Author Topic: PG transbrake release  (Read 537 times)

Offline spookie

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PG transbrake release
« on: July 15, 2017, 03:32:04 AM »
Transbrake release gets slow as trans heats up. The pattern is .007 rt 040 rt .080 rt. At first I thought it was me.Adding air in tires,changing 2 step all make small improvement,but pattern remains.New BTE valve body[not pro brake].I am using dexron VI synthetic.The dragster prints time slips the first two runs,but will loose .02-.03 in 330ft on third run.Trans temp at 150* on all runs.What going on?

Online masracingtd1167

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Re: PG transbrake release
« Reply #1 on: July 16, 2017, 02:02:06 PM »
A lot of variables there . Do your 60 ft times change too ? Did this start to happen right after you changed the brake ? Do you leave of of a chip or tach ? do you shift off of a chip ? A couple of easy things you could check are the spool valve for the brake . Make sure it moves nice and free in its bore and the solenoid too . Another thing could be the button it self . I have had buttons that were not smooth and would stick just a little . Another thing that can make a huge difference in your reaction times is where you hold your thumb on the button . I still have to remind my self every time I stage to put my hand in the same spot every time ! Let us know what you find ! 

Offline gordon

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Re: PG transbrake release
« Reply #2 on: July 16, 2017, 06:18:41 PM »
Some people use anodized aluminum valves in cast iron valve bodies and the expansion rate difference between the two different metals can cause stiction (technical redneck term) . The fluid pressure and assist spring is usually enough to push the valve when solenoid releases hold pressure but valve can be slower to release.  Usually not  a solenoid problem, that shows up as a transbrake apply problem not release.
« Last Edit: July 16, 2017, 06:21:14 PM by gordon »

Offline bikeguy307

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Re: PG transbrake release
« Reply #3 on: July 17, 2017, 06:27:46 PM »
How old is the solenoid? Solenoids do get dirty and as they warm up from use throught out the night. This can cause them to drag on release and apply. And when you are talking hundreds of a second you won't notice it on apply because you are not timing the apply. The BTE non pro brake is a very basic unit, and not prone to valve sticking. Something else the needs to be checked is piston to case clearance, just like a piston in bore of a block, if it is too much the piston will rock in the bore and could drag on release. Any of these problems will not only show in rt but will show in your 60ft. I had an issue like this and found it to be uneven spring pressure on the release spring of the reverse piston. 6 of the springs were 30% less at installed height and all were on the same side. I found the by watching the piston as I slowly applied the piston with air. Keep us up on your progress.

Offline spookie

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Re: PG transbrake release
« Reply #4 on: August 05, 2017, 02:32:09 AM »
Installed valve and spring from old V-B [.oo2] smaller.Spring is shorter,with lighter coils.Had to take .01 out of box,but printing time slips. First race with replacement valve,made to final round.Thanks for the help

Offline bikeguy307

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Re: PG transbrake release
« Reply #5 on: August 05, 2017, 02:42:00 PM »
Awesome!!!!