Drum brakes hanging up after sitting,

Parrformance · December 24, 2019

I caged the brake that was hanging up, before I test drove it. I was able to watch the brake shoes move away from the drum.

This makes me think the S-cam and shoes are good to go.

I am thinking that the parking brake side of the can may be what is not releasing the shoes from the drum.

I think I want to change the can next, the Volvo dealer had them for $30 when I was picking up seals and gaskets so I grabbed one.

Thoughts?

dennisvr · December 25, 2019

I also have a brake pot on my Volvo hanging up on the right side. I had a wheel seal replaced on that side last trip so I was thinking that maybe the return spring may have been bad on the brake shoes. So I removed the tires and drum, but the return spring looks good.
Dummy me if I would have thought before doing that I could have removed the cotter key on the clevis at the slack adjuster and worked the S Cam and the brake pot independently and seen which one was not releasing. When I have time that is what I will try next, before replacing the pot.

Ray,IN · December 25, 2019

Sometimes the rubber seal in the spring combo canister will get a pin hole it it, which may leak enough to partially apply the brake.

I suspect your new spring canister will solve the problem.

Edited December 25, 2019 by Ray,IN

Lance A Lott · December 25, 2019

How long does it sit? Mine will hang up after a month and a half or so but if I move the truck 6 inches every month there is no problem. The shoes sticks to the drum. I have considered caging the brakes so the parking brake cant come on, but its easyer to move it.

Parrformance · December 25, 2019

It does take a while for the brakes to stick, but it is always the same end of the forward rear axle(passenger side). My thoughts are if it was a sticking issue, caging the can would not have pulled the shoes away from the drum. In my mind Caging the brake is just the same as releasing the brakes from the dash knob.

dennisvr · December 25, 2019

Is the brake sticking after setting for awhile (brake shoe rusted to drum) or is it not releasing fully after the service brakes are released. On mine its dragging after I apply and release the foot brake driving down the road. I came to a stop sign and had a burnt brake smell.

Hewhoknowslittle · December 25, 2019

When building the bed on mine, I replaced all the can's and hoses, cheep insurance and I should add that my truck only had park can's on the front axle, has them on both now.

Roger

Parrformance · December 25, 2019

1 hour ago, dennisvr said:

Is the brake sticking after setting for awhile (brake shoe rusted to drum) or is it not releasing fully after the service brakes are released. On mine its dragging after I apply and release the foot brake driving down the road. I came to a stop sign and had a burnt brake smell.

Only sticks after being parked for a prolonged amount of time. In my mind if the shoes were rusting to the drum, I would have still had the shoes stuck when I went out and caged that brake(the one that hangs up) before I started the truck after several weeks.

Scrap · December 25, 2019

I've always wondered if the kevlar linings would stick less, or stick more? They might be a bit much for a light truck that doesn't spend much time in the city though. What edge color are your current linings? Or do they have numbers on them?

The dealer chamber, was it a welded clevis ordered by VIN? Or an off the shelf? If the latter, make sure the air ports match the other side square for square or round for round. Can't mix long stroke and standard stroke across an axle. That's probably well known ho-hum, but thought I'd mention it.

And yea, any truck that isn't a tractor anymore (ie: stuff added on the back) must be changed over to dual park chambers, if not already equipped. Even bare tractors that have to park a non-park brake trailer it's a really, really good idea as well. It just takes a couple piggybacks to put on. Single parks really only work for van trailer freeway trucks.

Lance A Lott · December 25, 2019

6 hours ago, Parrformance said:

Only sticks after being parked for a prolonged amount of time. In my mind if the shoes were rusting to the drum, I would have still had the shoes stuck when I went out and caged that brake(the one that hangs up) before I started the truck after several weeks.

You would have to cage the brake before they stuck and with the parking brake off or it would be very hard to do as you would be working against the spring. Block the wheels first. If it is already stuck you can usaly get it free with a big hammer then cage the brake.

dennisvr · December 26, 2019

23 hours ago, Parrformance said:

Only sticks after being parked for a prolonged amount of time. In my mind if the shoes were rusting to the drum, I would have still had the shoes stuck when I went out and caged that brake(the one that hangs up) before I started the truck after several weeks.

