cliffystephens:
all the hot air talked on here … you will never do this miracle fix with a bottle of fairy and a prayer to god you gotta have a new line or olives and it can be sky blue pink if you like…
Well, that will be news to everyone who has ever done it then.
I’ve gotta admit I was a bit miffed when I took my broken line into the workshop they just chucked it in the bin and gave me a new spare, it certainly looked repairable and not much different to fixings used on CNC machines (which I’m quite familiar with), or even compression fittings used in plumbing.
They cost us about £6 trade I think, just not worth repairing unless you’re stranded.
Own Account Driver:
I think people are getting mixed up with shunt valve operation and winding off chambers which will mean the trailer’s brakes will not apply in any circumstances -
Careful there amigo. Winding off the brake chamber doesn’t stop the brake from working.
When you’re parked up, there’s no air in the chamber. The brake is held on by a mahoosve spring inside the chamber.
When you let the park brake off, air pressure is allowed into one half of the chamber, this pushes on a diaphragm which in turn forces the mahoosive spring back, releasing the brake. This air is supplied from the red suzie. Hence when you lose air pressure the brakes lock on.
BUT… there’s also another half of the chamber, with a second diaphragm. When you apply the footbrake, the pressure is forced into the other side of the chamber, acting on the other diaphragm. This pushes the brake on.
When you wind a chamber off, you’re winding the mahoosive spring back to prevent it from locking the brake. When wound back the spring is ineffective and the park brake doesn’t work. But the footbrake still works. Winding the spring back doesn’t affect the operation of the footbrake.
I know, I’ve changed hundreds of chambers but I was under the impression that designs vary and sometimes the winding tool is just pulling the spring back off the diaphragm and the return springs are pulling the push rod back off the slack adjuster/caliper and on others the key is actually locking into the back of the push rod and pulling this in which scenario you’d have neither service or parking. I think the difference is (but don’t know 100%) whether the chamber can be user serviced ie new diaphragms fitted like used to be popular or not. I have a footvalve in the pit I use to operate the trailer service brakes from workshop air and several times I’ve had to undo the wind off key to make them work when I’ve fitted new chambers (unless there’s something else I’ve missed that was causing it) - generally what I like to do is nip the nuts up on the chamber watch it operate then slide up/down until I’m happy with the push rod angle and that it’s not scraping when it comes in and out the chamber.
To save any arguments though I’II change my original post to winding off slack adjusters which hopefully everyone can agree you’ll have neither service or parking. (We’'ll also avoid whether when you’re parked up it’s the springs or the pressurised yellow line which is holding the trailer brakes on as I think that one’s been done to death before as well)
Own Account Driver:
I think people are getting mixed up with shunt valve operation and winding off chambers which will mean the trailer’s brakes will not apply in any circumstances -
Careful there amigo. Winding off the brake chamber doesn’t stop the brake from working.
When you’re parked up, there’s no air in the chamber. The brake is held on by a mahoosve spring inside the chamber.
When you let the park brake off, air pressure is allowed into one half of the chamber, this pushes on a diaphragm which in turn forces the mahoosive spring back, releasing the brake. This air is supplied from the red suzie. Hence when you lose air pressure the brakes lock on.
BUT… there’s also another half of the chamber, with a second diaphragm. When you apply the footbrake, the pressure is forced into the other side of the chamber, acting on the other diaphragm. This pushes the brake on.
When you wind a chamber off, you’re winding the mahoosive spring back to prevent it from locking the brake. When wound back the spring is ineffective and the park brake doesn’t work. But the footbrake still works. Winding the spring back doesn’t affect the operation of the footbrake.
I know, I’ve changed hundreds of chambers but I was under the impression that designs vary and sometimes the winding tool is just pulling the spring back off the diaphragm and the return springs are pulling the push rod back off the slack adjuster/caliper and on others the key is actually locking into the back of the push rod and pulling this in which scenario you’d have neither service or parking. I think the difference is (but don’t know 100%) whether the chamber can be user serviced ie new diaphragms fitted like used to be popular or not. I have a footvalve in the pit I use to operate the trailer service brakes from workshop air and several times I’ve had to undo the wind off key to make them work when I’ve fitted new chambers (unless there’s something else I’ve missed that was causing it) - generally what I like to do is nip the nuts up on the chamber watch it operate then slide up/down until I’m happy with the push rod angle and that it’s not scraping when it comes in and out the chamber.
