I recently read about a "Hill Holder" or "Drop Sprag" accessory that mounted under the floorboards. This particular one was on a 1909 Overland. You dropped it down to prevent backward drift while stopped on a hill. Has anyone ever seen one of these?
Hi Phil,
I, too, have read about them and seen period pictures. I am reasonably certain that they were an aftermarket accessory and not supplied by any vehicle manufacturer. I have never seen one on any car at any show. Bill
Are you considering adding one to your Metz? ;-)
was there a pic???. i nave 09 overland cars. charley
was there a pic??? i 09 overland cars. charley
The "Sprag" was probably dismissed early on as being archaic. Not much is mentioned in later literature. I believe these are some designed to keep the car from going backward:
That looks a bit primitive. Studebaker had hill-holders in the drive train. As long as the clutch was in, the car would not roll back. I learned to drive on a '54. The hill-holder made all the difference. Other manufacturers had clutch-brakes. The clutch disengaged with the pedal partway down. All the way down engaged a brake on the drive shaft.
I'm surprised that most modern manual transmission cars have nothing to assist the driver like they used to.
Early Pierce Arrows had a sprag. I believe it was standard equipment.
The hill holder on 1940s Studebaker cars was a valve in the hydraulic braking system that held the pressure in the system until released. I think it was interconnected with the clutch pedal. But do not know for sure because I never saw one installed. I did at some time have a new old stock hill holder valve in my junk. My dad told me what it was.
I read about it in a 1968 issue of The Bulb Horn. No photos. It seems like it would be a useful accessory so long as you don't put the car in reverse with the it engaged.
Phil
Yes, that looks like it, Richard. Maybe I'll see a set one day.
Phil
Here is a link to an interesting article on these brakes:
http://www.american-automobiles.com/Articles/1909-Drop-Brakes.html
If anyone knows of a set, let me know!
Phil
what was the connection to the 09 overland ??charley
The article (Bulb Horn, May/June 1968), written by Dr. James Lyon, describes the restoration of his 1909 Model 31 Overland touring car. The car had this accessory, which Dr. Lyon preserved.
Phil
The Graf &Stift in which Archduke Ferdinand and his wife Sofie were riding when they were assassinated had a hill holder brake such as this. Thus began WWI.
In the book From Here to Obscurity at the back it shows a Model S that was being restored and it mentions it had an accessory sprag. Last paragraph on pg 286. I don't know why the hill holder idea didn't catch on. I don't have any vehicle with an automatic transmission and that hill holder would come in handy.
The Studie hill holder was a ball in a cage that would hold brake fluid pressure until the clutch was re- engaged I think they started this in the mid to late '30s. Worked on many of them.
When they started using automatics, the had a similar arrangement that used the fluid pressure until the throttle was moved.
The Stewart Warner automatic had a straight thru hi gear that didn't use the fluid drive portion of the tranny. And it could be push started.
The automatic came out in '53 along with the V-8.
Sincerely
Jim Weir
The automatics used this not only a hill holder, but an anti creep holder at stops.
Apologies for not proof reading!!
Sincerely
Jim Weir
Thank you Jim W for additional details!
The two early cars pictured (close ups) above look like they could be De Dion Bouton, however, there were many very similar cars built in those days. The Rochet and a Star (built in England?) are two that come to mind.
Sprag clutches, freewheels or holdbacks are still used extensively in automatic transmissions. They are generally used in first gear as they can cater for the extra torque generated to get the vehicle moving where a band or clutch may slip. The sprag is a solid mechanical lock. The sprags or cams can flip over or invert at about 2.5 their rated torque. once the transmission shifts into second gear the sprag commences to freewheel.
It will not hold the vehicle stationary on a incline even in first gear as the torque converter slips allowing it to roll in reverse.
Holdbacks are also used in my business to prevent the reverse direction rotation of ventilation fans and inclined conveyors.
My 2018 GMC pickup has it built into the 6 speed automatic transmission. Nice to have when pulling the RV.
It looks like it would work well on a gravel road but would slip on pavement. As roads improved there was more pavement so less use.