Car in reverse rolls backwards when parked on 11 degree slope driveway

Zak99b5

Veteran Member
Joined
Apr 30, 2021
Location
Albany NY
TDI
2003 Jetta TDI
You guys are funny. My camper is sitting in my sloped driveway right now, hitched to the back of my [stick shift] F150, wheels pointed straight ahead, and the whole mess is being held firmly and reliably in place with the parking brake. It won't roll. At all. I could reach in and move the gearshifter around right now, there is zero weight being placed on the transmission.

If your parking brake doesn't work, it is broken, and needs to be fixed. It isn't that big of a deal. I understand areas that get more road salt than we do will present more frequent need for servicing of ALL your brakes, but that doesn't mean you cannot drive a car.
I might be funny, but I replaced the parking brake shoes and adjusted them in the Suburban two years ago. They worked okay (but not like they ought to) for a few months, and now don’t hold it at all. Since they were only set with the car stationary, and I’ve not driven with them on, there should be zero wear to the linings and drums.

Maybe it’s just a bad design by GM. For some reason, they designed the pedal to require little effort to set the brake. Not sure if that has to do with the multitude of GM full-size trucks with non-functioning parking brakes.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Just google "GMT900 parking brake repair kit". Several companies make them, I know Dorman is one, but there are others. It is the whole backing plate assembly with the shoes already on it.

I thankfully do not work on these trucks myself, but other guys in the shop do. They also do a lot of brake like replacements, as GM used some really poor quality stuff for those, too.
 

Zak99b5

Veteran Member
Joined
Apr 30, 2021
Location
Albany NY
TDI
2003 Jetta TDI
Just google "GMT900 parking brake repair kit". Several companies make them, I know Dorman is one, but there are others. It is the whole backing plate assembly with the shoes already on it.

I thankfully do not work on these trucks myself, but other guys in the shop do. They also do a lot of brake like replacements, as GM used some really poor quality stuff for those, too.
Thanks.
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Yes, compression is what keeps the vehicle stationary...if you are in gear on a hill. Which is why reverse is normally the best choice (highest gear ratio).

Curb the wheels, parking brake on, put it in reverse.
You must be joking. Go put a wrench on the crank and turn it until you feel compression fighting you. Let it sit a few seconds and try again. You'll feel that there's less resistance. Or just hold torque on it. Note how the motor turns. Air leaks past the rings. Even if the ring/cylinder seal were to be perfect there's always leakage at the end gap.
 

Zak99b5

Veteran Member
Joined
Apr 30, 2021
Location
Albany NY
TDI
2003 Jetta TDI
True, but I wonder what the effective lever is.

Try turning the crank over with a stubby 1/4” drive ratchet instead of a 1/2” drive breaker bar.
 

KrashDH

Top Post Dawg
Joined
Dec 22, 2013
Location
Washington
TDI
2002 Golf
You must be joking. Go put a wrench on the crank and turn it until you feel compression fighting you. Let it sit a few seconds and try again. You'll feel that there's less resistance. Or just hold torque on it. Note how the motor turns. Air leaks past the rings. Even if the ring/cylinder seal were to be perfect there's always leakage at the end gap.
Technically, there is a list of things that are in play aiding in the vehicle being stationary on a hill. Compression is most certainly one of them. I didn't mean it to come out as "it's the one and only thing doing work".
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Good point Burn.


True, but I wonder what the effective lever is.

Try turning the crank over with a stubby 1/4” drive ratchet instead of a 1/2” drive breaker bar.
You couldn't turn the motor with the plugs out with with a short wrench.
 

PakProtector

Veteran Member
Joined
Jan 5, 2014
Location
AnnArbor, MI
TDI
Mk.4's and the Cummins
To echo BobinOH, 11 degrees is a 20% grade. This is in no way a trivial slope in any way shape or form. Grade% = tangent(angle)*100. Tangent 11 is .1934...

I don't think the TB likes to be rolled backwards, so which ever way you are planning this calamity, the diff between first and reverse ratios is rather small.
cheers,
Douglas
 
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