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Parked car rolling on a hill

when i park my car in my driveway wich is on a hill it will roll back slowly. ive always parked in 1st or reverse and never used parking break till now. fitst thing that went to mind was clutch or pressure plate. then was thinking about it and thinking i mght be losing engine compression. that could also cause it to roll back. it dont roll so much as jerk back slowly. what do you guys think id hate to replace on and find out its the other. or is this a normal thing i havent lived at this house long and normaly park at top where its flat. id say the slope is 10 to 15 degree. what do you think love the show.

First, I think you should get into the habit of using the parking brake no matter what - redundancies are good in this case.

Second, I would just check the compression, and if it is good test the clutch to find out if its slipping. A stall test will do.

yeah i know i should be using it, its a bad habit that i need to try to break. i do plan on doing a compression test, i was wandering if that made any sense that i was thinking it could be a compression issue, and i have no idea what a stall test is

My wife’s jeep has done this from new. It’s the overlap in the cam that allows them no EGR valve. I had it slowly back down a grade at the dealer while I was getting parts. It smashed into a new car sitting there. Smashed isn’t quite the word. It just marked the bumper …but it was enough to warrant a replacement. It just slowly chugged away …

You need to use your parking brake.


I had a new 83 Mustang GT that did the same and it had a V8. Just need to get into the habit of using the parking brake.

Ed B.

Doth thou hath a curb beside thy parking space? If thou doth, turn thy wheel toward the curb when thou parketh. Thus, when thine carriage rolleth, 'twill rolleth into the curb, so saith Drivers Learner’s Handbook.

i understand that its a good idea to set the parking break. i think it would be stupid to cur the wheels to a curb hellokit. when i can just pull up on the parking break, but nevermind my bad habits. what im looking for is if this is a normal thing or is there something wrong somewhere. my truck is normaly the vehicle parked on the slope my car was the first time there. and it was the one rolling back. my truck i dont think has had the break sat since i bought it new unless im warming it up in the morning while im in the house. and has never moved an inch

Use the parking brake. A 4 cylinder engine does not have enough compression to hold back a vehicle even when new.

You say, “I think it would be stupid to cur the wheels to a curb hellokit. when i can just pull up on the parking break, but nevermind my bad habits”.

Man! I am so sorry! I misunderstood your question. I should have read your statements more closely. I thought you wanted to know how to keep the car from rolling on an incline; but, no, you want to know WHY THE CAR ROLLS ON AN INCLINE, (manual transmission) when parked in 1st, or Reverse, and without the parking brake set, or the wheels turned to the curb. Good question!

Telling us you love the show is like preaching to the choir—the people answering your question have nothing to do with the show except perhaps listening to it once in a while.

Why is your car rolling backward? The smart-ass answer is: Gravity. Either your engine doesn’t offer enough resistance from compression, or your clutch is slipping. Either way, you should really use your parking brake. What if it pops out of gear some day with a child behind it? Or it could roll into the street and get T-boned by a very surprised driver.

A “stall test” is a method of testing the clutch by restraining the vehicle (vis the brakes, a tree, a wall, whatever) and seeing of the clutch when engaged will stall the engine. I prefer to put the “oedal to the metal” on the highway in high gear. If the clutch is failing, it’ll slip then.

This is not a normal thing with a modern car with good compression. I phase it that way because I’m ont sure my '61 Beetle would have held its ground with only the engine compression. But even with a new vehicle I’d strngly recommend using the parking brake on a hill. You cannot be too safe, only too lax, and lives may be at stake here.

Until you get a chance to check the compression and the clutch, let me suggest that in addition to using the parking brake you also chock the rear wheels (or the front wheels if you back in). You can run a rope from the chocks to the windshield or something so that you don’t forget they’re there in the morning.

You said you have never used the park brake 'till now. Does it still roll back with the brake on? The compression could be fine, an engine can slowely lose the compression on one cylinder and roll to the next one in line. When that compression leaks off, it will move again ETC. Next time buy an automatic, set the brake, put it in park, turn off the engine, get out and lock the door/s. That should solve the problem.