air over hydraulic brake away how?

[GMichaels]

If you have a vacuum over hydraulic system, how does the break away feature work? (if the trailer seperates from the truck, do the brakes lock up on the trailer,if so how)

 

[SGuidry]

The vacuum reservoir tank and check valve connected to this tank are your break away system. The booster on your trailer is "vacuum suspended" meaning there is equal vacuum being supplied to both the front and back sides of the chamber by your vacuum source via the control valve under your hood.



In a normal brake application, the control side of the system is opened to atmosphere while the manifold side stays charged with vacuum allowing proportional application of your trailer brakes as the control valve opens to atmosphere. The vacuum reservoir tank with it's check valve are on the manifold side.



In a true break away situation where both the manifold and control side of the system become disconnected from the tow vehicle, the check valve will close sealing the vacuum tank thus allowing the booster to have a vacuum supply.



Unless you open the drain on your tank, the trailer brakes should stay applied for 15 minutes. If you ever need to troubleshoot your system, do the "thumb test. " With the coupler plugs out and your thumbs over the manifold and control side couplers, have someone start the tow vehicle and allow vacuum to be built up. Once adequate vacuum is achieved, have your buddy apply the brakes. The control side should lose suction. If that is the case, you know the truck side of the equation is good. You can then begin to work your way back along the trailer.



Hope this helps and feel free to email me if you have any questions.

Steve / The BrakeSmart Co.

-- email address removed --

 

[GMichaels]

vac\uum

thank you for your reply, yes it does answer my question. Would our trucks (5. 9 diesel) vacuum pump have enough capacity to run a vacuum over hydrulic system?

 

[NIsaacs]

No they do not, you need a seperate belt drive, remote mounted pump, with more volume.