Faulty trailer brakes

UK PROFESSIONAL DRIVERS FORUMS THE UK PROFESSIONAL DRIVERS FORUM (INTERACTIVE)
21

pecjam23:
Driving back to base on the A14 this afternoon, traffic was the usual Friday afternoon, slow in patches. Anyway traffic was travelling at about 44-48 mph there was an artic and 1 car in front of me and there was a fair gap between me the car and the truck as I know what the a14 is like for sudden stops :open_mouth: :exclamation: .

Anyway going well, when all of a sudden smoke billows out of the trailer wheels on this truck :open_mouth: :open_mouth: :exclamation: . As if heā€™d just slammed on the brakes because somebody had pulled out of the slip road. Instantly I press by brakes harder expecting to come to a sudden stop but didnt and the truck hadnt come to a stop :confused: drive over bit were he had braked on and I could see the skid marks and could smell the burning rubber :exclamation: :exclamation: .

Didnā€™t think anything more of it, the car in front over took so I was behind him, leaving plenty of room between me and him. But it happened again, truck literally tapped the brakes, wheels locked for good 2-3 seconds, smoke, tyre burning smell. There was no slip road and traffic hadnā€™t stopped he was obviously just slowing down from 44 to 40 mph iā€™m guessing. It then happened a third time when he tapped the brakes wheels locked, smoke, tyre marks smell of burning rubber. He must have been aware of it but didnā€™t stop and I over took him on the A1 and his trailer wasnā€™t of fire so I donā€™t know :question: :question:

I donā€™t drive artics but that isnā€™t normal nor healthy is it :question: It was a empty 3 axel flat bed trailer being pulled by a 56ā€™ axor from a company in Mansfield I think. Trailer didnā€™t look that old either but surely if it was doing that when empty what would it be like with a load on and travelling at high speed :open_mouth: :open_mouth: :question:

Might be nothing, but just seemed odd to me.

cheers

what its sounds like is the the trailers just been for an M O T and there turned up the brakes for the brake test, have had it happen to me picked up trailer from other depot and just had to touch the brakes and it would lock up phoned office and was told to stop and someone would come out and sort it as the tyres would have worn down pretty quick

22

or it had its air pressure turned up at the trailer governor valve to get it through its last mot,and they forgot to adjust it back down.probably getting a straight ten bar to the brake chambers instead of the 4 bar :question: :exclamation: :wink: .
trailers are much easier to lock up empty,but shouldnt do it every time you touch the middle pedal.

23

Just what empty flats used to be like before the days of ABS. Once loaded it would be fine.

As Shuttlespanker says, most likely a faulty load sensing valve.

Sometimes you get the ABS packing up on just one wheel, but often drivers donā€™t spot this & canā€™t feel it.

Those old empty steel sprung flats without ABS didnā€™t half used to run funny on the road with flat spots on all the tyres all in different places!

You should see a reefer trailer being pulled off a ferry and accross the trailer park by a dock tug with all 6 locked up!!! :open_mouth: :open_mouth:
(the axles bounced)

24

Sounds very like the load sensing valve is fully adjusted probably been from an M.O.T (a wee trick i learned when iused to take trailers for M.O.T in previous employment) :wink:
Newer trailers have self adjusting slack adjusters which when fully adjusted reset themselves when the footbrake is pressed, older trailers can be wound off or tightened up accordingly this would cause harsh braking and give you thrupenny bit tyres

25

shuttlespanker:

pecjam23:

shuttlespanker:
or it could be a faulty load sensing valve or an ABS system fault causing the brakes to lock on when empty

just out of curiosity how long would tyres last if it they were being subjected to that on a long journey :question: :question:

depends on various things

such as, how old is the tyre, how much tread left, how long the brakes are locked on for

i had a trailer that the brake chamber failed and locked the wheel, it had a reasonable tyre on it, we dragged it 100 yards out of the way at slow speed and it took the tyre down to the metal chords :open_mouth: :open_mouth: :open_mouth:

I had that in Spain when a dump valve froze up, It dragged 12 tyres from new to scrap in about 300 yds :blush:

26

I would suggest it wasnā€™t all the trailer breaks you saw locking, just one axle. One set has been over adjusted by the driver I expect. Probably those type with the small nut, canā€™t undo them once tightened too far. Worked great when loaded but lock up when empty. I was told to tighten trailer breaks up hard, then turn them back half a turn. Those with small adjustment nuts, once theyā€™re up they stay up, too late.