The Ford Barn

drolston · 11-13-2017, 03:44 PM

Given that a Houdaille shock is not showing leaks or making noise, what is the test for a correctly functioning shock. After jumping on the bumper of my '41, the bounce damps with just one overshoot, which seems okay. Is there a more scientific test?

ford38v8 · 11-13-2017, 04:31 PM

That result may be a false positive for one reason or another, but you're on the right track.
The best way I know is with two matching L&R units in a large bench vise, push and pull both arms at once, comparing one to the other. You want a consistent resistance in both directions for the full travel, no free travel spots, and both units adjusted to each other.

As it's a pain to remove the whole assembly for a bench test, if only the mounting bolts are removed, you can test the function by twisting the unit against the arms one way then the other.

When filling, do this while in a mounted position, as the plugs will not allow overfilling, providing for a dead air space to compensate for heat expansion. Be sure to use the same type fluid as is in it presently.

Lawrie · 11-13-2017, 05:04 PM

If you get the info on the shocks (houdialle) they show a spring balance to set the force with.
Lawrie

Fe26 · 11-14-2017, 04:33 AM

From memory the Spring balance scale should read 7 pounds.

Kurt in NJ · 11-14-2017, 08:26 AM

In the model A service bulletins testing was a weight on a lever, about a 2 foot lever, and 30-40- lb weight, with times to complete 20 degrees of movement, like 30 seconds warm, and near 1 min cold, the compression (pushing lever up) should be much easier than rebound
If just moving the lever by hand it should move up with resistance, and it should move fast enough that you feel like you are getting somewhere, when pulling down it should feel almost locked, and it should take a while pulling with all you can
I have a couple of NOS shocks to compare to, it's hard to get a worn one to be as "tight", if the shock lever feels "bouncy" it could have trapped air, moving the lever to each stop by hand will purge air in a properly working shock---you can actually feel it at the end of the travel as the bubbles are forced through passages

fordor41 · 11-14-2017, 11:26 PM

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Quote:

Originally Posted by ford38v8

That result may be a false positive for one reason or another, but you're on the right track.
The best way I know is with two matching L&R units in a large bench vise, push and pull both arms at once, comparing one to the other. You want a consistent resistance in both directions for the full travel, no free travel spots, and both units adjusted to each other.

As it's a pain to remove the whole assembly for a bench test, if only the mounting bolts are removed, you can test the function by twisting the unit against the arms one way then the other.

When filling, do this while in a mounted position, as the plugs will not allow overfilling, providing for a dead air space to compensate for heat expansion. Be sure to use the same type fluid as is in it presently.

that's exactly the way I set my front shocks up.

drolston · 11-15-2017, 06:05 PM

Thanks for the input.

Next time the wheels are off I will see if I can come up with an easier way to test resistance.

rotorwrench · 11-15-2017, 06:57 PM

Weight on a lever is the most common form on Houdailles but the time it takes to cycle through the strokes is also included in the average procedure. The specs may be in a service bulletin but I don't know for sure if they are or not. The 1946 Service Manual only covers minor adjustments. The main thing would be that both are near the same in adjustment. Resistance needs to be felt in both directions and hopefully the resistance is about the same both ways. A spring scale could be used to pull them through their cycles.

11-13-2017, 03:44 PM	#1
drolston Senior Member Join Date: Jun 2014 Location: Williamsburg, VA Posts: 1,627	Shock Absorber Test Given that a Houdaille shock is not showing leaks or making noise, what is the test for a correctly functioning shock. After jumping on the bumper of my '41, the bounce damps with just one overshoot, which seems okay. Is there a more scientific test?

11-13-2017, 04:31 PM	#2
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 6,645	Re: Shock Absorber Test That result may be a false positive for one reason or another, but you're on the right track. The best way I know is with two matching L&R units in a large bench vise, push and pull both arms at once, comparing one to the other. You want a consistent resistance in both directions for the full travel, no free travel spots, and both units adjusted to each other. As it's a pain to remove the whole assembly for a bench test, if only the mounting bolts are removed, you can test the function by twisting the unit against the arms one way then the other. When filling, do this while in a mounted position, as the plugs will not allow overfilling, providing for a dead air space to compensate for heat expansion. Be sure to use the same type fluid as is in it presently. __________________ Alan

11-13-2017, 05:04 PM	#3
Lawrie Senior Member Join Date: May 2010 Location: Qld, Australia Posts: 4,215	Re: Shock Absorber Test If you get the info on the shocks (houdialle) they show a spring balance to set the force with. Lawrie

11-14-2017, 04:33 AM	#4
Fe26 Senior Member Join Date: May 2010 Location: Sydney, Australia Posts: 949	Re: Shock Absorber Test From memory the Spring balance scale should read 7 pounds.

11-14-2017, 08:26 AM	#5
Kurt in NJ Senior Member Join Date: May 2010 Location: on the Littlefield Posts: 6,159	Re: Shock Absorber Test In the model A service bulletins testing was a weight on a lever, about a 2 foot lever, and 30-40- lb weight, with times to complete 20 degrees of movement, like 30 seconds warm, and near 1 min cold, the compression (pushing lever up) should be much easier than rebound If just moving the lever by hand it should move up with resistance, and it should move fast enough that you feel like you are getting somewhere, when pulling down it should feel almost locked, and it should take a while pulling with all you can I have a couple of NOS shocks to compare to, it's hard to get a worn one to be as "tight", if the shock lever feels "bouncy" it could have trapped air, moving the lever to each stop by hand will purge air in a properly working shock---you can actually feel it at the end of the travel as the bubbles are forced through passages

11-15-2017, 06:05 PM	#7
drolston Senior Member Join Date: Jun 2014 Location: Williamsburg, VA Posts: 1,627	Re: Shock Absorber Test Thanks for the input. Next time the wheels are off I will see if I can come up with an easier way to test resistance.

11-15-2017, 06:57 PM	#8
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,431	Re: Shock Absorber Test Weight on a lever is the most common form on Houdailles but the time it takes to cycle through the strokes is also included in the average procedure. The specs may be in a service bulletin but I don't know for sure if they are or not. The 1946 Service Manual only covers minor adjustments. The main thing would be that both are near the same in adjustment. Resistance needs to be felt in both directions and hopefully the resistance is about the same both ways. A spring scale could be used to pull them through their cycles.