What is the best way to free up frozen trailer brakes?

[bigyellowpete]

Quick question!

How much free play should you have at the slack adjuster?

Trick Question Alert!

What size brake chamber are we talking about?

Maybe we should just assume you are talking about the most common C20 and C30 brake chambers, and you are looking for maximum pushrod stroke?

The maximum pushrod stroke for these brake chambers cannot exceed 2", although you should have less than maximum.

You make a good point about auto slacks being designed not being designed to require adjustment at any time. In normal operation, on well maintained equipment you won't need to adjust them manually. My rule is if they will not adjust themselves, and stay adjusted properly, after 3 hard brake applications (while stationary) with system pressure over 90 psi, the unit goes to the shop and the slack is replaced.


If you highlight my answer to the question regarding stroke the maximum measurement will be revealed.

 

[big10]

pour antifreez in the brake lines driver?

 

[colohayhauler]

S

Bear with ne since I'm in bfe on my phone getting loaded. On my trailers they don't have the hollow tube the shaft runs through. The purpose of the pipewrench is to help the springs that retract the shoes, do their job. Ill try to attach a picture.

 

[colohayhauler]

I guess part of.my post didn't make it, the pipe.wrench wont do much good if the shoes are froze to the drum, but it seems I have more problems with ice building up around the s cam or rollers and freezing them up. Sorry for the confusion

 

[Racer X 69]

Well all the years I worked on these things, and all the different types of setups I have seen and I have never seen an S cam that didn't pass through a support tube.

Thanks for the clarification.

 

[danj_otr]

I did not think of that, I usually just drag them long enough till they catch on fire and thaws itself out

Now that is funny right there.... I have smoked my brakes when I didn't realize a trailer wheel was locked up... Yeah Yeah Yeah... I was a rookie. I personally carried a small sledge hammer, but others used things like bleach, torches, or road flares...

 

[bigyellowpete]

I am sure that is a cam tube he is wrenching on in that picture. Without a cam tube, and the bushings, your spiders would fill with grit and become corroded in no time at all.

That trailer isn't late model though, I just noticed the old style slacks. My 7/16" wrench would feel all inadequate up against the old 9/16" adjuster nut.

 

[boone315]

pour antifreez in the brake lines driver?

That does not help when the shoes are frozen to the drums, I try to stay away from the alcohol anti freeze anyway, it usually eats everything up over a period of time, sometimes it is necessary though. my old pete used to freeze up pretty easy, I would just bypass the air dryer till I hit warm weather and everything would thaw out so I could train the tanks, knock on wood, my Volvo hasn't had a problem yet(new air dryer) but my water fuel separator has gelled up once though(I think that it was the problem), I parked it, got my bottle of 911 out but it had corrected itself and my fuel pressure sensor stopped lighting up.

 

[boone315]

I guess part of.my post didn't make it, the pipe.wrench wont do much good if the shoes are froze to the drum, but it seems I have more problems with ice building up around the s cam or rollers and freezing them up. Sorry for the confusion

Looks like it could use a little grease, things tend not to work right when needing some lube.

 

[colohayhauler]

The trailer is almost old enough to have stone wheels. There aren't any tubes. I can watch the shaft turn when I apply the brakes, all 4 of them

My truck has the tubes, that don't turn with the shaft inside of them. I haven't been around a whole lot of other trailers, but I'm assuming they look a lot like the ones on the tractor? There is no way to keep the tube, (if it is one) on the trailer, stationary. Not starting a pissing match, just trying to learn a little.

And yes boone, it could probably use some grease. It dosen't stick around too long, and I use expensive stuff. Too many dirt roads I guess? Don't know. I just bought this trailer so I'm learning its quirks and problems

 

[Racer X 69]

Yep, that is a dinosaur there. They don't put manual slack adjusters on anything anymore.

It does look like a little grease could be squeezed in there though.

 

[Racer X 69]

Trick Question Alert!

What size brake chamber are we talking about?

Maybe we should just assume you are talking about the most common C20 and C30 brake chambers, and you are looking for maximum pushrod stroke?

The maximum pushrod stroke for these brake chambers cannot exceed 2", although you should have less than maximum.

You make a good point about auto slacks being designed not being designed to require adjustment at any time. In normal operation, on well maintained equipment you won't need to adjust them manually. My rule is if they will not adjust themselves, and stay adjusted properly, after 3 hard brake applications (while stationary) with system pressure over 90 psi, the unit goes to the shop and the slack is replaced.


If you highlight my answer to the question regarding stroke the maximum measurement will be revealed.

Give the man a cigar!

Yep the max stroke is 2", but if everything is in good shape and operating properly, about 5/8" to 3/4" is about right. I don't remember seeing anything that was different with larger or smaller air cans though.

And I did neglect to comment on have the proper minimum amount of system air available.

There are many things that affect the performance of auto slacks. Improper initial setup and geometry are important. And if there is excessive play in either or both of the s-cam bushings, the slacks will either not adjust like they should, or over adjust.

And regular greasing is very important, to keep them working right.

 

[Racer X 69]

I am sure that is a cam tube he is wrenching on in that picture. Without a cam tube, and the bushings, your spiders would fill with grit and become corroded in no time at all.

That trailer isn't late model though, I just noticed the old style slacks. My 7/16" wrench would feel all inadequate up against the old 9/16" adjuster nut.

