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Trailer brakes not releasing on my 20-ton tag

skyking1

skyking1

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They've always been a little slow to release but today they're not releasing the maxis at all.
I'm getting air in the supply tank when I press the red valve, and it fills on up and stops filling.
Everything on the trailer runs through this valve. Could this be where the culprit is?


PXL_20230328_181117040.jpg
 
Truck Shop

Truck Shop

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That is a R-6 valve antiquated, If the trailer has 30-30 parking brake chambers. Really it
should be upgraded to a Midland FF2 full function valve Like a KN-2800 or so.

Is there any air at the brake cans with tractor brakes set and trailer released?

https://www.manualslib.com/manual/392676/Bendix-R-6-Relay-Valve.html

For some reason I'm thinking you have single diaphragms, Because that valve should be feeding
service brakes. I'm not seeing a spring brake valve. The top port is a control port the one right
below is supply.
 
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skyking1

skyking1

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I'll get a helper out there and check but I think the problem is at the tractor protection valve on the truck. I think that's the answer you were fishing for with that question?
 
Truck Shop

Truck Shop

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Pretty easy to check. FF2 valve below operates service brakes and park brakes. Simple to install.

d7f553473ea3be143fef157e9d275e89ab89ddfe_a9e240b2f1cda0f5f7cb0a55d344b68a815452d4_28600P_1.jpg
 
skyking1

skyking1

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Thank you for your help. I think that's going to be a good idea to modernize the trailer. I figured out what happened.
The last time the trailer moved was about December 5th. When I took it down to the truck shop to get the inspection done. He noted that the trailer brakes were out of adjustment and crawled under there and got to wrenching.
I think he just went the extra mile :)
I backed off the slack adjusters and lo and behold she moved. The cans were going full stroke. I think they need a little bit of room for parking rust.
They were trying to get a mobile mechanic out here to look at it where it was sitting and I'm going to call them back and say hey. How about if I bring it down and we readjust those brakes?
I probably erred on the side of loose, but the manual handle stops the truck and trailer fine.
The maxis are only on the front axle.
 
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C

cuttin edge

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Finish grader operator
skyking1 said:
Thank you for your help. I think that's going to be a good idea to modernize the trailer. I figured out what happened.
The last time the trailer moved was about December 5th. When I took it down to the truck shop to get the inspection done. He noted that the trailer brakes were out of adjustment and crawled under there and got to wrenching.
I think he just went the extra mile :)
I backed off the slack adjusters and lo and behold she moved. The cans were going full stroke. I think they need a little bit of room for parking rust.
They were trying to get a mobile mechanic out here to look at it where it was sitting and I'm going to call them back and say hey. How about if I bring it down and we readjust those brakes?
I probably erred on the side of loose, but the manual handle stops the truck and trailer fine.
The maxis are only on the front axle.
Click to expand...
I jumped in the old 2 stick Mack that once served as the service truck for the prep crew. It had a full load of gravel on, and was hooked to the tag along. I came to the stop sign at the end of the road leaving the plant, and sailed right through. Not a brake on truck or tag along. I got turned and went back to the shop. The driver, a fresh graduate of trucking school had backed all the slack adjusters fully off, and them tightened them up a quarter turn. Just glad nothing was coming.
 
skyking1

skyking1

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Yeah that's a sickening feeling. Before I worked here, and in between when I was gone, they would not bring the truck to the truck shop except for an occasional oil change. The first thing I did when I came back was crawl around under there and adjust the brakes. Now I have it at the truck shop often enough that those guys take care of it for me. Usually. :)
 
Acoals

Acoals

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Usually in the spring I have to crawl under mine with a hammer and give the drums a whack in order to move . . .
 
Truck Shop

Truck Shop

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doublewide said:
I've been thinking about upgrading my trailer brakes. Is it acceptable to have parking/spring brakes on just one of the two axles?
Click to expand...
Yes one axle is acceptable and two are better but some tag trailers won't accommodate both
because of clearance issues on rear axle. So only the front.

But I would like another photo of SK's front axle hose routing.
 
skyking1

skyking1

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I will post to the thread next time I move the trailer. It takes a machine to tip it up for photos.
Next stop is back to the truck shop for adjustment, and yes it looks like there is no room at the back axle for a maxi can when it is tipped.
 
skyking1

skyking1

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No. I will probably take it to the truck shop in the middle of next week if they can fit me in, and they can re-adjust that brake with my issue in mind. They have the appropriate card for doing that. Then I can tip it up and take a picture.
 
C

cuttin edge

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skyking1 said:
No. I will probably take it to the truck shop in the middle of next week if they can fit me in, and they can re-adjust that brake with my issue in mind. They have the appropriate card for doing that. Then I can tip it up and take a picture.
Click to expand...
You guys have to be certified to adjust brakes? They started that here before. I had to adjust brakes on a mock up axle for the guy that does driver exams. He said I would have to do it again in 8 years, but then they did away with it.
 
nowing75

nowing75

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coatesville indiana
Just a side note about slow to release brakes. Have had that problem several times on our tag trailers. Dirt a sand gets in them from our dump trucks and clogs the valve. Have put filters on them and seams to help.
 
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