FrontEngineDragsters.Org Forum
Technical => Dan Dishon's Transmission Den => Topic started by: grapro on August 03, 2015, 07:20:36 AM
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In my car I has a ATI brake and the car has a dozen passes on it, used the brake the firt time off the 7 passs and it held for 4 secs before releasing. Second time even longer. Brake is wired in direct no relay with a Large B and M button. Wondering should I be adjusting my low band or do I have other problems, without the brake foot pedaled it takes off like xxxx.
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Can you push the TB in by hand and then release it to where it pops back on its own? Try another button? Remove TB solinoid and manualy depress selector shaft to see if it hangs up,
For future issues add a manual peddle for back up and use button only for launch or if battery goes dead and will not hold.
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Grapo it could be as simple as the plunger for the brake is not coming back far enough to let the brake release . It should release instantly . You might have to shim the solenoid back just a little and try it on the jack stands . Just bring the rpm up a little like 3000 rpm don't stand on it and see how it releases . I just had the exact opposite problem with a friends brand new unit . At idle the trans brake would hold but when you stood on it it would creep . All it was the trans brake solenoid was not turned in enough .
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I'm not sure how old any of the parts you are working with are, so start with the button. hook it to a test light and not the solenoid, see if the light is delayed. If the light keeps up with the button it should be good so move on to the solenoid. Is your brake a fluid release or spring release? Do you have a "can" type or pancake/flapper solenoid? Must know these questions to in order to guide you further. A simple way to test your solenoid is to swap it out with a known good one. There is the slightest possibility that the reverse piston could be getting cocked in the case causing a slow release, although this is rare I have seen it happen.
Hope this helps, Dan
Keep us up on your findings.
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So who makes this unit?
(http://www.frontenginedragsters.org/forum/index.php?action=dlattach;topic=1777.0;attach=4545;image)
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Pretty sure Bruce builds these himself
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I made it to only engage reverse since we leave off the hand brake
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I don't know if you have transbrake solenoid like mine, but ours has removable valve, and spring. We mostly race Heritage JrFuel racing a 2 tenths Pro-tree, but when we race B/ND in Comp on a 5 tenths full tree, we put in slower releasing valve and weak spring to try and keep our driver from Red-Lighting.
So check your valve and spring [ go stiffer if you want it faster] One issue you need to know is with a slow transbrake is once you release your button, the motor free wheels until the brake comes into play, and what that means is if you are using a two-step, and you have a 4000 chip in the two step, the motor can climb to 5600+ before it hits the tires. So if your tires go-up in smoke you might want to run a higher chip and a quicker valve/spring. It's a real balance.
Or your valve is just hanging up. Also check your switch and ground wire.
Jon Hansen