Rear Drums Slowly Seize?

[dz63]

I have a '96 Camry 2.2L with rear drum brakes. In the Fall, I machined the drums and installed new shoes and brake hardware.

When I did this, the rear passenger shoes were dragging on the drum and I had to use a wooden 2x2 lever against the wheel studs in order to rotate the drum, so that the access hole was in the 11 o'clock position to back off the adjuster. Also, the parking brake handle was very loose - about 9-10 clicks before it would engage - even then, it did not engage very well. I freed up the parking brake cables - one was stuck and the other was free and I reset the tension on the parking brake handle.

Six months and 8,000km later, the right rear shoe is dragging on the drum again and the parking brake handle is loose again. I just backed it off the shoes tonight using the aduster wheel.

Any ideas what is causing this to happen and how to fix it?

[96paseo]

Hey dz63. My first two suggestions would be the e-brake cable and the wheel cylinder. Was the RR e-brake cable the one that gave you problems before? A seized or sticking cable will prevent the return spring from pulling the cable back, thus making the e-brake handle feel like its out of adjustment. A bad wheel cylinder could also cause this to happen. The piston may be getting stuck in the bore and not fully retracting.

[JohnGD]

Does the brake mechanism work fine when you had it apart? The pads return after you release the parking brake and such? (Car properly chocked from moving and other precautions taken).

If so the wheel cylinders may not be retracting. Then it's a hydraulic system issue.

Do the wheel cylinder pistons move freely?

[dz63]

96Paseo - Yes, the RR cable was the one that was stuck before. In order to free it up, I alternated pulling the cable at the drum with a pair of vice grip pliers and then pulling the parking brake lever up. I repeated this several times. On the left hand side, the cable moved freely back and forth. On the right hand side, the cable was stuck. After doing this a few times, I was able to free up the right hand cable.

JohnGD - As far as I know, the brake mechanism was working freely after I replaced the shoes. I took the adjusters apart, cleaned the threads and lubed the threads with special high temperature brake grease. I can't say for certain if the shoes retracted after the parking brake was released, because I didn't try pulling the parking brake handle with the drums off. I am 95% certain that the wheel cylinder pistons were moving freely. I could easily check both of these again on the weekend.

[96paseo]

Check your RR cable to see if its bound up again. I'm amazed you were able to free it up. When you changed the shoes, did you lube the contact areas on the backing plate? When checking the cable return, its good to have a hepler pull and release the e-brake while you watch it.

[dz63]

I will check the cable on the weekend and this time, I will get a helper to pull the parking brake lever so I can observe what is happening. Yes. I did lube the contact areas on the backing plate.

[jmborchers]

I don't understand when you mention the cable is bound on the right side when it should be the left side. My understanding is these cars use the parking brake to adjust the shoes. When you pull the parking brake which adjusts the shoes outward into the drum one side can not move therefore the other side becomes twice as tight as it should be.

So, if it is not the cable/adjuster moving the shoes outward and seizing the wheel it must be the hydraulic. But that doesn't make so much sense with the behavior described.

[dz63]

I removed both rear drums tonight. The shoes on the left side were also dragging on the drum. I had to use a 2x2 on the wheel studs to align the access hole with the adjuster.

The parking brake cable on the left side seems to be sticking slightly worse than the right side. I have to pull the end of both cables with about 40 lbs force in order to return the cables to the "home" position.

If I then go and pull the parking brake handle, both cables move forward fairly easily, however, when I release the parking brake lever, the cable at the lever goes slack.

Next, I removed the exhaust heat shield. What a pain that was - all of the bolts were rusted solid and all broke off except one. I had an assistant pull alternate between pulling the cables at the drums and pulling the parking brake lever, while I watched underneath the car. Both cables go tight when the parking bake lever pulled up, however, both go slack when the lever is released. It seems like both cables are getting stuck and not returning to the home position. The rubber boots on both the cables are torn, so potentially moisture has gotten into the cables. There are no visible signs of rust on the cable itself - the cables appear to be plastic coated inside.

I also tried moving both pistons in the brake cylinders back and forth and both move freely in both directions, so I am thinking that it is not a hydraulic problem.

I drilled out and tapped a few of the broken bolts, but can't get at one of them because my grinder won't fit in there. Also, the mounts on the rear exhaust shield that goes over top of the gas tank, have all rotted away. The shield has fallen down and is just sitting on top of the exhaust pipe. I will have to fix this next.

The parking brake cables shouldn't stick like this - yes? Your thoughts? Would a Dremel be able to grind off bolt heads in hard to get at locations? Might be a good excuse to add another tool to my arsenal.

[96paseo]

Make sure the e-brake mechanism that spreads the shoes is lubed and not binding on both sides. After that, go about replacing both cables. You won't usually see any rust or damage at the cable ends where they hook up to the drums. Water gets down into the cable housing and rots the housing. Over time, this will strip the plastic liner off the cable and make it bind. As for the bolts, a dremel would probably work in the tight spots. A right-angle drill might be a good thing to consider purchasing.

[jmborchers]

The parking brake cable shouldn't stick.

What happens to these is over time the stainless steel or steel wires inside break. When they do the cable binds because it has to fight the resistance of the broken wire dragging against the sheathing.

This happened to me with a clutch cable.

[dz63]

Thanks guys. The exhaust pipe is really annoying. It is blocking the access to one of the bolts that I have to re-tap. Also it is really going to get in the way of securing the rear exhaust shield. Is it hard to take it off or would i just be asking for more trouble?