the hulk

1982 RX-7.
Can someone help. I’m trying to bleed my back brakes. In the Haynes manual it says I can only bleed on the right side. Also it says that I have two screws behind each of the back plates to adjust my pads. Well I don’t have those screws. I do have the regular adjustment inside the brake, am I suppose to adjust adjuster before installing the drum ? On the left hand side the adjustment there as no wheel to turn for adjusting. What if I put an regular adjustment on the left the side and another regular brake cylinder so that I can bleed, would that be a good idea. All the help is appreciated.

RotaryRyan

Ive heard to not follow the haynes on brakes.

LongDuck

Well, if you're looking at a Mazda FSM and it says that, you're looking at the wrong model year. The Haynes manual has it all screwed-up, so I wouldn't put too much faith in the Hayne's belief that your car is a 'one-of-a-kind' from Mazda with something non-standard.

That said; here's the rundown on the NON-Disk rear brake, 12a cars, 81-85.

The rear drum braking system of these cars uses a single pressure feed line to the rear axle from the Master Cylinder. This single pressure feed line first goes from the chassis (by the fuel pump) to a flexible line (brake hose) to the rear axle mount, and from there to the LEFT REAR wheel and brake drum assembly. Here the pressure line enters the Left brake piston assembly and has NO bleeder available - when you bleed this system correctly, it doesn't need one here. From the Left piston, another feed line goes out to the RIGHT REAR wheel and brake drum assembly, and this piston set has a bleeder - it is the furthest pressure piston assembly from the Master Cylinder.

In this arrangement, Mazda engineers have simplified the braking system on the rear to allow for bias-control, or differential pressure braking between front and rear, which serves to stabilize the braking force applied between the rear wheels. When you apply the brakes, the rears are automatically stabilized for force applied at each wheel because as pressure gets to one wheel up to maximum line pressure, the other side is getting the exact same amount of force. This is important in a car with a differential (all cars) because if one rear wheel gets more braking pressure than the other, it overpowers the brakes on the other side through the differential doing it's job.

With that in mind, only bleed the system from the Right Rear corner, and set your internal adjusters BEFORE you install the brake drums, mount screws (torqued to specs), and the wheels/tires themselves. The internal adjusters are also active for the emergency brake, and are supposed to be self-adjusting, so you shouldn't need to mess with these too much. Set them so that they don't drag, and you should be fine.

The reason why the Haynes manual has it screwed up is that the 79/80 drum brake cars (all 79/80's) had two EXTERNAL adjusters that once you had the brakes and drums mounted, the adjustment was performed with the car in the air. You'd spin the wheel/tire, and turn the front and rear adjusters and lock nuts until you got just a slight bit of rubbing of the shoes. Then you did the other side.

Let me tell you that the 79/80 (SA22) rear brakes were a complete pain in the *** to keep adjusted well, and never worked well, IMO.

Another case where you should pitch your Haynes manual and step up to the mothership and buy a Mazda FSM! Good luck,

the hulk

Thanks alot...your knowledge is greatly appreciated and helpul. So aways bleed from the right back wheel first, after adjusting the pads inside.
I guess I was did it wrong because after I had put new calipers (disks were still good) and drums and pads, we had bled from the front first then to the right rear. I guess that's were I went wrong cause the brakes are catching low...and I need to pump them to have better pressure..