Do I have Duo-Servo or Leading/Trailing drum brakes?? How to adjust? One is dragging [Archive] - Diesel Place : Chevrolet and GMC Diesel Truck Forums

: Do I have Duo-Servo or Leading/Trailing drum brakes?? How to adjust? One is dragging


mgray1982
01-13-2009, 09:23 PM
In an attempt to fix my constantly leaking axle seals once and for all, I had a different shop install sleeves and new seals. Seems they didn't adjust the brakes(although they tightened up my e-brake as I requested) when they were done, as I can smell a hot wheel, and the drum is really hot to the touch(backing plate is cool). It's only the drivers side rear wheel. The passenger side is cool. So I assume the drivers side just needs to be let off a bit? As it's a long drive back to the shop where I had the work done, and the fact that this should be a simple adjustment, I'm going to try it myself. There is only a very slight odor of gear oil, so hopefully the seal has survived some very hot miles!

I have the factory shop manual for my truck, but it has 2 sections for rear brakes; leading/trailing drums, and Duo-Servo drum brakes. They have different adjustment procedures and values, so I need to know what type I have.

Just for reference I'll include the procedures for each type(differences shown in bold);

Leading/Trailing Drum Brakes:
1) Turn the adjusting screw until the wheel can just be turned by hand
*The brake drag should be equal at both wheels
2) Back off the adjusting screw 20 notches
*Brakes should have no drag after the adjusting screw is backed off about 10 notches.

Duo-Servo Drum Brakes:
1) Turn adjusting screw until the wheel can just be turned by hand.
*The brake drag should be equal at both wheels
3) Back off the adjusting screw 33 notches
*Brakes should have no drag after the screw has been backed off about 15 notches.

nmband13
01-13-2009, 10:40 PM
I think you'll have to take off the drum and look, Leading/trailing type has only one servo(located @ the top), duo has two(one top & bottom). My guess is its a single, could be wrong. i'm not an expert

mgray1982
01-14-2009, 12:06 AM
Hmm....I can't really take off the drum as I have full floating....

damn shops that can't do their job right!!