Author Topic: Parking brake releases only manually  (Read 1107 times)

Klaus

  • Guest
Parking brake releases only manually
« on: October 30, 2006, 03:39:19 PM »
Hi!
I am the owner of a 1975 Cadillac Eldorado now experiencing a problem with the parking brake release mechanism. When putting the car into reverse or drive, the parking brake won’t release by itself anymore. This happened after having the TH425 transmission rebuilt. Is there a way I can fix the brake so that it releases on its own again?  

Thanks
Klaus

Bruce Reynolds # 18992

  • Guest
Re: Parking brake releases only manually
« Reply #1 on: October 30, 2006, 04:01:28 PM »
Gday Klaus,

Sounds like you might either have a vacuum leak in the vacuum hose that operates the switch, or the hose has come away from the port.

My tip would be to physically trace the hose, from the actuator on the park brake all the way back to the engine.   Plus, make sure that the unit on the Steering Column is operating correctly.

Bruce,
The Tassie Devil(le),
60 CDV

Klaus

  • Guest
Re: Parking brake releases only manually
« Reply #2 on: November 01, 2006, 07:24:51 AM »
Hi Bruce!

Thanks for your answer. Ill try to proceed as you described.
Best,
klaus

Rhino 21150

  • Guest
Re: Parking brake releases only manually
« Reply #3 on: November 01, 2006, 09:50:26 PM »
The brake release switch is actually a valve for vacuum lines. It is mounted on, or is part of, the neutral safety switch. The  switch is on the lower end of the steering column. When the shift lever is moved through reverse the valve opens allowing engine vacuum to pull the release solenoid. If the valve doesnt open, then the valve or the actuating lever is not adjusted correctly. The folks who fixed your trans need to readjust the shift mechanism. Are you also having a little difficulty shifting into reverse or drive, or more likely, lower gears (2,1)?
The manual release is there in case the automatic release fails, a good thing you have this!

Klaus

  • Guest
Re: Parking brake releases only manually
« Reply #4 on: November 04, 2006, 07:49:21 AM »
Hi Rhino 21150!

Thanks for helping. I think youre right. Ive traced the vacuum hose all the way back to the engine and couldnt find any leaks. I do think this has to do with linkage. As you asked, Im also having difficulty shifting into all gears. When in reverse theres also a problem with the reverse lights that just actuate somewhere between P and R.
Unfortunately the car is now in Portugal and the TH425 was fixed in Waterloo (Belgium)where I have the car from. These folks did really a lousy expensive job.
I wonder if someone knows anything about transmissions around here in Portugal.
Thanks again for your help.

Rhino 21150

  • Guest
Re: Parking brake releases only manually
« Reply #5 on: November 05, 2006, 07:10:53 PM »
The problem is in the adjustment of the linkage. Can you find a manual for the car? That is something you should be able to do. Its similar to adjusting the shifter in a manual shift car, but not identical. I think you put the shifter in park, then loosen the adjuster nut (or screw) where the shift rod attaches to the trans. Make sure the lever on the side of the trans is engaging park also, then tighten the adjuster nut (or screw). Also check to see that the transmission is properly in its cradle or mount and that its fasteners are tight. Good luck! If this doesnt help, repost the problem with the subject Adjust shifter in 19XX Model. Someone who knows trannys better than I do should help you.

everett marabian

  • Guest
Re: Parking brake releases only manually
« Reply #6 on: November 06, 2006, 06:13:08 AM »
Quote from: Klaus
Hi!
I am the owner of a 1975 Cadillac Eldorado now experiencing a problem with the parking brake release mechanism. When putting the car into reverse or drive, the parking brake won’t release by itself anymore. This happened after having the TH425 transmission rebuilt. Is there a way I can fix the brake so that it releases on its own again?  

Thanks
Klaus

Everett Marabian

  • Guest
Re: Parking brake releases only manually
« Reply #7 on: November 06, 2006, 06:22:17 AM »
Just try following the vacuum hose connection to a vacuum source and be certain the hose is in good shape and connected properly.  Sppay a little silicone on the brake release to be certain it moves freely.  Otherwise, whoever rebuilt your transmission may have accidently disconnected something.

 



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