To save any arguments though I’II change my original post to winding off slack adjusters which hopefully everyone can agree you’ll have neither service or parking. (We’'ll also avoid whether when you’re parked up it’s the springs or the pressurised yellow line which is holding the trailer brakes on as I think that one’s been done to death before as well)
not any more, they are a sealed unit, there have been many serious accident where un-trained people have taken the spring brake chamber apart without having it held in place in some way, and the spring flies out and hits someone
it comes out with enough force to kill someone, so, they do not have the ring with the nut and bolt any more
cliffystephens:
dont we need olives/ big spanners / stanley knife to do this still not getting the just push it back in and i have changed a few of these buggers all okay as long has you got tools and every one dont carry em…
No you don’t. You’re thinking of a completely different type of union. The one I’m on about is what is fitted to a lot of modern trucks now at the cab end of the suzies and the brass union has ridges on it. When they manufacture the lines they just press fit the tube onto the union so all you’re doing is the same. The ridges stop the pipe from being pulled off which is why when you rip them off they go just after the tip of the union and leave an inch behind.
Like below
Going back to Harry’s comments about expecting driver to know basic stuff like this…
I reckon every driver should work for a small firm who don’t have recovery trucks and you’re expected to sort minor stuff like this out on your own. I learned stuff like this in the 90’s working for a mate who ran three knackered old sheds. In that job I did brake drums, wheel bearings - even changing one on a trailer at the side of the A64, shoes, pots, suzies, springs, kingpins, power steering pump hoses, curtain rails and once had to repair a gear linkage at the side of the M62 that had a bolt shear.
shuttlespanker:
not any more, they are a sealed unit, there have been many serious accident where un-trained people have taken the spring brake chamber apart without having it held in place in some way, and the spring flies out and hits someone
it comes out with enough force to kill someone, so, they do not have the ring with the nut and bolt any more
Ha ha, I’m not just trying to be difficult, honest but…
You can still change the front diaphragm, just not the rear one The band clamp on the rear one is crimped on.
To put it into perspective, the poundage on the brake chamber spring is higher than a Transit suspension spring.
I agree, mess with a chamber when you don’t know what you’re doing, and it will kill you.
shuttlespanker:
not any more, they are a sealed unit, there have been many serious accident where un-trained people have taken the spring brake chamber apart without having it held in place in some way, and the spring flies out and hits someone
it comes out with enough force to kill someone, so, they do not have the ring with the nut and bolt any more
Ha ha, I’m not just trying to be difficult, honest but…
You can still change the front diaphragm, just not the rear one The band clamp on the rear one is crimped on.
To put it into perspective, the poundage on the brake chamber spring is higher than a Transit suspension spring.
I agree, mess with a chamber when you don’t know what you’re doing, and it will kill you.
had to do a transit front spring a couple of month’s back, god never again i had a 1.2 ton spring compressor (hydraulic) and 2 hand tightned draper spring clamp’s even with all that on it,it didn’t feel very safe so it was a bloody quick top mount change…
shuttlespanker:
not any more, they are a sealed unit, there have been many serious accident where un-trained people have taken the spring brake chamber apart without having it held in place in some way, and the spring flies out and hits someone
it comes out with enough force to kill someone, so, they do not have the ring with the nut and bolt any more
Some used to have 6 or 8 bolts going through two alloy plates which got kankered up. Often I have gone out with a new diaphragm and ended up replacing the lot.
well connor thats a handy piece of kit stand corrected on that … blind man could fit the bugger …so i would say if your driver wouldnt change that he needs a good slap…
shuttlespanker:
not any more, they are a sealed unit, there have been many serious accident where un-trained people have taken the spring brake chamber apart without having it held in place in some way, and the spring flies out and hits someone
it comes out with enough force to kill someone, so, they do not have the ring with the nut and bolt any more
Ha ha, I’m not just trying to be difficult, honest but…
You can still change the front diaphragm, just not the rear one The band clamp on the rear one is crimped on.
To put it into perspective, the poundage on the brake chamber spring is higher than a Transit suspension spring.
