Machines | Hino Truck, Brake/Clutch problem, Possible lack of Vacuum??

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1. Did you sort it out? Servo.....
2. have you had a look on ebay for the workshop manual on cd, cheap enough and it might have the vacuum specs
3. Don't know anything about lorries so I'll just do a bit of moral boosting: You'll fix it good in the end mate! 
4. Alex, on this truck, the vacuum pump is on the back of the starter motor, its a drag to fix,, you can buy that part separately, or look into replacing the seals inside it, its a very difficult unit to fix, like i said, but it can be done.
5. both in this case are vacuum assisted hydraulic!
6. No idea Alex. I thought brakes are normally by vacuum pump and clutch is hydraulic or mechanical.
7. great idea.. i had considered this :)
8. great idea, but not a fix i would present to the customer unless the mechanical replacement was not available 
9. maybe get 2 electric vac pumps and a tank to replace the tired mechanical vac pump???
10. it depletes very quickly.. one pump of the clutch and it starts to lose assistance already. it has a reservoir tank already from the factory 
11. maybe the vac pump is a bit tired??
12. Hi alex, watcing the gauge , it builds up vacuum fast enough ok, 30hg inches of mercury is plenty, seen many truck run at 25hg with no problems, you should get at least 5-6 pumps on the pedal with the engine off and still work at 15hg, and on the gauge the vac is depleted very quick on the brakes, check th lines, has it got reservoir tank,if so there could be a blockage at the tank, if this doesnt help then i would install one on the chassis, then you would have plenty for brake/clutch
13. already thinking the second hand route for the customer benefit as a "test" subject, but also, the problem with the truck wreckers here, they have the supremist attitude as they are the only truck wrecker in the area, and will charge you, two axles, an arm, a leg, and a gearbox, for a simple vacuum pump :)
14. you might want to check for leaks, but the pump is probably bad. look for a good second-hand part instead?
15. one pump increases pedal resistance dramatically. if you pump the brake once, then try to clutch, you dont have enough assistance :) im starting to think my original diagnosis at the customers premise was correct.. vacuum fault caused by weak pump!
16. it does have a vacuum tank, and at reasonable revs, the problem still exists, therefore the diagnosis of the pump being faulty becomes even more valid. 
17. im worried that taking it apart, it is sectioned, may render it completely inorperable.. i dont want the customer accusing/blaming me for an immobile truck, even though its out of work in its current state.. for $1000 i want to get the customers OK first :) convincing him to risk that, is another problem, as even with all my experience, ive never had this particular problem before, even though im 90% sure :)
18. Yes it gets odd, and if you include the local air pressure on this planet, the understanding gets odder lol. I choose to ignore planet air pressure, and its suction and not negative pressure in respect to....lol. I find the same mental block with switching negative wires instead of positive, im odd that way :-)
19. Your only supposed to get. About 3 to 4 pumps out of the brake booster before vaccume is depleted with engine off
20. I find vacuum systems very hard to understand as everything is in reverse. Only thing i know about vacuum pumps is they usually need oil running in their system to work, without it they lose ability to seal, sort of like rotary screw compressors. I think these may use oil from the engine, just a mist and put it back but to be honest i have never investigated one so stabbing in the dark.