Clementine's Garage
Clementine the Cat
 
Image of flower
Yellow R4
 
Réparateur d'automobiles

Brake balancing

Messages
119
Location
English but live in France 87250
#1
I have got involved, as you do, with a neighbours R4 1983 GTL which has recently been CT tested in France and had brake results of

Front left 169
Front right 127
Rear left 139
Rear right 106

Overall efficiency 71% and handbrake 25%

We have changed discs and pads at the front and freed off a sticky caliper so expect that the front will now be okay. The back brakes appear good with wheel cylinders free, not leaking and good linings so i am assuming the difference must be down to adjustment. It is fitted with Bendix brakes. However i had expected that the auto adjusters whould adjust them evenly in which case what would explain the 139 to 106 difference.

Also does the difference front to back look about right. Sorry to ask if it was my car i would just fiddle until i was happy but with someone else car i feel under more pressure to know its right and to get it so first time.

Thanks, Bruce
 

angel

Enthusiast
Messages
1,873
Location
Athens, Greece
#3
Adjusting the brake shoes does nothing more than decrease brake pedal travel, so if the rest of the system is OK and one or both rear brakes slightly out of ajustment, you won't expect to see any difference in braking performance.
Brake imbalance comes from a number of reasons, like air in one wheel cylinder, lining glazing or oil contamination on one side, differences in drum and/or shoe lining wear, partially seized wheel cylinders, new brake shoes not bedded in (they take a lot of time) etc. Without checking components one by one it's hard to tell, because, for example, what shows like a " set of brake shoes in perfect condition" coud be a mixed set of brake shoes fitted at some point of the vehicle's life.
 
Messages
119
Location
English but live in France 87250
#4
Adjusting the brake shoes does nothing more than decrease brake pedal travel, so if the rest of the system is OK and one or both rear brakes slightly out of ajustment, you won't expect to see any difference in braking performance.
Brake imbalance comes from a number of reasons, like air in one wheel cylinder, lining glazing or oil contamination on one side, differences in drum and/or shoe lining wear, partially seized wheel cylinders, new brake shoes not bedded in (they take a lot of time) etc. Without checking components one by one it's hard to tell, because, for example, what shows like a " set of brake shoes in perfect condition" coud be a mixed set of brake shoes fitted at some point of the vehicle's life.
That is always the problem of playing with someone elses toy, not knowing any past history or wanting to suggest swapping too many components. As you suggest i just need to work thorough them all until the problem is located. I will admit to having not considered a mixed set of brake shoes.
 
Top