Notices
928 Forum 1978-1995
Sponsored by:
Sponsored by: 928 Specialists

Transmission won't hold car on a slight hill, why not?

Thread Tools
 
Search this Thread
 
Old 11-07-2010, 12:35 PM
  #1  
Brett Jenkins
Drifting
Thread Starter
 
Brett Jenkins's Avatar
 
Join Date: Apr 2002
Location: Hermitage, TN
Posts: 2,054
Received 27 Likes on 16 Posts
Default Transmission won't hold car on a slight hill, why not?

Yesterday, I parked in front of a house. I left the car in 1st gear. The E-brake is worn and useless. The road is slightly inclined there. A bit later, someone said, "Hey, why did you block the driveway?"

I looked out the front door and my car had rolled back 10-15 feet and stopped. I'm glad it stopped there, another 10 feet and there is a long steep hill with lots of parked cars, mailboxes and trees.

I had noticed in the last week that a few times when I parked the car, and turned it off, the car rolled back a slight bit when i let the clutch out. This was new and I thought it odd. It hasn't done this forward, only backward.

So, what's the prognosis?
Old 11-07-2010, 12:44 PM
  #2  
Speedtoys
Rennlist Member
 
Speedtoys's Avatar
 
Join Date: Sep 2010
Location: Boulder Creek, CA
Posts: 13,582
Received 1,034 Likes on 623 Posts
Default

Originally Posted by Brett Jenkins
Yesterday, I parked in front of a house. I left the car in 1st gear. The E-brake is worn and useless. The road is slightly inclined there. A bit later, someone said, "Hey, why did you block the driveway?"

I looked out the front door and my car had rolled back 10-15 feet and stopped. I'm glad it stopped there, another 10 feet and there is a long steep hill with lots of parked cars, mailboxes and trees.

I had noticed in the last week that a few times when I parked the car, and turned it off, the car rolled back a slight bit when i let the clutch out. This was new and I thought it odd. It hasn't done this forward, only backward.

So, what's the prognosis?
In gear..the only thing holding the car there is gear friction, and engine compression...so...Id fix up that Ebrake.
Old 11-07-2010, 12:48 PM
  #3  
mickster
Race Car
 
mickster's Avatar
 
Join Date: Jan 2010
Location: Greensboro, NC
Posts: 3,721
Likes: 0
Received 5 Likes on 3 Posts
Default

Yup--fix the eBrake-that's part of its job.

Also, until then, but a set of $10 wheel chocks and chock the back tires.
Old 11-07-2010, 12:57 PM
  #4  
Mark SF
Instructor
 
Mark SF's Avatar
 
Join Date: Sep 2010
Location: San Francisco Bay Area, Santa Clara
Posts: 187
Likes: 0
Received 1 Like on 1 Post
Default

All that was required to fix my parking brake was to tighten the cable by the lever. Works great now.
Old 11-07-2010, 02:11 PM
  #5  
supercedar
Rennlist Member
 
supercedar's Avatar
 
Join Date: Jul 2010
Location: Mukilteo, Wa.
Posts: 990
Received 22 Likes on 10 Posts
Default

Would a weak pressure plate cause this, or clutch? A car parked on incline in first gear should not roll back. Maybe even poor engine compression.
Thomas
Old 11-07-2010, 02:15 PM
  #6  
m750rider
Instructor
 
m750rider's Avatar
 
Join Date: Nov 2009
Location: Western NC 1991 S4
Posts: 134
Likes: 0
Received 1 Like on 1 Post
Default

Low engine compression will cause this. Instead of 1st gear, put it in reverse, it's lower gear ratio, at least until you get your e brake fixed.
Old 11-07-2010, 03:43 PM
  #7  
Speedtoys
Rennlist Member
 
Speedtoys's Avatar
 
Join Date: Sep 2010
Location: Boulder Creek, CA
Posts: 13,582
Received 1,034 Likes on 623 Posts
Default

Originally Posted by m750rider
Low engine compression will cause this. Instead of 1st gear, put it in reverse, it's lower gear ratio, at least until you get your e brake fixed.

Flashback to drivers ed...turn the wheels into the curb.


IMHO..I never park my cars with stress on the drivetrain. Ebrake to hold, gear as a backup of sorts..but I hit the clutch to make sure the drivetrain is slack after setting the ebrake.
Old 11-07-2010, 03:46 PM
  #8  
Mrmerlin
Team Owner
 
Mrmerlin's Avatar
 
Join Date: May 2004
Location: Philly PA
Posts: 27,899
Received 2,254 Likes on 1,247 Posts
Default

First fix the E brake or dont drive the car, this system not working could possibly case great damge to person or property..

Note, first gear up a hill will turn the engine backwards NOT GOOD,

as previously suggested put it in reverse, and turn the wheels so that the rear edge of the front wheels are curbed

To adjust the E brake after you install new shoes adjust the stars till the rotor wont turn then set the brake, then release it ,

then back off 3 clicks of the star,
do both sides setting the brake while its adjusted tight will set the cable and the shoes to proper location.

After you have both sides done then the handle should give 3 clicks till the brakes are set if not then adjust the handle by removing the housing and then the cable is at the rear of the handle
Old 11-12-2010, 12:05 PM
  #9  
Brett Jenkins
Drifting
Thread Starter
 
Brett Jenkins's Avatar
 
Join Date: Apr 2002
Location: Hermitage, TN
Posts: 2,054
Received 27 Likes on 16 Posts
Default

I'll check the E-brake this weekend and adjust or replace if needed.

Another think I just noticed is that the car lurches when I let off the gas and then give it gas again, like the clutch is disengaging a bit. The entire clutch has maybe 20k miles on it and the master and slave are new, as well as the pivot cup and pilot bearing. The soft line has been replaced in the last couple years too. Might be unrelated. Any thoughts?
Old 11-12-2010, 12:27 PM
  #10  
Mrmerlin
Team Owner
 
Mrmerlin's Avatar
 
Join Date: May 2004
Location: Philly PA
Posts: 27,899
Received 2,254 Likes on 1,247 Posts
Default

might have a TPS switch thats going bad

Note 928INTL is holding half priced sale on used parts try them for a good set of E brake shoes

Last edited by Mrmerlin; 11-12-2010 at 02:15 PM.



Quick Reply: Transmission won't hold car on a slight hill, why not?



All times are GMT -3. The time now is 08:26 AM.