rear brakes working a little TOO well now

[chickenpot]

Rebuilt the rear brakes on the chief. new hardware, wheel cylinders, shoes, drums, adjusters, parking brake cables. my problem is now with no load, the rears are trying to lock up on me. found out when a car in front of me chickened out on a yellow lights and i almost did a fish tail. Is the rear abs worth fixing or should i just look into loading more static weight onto the truck?

 

[rreegg]

I’m not super experienced with brakes and am curious what other more knowledgeable folks will say. But my first inclination would be the drum adjustments may be too tight?

regarding the RABS is the light on or any indication it’s not working as expected? Also curious on the health of the front discs since in theory they should be like 70% of the braking force

 

[Rdnck84_03]

Also curious on the health of the front discs since in theory they should be like 70% of the braking force

This is what I'm thinking also. I recently did the rears on my 84 f150 and they now lock up very easily, the front brakes are atleast 15 years old and well glazed.

If you're fronts are in good condition then my next thought would be the proportioning valve being seized up.

I have never owned a truck that the RABS system actually prevented the rear from locking up on under a panic breaking situation. I have 4 different trucks with that system.

James

 

[Jesus Freak]

I'd get on some dirt and see if your fronts are locking up. From there I'd guess the proportion valve or a slightly compromised master cylinder.

 

[chickenpot]

Did everything on the front brakes a few months ago, except the rotors. pads, calipers, hardware, rubber hoses. I have new rotors on the shelf now cause i bought them on closeout but the originals still were looking just fine. So I'm not sure if they are actually boned or my rears are just working like they should with no load on the truck. it doesnt lock up under normal circumstances just under a quick stop situation

 

[Nero]

I'm a huge advocate for keeping the RABS working. It's saved my bacon plenty of times. It also helps prevent the situation you were in.

 

[chickenpot]

I'd get on some dirt and see if your fronts are locking up. From there I'd guess the proportion valve or a slightly compromised master cylinder.

I haven't looked into the proportioning valve yet, but will admit the master is salvaged from a parts truck and by all appearances and feel, seems normal

 

[chickenpot]

I'm a huge advocate for keeping the RABS working. It's saved my bacon plenty of times. It also helps prevent the situation you were in.

So i have everything hooked up, and the old fluid was clean when i did the rears so I'm not automatically assuming the abs unit is toast. but the light is on on the dash and i cant really find too many write-ups about the abs system on these trucks. I'd like it to be operational but don't really know where to start just yet. never felt the need to dig into it until now

 

[Rdnck84_03]

When you did the fronts and didn't replace the rotors, did you glaze break the old rotors before installing the new pads?

James

 

[Jesus Freak]

I haven't looked into the proportioning valve yet, but will admit the master is salvaged from a parts truck and by all appearances and feel, seems normal

Well, it sounds like everything else is new.

 

[Nero]

The main fault I've found on these is the ground wire breaks. For some reason they grounded the RABS valve to the core support. Found it will either be on the core support behind one battery, or the other.

If it's not that I can screen cap the diagnostic steps and post them for you

 

[Rdnck84_03]

I'd like it to be operational but don't really know where to start just yet. never felt the need to dig into it until now

Start with pulling the abs codes. If I remember correctly I think that system flashes the code.

James

 

[chickenpot]

Well, it sounds like everything else is new.

it just occurred to me that i left the valve on the master when i pulled it, and the master is out of a 1997 f250 HD with SRW. I wonder if it's the wrong valve and i need to change it out from the dead master that was on the dually when i got it. anybody know if there are different proportioning valves?

 

[chickenpot]

Start with pulling the abs codes. If I remember correctly I think that system flashes the code.

James

This truck has the capability for codes?? hahaha

 

[chickenpot]

When you did the fronts and didn't replace the rotors, did you glaze break the old rotors before installing the new pads?

James

I did not. that may have something to do with it. when you say glaze break are we just talking a braided wire wheel?