Anyone know about twin splitter up shift brakes ,can I take one off a other gear box and swap it for mine ,is it just un bolt and bolt back in or is there some rocket science involved ,it’s got air to it but iam struggling to engage gear from standing and the clutch is fully adjusted ,any advice appreciated .
Dan Punchard:
Anyone know about twin splitter up shift brakes ,can I take one off a other gear box and swap it for mine ,is it just un bolt and bolt back in or is there some rocket science involved ,it’s got air to it but iam struggling to engage gear from standing and the clutch is fully adjusted ,any advice appreciated .
In an old article on clutch brakes, Pat Kennett had this to say:
‘‘First of all the clutch brake has to be properly adjusted by the the workshop fitter and properly used by the driver. Adjustment, on manual types like the Lipe, is simply a matter of removing a two-stud cover plate on the bell housing. Then slackening off a large locknut around the spigot shaft, and screwing in the adjusting ring until there is a set clearance - usually 13mm - behind the clutch brake ring itself. If there is too much clearance the brake won’t work properly. If there isn’t enough it will come in on every shift, up as well as down, and your progress will be audible to every man and beast in the neighbouring countryside. The driver needs to do his bit too. The two main sins are booting the clutch down too far on normal shifts, so engaging the brake when it’s not needed, and holding both clutch and brake pedal down when coming to a stop, for example in traffic. If you do that the clutch brake is, in effect, being used to help slow the vehicle. As it is only a small friction device a few inches in diameter it won’t stand that treatment for long.’’
Hope that’s a help! Robert 
Not familiar with the twin-splitter clutch brake myself but what Robert put was OK for the standard Fuller box. Sometimes though you had to ignore the 13 mm part and just set it so that the brake was just engaging when the pedal was almost touching the mat. You still needed to make sure that the clutch was clearing properly though. Some of our drivers with short legs liked their clutch adjusting so that the clutch ‘bit’ when the pedal was near the bottom, others liked it to bite right at the top, so we got used to their individual prefferences and adjusted them accordingly! 
The Dana/Spicer was adjusted differently however, more awkward than the Lipe.
Pete.
Thanks Robert and Pete but what iam referring to is when you fully press the clutch pedal down until you push the air switch open with the pedal ,which sends air to the gearbox brake ,as seen here .
In his article, Pat Kennett does touch on the difference between the Road-Ranger and the Twins-splitter, so I’ve scanned the whole thing for you: here it is. Robert 
Thanks Robert ,the only issue with it is that it’s just starting to grind a bit when stationary ,obviously with the ts the clutch is not required once rolling .
My thoughts are that I have another box with a back end bearing gone amongst other faults but though I’d swap the brakes over and try that but just wondered if it was that straight forward ?
Dan Punchard:
Thanks Robert ,the only issue with it is that it’s just starting to grind a bit when stationary ,obviously with the ts the clutch is not required once rolling .
Twin-splitters can be fickle creatures. Probably teaching grandmothers to ■■■■ eggs here, but have you tried flooring the clutch and then easing up a fraction to feed the gear-stick into starting gear when stationary? robert
Only with other lorries Robert ,I’ve not tried it ,I don’t think ,but really the bottoming of the pedal in to the air switch is what I’d like to have working again ,however it’s poorly at the moment the jake has finally done a valve in so it’s heads of time !!!
Just a matter of interest (and no help I’m afraid, Dan), I noticed a sentence in Pat’s article that appeared to reveal that he had never come across the gear-stick mounted clutch-brake switch as fitted to ‘pull’ clutch vehicles such as the Guy Big-J. There are some nice pictures of this set-up taken by Fryske on other threads. Robert
Dan / different arrangement between say a Fuller 9sp and a twin splitter / the valve at the bottom of the pedal on the twin split is the key / check air is at gearbox end when pedal fully depressed and valve down. if ok its in the box/ not a big job have done them but usualy on rebuild. unusual for them to give trouble thats why i say check the valve at bottom of foot pedal first. Did you say you were having probs with Jake as well? if so sounds like an air supply prob on the ERF you have a valve that only opens at 60 psi and lets air through to aux such as clutch brake , exhaust brake ect. The gauges ect only tell you the pressures in tanks ect and can fool you into thinking all is ok. Hope this helps.
robert1952:
Just a matter of interest (and no help I’m afraid, Dan), I noticed a sentence in Pat’s article that appeared to reveal that he had never come across the gear-stick mounted clutch-brake switch as fitted to ‘pull’ clutch vehicles such as the Guy Big-J. There are some nice pictures of this set-up taken by Fryske on other threads. Robert
I think that was the best application ever for a clutch brake in the Guy’s with a fuller box as it didn’t receive the harsh treatment a pedal operated one got.
