Brakes are not working

[88chevota]

I have done my brakes on all my vehicles since I was in high school, but I cannot seem to figure this one out

So I am almost done with my project but my darn brakes are not working. I need to pump the brakes 3-4 times and then they work. I thought it was the master cylinder so I replaced it but it still does the same thing. I have bled the system like 8 times, but still the same problem. Any suggestions? I am going to try a bleed kit that is suppossed to draw out any air in the line if it is trapped, but if I am heading in the wrong direction someone please help!

 

[mrsvle]

Could be the brake booster. There is a procedure in the FSM for testing the brake booster.

HTH

Matt

 

[NocalFJ60]

You pulled up a few times on the emergency brake to adjust the rear shoes yet? What did you replace? Just pads and shoes?

Can you pump it hold it without pedal dropping more?

 

[Man Jerk]

Have you tried adjusting the adjuster stars on the rear brake shoes yet? Snug them up, and back them off a little.

I just ended up replacing a brake caliper because 2 of the pistons were frozen, and it shows symptoms like you describe as well.

 

[88chevota]

yes I can pump it and hold it without loosing the pedal. I wait 15 seconds, then the pedal drops to the floor when I push it with little resistance. It does not matter if the car is on or off.

I have no e-brake at the moment. When I bleed the rear brakes out the pedal seems to hold but when I bleed the front I loose the pedal again.

I thought it might have been the front calipers but they are showing no signs of leaking and everything works when I pump the brakes.

I sure hope it is not the booster, That thing is $300

 

[NocalFJ60]

Did you replace the front calipers? Wonder if you can bolt them up backwards making the bleed screw on the bottom on both which would trap air.

Double check all the lines in the front and make sure they are tight.

 

[fourand20]

if your brake booster is bad, its an easy job to replace. just had to replace the booster in my 60. only took about an hr to do. hardest thing was getting to the top right nut at the firewall above the pedal.

got the part from rock auto. had it in stock and shiped to me from a warehouse in CA. took 3 days to get it. part was 260 with a 50 core charge.

 

[flowman]

if your brake booster is bad, its an easy job to replace. just had to replace the booster in my 60. only took about an hr to do. hardest thing was getting to the top right nut at the firewall above the pedal.

got the part from rock auto. had it in stock and shiped to me from a warehouse in CA. took 3 days to get it. part was 260 with a 50 core charge.

That's an awesome deal...I know people bash $OR, but they're out of stock on new units, and want $700 for a rebuild!

(I've had great experiences with SOR, and their online catalog diagrams are a great service to the community, but this just proves...shop around!)

 

[88chevota]

Thanks everyone. I am going to try the bleeding kit that is supposed to draw out any trapped air. It won't be until thursday night. I'll post up the results. I found a rebuilt booster through partsamerica.com for $245. I sure hope that is not it though. I would rather spend that money on a locker!

 

[chicago]

Hey 88chevota...
Im wondering... Have you adjusted the LSPV after the lift...
Its that POS arm that attaches to the top of the rear axel housing.
When you lift your rig, it has to raise porportionately with the height of the lift. I made a bracket and welded it on to the upper shock mount/ x member and my brakes have been GREAT ever since!
You can wire tie it up and see how it is, like that...

BTW, prior to that, I had NO REAR brakes and a soft pedal!

Just something to throw out there for ya!

Chicago

 

[88chevota]

I ditched the LSVP a long time ago. I am running straight lines now. my braking power was incredible.

 

[Vicm]

You still have air intering the front brake or the master cyl.
Bleed you master first, make sure it is air free and and lines are tight.
Bleed rear brakes.
Then tighten the lines in the front and rebleed.
Calipers should be the easiest to bleed, I have never used a bleeding kit or help from any body to beeld toy calipers.
If the master is air tight, All I do is pump the brake few times.
Lossen the bleeder till fluid is coming out. Then tighten the bleeder
and reapet 2 more times.
It always worked for me , on new calipers old calipers, new lines and old lines.
I don't hear good things about the bleeding kit , so you maybe just wasting your money there.
Vic

 

[Mace]

bleeding kit is a waste..

Speed bleeders are awesome and almost idiot proof..

If your booster is bad, it is like you are pressing against a wall. Not mushy..

Most likely, your booster is good..

 

[88chevota]

VICM, I have done what you have said at least 8 times now.

I have never had problems either until now.
The kit I am borrowing from my brother-in-law so no $$ spent just a little time.

So I also just remembered that when I was bleeding the master cylinder out the lines were clear but bubbles kept showing up in the reservoir from who knows where.

Mace,
I would think the same thing about the booster but...

Someone told me that my booster seal at the master side was bad and was pushing air into the master. It makes sense I guess? I bled the master out for nearly 5 minutes and bubbles still kept showing up??? The booster leaking air into the master makes sense but I am still not convinced, unless someone has had the same problem and can tell me for sure it is the booster. I would be pissed at myself if I dropped $250 and still had no brakes!

This is driving me crazy!

 

[cruiser88]

adjust the booster rod or whatever the hell its called.

 

[cruiser88]

take loose your 4 nuts holding your masster cy and there it is hanging out of the booster. it should set about 1mm from the master when the brake pedal is not pushed

 

[Mace]

booster cannot frrd air into the master. it is under vaccum..

are the brake lines to the master good and tight???

Pinhole leak somewhere???


pump up the brakes and hold press on them for a while... does the pedal drop to the floor slowly?

 

[cruiser88]

booster cannot frrd air into the master

cool

 

[Tinker]

Whaddya mean you "have no e-brake at the moment"?

As at least one person noted, the ebrake adjusts the shoes. If the shoes aren't adjusted (too loose), you'll have a soft pedal.

 

[Vicm]

I have been trying to make some sense of this air from the boaster to the master. First I don't think it could happen and even if it did wouldn't that mean the master is not sealing properly for air to go in from the boaster.
Have you bleed the master before installing it? bench bleeding it.
If you think it is the boaster then disconnect the hose to the boaster and try bleeding that master again.
The shoes beeing not close to the drums ,will effect a little ,but once you get good paddle , it should stay good till you reapply it againg.

I still think it is air inthe master.
You can also shut the flow the front brakes and use the rear only and vice-versa , to determine what lines are giving the problem.
I have had a brake line hold fluid and leak air . That is possible.
That was a nasty day when that happen.