Technical Brake Drums

[jolly500]

Morning everyone,

I've got what I can only imagine to be an 'out of round' brake drum on my car - distinct vibration felt when braking. I've lifted the car on to axle stands and by gradually applying the brake have attempted to establish which wheel is the problem. The 2 fronts spin freely and don't appear to 'grab' as the brake is applied. The rears are more difficult - anyone got an easy way to establish where the problem is.

Or alternatively can any other problem give the same symptoms?

Thanks
Steve
Johannesburg

 

[jjacob]

Hi Steve,

Grabbing drum brakes can be caused by wheel cylinders that are sticking or leaking or where only one of the small pistons in the wheel cylinder is moving smoothly. Broken springs in the brakes can also cause this.
The wheel cylinders are cheap. If they have not been done in a long while, I would replace them and bleed the entire system. Note that the later cars have two different sizes of wheel cylinders for the front and back.
Also make sure that the rear handbrake cables are adjusted correctly and are fully releasing.
John