trans brake not holding

Posted By: hemibee69

trans brake not holding - 07/05/10 01:48 AM

727, Griner low band apply transbrake will not hold the car at the starting line. The electric side is ok because I can back up with it. I went down the track after it rolled the beams and all 3 gears seemed OK, but above about 2000rpm the car rolls forward with the brake applied. I wish it was something easy, but high gear clutch pack or it's sealing rings seems like the likely culprit. What else to check before pulling the trans? Any easy checks or fixes other than remove and teardown?
Thanks

Posted By: WILD BILL

Re: trans brake not holding - 07/05/10 04:06 AM

Start with the basics like adjusting the bands and if that doesn't help pull the VB and do an air check.

Posted By: Anonymous

Post deleted by Defbob - 07/05/10 04:36 AM

Posted By: 506RR

Re: trans brake not holding - 07/05/10 04:50 AM

My Turbo Action Transbrake would always creep a little as well. Do yourself a favor and just tie it to the Line Lock. That is the way everyone I know does it.

Posted By: 727builder

Re: trans brake not holding - 07/05/10 05:03 AM

We tie in the line lock as well. But like you said, Sounds like a high gear clutch/seal problem. Good luck!

Posted By: Leon441

Re: trans brake not holding - 07/05/10 06:17 AM

Rear band worn and out of adjustment.

Posted By: 727specialist

Re: trans brake not holding - 07/05/10 06:20 AM

It is not normal for a Griner brake to not hold.
A good brake should keep your car stopped without a line lock.

The first thing you need to do is adjust your rear band and check the line pressure.
The band needs to be adjusted on the tight side and the line pressure should be around 160 to 180 but not much higher than 180.

Posted By: MR_P_BODY

Re: trans brake not holding - 07/05/10 12:25 PM

Quote:

My Turbo Action Transbrake would always creep a little as well. Do yourself a favor and just tie it to the Line Lock. That is the way everyone I know does it.

Either your line pressure is low or you could increase
the revs before hitting the button... my TA brake
has never creeped(it been in there about 10 years)

Posted By: hemibee69

Re: trans brake not holding - 07/05/10 12:49 PM

Thanks for all the replys, I do have it tied to the line-lock. The brake has always locked and held the car until this problem started.Air checking the high clutch pack with the valve body removed is something I did not think of. That will be the first thing to do after the valve body is out. I also had an early Turbo action transbrake before the Griner. The Engine RPM needed to be up for it to lock in as said earlier. The Griner is not like that.

Posted By: savoyracer

Re: trans brake not holding - 07/05/10 01:47 PM

I would do some easy checks before removing anything. #1 place a ground strap from the trans to the frame , or battery, in order to eliminate a grounding problem. #2 increase engine RPM's when staging, to ensure adequate line pressure. #3 charge the battery, and then do a battery check, to be absolutely positive you have the voltage, just because you can back up, does NOT mean that you have adequate voltage to set the brake!!. and #4, if you are using synthetic fluid, take it out, replace with a good quality non- synthetic fluid. Only after these checks would I look internally.

Posted By: 65dragnet

Re: trans brake not holding - 07/05/10 02:26 PM

I agree with 727 specialists if you have a lowband apply you don't need to tie it in with the line lock

Posted By: Efidart

Re: trans brake not holding - 07/05/10 03:39 PM

I had problems with my 727 creeping on the TB under boost with a t/a vb, I always activated the TB above 2000.
Went through the whole trans and couldnt find a problem, we upped the line pressure with no change at all. It never became a problem until I started putting it to higher rpm's with boost on the TB.

I cured the problem by going to a turbo 400, now the car is rock solid on the TB at any rpm/boost.