Faulty trailer brakes

UK PROFESSIONAL DRIVERS FORUMS THE UK PROFESSIONAL DRIVERS FORUM (INTERACTIVE)
1

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

Here is another question, trailer ABS warning comes on on dash then about 5 minutes later stopped at some traffic lights and the trailer brakes get stuck on,so put it in shunt mode and move it to a safe place off road then connect lines again going about 100 yards and brakes locked on again but moves in shunt mode, is that a trailer fault ?

2

Must be an old turd with fresh paint if its still got an LSV fitted.

3

Ghost01:

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

Here is another question, trailer ABS warning comes on on dash then about 5 minutes later stopped at some traffic lights and the trailer brakes get stuck on,so put it in shunt mode and move it to a safe place off road then connect lines again going about 100 yards and brakes locked on again but moves in shunt mode, is that a trailer fault ?

Sounds like a lack of air either from the tractor or the C coupling self sealer.

4

Trickydick:

Ghost01:

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

Here is another question, trailer ABS warning comes on on dash then about 5 minutes later stopped at some traffic lights and the trailer brakes get stuck on,so put it in shunt mode and move it to a safe place off road then connect lines again going about 100 yards and brakes locked on again but moves in shunt mode, is that a trailer fault ?

Sounds like a lack of air either from the tractor or the C coupling self sealer.

There is no leaks on the unit, and it drove ok for 2.5 hours before doing it and when the unit is solo the unit drivers ok …

5

Ghost01:

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

Here is another question, trailer ABS warning comes on on dash then about 5 minutes later stopped at some traffic lights and the trailer brakes get stuck on,so put it in shunt mode and move it to a safe place off road then connect lines again going about 100 yards and brakes locked on again but moves in shunt mode, is that a trailer fault ?

Check the red airline filter on the trailer isn’t blocked.

6

Own Account Driver:

Ghost01:

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

Here is another question, trailer ABS warning comes on on dash then about 5 minutes later stopped at some traffic lights and the trailer brakes get stuck on,so put it in shunt mode and move it to a safe place off road then connect lines again going about 100 yards and brakes locked on again but moves in shunt mode, is that a trailer fault ?

Check the red airline filter on the trailer isn’t blocked.

Just a quick update

Had a new Red airline connector fitted, new ABS module and air tank fill up as they should used it for a week and now it’s put the ABS warning light on again and locked the trailers brakes, disconnect the trailer turns light off and unit drivers ok, plug it back to the trailer warning light on again … ideas

7

I hasn’t had a new shunt valve fitted recently has it and it all started after that? There are three different types. It may end up that a roadside call out when it all locks up is the only way to find out what has happened. Otherwise if the trailer is new enough then a plug-in to the trailer EBS diagnostic port may be needed. Both Knorr Bremse and Haldex have technical help lines only too willing to offer assistance.

8

cav551:
I hasn’t had a new shunt valve fitted recently has it and it all started after that? There are three different types. It may end up that a roadside call out when it all locks up is the only way to find out what has happened. Otherwise if the trailer is new enough then a plug-in to the trailer EBS diagnostic port may be needed. Both Knorr Bremse and Haldex have technical help lines only too willing to offer assistance.

It’s not the trailer causing the issue as we ran the trailer on our other unit fine, it’s something to do with our unit, when you plug the ABS lead in to the trailer it comes on and locks the trailer brakes, take the ABS lead out the trailer socket and the light goes off on the dash … so could it be wiring on the unit ?

9

I’d see what a diagnostic plug in says as anything else at this stage is potentially a wild goose chase if you’re satisfied everything on the air system side is as it should be. I would discount the unit if it’s working fine on other trailers.

10

I would check the suspension level first, and make sure it wasnt in the wrong position on either trailer or unit.

11

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 he’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: .

Didn’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 hadn’t stopped he was obviously just slowing down from 44 to 40 mph i’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 didn’t stop and I over took him on the A1 and his trailer wasn’t of fire so I don’t know :question: :question:

I don’t drive artics but that isn’t normal nor healthy is it :question: It was a empty 3 axel flat bed trailer being pulled by a 56’ axor from a company in Mansfield I think. Trailer didn’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

12

I’m no mechanic but it seems like the brakes need adjustment :question: :question: :question:

13

brakes might not be adjusted correctly, but also with the trailer being empty and light the brakes work sharper,

if it was under load am sure the brakes would be great, nothing really to woryy about i would rather the tyres lock up than not stop me at all !!

14

Definately needs adjustment of brakes, probably been wound right up to get it through its MOT.

Once loaded it could possibly cause brake bind.

15

Nothing too much to worry about if the brakes lock on when the trailer is empty, soon as the trailer has a bit of weight on it then the brakes will be very efficient. Trailers probably just been serviced/mot’d and the brakes adjusted up pretty tight.

Tiger.

16

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

17

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:

18

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:

19

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:

Imagine the ride,you’d have tyres like thrupney bits! :astonished: :astonished: :smiley: :smiley:

20

we have had this happen on one of our older trailers. the air supply on the unit is higher than the trailer was designed for, so the slightest touch of the brakes locks everything up. fitting a load sensing valve cures it.

Dunno then?:

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:

Imagine the ride,you’d have tyres like thrupney bits! :astonished: :astonished: :smiley: :smiley:

our oldest trailer dates from 1971 and is a 45ft extender on springs with the axles right at the rear. even with new tyres, it bounces and clatters constantly! :smiley: (in fact, thats it in my signature.)