aa-fords.com

Does anyone know the factory dimensions for the AA front spring? Mine was very obviously sagged, with perches worn and lying flat on the axle and the wheels high up in the fenders. Also, there was virtually no movement in the front suspension. I was able to re-arch the main leaf to 30-5/8" centre of eye to eye. Each other leaf was re-arched to match its adjacent leaf. The result is a height off truck from top to bottom sitting on the floor of 9-1/2". Just wondering if this is close to where it should be.
My spring has 11 leaves, one of which is obviously not standard as it is 3/8" thick with square ends. The main leaf is 1/4" thick and has the Ford script. Each leaf is 1-3/4" wide and has a thickness of 1/4" with the exception of the top leaf which is 7/32".
I used my hydraulic pipe bender to gradually re-arch the springs at the centre and at 3" stations and carefully checking for symmetry before moving to the next leaf. It took a few hours, but the result looks good. The spring was very dry and lightly rusted, bit it is all cleaned up and painted now.
While the paint is drying I will make a spring spreader from redi-rod and steel pipe. When the paint is dry, I will coat each leaf with graphite and assemble it with new bushings and shackles.
I will report back when the spring is installed.
Alan in Roberts Creek

I meant to say shackles where it says perches.
Alan in Roberts Creek

The attached drawings are based on Ford engineering drawings for the AA-5310, stock, 12 leaf front spring. The leaves are slightly thinner at the centers. So, only the outside edges of the leaves would make contact. I have seen early 1928 rear spring leaves with embossed Ford script in random locations.

Thanks Neil, that is exactly the information that I need. I did not realize that the springs are slightly thinner in the centre. I will assemble the spring and re-check the measurements. I also read that it is good to grind a slight taper on the underside at the ends of each leaf so that they do not "dig in". There is some evidence of that sort of wear on the tops of some of the leafs, So I will make sure there is enough chamfer to alleviate that condition.
Alan in Roberts Creek

Moto Largo wrote: ↑

November 24th, 2017, 2:42 am

Thanks Neil, that is exactly the information that I need. I did not realize that the springs are slightly thinner in the centre. I will assemble the spring and re-check the measurements. I also read that it is good to grind a slight taper on the underside at the ends of each leaf so that they do not "dig in". There is some evidence of that sort of wear on the tops of some of the leafs, So I will make sure there is enough chamfer to alleviate that condition.
Alan in Roberts Creek

Yes, most original springs are worn (grooved) on the top side from the leave above. I have ground this ware area smooth - used a belt sander to finish/hide circular grind marks. And, I grind the bottom outer edges to prevent more ware.

Thanks for posting that chart. Very usefull

Would this crart also work for 30-31's ? I replaced some of mine with pasanger car rear leafs. Seams to work fine but now i can fine tune with help from your chart. My truck is a 29cab 1930 chassie.

Langan wrote: ↑

November 29th, 2017, 6:50 am

Would this crart also work for 30-31's ? I replaced some of mine with pasanger car rear leafs. Seams to work fine but now i can fine tune with help from your chart. My truck is a 29cab 1930 chassie.

Actually your cab would be an 82-A and that is a 1927 through June 1930 cab.

The 1930 -1931 front spring is completely different

AA-5310-C – A 13 leaf spring assembly with 2-1/4” wide leaves. Used January 1930 to the end of production for the AA131.

The overhauled spring with new shackles is now installed. My home made spring spreader worked well. The truck now sits right and has some decent suspension travel up front. It all looks good with fresh paint on axle, backing plates, drums, radius rod and wheels. Next job is to install the shock links, order a new splash apron and adjust the toe-in.
Alan in Roberts Creek