620 Brakes really weak

[Jasper]

So, here's my situation:

 

The brakes don't really seem to be grabbing until it feels like the pedal is hitting floor. If I push the pedal all the way to the floor really hard, the fronts can both lock up, but it just doesn't seem like they are engaging as high in the pedal as they should.

 

 

I've replaced the Master Cylinder because the old one was leaking, and I flushed and bled the lines.

 

The front right and rear left wheel cylinders are leaking, but it doesn't seem like this would cause the problem as they are only small leaks. The front pads look almost new, and the rears are pretty worn. The pads on the front were actually on wrong, and I had to flip 2 of them.

 

 

Also, I can't stop at all when moving backwards. I push the pedal to the floor as hard as I can, and it just doesn't seem like they're grabbing.

 

 

I've adjusted all 4 pads down, but it doesn't seem to help. I even adjusted the fronts to the point where they were rubbing pretty bad, and the pedal feels the same.

 

 

Thoughts?

[datsunaholic]

Shoes installed the right way? It's really easy to get them backwards and/or upside-down on the front. Dunno how many times I've seen both leading shoes on one side and both trailing shoes on the other. That's not gonna work. Though the fact they work better going forwards is a good sign- they're supposed to. Though they still should stop the thing in reverse.

 

Any leak, however small, is a problem though. Pressure loss plus you end up saturating the pads making them far less efficient.

 

You also need to adjust the shoes (you don't have pads) several times. Just tightening the adjusters to "drag" doesn't do it- you need to re-center the shoes each time. You'll find it suddenly stopped dragging.

 

Are you 100% positive you got all the air out? The leaks work both ways- let fluid out and air in. Plus I've had bad master cyls right out of the box. No-name O'Reilley or Autozone "remanufactured" master cylinders are pretty bad.

 

Lastly, if the rear shoes aren't also adjusted you'll have way too much pedal travel.

[Eagle_Adam]

Shoes installed the right way? It's really easy to get them backwards and/or upside-down on the front. Dunno how many times I've seen both leading shoes on one side and both trailing shoes on the other. That's not gonna work. Though the fact they work better going forwards is a good sign- they're supposed to. Though they still should stop the thing in reverse.

 

Im doing mine later tonight, how do you tell which one is which?

[metalmonkey47]

Are you 100% positive you got all the air out? The leaks work both ways- let fluid out and air in. Plus I've had bad master cyls right out of the box. No-name O'Reilley or Autozone "remanufactured" master cylinders are pretty bad.

 

Correct! I went through 3 on my 210 from Advanced Auto before I got a good one.

[Jasper]

I used a Bendix master cylinder if I recall correctly.

 

 

I'm going to change out the leaky wheel cylinders, and try to get it inspected. The brakes are adequate for the driving I do. If it doesn't pass, I'll have a shop look at them.