It is hard to tell by the picture, but the bushing support that is welded to the axle looks like it is separate from the shaft. And yes, that set up is going to get crap where it shouldn't be, and there will be premature wear.

 

[colohayhauler]

Someday ill buy some trailers that were at least made in the last decade, lol
Both of mine are set up this way so its what I'm used to I guess. I just have to grease the hell out of them to keep them from binding up, but it dosent take long for dirt and sand to clean the grease off or work into everything. Plus like you said proper maintenance is key. I just wish all the previous owners of my equipment knew that

 

[boone315]

Someday ill buy some trailers that were at least made in the last decade, lol
Both of mine are set up this way so its what I'm used to I guess. I just have to grease the hell out of them to keep them from binding up, but it dosent take long for dirt and sand to clean the grease off or work into everything. Plus like you said proper maintenance is key. I just wish all the previous owners of my equipment knew that

I know what you mean, I had all old stuff but the way I look at it is you spend a couple grand buying the thing, put a couple more into it to fix it up and it will make just as much money per mile as something you go out and spend 25 grand on. I am looking at a '86 flat w/side kit, the guy wants $4,500 for it, great shape, the light weight side kit and tarps on it are worth that much but it is only a 45'x96", I want something bigger. but might buy it anyway.

 

[boone315]

Good points.

Actually, when the automatic slack adjusters became the standard the word was that if there is any reason to turn the adjuster manually, don't do it.

As a mechanic I questioned why the hell is there an adjustment screw if you can't turn it.

Really though, the ratchet mechanism can be damaged from excessive manual turning, and some types are not supposed to be rotated any direction but to tighten them (again I have to question the logic here, what are you supposed to do if you go a click or two too much? Drive the dam thing around the parking lot until you wear enough lining off to get the damn brakes where they need to be?).

Back to freeing up frozen brakes. Like BYP says, release the trailer brakes, (back them off if you dare, oh come on, live a little!) and give a brisk, sharp rap on the drum until you hear a nice ring. No ring means the shoes are still stuck to the drum.

Or use the cell phone method.

And then stop driving trucks, because truck drivers are supposed to know how to do things like check and adjust brakes, replace burned out lights, troubleshoot electrical problems, deal with moisture in the air lines, etc.

And free up stuck brakes when they get set in freezing weather. (who does this anyway? The only time I set the trailer brakes is when I drop the trailer.)


Quick question!

How much free play should you have at the slack adjuster?

I have the 'auto' adjusters on the Volvo, I adjust them every oil change, during a company inspection, I was told the adjustment was right on the edge, that D.O.T. will allow you a max of three inches on the rod stroke before they fail it(I used to think that they went by the distance of the brake shoe from the drum) So I went to NAPA bought the little wrench and pry tool designed for the auto adjusters and it takes me less the 5 minutes to check all three axles, better then being shut down by D.O.T. and have to call road service, D.O.T. won't let you adjust your own brakes.

 

[Racer X 69]

I have the 'auto' adjusters on the Volvo, I adjust them every oil change, during a company inspection, I was told the adjustment was right on the edge, that D.O.T. will allow you a max of three inches on the rod stroke before they fail it(I used to think that they went by the distance of the brake shoe from the drum) So I went to NAPA bought the little wrench and pry tool designed for the auto adjusters and it takes me less the 5 minutes to check all three axles, better then being shut down by D.O.T. and have to call road service, D.O.T. won't let you adjust your own brakes.

3 inches? I was taught 2 inches. Interesting how there seems to be so many differing opinions on what it should be.

As for DOT not allowing a driver to adjust their own brakes, there was a time when drivers were expected to know how to check and adjust their brakes. Of course that was back in the dark ages when auto slacks had not been invented yet.

 

[Phantom_of_the_Opry]

I have a friend who leased on with Knight for a bit. Just about every other trailer he'd find something small wrong with, and he would do exactly that.

I have an impact wrench, a 50' air hose, and a pile of other tools of my own that I carry. They expect us to fix lights, change tires, and at least attempt to troubleshoot anything we run up against before calling anyone.

And calling people here is pretty useless. Ever heard someone shrug on the phone? You almost can here...

So in your arsenal of tools, you have a 40 tonne Air Jack or is it Hydraulic??
Change many Wheels OTR do you or only when hauling Haz-Mat and a Inner Tire gets hotter than an Outer?
You have a folding Ladder or a Grappling Hook for the Upper Clearance Lights?
What other Spare Parts have ye?

You're a Drivers' Driver!! WELL DONE Hand, see ya on the flip side!!:gratzie:

 

[boone315]

3 inches? I was taught 2 inches. Interesting how there seems to be so many differing opinions on what it should be.

As for DOT not allowing a driver to adjust their own brakes, there was a time when drivers were expected to know how to check and adjust their brakes. Of course that was back in the dark ages when auto slacks had not been invented yet.

Maybe it was two, but pretty sure he said three and yes, everybody used to be expected to adjust their own brakes, even company drivers, now companies like Schneider and JB don't even want their drivers to carry tools at all.

 

[bigyellowpete]

Some of the smaller chambers are shorter stroke, as on the steer axle of some trucks and max stroke is only 1.5". I have never encountered a chamber with a max 3" stroke myself, although they may exist. I am sure that would spin most DOT inspectors heads as well. I have had to argue with them when they tried to tell me that 1 7/8" was too much, I am sure they would be too busy writing a ticket at 2.5" to even listen!