I agree, mess with a chamber when you don’t know what you’re doing, and it will kill you.
it was the rear one that i was referring to, hence the mention of the spring
also, every time i have had a spring brake chamber go, it has always been the rear diaphragm that has gone
Used to work for a bloke who bought clutches/brake Chambers etc.we would go round scrap yards cutting them off axles…you should see them fly,when the bolt went
Just to throw another spanner in the works. If the trailer were to have ebs braking, and assuming the air is up in the trailer, the brakes will work in a limited capacity with neither air suzie in as long as the electrics are connected. They will be electrically applied when you press the brake pedal
If any line snaps at either end all you need is 2 spanners[forgot size]Stanley knife and a tin with some olives in it,the brass sort.Undo at the broken end,cut small piece off the line,replace nut on line,replace olive tighten connection job done 10 mins.
regards dave.
cliffystephens:
well connor thats a handy piece of kit stand corrected on that … blind man could fit the bugger …so i would say if your driver wouldnt change that he needs a good slap…
You don’t actually change it. It is bolted to a metal bar along the back of the cab. The ridged bit is what sticks up on a hose side and thats what is left when you rive the hose off. Cut off the inch of hose still left on the union, get the pipe, make the snapped end nice and square and push down hard onto the union. Other than the fact the suzie is an inch and a half shorter than it was, you’d be hard pressed to find anyone who would notice it had been repaired.
Only downside is that when you’ve had some moron drive the wagon and blather the suzies in fifth wheel grease it makes pushing the pipe back on the fitting bloody hard.
it gets better then… i ran erfs until 2000 and they never had em… then done a couple years driving for a well known llaneli firm running steel and if they broke they just fitted new line…
cliffystephens:
well connor thats a handy piece of kit stand corrected on that … blind man could fit the bugger …so i would say if your driver wouldnt change that he needs a good slap…
You don’t actually change it. It is bolted to a metal bar along the back of the cab. The ridged bit is what sticks up on a hose side and thats what is left when you rive the hose off. Cut off the inch of hose still left on the union, get the pipe, make the snapped end nice and square and push down hard onto the union. Other than the fact the suzie is an inch and a half shorter than it was, you’d be hard pressed to find anyone who would notice it had been repaired.
Only downside is that when you’ve had some moron drive the wagon and blather the suzies in fifth wheel grease it makes pushing the pipe back on the fitting bloody hard.
You surprised me with that one conor, you can probably tell by my previous post thanks for the info been ret 11yrs
regards dave
Well, I had the yellow air line let go today, at the trailer end. Much later on I can see what the boss wanted me to do, which was, I think, insert a pen into the airline and then reattach it back on the trailer. The pen would then limit the air going out the breakage. But I wasn’t too happy with that arrangement and eventually got the local commercial repair place out to fix the line.
Considering the advice I’ve had elsewhere after the repair was if I had a proper palm repair kit thingy and knew what I was doing, I probably could have repaired it properly but also its not worth getting wrong is it.
Even less in this weather, and returning with a full load… 200 or so miles…
madguy:
I was talking to a mate the other day who was telling me his red airline had snapped, he didnt have a spare so he clamped it off and put the trailer on shunt, then drove back to the yard loaded about 20 miles away.
Usually when they snap it is at the cab end. Just cut the remnants off the brass union on the cab, shove the red pipe back on and you’re good to go again as its a seriously tight fit and ain’t going anywhere.
But if it comes off on the motorway and you have an accident someone gets killed, who gets jail for endangering life due to tampering with a safety system ? I would let the firm sort it out. PASS THE BOOK BECAUSE THE FIRM WILL
K5Project:
Dunno, but when your been recovered in an artic and they put the underlift under your tractor unit and pull the whole lot do you think they have brakes on your unit or the trailer
Look closely and you’ll see the suzies, even towing a rigid.
You can only see the red one on this pic but I’ve seen them with both on. Perhaps the yellow is round the other side. Amazingly there aren’t many pics on Google of artics being towed.
(We’'ll also avoid whether when you’re parked up it’s the springs or the pressurised yellow line which is holding the trailer brakes on as I think that one’s been done to death before as well)
The band clamp on the rear one is crimped on.
Boom!
thanks for the info been ret 11yrs 