brakes Weak brakes

[TobyB]

Ayup. 

 

t

 

[Stevenc22]

Yes 76 but my brake bias switch is gone.

[borgpj]

When pressure bleeding my brakes, I found that I had zero fluid at the rear bleeders.  Thought they were plugged, but not so.  Eventually found that the two flex hoses were completely occluded.  When I cut them open, they were filled with some sort of brownish jello-like stuff.  Maybe your flex hoses are partially occluded.  There is definitely something going on back there,  You should be able to gravity-bleed the backs, although pressure bleeding is best.  If you have already replaced the flex hoses, then I'm stumped.

[Stevenc22]

Yeah I have 2 year old stainless steel braided lines. I think the master is jammed up. Ordered my fourth master

[Stevenc22]

Update: replaced master, rear wheel cylinders and shoes and now the brakes bleed nicely. 

 

Took it for a test drive and still no real stopping power.

 

The brake pedal feels like it has alot of travel. It feels like the brakes dont start to grab until half way through the throw and then when you bottom out the pedal you havent built enough pressure to really stop. Rears are adjusted and the pedal linkage moves the booster rod very precisely so the problem isnt there.

 

Could be air in the master but i tried to benchbleed it well before installing. 

Edited April 23, 2016 by Stevenc22

[kinarcy]

I'm wondering if it could be an adjustment in your linkage somewhere (either too much lash or not enough lash between the linkage and the master).  You say the travel feels long.   It could be that the linkage is adjusted "short" of the master so there is lash between the pushrod and the master and you aren't getting full travel at the master cylinder (the first part of your pedal travel wouldn't be moving the master).  I experienced a similar situation on a 72 corvette. Bled the brakes repeatedly and only the fronts would lock, rears would not.  In that case I believe the pushrod was too long and the mastercylinder wasn't retracting completely so we weren't getting full stroke. --different linkage i know, but the principle at the master is the same.

Edited April 23, 2016 by kinarcy
remembered more detail

[ray_]

Your calipers are right side up, right?

 

Bleeding from all the fittings?

 

I replaced everything in the hydraulics on the project car. The pedal is high, no travel, bite is instant with stock components.

 

Gotta be some '02 guys near you. Invite them for pizza.

 

Cheers,

[Hans]

Did you replace the rubber hoses all around? That's where I'd be starting if you're happy with previous bleeding. Also, pads can make a difference, if you are using a hard pad that needs to be warmed up to work properly. I swapped out Metal Masters for regular pads and suddenly my brakes worked  much better.

[Stevenc22]

I am starting to think my problem is with my brake booster linkage. All my problems started when i installed a new rebuilt centric booster and new master. I keep blaming the master but maybe the problem is with the booster. I removed the master and pressed the brake pedal and the pedal did NOT hit the floor. It stopped 2/3rds of the way to the floor. These pictures are with the master removed. The booster rod on the back on the booster is starting to make contact with the air filter tube thing on the back of the booster when the pedal is depressed.

 

Is this normal? Should the booster mechanism be the limiting factor? Should the pedal hit the floor with no master? Is this enough throw in the linkage? Does anyone have a picture of the back of a booster disassembled so i can see if there is something that could go wrong?

Edited April 26, 2016 by Stevenc22

[2002]

Do you have a good check valve between the brake booster and your intake manifold?  Are the hose clamps on the vacuum line from the intake manifold tight?  Is the O-Ring sealing between the master cylinder and the brake booster?  Is there fluid in the brake booster? 

[zinz]

Steven,

 

My Centric booster failed me while we were attending the 50th Party in Plano, last month...it lasted about 15,000 miles? I ordered another one but they sent me some wonky booster that only barely resembled an '02 booster... Terry Sayther's bunch saved the day with a good-used standard booster.  It works very well... much better than the rebuilt Centric unit I'd been running these last couple of years.

 

Braking is immediate and no slop in the pedal throw.

 

Finding a good used booster is a crap shoot... I'd suggest sending yours to White Post Restorations... I know that I am done with the Centric rebuilds...

 

Ed

[silasmoon]

Did you ever figure this out? I am having nearly the same issues:

76 with an IE rebuilt booster and new MC. New stainless steel lines. New pads and calipers. The car felt fine for 1,500 mi but now suddenly the brakes feel like weak shit. I can't lock the wheels up if I try. Is this an adjustment of the linkage? 

Checked the hoses and all seems well. When I pull the tube from the booster to the check valve I get a good vacuum WOOSH with the car off. 

['76mintgrün'02]

Have you adjusted the rear brakes lately?

Do you have a pressure bleeder?

[silasmoon]

I have access to one yes. And yes we adjusted the rear brakes some 1,500 mi ago when I changed the brake shoes. E-brake works well. 

['76mintgrün'02]

I would start with bleeding them.  I like to do it symmetrically, with a catch cup on each side of the car, following the Upper Inner Outer  sequence, in matched pairs.

(I think that is the sequence "You I Owe")