yes the calipers were moving. But the pedal was spongy without the booster and after the engine was running, the pedal went to the floor but I still had "some" stop. Kind of like if I made the rod from the booster to the pedal longer, it would be better.
After I took off the master and took it apart, I saw so much gritty crap in the piston area that it is pretty much a given that this master is in dire need of a good cleaning. I searched for a local rebuilders but couldn't find any located in Orlando. I know there has to be someone here but they make it difficult to locate them either on the net or by phone book. So, I have opted to buy a rebuilt one or look at a new one. Am using CarQuest for parts, they seem to have pretty good parts at decent prices. I got the wheel bearings, disc pads and grease seals from them.

Bruce

BFS57 · February 03, 2010, 03:55:09 PM

Hello;
been working on this now for this afternoon. Got the new master on, brakes bleed, rear shoes adjusted. When the car is not running, (booster not working) the pedal seems good but a slight bit spongy! When I start the car (booster working) the pedal goes down to the floor with no effort!
What the heck is going on? Could I have a bad booster too?
Someone please give me some pointers!

Bruce

phat46 · February 03, 2010, 05:20:17 PM

Quote from: "BFS57"Hello;
been working on this now for this afternoon. Got the new master on, brakes bleed, rear shoes adjusted. When the car is not running, (booster not working) the pedal seems good but a slight bit spongy! When I start the car (booster working) the pedal goes down to the floor with no effort!
What the heck is going on? Could I have a bad booster too?
Someone please give me some pointers!

Bruce

I wouldn't be surprised if you got a bad MC, even if it's "new". I went through the same thing a few years back and finally took the car to a friends shop. He knew right away the MC was bad, even though I had a "new" one on it from Murrays. He said it's very common now to get bad ones, plural, from these places.

enjenjo · February 03, 2010, 05:54:37 PM

A spongy pedal is air in the lines. where it's coming from is a different thing.

kb426 · February 03, 2010, 06:34:13 PM

I agree with Frank. Air is either coming in from a leak or you may need to find a pressure bleeder to purge the lines.

BFS57 · February 03, 2010, 06:37:12 PM

Hello;
Is there a way to test to see if it is the booster?

When I first mounted the master, I took the little plastic fittings and lines and did the bench bleed on the car with the pedal. I noticed that I couldn't get rid of the air bubbles coming from the front reservoir. I pushed the little plastic ends in, held them, had someone pump, and then it was (or so I thought) just fine.
I'm so puzzled why this is happening, I guess that I remember that you could buy parts that worked right out of the * box!

Bruce

enjenjo · February 03, 2010, 06:50:51 PM

A bad booster will not make the pedal spongy. It may suck fluid out of the master cylinder without a visible leak. But only of the master cylinder seals are bad.