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Hartford, disc type shocks - adjustment

Stutz in the UK

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Hi There, Does anyone have any instructions or ideas on adjusting Hartford type shocks

These are the type with the round friction discs held between two metal plates and then with two arms to connect them between the axel and the chassis

I have a set of these attached to an old car (1917 Stutz) and I would like to set them up properly

I have taken them apart and greased them up (they were fairly dry), to adjust them its a matter of tighting up the center nut, but how much?


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For a start, putting grease on them is the worst thing to do. They are meant to be absolutely dry so they create the most friction possible between the discs and the arms.

Below is a copy from Paul Becks web site in England. He sells these shock absorbers and spare parts and if you have a look at his catalog you will be able to judge the size of yours to get the correct torque setting for the adjustment bolt.

Andre Hartford Shock Absorber Category Help

these proven shock absorbers are made up to customer's requirements, with either equal length or odd length arms. please measure from the centre of the shock absorber to the centre of the mounting bolt to the nearest 0.5" (12.7mm). supplied fitted with silentbloc bushes in arms. we keep some pairs of equal length units in stock which are available for immediate delivery, otherwise please allow four weeks for despatch. the makers surcharge unequal arm units and some specials.

as a guide the centre axis of the arm action is normally horizontal, thus on equal lengths arm units the mounting bolts are vertically above each other. the normal 'at rest' angle between the arms in this format is approximately 70 degrees.

setting the torque on the friction centre nut/bolt is more by trial and error. however we are able to suggest initial torque settings of:

502S - 16 to 19lbs for vehicle weight 600kg to 1000kg,

506S - 23lbs for vehicle weight over 1000kg,

502M - 16 to 19 lbs for vehicle weight 1250kg to 1500kg,

506M - 23lbs for vehicle weight 2000kg.

set the pair of units to the same torque, then take the vehicle for a run and make adjustments (the same to both units) to either tighten or slacken the unit to suit the ride required.

Telecontrol units operate in the came way but have pressure bags which enable adjustments to ride to be made from the vehicle cockpit. the fluid used is a mixture of 30% glycerine and 70% water.

Vintage Car Parts

Edited by DavidAU (see edit history)
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  • 8 years later...

It's absolute nonsense to say (as DavidAU does) that "putting grease on them (the wooden discs of Andre Hartford Shock Absorbers) is the worst thing to do".
Actually it is VITAL that you do it - if they are wood and not oiled they will deteriorate very soon after a few drives as the excess friction prevents a smooth operation and quickly wears them thin or even destroys them.
Therefore soaking them overnight in thick SAE 140 oil is required.
However, if you buy new wooden ones they will already be pre-oiled while the modern, fibre discs do not need oiling.
As for adjusting them; the easiest way is to place one arm on an old fashioned (non-digital) bathroom scales and push the other arm down in a smooth movement and read how much the pressure is. 
Adjust to the required figure with the nut. My 1500 + kg Lagonda requires roughly 30 Lbs at the front shocks and 20 Lbs at the rear.


Edited by Harry Oakley (see edit history)
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