Technical Articles - National DeSoto Club Forum

Propshaft U/J,s

EricWalker — Mon, 20 Oct 2025 10:34:31 +0000

Does anyone have the dimensions of the U/J,s on the 1951 IL6. Trying to see if I can get a similar one here in the UK.

Steering box filler plug

EricWalker — Mon, 11 Aug 2025 07:04:38 +0000

Does anybody know the thread of the steering box filler plug on a 1951 coupe. I'm across in the UK and it doesn't seem to be a standard UK thread.

Eric.

1948 Custom Convertible Wiring harness

Michael Potter — Thu, 10 Jul 2025 01:29:40 +0000

The wiring on my 48' Custom is pretty frail. What is available out here to do a re-wire and keep the 6V? Also, should I consider a complete upgrade to 12V? Thanks!

1957-1959 KH Bellows Brake Booster Rebuild

DavidFrank — Mon, 14 Apr 2025 02:05:53 +0000

Since I just completed a rebuild of my Kelsey-Hayes bellows-style power brake booster for my '59 DeSoto, I figured I would document all my resources here to help others.

Rebuild kit: This can be ordered from several vendors and with or without the bellows. This was the cheapest kit I found with the bellows and they are a reputable company. SKU khbellowkit, https://www.powerbrakebooster.com/

Cad plating: The original plating is yellow cad(mium) #2. When you go to take the front and rear plates off, you'll see the original color where it was protected by the elements. I used The Chrome Shop in Menasha, who has done chrome work for me before. They had the plating done and back out the door in under a week. Note that there is a $200 minimum order charge, so you may want to throw in other parts if you have other stuff to be yellow plated. https://the-chrome-shop.com/services/

Disassembly and reassembly: Besides the factory shop manual, I used this video as a guide. However, since they only replaced one o-ring, they do not show that there are two "internal" seals - one inside the copper ball bushing and one at the bottom of the assembly when everything is apart (flip over the plate) inboard of the tin cap. You'll need to get a dental pick or equivalent to dig the seals out. https://youtu.be/FdLblLTVe3s?si=mmRNE8OYQqHDt_a_

Removal and installation from the car: I made this summary video to help make it clear what needs to be done. https://youtu.be/ndgD19VxWtU?si=xdHwuMD8D1faSwoE

1931 SA head torque specs

Rick Miller — Mon, 22 Aug 2022 19:03:11 +0000

I’m going to be replacing the ignition wires on my 1931 Standard Coupe. The wires are routed through a shield (or is it considered a loom). It appears that I may need to remove the shield to change the wires. That will require the removal of 2 head stud nuts. I’ll need to torque those when I reinstall the shield. I haven’t been able to find the head torque specs for this 6 cyl engine. Does anyone happen to know the correct torque for those nuts?

Thank you

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New Motor Oil Castrol GTX Classic 20/50

RichardHartung — Fri, 29 Jul 2022 00:17:26 +0000

I recently wrote to Castrol Oil Company regarding their new oil product called Castrol GTX Classic 20/50.

This oil now has been formulated to contain ZDDP and Phosphorous that is to be beneficial for our flat tappet engines. With the advent of the catalytic converters, they had to stop the use of ZDDP and Phosphorus in the oils because they would cause the catalytic converts to fail.

Some owners add ZDDP into their engines when an oil change is done. Now you no longer have to purchase the ZDDP separately.

Below is the information that Castrol sent to me on their new product. You might find this oil in your local Walmart or if the local store does not carry it you can order it off their webpage around $25 for a 5 qt container.

Happy reading

Rich Hartung

Desoto1939@aol.com

1031

1950 Suburban wheel Qs

Rob Shapiro — Fri, 04 Feb 2022 01:22:59 +0000

Ok. The Suburban wheel is the heavier duty 15"x6" wheel/5 x 5.5" bolt pattern. Anyone know the backspacing and center hub size, OR if there's a replacement wheel that's disc brake compatible and which my regular DeSoto wheel covers will fit on properly?

Thanks --

Rob

Color Code of Red on 1953 DeSoto Hubcaps

PatGregory — Sat, 08 Jan 2022 01:25:41 +0000

Seeking the name and color code for the red on the 1953 DeSoto Firedome hubcaps. Found color pallets for body colors but nothing on hubcaps.

Thank you for any information you can provide.

For Lube: Must I Remove Speedometer Housing 1959 Firedome

Norman Silverman — Mon, 10 May 2021 00:03:59 +0000

Hello All.

I want to reach the two lubricating wicks for the speedometer in my car. It makes noise that I believe some lube will help. The FSM says to lubricate the wicks that are located on the speedometer head every 10,000 miles. Is it necessary to remove the speedometer cluster to access them or can you reach up and push some oil on them from behind? Thanks

Thermostats

SteveMcManus — Thu, 26 Jul 2018 18:26:02 +0000

I've had some vapor-lock issues with my '55 Firedome. In an effort to cool things off, I decided to use a 160 degree thermostat. I removed the old one and tested it in a pot of water with a candy thermometer. 63 years old and still works as designed.