I remember them in years gone by and my understanding was that they worked by operating the trailer breaks so if you where in icy conditions or snow there was less chance of jack knifing so that being the case why do we not have a set up on modern trucks that works the same or have i got this wrong ?
Think you might have it wrong. Jake brake was an engine brake.
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Sorry having issues here I think you may well be right I was on class 2 in those days so never actually used said joke brake
Its an engine braking system. Some places in the States have areas where Jake brakes are banned because of the noise.
The Jake is a compression brake, turning the engine into a high powered compressor, very effective but quite noisy.
Scanias used to come with a seperate lever that would operate the trailer brakes alone, you had to be careful cos fully locked brakes on a trailer can see it slew right across the road wiping out anything in its path.
Mercedes (i believe but happy to be put right if wrong) dabbled with automatic partial trailer braking when the exhaust brake was operated, 10% of full trailer brake pressure springs to mind but don’t quote me, this would have been the late seventies, i seem to recall that one incident involving a trailer brake locking up due to this system involved a tragic fatal involving a pedestrian.
The reason i know about this is that i took my non Merc tractor unit to the MOT testing station that year and the very first thing the tester did was check for any pressure coming down the brake lines when the exhauster, retarder or Jake was operated, ahd there been any at the vehicle would fail and instant GV9 issued.
What you have to remember is ABS wasn’t fitted and load sensing proportioning valves very rare in those days so braking lock ups were too easy to provoke…one company i worked for fitted manual turn down valves to the trailers, three positions loaded, half loaded and empty, something you had to remember to set but helped no end with this problem.
Our 3litre diesel Isuzu NKR 3.5 t. Gvw had one …it worked well !
3 wheeler:
Our 3litre diesel Isuzu NKR 3.5 t. Gvw had one …it worked well !
Do you mean exhaust brake ?
The amount of noise that a jake makes is only down to the silencer box .
Punchy Dan:
The amount of noise that a jake makes is only down to the silencer box .
aye and when you run with a halfwit with 2 straight pipes with a big banger engine that has the jake on allday from 5 am its no wonder the dot were on our arses .
Punchy Dan:
3 wheeler:
Our 3litre diesel Isuzu NKR 3.5 t. Gvw had one …it worked well !Do you mean exhaust brake ?
Yep exhaust brake
JIMBO47:
Punchy Dan:
The amount of noise that a jake makes is only down to the silencer box .aye and when you run with a halfwit with 2 straight pipes with a big banger engine that has the jake on allday from 5 am its no wonder the dot were on our arses .
I’ve a 14 litre with jake on all 6 ,a silence box not straight through but just empty is deafening and sometime embarrassing ,my m11 has a standard eminox and you can hardly hear it .
Juddian:
The Jake is a compression brake, turning the engine into a high powered compressor, very effective but quite noisy.Scanias used to come with a seperate lever that would operate the trailer brakes alone, you had to be careful cos fully locked brakes on a trailer can see it slew right across the road wiping out anything in its path.
Mercedes (i believe but happy to be put right if wrong) dabbled with automatic partial trailer braking when the exhaust brake was operated, 10% of full trailer brake pressure springs to mind but don’t quote me, this would have been the late seventies, i seem to recall that one incident involving a trailer brake locking up due to this system involved a tragic fatal involving a pedestrian.
The reason i know about this is that i took my non Merc tractor unit to the MOT testing station that year and the very first thing the tester did was check for any pressure coming down the brake lines when the exhauster, retarder or Jake was operated, ahd there been any at the vehicle would fail and instant GV9 issued.What you have to remember is ABS wasn’t fitted and load sensing proportioning valves very rare in those days so braking lock ups were too easy to provoke…one company i worked for fitted manual turn down valves to the trailers, three positions loaded, half loaded and empty, something you had to remember to set but helped no end with this problem.
There was a tragic incident in Maidstone in May 1986, so it will shortly be the 30th anniversary of when three primary schoolchildren were killed. IIRC this was a result of the unladen trailer brakes locking up when the Merc’s dauerbremse (exhaust brake) was operated. A friend of mine is a GP and this happened right outside his surgery. He doesn’t like to be reminded of this since in spite of his efforts at the scene he was unable to save any of the little girls. I remember passing the ambulances coming the other way en route to the scene.
Edit add:
cav551:
Juddian:
The Jake is a compression brake, turning the engine into a high powered compressor, very effective but quite noisy.Scanias used to come with a seperate lever that would operate the trailer brakes alone, you had to be careful cos fully locked brakes on a trailer can see it slew right across the road wiping out anything in its path.
Mercedes (i believe but happy to be put right if wrong) dabbled with automatic partial trailer braking when the exhaust brake was operated, 10% of full trailer brake pressure springs to mind but don’t quote me, this would have been the late seventies, i seem to recall that one incident involving a trailer brake locking up due to this system involved a tragic fatal involving a pedestrian.
The reason i know about this is that i took my non Merc tractor unit to the MOT testing station that year and the very first thing the tester did was check for any pressure coming down the brake lines when the exhauster, retarder or Jake was operated, ahd there been any at the vehicle would fail and instant GV9 issued.What you have to remember is ABS wasn’t fitted and load sensing proportioning valves very rare in those days so braking lock ups were too easy to provoke…one company i worked for fitted manual turn down valves to the trailers, three positions loaded, half loaded and empty, something you had to remember to set but helped no end with this problem.
There was a tragic incident in Maidstone in May 1986, so it will shortly be the 30th anniversary of when three primary schoolchildren were killed. IIRC this was a result of the unladen trailer brakes locking up when the Merc’s dauerbremse (exhaust brake) was operated. A friend of mine is a GP and this happened right outside his surgery. He doesn’t like to be reminded of this since in spite of his efforts at the scene he was unable to save any of the little girls. I remember passing the ambulances coming the other way en route to the scene.
Thanks Cav, i was fairly sure it was at Maidstone, but didn’t realise it was three little uns, hell fire it don’t get much worse than that.
Also didn’t know it was as late as 1986 i really thought it happened around the 82/3 mark, i’d packed in with general haulage by then so would have thought this was around 85, however thats only my poor memory speaking and i have no doubt at all that your friend the GP has imprinted on his mind and will recall every second of that day to his own dying breath.
There but for the grace of God go any of us.
Brilliant piece of kit. Even better when mated to a 10 or 12 litre Cat engine. Great fun spooking tourists when travelling down Burford High Street. 
Punchy Dan:
JIMBO47:
Punchy Dan:
The amount of noise that a jake makes is only down to the silencer box .aye and when you run with a halfwit with 2 straight pipes with a big banger engine that has the jake on allday from 5 am its no wonder the dot were on our arses .
I’ve a 14 litre with jake on all 6 ,a silence box not straight through but just empty is deafening and sometime embarrassing ,my m11 has a standard eminox and you can hardly hear it .
at a junction we had to stop at to turn onto a backroad on the quarry run …we were asked nicely not to have the jake on before 8am ooohh kin noo not the halfwit kept it o finally the owners got onto the dot and they made live v difficult at times.