It was only needed when stationary to select forward or reverse gears, quite effective too you could hear it slow the mainshaft in the box.
Trev_H:
robert1952:
Just a matter of interest (and no help I’m afraid, Dan), I noticed a sentence in Pat’s article that appeared to reveal that he had never come across the gear-stick mounted clutch-brake switch as fitted to ‘pull’ clutch vehicles such as the Guy Big-J. There are some nice pictures of this set-up taken by Fryske on other threads. RobertI think that was the best application ever for a clutch brake in the Guy’s with a fuller box as it didn’t receive the harsh treatment a pedal operated one got.
It was only needed when stationary to select forward or reverse gears, quite effective too you could hear it slow the mainshaft in the box.
Don’t forget there was a different system for Big Js fitted with AEC boxes- it was operated by the bottom half inch of clutch pedal like the twin splitter, the air acting on the shaft at the rear of the gearbox to slow the plot down.
Retired Old ■■■■:
Trev_H:
robert1952:
Just a matter of interest (and no help I’m afraid, Dan), I noticed a sentence in Pat’s article that appeared to reveal that he had never come across the gear-stick mounted clutch-brake switch as fitted to ‘pull’ clutch vehicles such as the Guy Big-J. There are some nice pictures of this set-up taken by Fryske on other threads. RobertI think that was the best application ever for a clutch brake in the Guy’s with a fuller box as it didn’t receive the harsh treatment a pedal operated one got.
It was only needed when stationary to select forward or reverse gears, quite effective too you could hear it slow the mainshaft in the box.Don’t forget there was a different system for Big Js fitted with AEC boxes- it was operated by the bottom half inch of clutch pedal like the twin splitter, the air acting on the shaft at the rear of the gearbox to slow the plot down.
That’s interesting. From this I infer that it must have been the choice of engine that dictated whether the unit had a ‘push’ clutch or a ‘pull’ clutch. Cheers! Robert
Don’t be tempted into using silicone instead of a proper gasket and any shims.
Double post, apologies.
norfolk:
Dan / different arrangement between say a Fuller 9sp and a twin splitter / the valve at the bottom of the pedal on the twin split is the key / check air is at gearbox end when pedal fully depressed and valve down. if ok its in the box/ not a big job have done them but usualy on rebuild. unusual for them to give trouble thats why i say check the valve at bottom of foot pedal first. Did you say you were having probs with Jake as well? if so sounds like an air supply prob on the ERF you have a valve that only opens at 60 psi and lets air through to aux such as clutch brake , exhaust brake ect. The gauges ect only tell you the pressures in tanks ect and can fool you into thinking all is ok. Hope this helps.
Thanks I’ll check the pressure to the under side of the gearbox ,the jake is all electric ,the exhaust brake I removed it yrs ago and took the air supply to the pto instead .
robert1952:
Just a matter of interest (and no help I’m afraid, Dan), I noticed a sentence in Pat’s article that appeared to reveal that he had never come across the gear-stick mounted clutch-brake switch as fitted to ‘pull’ clutch vehicles such as the Guy Big-J. There are some nice pictures of this set-up taken by Fryske on other threads. Robert
That’s only relevant to the 240 Percy powered Big J Robert 
David
I wondered how long it would be… 
robert1952:
I think that was the best application ever for a clutch brake in the Guy’s with a fuller box as it didn’t receive the harsh treatment a pedal operated one got.
It was only needed when stationary to select forward or reverse gears, quite effective too you could hear it slow the mainshaft in the box.
Don’t forget there was a different system for Big Js fitted with AEC boxes- it was operated by the bottom half inch of clutch pedal like the twin splitter, the air acting on the shaft at the rear of the gearbox to slow the plot down.
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That’s interesting. From this I infer that it must have been the choice of engine that dictated whether the unit had a ‘push’ clutch or a ‘pull’ clutch. Cheers! Robert
[/quote]
The Big J in question was the ■■■■■■■ 205/AEC 6-speed as specced by BRS in the 60s. It’s of little use to Dan but it was a superb combination.