The way I would trouble shoot it is to have someone release the brakes as I was watching the pushrod/slack adjuster at the pot (blocked tires so I don't get ran over). If the rod moves to the release position and the brake is still locked its not a bad brake pot but shoes rusted to the drum. If the rod does not move back into the pot, then it could be a bad pot.

Darryl&Rita · December 26, 2019

I don't understand what's going on here, from the original post. If the brake shoes are pulled away from the drum, and the truck is still dragging that wheel, then there's bigger problems at play. If the wheel isn't dragging, pull the caging bolt, and test the wheel again. If it's dragging again, brake pot time. Proof? Block the wheels, push in the red knob and walk around the truck. Listen for leaks. Leaks mean brake pot time, or brake hoses, or flow splitter. Don't shotgun parts just because somebody said to.

Parrformance · December 26, 2019

Mr. Darryl, with the brakes caged, all is working fine. However if I leave the truck parked for several weeks, the brake passenger side front tandem does not easily release. I replaced the turbo on the truck, and because I wanted to check my work with a test drive, I caged the brake beforehand, so in case it was stuck I would not need to deal with the brakes before taking a test run.

I am going to test for leaks on that pot as soon as I get access to the driveway again. Wife has it tied up currently. Do not want to release the brakes in its current location, the slight incline is not conducive to proper caulking of the wheels.

Darryl&Rita · December 26, 2019

Gotcha. I knew you had a brake hang awhile back, but wasn't sure where that was at. It's a typical thing, depending on road conditions before parking, relative humidity while parked, and equipment conditions. Wheel seals passing can also cause the brakes to hang. Good luck.

Parrformance · December 26, 2019

Thanks, I will keep you posted.

Parrformance · December 28, 2019

So....... Between rain drops, I moved the truck in the driveway and chalked the wheels. Released the park brake, first thing I noticed was a lot of travel from the pushrod.

I adjusted the slack adjuster, shoes tight to the drum, then pried up the cam lock and backed off a 1/2 turn.

Then found a new leak on the center air tank. Removed the leaky fitting, disassembled the PTC, removed the brittle O-ring, and replaced with new.

Trimmed the air line, and reassembled. No more leak there.

Restarted the truck, released the parking brake, and climbed under the truck.

Heard an air leak internally on the park side of the can where the brakes stick. Replaced the piggy back, readjusted the slack adjuster took the truck for a spin, parked it.

Came inside had a beer, then wrote this long winded explanation of what I did so far.

Now I am going to have another beer.

I will check the truck again on Monday.👍

Edited December 28, 2019 by Parrformance
Spelling

Exile · December 29, 2019

On 12/25/2019 at 2:38 PM, Scrap said:

I've always wondered if the kevlar linings would stick less, or stick more? They might be a bit much for a light truck that doesn't spend much time in the city though. What edge color are your current linings? Or do they have numbers on them?

The dealer chamber, was it a welded clevis ordered by VIN? Or an off the shelf? If the latter, make sure the air ports match the other side square for square or round for round. Can't mix long stroke and standard stroke across an axle. That's probably well known ho-hum, but thought I'd mention it.

And yea, any truck that isn't a tractor anymore (ie: stuff added on the back) must be changed over to dual park chambers, if not already equipped. Even bare tractors that have to park a non-park brake trailer it's a really, really good idea as well. It just takes a couple piggybacks to put on. Single parks really only work for van trailer freeway trucks.

Er- what is a dual park chamber you mention?

my tractor has a sticker talking about a brake mod required should it become a truck, and i thought it had spring brake cans. . .

Scrap · December 29, 2019

Nothing special, just a normal parking brake can on both rear axles. Highway tractors can have a single set on the rear with the other rear axle being a set of service only chambers. Put some constant weight on the rear and it doesn't work so well anymore.

The sticker wants the bobtail proportioning valve changed into a regular relay valve and it wants the QR-1C valve changed into an SR-7 valve that straight trucks use. Boy haven't seen one of those stickers in forever!

http://www.plazafleetparts.com/piping-diagrams-spring-brake-control-for-trucks.html