The hill holder is a feature that's now pretty much unique to Foresters, and as such it's been the source of some confusion to those encountering it for the first time. Here's my attempt to put together the relevant facts about it. This discussion applies to the totally mechanical hill holder in the 2003-2008 (SG model) Foresters. The SH model Forester, which started in 2009, brought with it a new electronically controlled hill holder, with all the attendant fun of a computer that knows your job better than you do!
Mission Statement: The purpose of the hill holder is to keep the manual transmission Forester which is stopped facing uphill from rolling backwards during that time when the driver’s right foot moves from the brake pedal to the gas pedal while still holding the clutch pedal down with the left foot. The three necessary and sufficient conditions:
uphill,
clutch down, and
not moving forward.
History: Studebaker introduced the hill holder in 1936. See
en.wikipedia.org/wiki/Hill-Holder
Technical Description: When the clutch is depressed while the Forester is facing 3 degrees or more uphill and not moving forward, the hill holder actuates a one-way valve that retains the existing pressure (if any) in one of the two diagonal circuits of the brake system, allows increased pressure to be added, but prevents pressure from escaping until the clutch is released.
Operational characteristics:
- The hill holder has no connection whatever to the transmission, so it functions in all gears, including neutral and reverse. As a result, the hill holder can kick in while backing down a driveway, as all three of the conditions may be satisfied in this situation. It takes a bit of experience to get comfortable with this - light application of brakes, coasting in neutral with the clutch up, etc.
- Since the hill holder only
retains brake system pressure and doesn’t
add any pressure by itself, the Forester might begin to roll backwards if it had been stopped with just gentle brake pressure on a steep hill. The solution is simply to add more pressure to the system by pressing the brake pedal again, a bit harder.
- It would be nice if the hill holder could provide a similar capability when one wanted to back up while facing downhill, but this fails to satisfy the
uphill condition and will not work. The reason for this is that the gravity/inertia-based mechanism in the hill holder can't distinguish between a downhill orientation and a normal braking condition while traveling forward, and one would not want the hill holder to engage in the latter situation.
Maintenance:
- There's only one adjustment available, and it deals with the linkage between the clutch and the hill holder. When releasing the clutch, there should be just a brief interval between release of the brake and engagement of the transmission. If there's an overlap or too great an underlap, see Peaty's post at
www.scoobymods.com/forums/showthread.php?t=2746 (his pix are posted below) for directions regarding this adjustment. Note, that if you really hate the hill holder you can "adjust" it as to effectively disable it completely. Our Peaty got himself written up in the
New York Times for his discovery of this. You can also disable it by removing the cable that connects the clutch to the hill holder mechanism, and then aligning the arm parallel to the body of the hill holder and anchoring it there with a zip tie. One member actually removed the mechanism itself and replaced it with a custom-made fitting that spliced the two ends of the brake line together.
- The hill holder relies on a simple gravity/inertia-based mechanism to determine whether or not it should function. Not that many of us carry inclinometers with us, but if it fails to function when the Forester is at an angle greater than 3 degrees (about 1 foot in 20,
i.e. slightly uphill), or functions at angles less than that, its mounting must have gotten bent or something such as spring sag or suspension mods altered the Forester's orientation. There's no simple adjustment specified for this. If somebody comes across one, please let us know so we can update this.