I am looking for a replacement main spring for my ’37 GA, Knee Action -enclosed type- shock absorber - 5 wheel jobs.
According to the Parts Manual part number 374631 is compatible for the ’34 Passenger Sedan (DA), ’35, ’36, ’38 Master Deluxe (EA, FA, HA).
My shocks were recently rebuilt. All is well except I can not get the proper height adjustment between the brake flange plate and the kingpin. The adjustment is just slightly more than one (1) inch too low. My car’s front end looks more like a low rider. The ride is nice and smooth as advertised in 1937.
I am working with the vendor who rebuilt my shocks and they too are in search of the technical information for the main spring. I would like to help them along with this search. We are both lead to believe the main shock is very tired and has lost its springiness over the course of 80+ years.
Does anyone in the ”˜knee action’ world know of a vendor who has the correctly milled main spring? Or, is any information available for the specifics / technical info of the main spring.
While searching thru the forum I found this link which was quite helpful: https://vccachat.org/ubbthreads.php/ubb/showflat/Number/318967/Searchpage/1/Main/49922/Words/%2Bknee+%2Baction+%2Brebuild/Search/true/Re:_Knee_Action_Rebuild#Post318967
Does an alternative exist to get the proper height adjustment without the expense of a new main spring?
Is it allowed to ask via this forum if there are others who would be interested in replacing their main spring? The vendor I am working with has indicated they would sell the springs as a kit … thus avoiding the cost of them replacing the spring and shipping costs.
Thank you in advance for your help Jim VCCA 51601
-------------------------- If your woman can't find you handsome, maybe she can find you handy ....
The heigth is adjustable. It is done by trning in the plate on top of the knee-action unit. There is a tool made for this but I am sre that it can be don without it. Remove the bolt and plate on top and use the then exposed slots to increase tension.
Gene, thank you for the reply .... I made my own tool to adjust the top plate and the main cap and made the adjustment according to the shop manual. The problem does appear to be a tired main spring.
Jim, here are a couple pictures of spacers that were used years ago to compensate for weak springs. The dimensions are 3-7/16 inch outside diameter, 2-5/16 inch inside diameter and 5/16 inch thick. I think it would be pretty easy to make some. Do you know anyone with a plasma cutter? Apple Hydraulics in Calverton, New York may have some and may be able to give you some advice. http://www.applehydraulics.com/
hello Bill .... Thank you for the info on the spacers. If I am unable to find a replacement enclosed type spring for a reasonable cost I may elect to go with the spacer. According to the shop manual the adjusting plug must not be more than 1/8 in above or below the adjusting cover ... which gives me a 1/4" swag. I am guessing that if my springs are in need of a 1 (one) inch lift, then I would need a spacer to equal about 3/4 in to 1 inch, correct? regards ...
I think you are on the right track with the spacers.
I think the spacer thickness needs to be quite a bit less that the height you want to raise the car.
In general terms the spring is about 1/2 the distance from the pivot point to the wheel. So a 1/2” spacer is going to raise the car 1”.
I suggest you do make some measurements to better estimate the distances and the ratio. The closer the spring is to the pivot on the frame the more lift a spacer will give to the car overall.
My guess is that is why the spacers that Bill has are 5/16”. Based on the lever arm ratios they could raise the car quite a bit.
You are welcome, Jim. I know it would require quite a bit of work, but if you want to obtain the correct height, you may have to experiment with different thicknesses of spacers and follow Rusty's advice.
If you are suspecting 1 side is lower than the other I would lift the rear wheels clear of the ground at a central point allowing the front to settle on its own merits. Tony
I am in the process of prepping my '37 MD for a tour, The manual calls for a knee measurement of 4 7/8" height. The Right side is on the mark, but the Left side is 4 3/4" . How critical is the 1/8" ?? The manual does not get into specifics, adjust with weight on the spindle, no weight on spindle (this one seems to be the logical approach ) , Back it off making the spring longer, screw it in adding tension ?? Currently I can not move the adjuster either way with or without weight on the spindle. I have a home made tool, but as I said, the adjuster won't budge. I am contemplating an air hammer to see if I can shock it .... Any suggestions ??
Dave old cars are meant to be driven !! VCCA # 047832
Having come across this particular forum, I thought it would be worth while to check.
Well I will agree with you both, but I have never actually checked this measurement in all the years I have had the car. I believe the Knees were rebuilt a couple of owners ago as I did pull off the cross shaft cap and saw a bushing instead of roller bearings when I received the car.
As for the tour, I was checking everything that needed to be lubed and decided while I had the front hubs off, to pack the bearings, I would check that measurement.
Thank you for your insight, see you on the road.
Dave old cars are meant to be driven !! VCCA # 047832
I had a set of spacers made to help with the correct measurement for the proper height adjustment between the brake flange plate and the kingpin. Earlier in my project I coated the top cap with a 'shellac type' sealant to help reduce the fluid leakage. That stuff must really work 'cause it made removing the top cap very difficult. (The word very should be in all caps.) #1 question: what would be a recommended thread sealant that will do the trick but not act like super glue as the shellac sealant did.
Question #2. One of the adjusting cap's bottom set of threads was rather corroded. (I have no idea how it got that way.) I have been able to clean up the threads some so it may still be ok. The top threads are in very good condition. Other than screwing in the adjusting cap do the bottom threads matter that much? Does anyone have a good source for a replacement adjusting cap ... if one can be found?
Update on the Knee Action adjustment .... I had a set of 5/16" spacers made as suggested by Bill Masters plus a set a of thinner spacers. The 5/16" thick spacers did the trick .... I now have the correct adjustment according to the shop manual. My '37 MD rides as tho it is on a cloud. Also, when installing the adjusting cap (one was slightly corroded on the bottom few threads) I installed the cap from the bottom side up and then installed the top cap ... all is well and I am happy with the results. Thanks to all for the help and suggestions. rgds Jim
