TURMOIL Posted June 22, 2009 Share Posted June 22, 2009 I've got a ARB air diff lock which I'm about to install, bought it second hand, as usual it came without any instructions, I can sort out the fitting side of things without to much trouble (joy of running a Haulage Company, big workshop, plenty of helpfull machanics willing to help) I have purchased a new T-Max crompressor which I must admit looks excellent value for the £60 it cost. but does the Diff lock need contant air supply, it looks to me to be a piston mechanisn, i.e its either in or out, if this it the case could I not just use a lorry air tank to provide the air??? Quote Link to comment Share on other sites More sharing options...
HoggyN Posted June 22, 2009 Share Posted June 22, 2009 I've got a ARB air diff lock which I'm about to install, bought it second hand, as usual it came without any instructions, I can sort out the fitting side of things without to much trouble (joy of running a Haulage Company, big workshop, plenty of helpfull machanics willing to help) I have purchased a new T-Max crompressor which I must admit looks excellent value for the £60 it cost. but does the Diff lock need contant air supply, it looks to me to be a piston mechanisn, i.e its either in or out, if this it the case could I not just use a lorry air tank to provide the air??? Yes, you could use a lorry air tank. We have used paintball co2 cylinders for pneumatic gearshifters, I dare say one of those could be adapted too. I would say that the compressor would be more versatile because you can use it to inflate tyres etc. You'd need a big lorry tank to do that! Quote Link to comment Share on other sites More sharing options...
Mark Posted June 22, 2009 Share Posted June 22, 2009 Basically you need to keep about 80PSI in the locker to keep it engaged. That could come from a compressor or an air tank. Obviously with a tank you would only have a finite number of actuations whereas a compressor gives you an infinite amount of actuations... Quote Link to comment Share on other sites More sharing options...
bishbosh Posted June 22, 2009 Share Posted June 22, 2009 and less than 100psi fi you want the seals to survive...... Quote Link to comment Share on other sites More sharing options...
discomikey Posted June 22, 2009 Share Posted June 22, 2009 You'd need a big lorry tank to do that! errrr, no, do you know how much braking force a lorry tank gives a lorry, methinks a tank off a 6 or 8 wheeler would do the job. would be cheap as chips too. mikey Quote Link to comment Share on other sites More sharing options...
landroversforever Posted June 22, 2009 Share Posted June 22, 2009 the system looses air each time the lockers are disengaged... so would need to be a big tank for the volume used over the time. (assuming the locker isnt just left in) Quote Link to comment Share on other sites More sharing options...
SteveG Posted June 23, 2009 Share Posted June 23, 2009 Having a tank is optional. You can plumb your T-max in with a regulator to give ~85-90psi to give safe actuation of locker/s. So you put regulator on output of compressor and then feed into air solenoid. If you want to use the compressor to inflate tyres too, fit either a two way switch before the regulator or fit some quick disconnect fittings between the compressor and regulator. To save activating the compressor all the time and to give more air volume for inflating tyres etc you could fit a tank. You now need to fit a pressure switch to tank and this switch operates the electrical feed to the compressor. You have two options for the pressure switch, one that works at safe operating pressures of ARB or one that works at the maximum safe operating pressure of the tank you have fitted. The first keeps things simple and you can feed the arb's and a tyre air line straight from the tank. The second gives you more air volume per fill from the compressor, but you'll need a regulator on the output line for the arb's to keep it a their operating pressure. btw, you'll need 5mm air line for the arb's fittings. Also there isn't much air volumes used in activating the arb's, so you'd get quite a few activations before starting the compressor on a 2.5+ gallon tank Cheers Steve Quote Link to comment Share on other sites More sharing options...
zim Posted June 23, 2009 Share Posted June 23, 2009 errrr, no, do you know how much braking force a lorry tank gives a lorry, methinks a tank off a 6 or 8 wheeler would do the job. would be cheap as chips too.mikey what sort of pressure do these tanks run at ? Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted June 23, 2009 Share Posted June 23, 2009 errrr, no, do you know how much braking force a lorry tank gives a lorry, methinks a tank off a 6 or 8 wheeler would do the job. would be cheap as chips too. Hang on, you're at risk of confusing pressure, and volume, required. Chucking some rough figures around, an air brake tank at 120 PSI will only fill 3 tyres of equivilant volume from 0 to 30 psi. (and that third tyre would take a while to fill!) Granted, you won't be filling from 0psi, and you may not fill to 30psi, nor may your reservoir be at 120psi, or of equivilant volume (probably significantly less) but using a lorry tank without a compressor to fill tyres doesn't add up. Diving/welding cylinder is a different matter, due to the higher fill pressure. Quote Link to comment Share on other sites More sharing options...
Dave W Posted June 23, 2009 Share Posted June 23, 2009 You really need a tank of some description, to make life easy the pressure switch on the tank should turn the compressor off at 90PSI and on below 80PSI. You could possibly use a regulator but running a compressor when you have the lockers in for a period of time is a waste and may well lead to the compressor overheating, not to mention the noise ! You should also have a pressure relief valve to ensure the tank can't exceed it's safe working pressure if something goes wrong with the electrics and leaves the compressor running. You probably don't want to be anywhere near a steel tank that is pumped up past it's tested pressure... Quote Link to comment Share on other sites More sharing options...
freeagent Posted June 23, 2009 Share Posted June 23, 2009 If you do fit a tank, make sure you put a PRV (presure relief valve) in the system somewhere (preferably on the tank itself) set at below the tanks design pressure. This should always blow before the tank splits in half... Quote Link to comment Share on other sites More sharing options...
cieranc Posted June 30, 2009 Share Posted June 30, 2009 what sort of pressure do these tanks run at ? Nearly everything on the roads here run at 8 bar for the brakes, and 12 bar for the suspension. The huge braking force trucks have is down to the spring pressure in the brake chambers/anchor locks. The brakes are constantly mechanically applied (as said, a very strong spring), and are released by applying air pressure to a diaphragm operating against the spring to release them. But 8 bar, ~120psi, is sufficient to release them. Most half decent compressors will put out 120psi. Charge the airtank at base, have a regulator set at the 90psi required. Sounds simple ! You should also have a pressure relief valve to ensure the tank can't exceed it's safe working pressure if something goes wrong with the electrics and leaves the compressor running. You probably don't want to be anywhere near a steel tank that is pumped up past it's tested pressure... It's unlikely you'll need a prv in a truck air tank. They normally run at 12bar/180psi. What's the maximum you'll get out of your workshop compressor? Mine's all out at 140psi. Most truck tanks these days are aluminium. Diving/welding cylinder is a different matter, due to the higher fill pressure. You're very right, but my understanding was the OP was about pre-filling a tank, to use in place of a compressor. How many people have the facilty to charge an air tank past the capacity of their workshop compressor? Quote Link to comment Share on other sites More sharing options...
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