Parking Brake Spring - The one UNDER the truck

[68RGR]

I have a '73 truck and, one day, a few months ago, I noticed a spring hanging down under my truck. When I checked, a really long spring had broken. Actually, the spring portion is only about five inches long. But, there is a LONG straight section of wire on the back end of the spring. That long straight section ends in a hook. My '68 F-100 has an identical spring which is still in one piece.

I checked the usual places for a replacement and saw one for a SWB truck but not a LWB.

When I was at Lowes last week, I bought a package of two springs (Lowes # 246637, Hillman # 543035 - Spring dimensions: 23/32" X 4 3/8" X 0.072") that were about the same size as the actual spring portion of the original part. I took the old spring and hooked it into one of the loops on the ends of the Lowes spring. When I stretched the combination of the two springs, both springs seemed to extend about the same amount. So, I figured the Lowes spring was close enough to work.

I proceeded to straighten one of the end loops on the Lowes spring and to reform it to resemble the loop on the front end of the original spring. My original spring had broken so that a turn or two remained connected to the long straight wire. So, I just threaded the long straight wire through the other loop on the Lowes spring. Now, I had a replacement assembly. I installed the spring and thought it was OK until the back hook on the long straight wire broke off. Man, that's a some a brittle spring!

I wasn't giving up. I took some 109 wire (the old telephone open wire) which is just under an 1/8 of an inch in diameter and formed it to replace the rear section. I don't have a photo of the assembly but I took the other Lowes spring and made a similar "extension" for the front from the 109 wire. Photo of the second spring:





If you can picture another 109 wire extension (20+ inches long) on the other end of the spring making the total length 27 1/2" inches, you'll have an idea of how the finished product will look.

Now, for my question: How important is this spring?

While mine was broken, I really didn't notice anything out of the ordinary regarding the parking brake.

Anyone have any thoughts or experience on this?

[FORDification]

The spring is important. It's what retracts the rear brake shoes off the drum when you release the parking brake lock. Without that spring, the shoes will remain engaged with the rear drums....or at least partially engaged. Maybe not enough to make a noticeable 'seat-of-the-pants' difference, but the rear brakes will get hot, the rear shoes and drum will wear out prematurely, and you'll notice a decrease in fuel mileage due to the increased drag, however minor it might be.

If you tell me the specifics on the truck (2WD/4WD, SWB/LWB) I can give you the OEM part number for the spring, as well as it's general dimensions (diameter and free length), courtesy of the factory parts manual.

[68RGR]

I had thought about the very issue you mentioned. Didn't spend time checking it out to see what went on with the cables with and without the spring in place. Just decided to replace it.

Both trucks are 2WD, LWB and the spring appears to be the same on both trucks.

I found info online indicating the LWB spring was no longer available. But, you have a lot more experience and resources than I do!

It might be a C7TZ 2A651-C based on the overall length which is within an inch of my measurement of the broken spring.

[FORDification]

According to the MPC, a '73 LWB 2WD truck uses the following:

D2TZ 2A651-B - Spring (equalizer lever) - 27 1/2" free length

There are several NOS dealers online that show that part in stock. However, I'd imagine you could find someone with a parts truck and get a good used one much cheaper.