Seat post assembly

[MassHarley]

Does anyone have a drawing that shows the proper assembly of a JD seat post. I have what seems like way too many pieces and am confused what I actually need and what is just spares.

Also does anyone know a good source for seat post springs? I ordered the kit from comp dist. But the springs all seem to be too small in diameter?

[Steve Swan]

my seat post is assembled in my 27 frame. unfortunately i cannot be of help now with a pictorial showing correct sequence of assembly. this winter i will hopefully be disassembling my bike for final restoration stage, so if you still need pics then, i can disassemble my post and show order of assembly.

anyone can correct me, but the Comp.D springs not correct for 25-28 (as is their seat post assembly, which i initially purchased and was waaay too short and would not anywhere begin to reach to bottom of frame tube) are for the earlier pre-25 models, even though if i recall correctly they advertise them to fit up through 1927. there is a total of 3 springs in my 27 seat post, one long one below and 2 short ones above.

referring to the 22-26, 22-27 and 27-31 parts books and my memory, the part with the raised "slot" on (part of) your seat post rod pn 3137-25, if i recall correctly, it is threaded and can set the preload tension for both the lower 3127-25 spring and the middle or bottom lower 3133-25 spring as well as the uppermost 3135-25 spring.

there are 3 types of lower springs

1 - 3127-25 seat post long spring, standard (14")
or
1 - 3128-25 seat post long spring, heavy (14")
or
1- 3129-25 seat post long spring, light (14")

upper springs

1 - 3133-25 seat post recoil spring (2-3/4") if i recall correctly, this is the lower spring, fits inside 3115-25 seat plunger/link.
1 - 3135-25 seat post bumper spring (no length given) i believe this is the uppermost spring

again, anyone can correct me, but if my memory serves me, your seat post rod and attached parts looks correct.

your loose parts, bottom left (above seat post rod) with special shouldered hex nut pn 3144-25 next to it look familiar to what i remember mine looking like. i believe there should be a lock washer that goes atop that nut.

the 4 parts to the right of the nut, i do not recall looking familiar.

the very far right threaded round "plunger lock nut" pn 3141-25 threads into bottom your seat plunger and link (pn 3115-25.)

it appears you have everything you need except the 2 short upper springs (3133-25/3135-25) and the 1 long lower spring (as per noted above, light, standard or heavy.)

if i recall correctly, the order of assembly is:

1. install 3135-25 into 3115-25
2. install 3137-25 against 3135-25 which you placed inside 3115-25
3. install 3133-25 on to 3137-25
4. screw 3145-25 in to 3115-25
5. your long lower spring can go inside frame seat post tube
6. then slip your entire seat plunger assembly into frame tube.
7. your seat post rod 3137-25 should protrude out the bottom of frame tube so you can install the lock washer and rod lock nut 3144-25. you have a certain length of threads at bottom of rod, so you can set the preload tension on bottom spring with nut 3144-25.

if my math is correct, for a complete seat post assembly, including a lock washer, the are 8 separate parts.

again, this is from my memory, disassembling and reassembling my seat post while now looking at my 22-26, 22-27, and 27-31 parts books, but i believe my memory is approximately 99.9% accurate and anyone can correct me please if i am wrong.

hope this is helpful. that seat post set up on the JD's is really a nice firm but cushy setup.

ps - i do not see the parts book calling for a lock washer to go between 3144-25 and the bottom of the frame tube. i removed my seat post assembly from a 1928 frame, which the the 1927 - 1931 parts book show same parts for 1925 -1928 models (it had lock washer on it and because it fitted the shoulder of 3144-25, i retained it.) maybe Mark Masa or Jon Neuman can suggest where to get springs or try a spring supply company. i guess you would need to know diameters of actual spring wire as well as diameter of the spring it's self and number of winds.....

[23JDCA 808]

Does anyone have a drawing that shows the proper assembly of a JD seat post. I have what seems like way too many pieces and am confused what I actually need and what is just spares.

Also does anyone know a good source for seat post springs? I ordered the kit from comp dist. But the springs all seem to be too small in diameter?

What year are you working on?

[MassHarley]

Steve, thank you very much that was helpful! I have been looking and if I can narrow down the wire size McMaster Carr sells a large assortment of springs. I should be able to make something work with what they sell.

Bill, I am working on a 1926.